ACFH-3548T Data Sheet
Transcript of ACFH-3548T Data Sheet
Data Sheet
ACFH-3548TAutomotive Gate Drive Optocoupler with Flyback DC-DC Controller, Adaptive Blanking, Advance Short Circuit Protection and Isolated Analog Feedback for Temperature Sensing
Description
The Broadcom® automotive gate driver optocoupler features integrated flyback controller for an isolated DC-DC converter with adjustable output voltage, adaptive blanking for precise kick-in of protection mechanism to enable fast protection, and patented adaptive soft-shutdown using IGBT desat/emitter current sensing. Temperature information from diodes or a thermistor is provided by an isolated analog feedback channel to the microcontroller on the low voltage side. This information is coupled with a simple compensation circuit that allows for accurate emitter sensing across operation temperature.
This full-feature optocoupler comes in a compact, surface-mountable SO-32 package with 0.8-mm pitch for space-savings and is suitable for HEV and EV applications. Broadcom R2Coupler™ isolation products provide reinforced insulation and reliability that deliver safe signal isolation critical in automotive and high-temperature industrial applications.
Figure 1: ACFH-3548T Functional Diagram
Features
Qualified to AEC-Q100 Grade 1 test guidelines
Automotive temperature range: –40°C to +125°C
Integrated flyback controller for isolated DC-DC converter for power supply control and diagnostic
– Adjustable regulated output supply voltage: 14.5V to 17.5V
– Programmable negative supply
– Supply output over load protection
– Supply output short-circuit protection
– External primary switch good for Load Dump test conditions and high power scaling
Integrated isolated analog feedback for IGBT temperature sensing
Integrated fail-safe IGBT protection
– IGBT emitter and desaturation sensing
– Temperature compensation for emitter sensing
– Adaptive shutdown during fault detection
– Short-circuit fault feedback
– Under Voltage Lock-out (UVLO) protection with feedback
High noise immunity
– Common-mode Rejection (CMR): 50 kV/µs at VCM = 1500V
– Miller current clamping
– Direct LED input with low input impedance and low noise sensitivity
– Support negative gate bias
SO-32 package with 8-mm creepage and clearance
Regulatory approvals: UL1577, CAN/CSA, IEC 60747-5-5
Applications
IGBT/SiC MOSFET gate driver for traction inverter, charger, and HVAC.
VEE2
LED2+ VCC2VE
VCC1
COMP
CA
/FAULT
/UVLO
AN
OSC
RS
Output Driver
PGD
VO
SSD Control
ControlLogic
Turn-on Control
MC
SSD
HSD Control
Miller Control
CS
VEE2
OT
TOK
FeedbackDecoder
TINTREF
TOUT
P_GND
VADJ
DSTVEE1
ISEN TemperatureCompensation
TB
VDST_TH
VUVLO
VTB_TH
VMC_TH
VISEN_TH
Broadcom ACFH-3548T-DS103July 14, 2021
ACFH-3548T Data Sheet Automotive Gate Drive Optocoupler with Flyback DC-DC Controller, Adaptive Blanking,
Advance Short Circuit Protection and Isolated Analog Feedback for Temperature Sensing
Ordering Information
To order, choose a part number from the part number column and combine with the desired option from the option column to form an order entry.
Example 1:
ACFH-3548T-500E is to order product of SO-32 surface mount package in tape and reel packaging with IEC/EN/DIN EN 60747-5-5 safety approval in RoHS compliant.
Option data sheets are available. Contact your Broadcom sales representative or authorized distributor for information.
Part Number Option (RoHS Compliant) Package Surface Mount Tape and ReelIEC/EN/DIN EN
60747-5-5 Quantity
ACFH-3548T -000E SO-32 X X 35 per tube
ACFH-3548T -500E X X X 850 per reel
Broadcom ACFH-3548T-DS1032
ACFH-3548T Data Sheet Automotive Gate Drive Optocoupler with Flyback DC-DC Controller, Adaptive Blanking,
Advance Short Circuit Protection and Isolated Analog Feedback for Temperature Sensing
Package Outline Drawing
Figure 2: Package Outline Drawing (32-Lead Surface Mount)
Recommended Pb-Free IR Profile
Recommended reflow condition as per JEDEC Standard, J-STD-020 (latest version).
NOTE: Non-halide flux should be used.
Product Overview Description
The ACFH-3548T (shown in Figure 1) is a highly integrated power control device that incorporates all the necessary components for a complete, isolated IGBT gate drive circuit. It features flyback controller for isolated DC-DC converter, Miller current clamping, integrated temperature sensor and feedback, IGBT desaturation and emitter current sensing, under voltage lock-out protection and feedback in an SO-32 package. It also features an integrated temperature compensation circuit for emitter sensing short-circuit protection and adaptive turn-off during fault conditions. Direct LED input allows flexible logic configuration and differential current mode driving with low input impedance, greatly increasing noise immunity.
Broadcom ACFH-3548T-DS1033
ACFH-3548T Data Sheet Automotive Gate Drive Optocoupler with Flyback DC-DC Controller, Adaptive Blanking,
Advance Short Circuit Protection and Isolated Analog Feedback for Temperature Sensing
Package Pin Out
Figure 3: ACFH-3548T Pin Configuration
Pin Description
Table 1: Pin Description
Pin Number Pin Name Description
1 PGD Primary gate driver for external MOSFET
2 P_GND Power ground reference for primary gate drive. Connect to the VEE1 plane through vias locally.
3 ISEN Current sense for flyback controller
4 VEE1 Input ground
5 VCC1 Input power supply
6 VADJ Voltage to adjust VCC2
7 COMP Compensation network for flyback controller
8 /UVLO Under-voltage feedback for VCC1; under-voltage lock out feedback for VCC2
9 /FAULT IGBT short-circuit or over-current fault feedback triggered by the DST or CS pin
10 TOK TOUT validity indicator
11 NC No connection
12 TOUT Analog output for temperature sense
13 AN Input LED anode
14 CA Input LED cathode
15 DNC Do not connect (internally connected to VEE1 lead frame)
16 DNC Do not connect (internally connected to VEE1 lead frame)
17 VEE2 Output negative power supply
18 MC Miller current clamping output
19 TB Blanking time control
27
26
25
24
23
22
21
20
LED2+
NC
VEE2
VCC2
CS
VE
DST4
5
6
7
8
9
10
11
PGDP_GND
/UVLO
/FAULT
TOUT
VCC1
VADJ
VEE1
19
18
17
VO12
13
14 CA
TOK
MC15 DNC
VEE2
30
29
1
2
28
3
SSD
TIN
NC
TB
TREF
ISEN
COMP
NC
AN
16 DNC
32
31
VEE2
Broadcom ACFH-3548T-DS1034
ACFH-3548T Data Sheet Automotive Gate Drive Optocoupler with Flyback DC-DC Controller, Adaptive Blanking,
Advance Short Circuit Protection and Isolated Analog Feedback for Temperature Sensing
Organization Approval
The ACFH-3548T is approved by the following organizations.
20 SSD Soft shutdown output
21 VO Output driver for IGBT/MOSFET gate
22 VCC2 Output positive power supply
23 VE IGBT emitter/MOSFET source reference
24 TIN Temperature sensing input
25 CS Current sense input
26 NC No connection
27 TREF Reference voltage input for temperature compensation
28 NC No connection
29 DST Desaturation over-current sensing
30 LED2+ Do not connect, for testing only
31 VEE2 Output negative power supply
32 VEE2 Output negative power supply
UL Approved under UL 1577, component recognition program up to VISO = 5000 VRMS
CAN/CSA Approved under CAN/CSA-C22.2 No.62368-1
IEC/EN/DIN EN 60747-5-5 Approved under: IEC 60747-5-5, EN 60747-5-5, DIN EN 60747-5-5
Table 1: Pin Description (Continued)
Pin Number Pin Name Description
Broadcom ACFH-3548T-DS1035
ACFH-3548T Data Sheet Automotive Gate Drive Optocoupler with Flyback DC-DC Controller, Adaptive Blanking,
Advance Short Circuit Protection and Isolated Analog Feedback for Temperature Sensing
IEC/EN/DIN EN60747-5-5 Insulation Characteristics1
Insulation and Safety-Related Specifications
1. Isolation characteristics are guaranteed only within the safety maximum ratings that must be ensured by the protective circuits in the application. The surface mount classification is class A in accordance with CECCOO802.
Description Symbol Characteristic Units
Insulation Classification per DIN VDE 0110/1.89, Table 1
For rated mains voltage ≤ 150Vrms I-IV
For rated mains voltage ≤ 300Vrms I-IV
For rated mains voltage ≤ 600Vrms I-IV
For rated mains voltage ≤ 1000Vrms I - III
Climatic Classification 40/125/21
Pollution Degree (DIN VDE 0110/1.89) 2
Maximum Working Insulation Voltage VIORM 1230 VPEAK
Input to Output Test Voltage, Method ba
VIORM × 1.875 = VPR, 100% production test with tm = 1s, partial discharge < 5 pC
a. Refer to the optocoupler section of the Isolation and Control Components Designer's Catalog, under Product Safety Regulation section IEC/EN/DIN EN 60747-5-5, for a detailed description of Method a and Method b partial discharge test profiles.
VPR 2306 VPEAK
Input to Output Test Voltage, Method aa
VIORM × 1.6 = VPR, type and sample test, tm = 10s, partial discharge < 5 pC
VPR 1968 VPEAK
Highest Allowable Overvoltage (transient overvoltage tini = 60s) VIOTM 8000 VPEAK
Safety-limiting values – maximum values allowed in the event of a failure
Case Temperature TS 175 °C
Input Current IS,INPUT 350 mA
Output Power PS,OUTPUT 1200 mW
Insulation Resistance at TS, VIO = 500V RS > 109 Ω
Parameter Symbol Value Units Conditions
Minimum External Air Gap (Clearance)
L(101) 8.5 mm Measured from input terminals to output terminals, shortest distance through air.
Minimum External Tracking (Creepage)
L(102) 8.5 mm Measured from input terminals to output terminals, shortest distance path along body.
Minimum Internal Plastic Gap (Internal Clearance)
0.5 mm Through insulation distance conductor to conductor, usually the straight line distance thickness between the emitter and detector.
Tracking Resistance (Comparative Tracking Index)
CTI >175 V DIN IEC 112/VDE 0303 Part 1.
Isolation Group IIIa Material Group (DIN VDE 0110).
Broadcom ACFH-3548T-DS1036
ACFH-3548T Data Sheet Automotive Gate Drive Optocoupler with Flyback DC-DC Controller, Adaptive Blanking,
Advance Short Circuit Protection and Isolated Analog Feedback for Temperature Sensing
ESD Ratings
Absolute Maximum Ratings
Unless otherwise specified, all voltages at input IC reference to VEE1, all voltages at output IC reference to VEE2.
Parameter Classification Note
Human Body Model 2 Per AEC Q100-002
Charge Device Model C2a Per AEC Q100-011
Parameter Symbol Min. Max. Units Note
Storage Temperature TS –55 150 °C
Operating Temperature TA –40 125 °C
IC Junction Temperature TJ — 150 °C
Average LED Input Current IF(AVG) — 20 mA
Peak Transient LED Input Current (<1-µs pulse width, 300 pps) IF(TRAN) — 1 A
Reverse Input Voltage (VCA – VAN) VR — 6 V
Primary Gate Drive Voltage VPGD – VP_GND –0.5 VCC1 + 0.5 or 6 V
ISEN Pin Voltage VISEN – VP_GND –0.5 VCC1 + 0.5 or 6 V
Input Supply Voltage VCC1 –0.5 6 V a
VADJ Pin Voltage VVADJ –0.5 VCC1 + 0.5 or 6 V a
COMP Pin Voltage VCOMP –0.5 VCC1 + 0.5 or 6 V a
/UVLO Pin Voltage V/UVLO –0.5 6 V a
/FAULT Pin Voltage V/FAULT –0.5 6 V a
TOK Pin Voltage VTOK –0.5 6 V a
TOUT Pin Voltage VTOUT –0.5 VCC1 + 0.5 or 6 V a
/UVLO Output Current (Sinking) I/UVLO — 4 mA
/FAULT Output Current (Sinking) I/FAULT — 4 mA
TOK Output Current (Sinking) ITOK — 4 mA
TOUT Output Current (Sinking) ITOUT — 1 mA
Total Output Supply Voltage VCC2 –0.5 30 V b
Positive Output Supply Voltage VCC2 – VE –0.5 22 V
Negative Output Supply Voltage VEE2 – VE –12 0.5 V
DST Pin Voltage VDST – VE –0.5 VCC2 – VE + 0.5 V
CS Pin Voltage VCS – VE –0.5 VCC2 – VE + 0.5 V
TREF Pin Voltage VTREF – VE –0.5 6 V
TIN Pin Voltage VTIN – VE –0.5 6 V
TB Pin Voltage VTB –0.5 VCC2 + 0.5 V b
Gate Drive Output Voltage, VO VO –0.5 VCC2 + 0.5 V b
Gate Drive Output Voltage, SSD VSSD –0.5 VCC2 + 0.5 V b
Gate Drive Output Voltage, MC VMC –0.5 VCC2 + 0.5 V b
Broadcom ACFH-3548T-DS1037
ACFH-3548T Data Sheet Automotive Gate Drive Optocoupler with Flyback DC-DC Controller, Adaptive Blanking,
Advance Short Circuit Protection and Isolated Analog Feedback for Temperature Sensing
Recommended Operating Conditions
Unless otherwise specified, all voltages at input IC reference to VEE1, all voltages at output IC reference to VEE2.
Peak Output Current, VO |IO(PEAK)| — 2 A c
Peak Output Sinking Current, SSD ISSD(PEAK) — 2 A c
Peak Output Sinking Current, MC IMC(PEAK) — 5 A c
Output IC Power Dissipation PO — 600 mW d
Input IC Power Dissipation PI — 150 mW e
a. Reference to VEE1.
b. Reference to VEE2.
c. Maximum pulse width = 1µs, maximum duty = 1%.
d. Output IC power dissipation is derated linearly above 105°C from 600 mW to 550 mW at 125°C for a high effective thermal conductivity board. For a low effective thermal conductivity board, output IC power dissipation is derated linearly above 105°C from 600 mW to 400 mW at 125°C. PCB thermal resistance characteristic must be considered so as not to exceed the absolute maximum rating. See Thermal Resistance Model for ACFH-3548T for details.
e. Input IC power dissipation does not require derating for a high effective thermal conductivity board. For a low effective thermal conductivity board, input IC power dissipation is derated linearly above 105°C from 150 mW to 120 mW at 125°C. See Thermal Resistance Model for ACFH-3548T for details.
Parameter Symbol Min. Max. Units Note
Operating Temperature TA –40 125 °C
Input IC Supply Voltage VCC1 4.75 5.5 V a
a. Power-up sequence: Battery supply (VBAT+) to the DC-DC flyback transformer must be ready before VCC1 power up. When VCC1 is powered up from 0V to VCC1_TH+, DC-DC soft start current starts to charge the compensation network that is connected to the COMP pin. Subsequently, the VCC2 supply is regulated to its designed value. See Soft Start Operation for details.
Input IC Supply Decoupling Capacitor CVCC1 1 — µF
ISEN Input Voltage VISEN – VP_GND 0 1 V
Positive Output IC Supply Voltage VCC2 – VE 14.3 17.7 V
Negative Output IC Supply Voltage VEE2 – VE –6 0 V b
b. This supply is optional. It is required only when negative gate drive is implemented. Negative gate drive voltage can be programmed easily by connecting a Zener diode from VE to VEE2. Connect VE to VEE2 if negative gate drive bias is not required.
Output IC supply decoupling capacitor, VCC2 to VEE2 CVCC2 1 40 µF
Input LED Turn-on Current IF(ON) 10 16 mA
Input LED Turn-off Voltage (VAN – VCA) VF(ON) –5.5 0.8 V
DC-DC Flyback Controller PWM Duty Cycle DMAX — 50 % c
c. See Operation of Integrated DC-DC Flyback Controller for details.
TOUT Output Decoupling Capacitor CTOUT 1 10 µF
Full Scale TIN Input Voltage VTIN – VE 1.9 3.5 V
TREF Input Voltage VTREF – VE 2 5 V
CS Sense Voltage VCS – VE 0 5 V
Parameter Symbol Min. Max. Units Note
Broadcom ACFH-3548T-DS1038
ACFH-3548T Data Sheet Automotive Gate Drive Optocoupler with Flyback DC-DC Controller, Adaptive Blanking,
Advance Short Circuit Protection and Isolated Analog Feedback for Temperature Sensing
Electrical and Switching Specifications
Unless otherwise specified, all minimum/maximum specifications are at recommended operating conditions; all voltages at input IC reference to VEE1, all voltages at output IC reference to VEE2. All typical values at TA = 25°C, VCC1 – VEE1 = 5V, VCC2 – VE = 16V, VE = VEE2 = 0V.
Parameter Symbol Min. Typ. Max. Units Test Conditions Figure Note
DC-DC Flyback Converter
VCC1 MOS Threshold VCC1_MOS_TH 0.85 1.3 1.7 V I/UVLO = 2 mA
VCC1 Turn On Threshold VCC1_TH+ 3.7 4.0 4.3 V
VCC1 Turn On Threshold
Hysteresis
VCC1_TH_HYS 0.05 0.25 0.5 V
PGD PWM Switching Frequency
fPWM 84 120 152 kHz a
Primary Gate Drive Output High Level
VPGD_H VCC1 – 0.5 VCC1 – 0.25 VCC1 – 0.01 V IPGD = –50 mA b
Primary Gate Drive Output Low Level
VPGD_L 0.01 0.2 0.4 V IPGD = 50 mA
Primary Gate Drive Rise Time tr_PGD 10 23 40 ns CPGD = 1 nF
Primary Gate Drive Fall Time tf_PGD 10 20 40 ns CPGD = 1 nF
Maximum PWM Duty Cycle DMAX 50 65 60 % VCOMP = 3.5V 7 c
ISEN Threshold VISEN_TH –
VP_GND
0.16 0.2 0.24 V
Regulated VCC2 Voltage
Tolerance
(VCC2 – VE) –5 0 5 % ICOMP = 0A,
VCC2 – VE = 16V
8
VCC2 Over-voltage Protection
Threshold, Low to High Reference to VE
VOV2_TH+ – VE 18.5 19.5 21 V
VCC2 Over-voltage Protection
Threshold, High to Low Reference to VE
VOV2_TH– – VE 17.5 18.5 20 V
IC Supply Current
Input Supply Current ICC1 4.7 7.5 9.8 mA 9
Output High Supply Current ICC2H 9.7 13.7 17.9 mA IF = 10 mA,
VCC2 – VE = 16V,
VE – VEE2 = 0V
10
Output Low Supply Current ICC2L 9.5 13.5 17.7 mA IF = 0 mA,
VCC2 – VE = 16V,
VE – VEE2 = 0V
10
Output High VE Supply Current IEH –2.3 –3.5 –4.8 mA IF = 10 mA,
VCC2 – VE = 16V,
VE – VEE2 = 5V
11
Output Low VE Supply Current IEL –2.3 –3.5 –4.8 mA IF = 0 mA,
VCC2 – VE = 16V,
VE – VEE2 = 5V
11
Broadcom ACFH-3548T-DS1039
ACFH-3548T Data Sheet Automotive Gate Drive Optocoupler with Flyback DC-DC Controller, Adaptive Blanking,
Advance Short Circuit Protection and Isolated Analog Feedback for Temperature Sensing
Logic Input and Output
LED Forward Voltage (VAN – VCA)
VF 1.25 1.55 1.85 V IF = 10 mA 12
LED Reverse Breakdown Voltage (VCA – VAN)
VBR 6 — — V IF = –10 µA
LED Input Capacitance CIN — 90 — pF
LED Turn On Current Threshold, Low to High
ITH+ — 2.6 7 mA VO = 5V 13
LED Turn On Current Threshold, High to Low
ITH– 0.3 2.0 — mA VO = 5V 13
LED Turn On Current Hysteresis
ITH_HYS — 0.6 — mA
/UVLO Logic Low Output Voltage
V/UVLO_L — — 0.4 V I/UVLO = 3 mA
/UVLO Logic High Output Current
I/UVLO_H — 0.015 10 µA V/UVLO = 5V
/FAULT Logic Low Output Voltage
V/FAULT_L — — 0.4 V I/FAULT = 3 mA
/FAULT Logic High Output Current
I/FAULT_H — 0.015 10 µA V/FAULT = 5V
TOK Logic Low Output Voltage VTOK_L — — 0.4 V ITOK = 3 mA
TOK Logic High Output Current
ITOK_H — 0.015 10 µA VTOK=5V
Gate Driver
High Level VO Voltage VOH VCC2 – 0.2 VCC2 –0.05 VCC2 – 0.01 V IO = –20 mA 14 d, e
Low Level VO Voltage VOL 0.01 0.05 0.2 V IO = 20 mA 15 e
Low Level SSD Voltage VSSD_L 0.01 0.05 0.2 V ISSD = 20 mA e
High Level VO Current IOH — — –1.5 A VO = VCC2 – 6V f
Low Level VO Current IOL 1.5 — — A VO = 6V f
Low Level SSD Current ISSD_L 2 — — A VSSD = 6V 16 f
VIN to High Level VO
Propagation Delay Time
tPLH — 130 250 ns VSource = 5V,
RLED = 260Ω,
Rg = 10Ω,Cload = 1 nF,f = 10 kHz,Duty cycle = 50%
17 g
VIN to Low Level VO
Propagation Delay Time
tPHL — 140 250 ns 17 h
Pulse Width Distortion PWD –50 10 100 ns i
Dead Time Distortion (tPLH – tPHL)
DTD –100 –10 50 ns j
VO 10% to 90% Rise Time tR — 25 — ns
VO 90% to 10% Fall Time tF — 25 — ns
Parameter Symbol Min. Typ. Max. Units Test Conditions Figure Note
Broadcom ACFH-3548T-DS10310
ACFH-3548T Data Sheet Automotive Gate Drive Optocoupler with Flyback DC-DC Controller, Adaptive Blanking,
Advance Short Circuit Protection and Isolated Analog Feedback for Temperature Sensing
Output High Level Common Mode Transient Immunity
|CMH| 50 — — kV/µs TA = 25°C
IF = 10 mA,
VCM = 1500V
k
Output Low Level Common Mode Transient Immunity
|CML| 50 — — kV/µs TA = 25°C
IF = 0 mA,
VCM = 1500V
l
Active Miller Clamp
Clamp Threshold Voltage VMC_TH 1.5 2 2.5 V
Clamp Low Level Sinking Current
ICLAMP 1.5 2.5 — A VCLAMP = VEE2 +
2.5V
18
VCC2 UVLO Protection (UVLO Voltage VUVLO Reference to VE)
VCC2 UVLO Threshold Low to
High
VUVLO2_TH+ 11.25 12.5 13.75 V VO > 5V m, n
VCC2 UVLO Threshold High to
Low
VUVLO2_TH– 10.35 11.5 12.65 V VO < 5V m, o
VCC2 UVLO Hysteresis VUVLO2_HYS 0.8 1 1.3 V
VCC2 to /UVLO High Delay tPLH_UVLO2 — 11.4 35 µs p
VCC2 to /UVLO Low Delay tPHL_UVLO2 — 38 100 µs q
VCC2 UVLO to VO High Delay tUVLO2_ON — 2.8 8 µs r
VCC2 UVLO to VO Low Delay tUVLO2_OFF — 1.9 6 µs s
Short-Circuit Protection (Reference to VE)
Blanking Release Threshold VTB_TH – VE 11.4 12.8 14.3 V
Desat Sensing Threshold VDST_TH – VE 9 10 11 V 19 t
Short-circuit Sense to /FAULT Low Signal Delay
TSC_FLT — 4.2 8 µs u
Output Mute Time due to Short-circuit FAULT
TSC(MUTE) 1.6 3 4.8 ms v
Time Input Kept Low Before /FAULT Reset to High
TSC(RESET) 1.6 3 4.8 ms w
Temperature Sense (TOUT Pin Reference to VEE1)
TOUT Output Voltage VTOUT – VEE1 1.692 1.750 1.830 V VTIN = 1.75V x
1.939 2.000 2.083 V VTIN = 2V x
2.185 2.250 2.336 V VTIN = 2.25V x
2.675 2.750 2.841 V VTIN = 2.75V x
Short Circuit Current Sense Threshold with Temperature Compensation (Reference to VE)
Short Circuit Current Sense (CS pin) Threshold
VCS_TH — 0.6 — V VTREF – VTIN =
1.2V
(VTREF –VTIN) / 2
a. PWM switching frequency of primary gate drive (PGD) is dithered in a range of ±6% typically over 3.3 ms.
b. The VPGD_H specification is guaranteed by design and is not subjected to production test.
c. The maximum PWM duty cycle, DMAX, is the hard limit set by IC for protection purposes. For discontinuous mode (DCM) operation, the maximum duty cycle for transformer design should be limited to 50% under system full load conditions.
Parameter Symbol Min. Typ. Max. Units Test Conditions Figure Note
Broadcom ACFH-3548T-DS10311
ACFH-3548T Data Sheet Automotive Gate Drive Optocoupler with Flyback DC-DC Controller, Adaptive Blanking,
Advance Short Circuit Protection and Isolated Analog Feedback for Temperature Sensing
Package Characteristics
d. For High Level Output Voltage testing, VOH is measured with a DC load current. When driving capacitive loads, VOH will approach VCC2 as IOH approaches zero.
e. Measured with a DC load, maximum pulse width = 1.0 ms, maximum duty cycle = 20%.
f. Maximum pulse width = 1 µs, maximum duty cycle = 1%.
g. tPLH is defined as propagation delay from 50% of input voltage source, VSource to 50% of high level output VO.
h. tPHL is defined as propagation delay from 50% of input source voltage, VSource to 50% of low level output, VO.
i. Pulse Width Distortion (PWD) is defined as (tPHL – tPLH) of any given unit.
j. Dead Time Distortion (DTD) is defined as (tPLH – tPHL) between any two parts under the same test conditions.
k. Common-mode transient immunity (CMTI) in the high state is the maximum tolerable dVCM/dt of the common-mode pulse, VCM, to ensure that the output will remain in the high state (that is, Output > 13V). A 330-pF and a 10-kΩ pull-up resistor are needed in fault, UVLO, and TOK detection modes.
l. Common-mode transient immunity (CMTI) in the low state is the maximum tolerable dVCM/dt of the common-mode pulse, VCM, to ensure that the output will remain in a low state (that is, Output < 1.0V). A 330-pF and a 10-kΩ pull-up resistor are needed in fault, UVLO, and TOK detection modes.
m. When UVLO is not active (VCC2 – VE > VUVLO2_TH+), VO of the ACFH-3548T is allowed to go high, the short-circuit protection features sensed by DST and CS pins of the ACFH-3548T will be the primary source of IGBT protection. When VCC2 exceeds VUVLO2_TH+, DST and CS sense remains functional, until VCC2 crosses below VUVLO2_TH–. Thus, the DST/CS detection and UVLO features of the ACFH-3548T work in conjunction to ensure constant IGBT protection.
n. This is the “increasing” (that is, turn-on or “positive going” direction) of VCC2 – VE.
o. This is the “decreasing” (that is, turn-off or “negative going” direction) of VCC2 –VE.
p. The delay time when VCC2 exceeded VUVLO2_TH+ to 50% of /UVLO positive going edge.
q. The delay time when VCC2 exceeded VUVLO2_TH– to 50% of /UVLO negative going edge.
r. The delay time when VCC2 exceeded VUVLO2_TH+ to 50% of VO positive going edge (that is, VO turn-on).
s. The delay time when VCC2 exceeded VUVLO2_TH– to 50% of VO negative going edge (that is, VO turn-off).
t. See During IGBT Short Circuit Event for further details.
u. The amount of time from when DST/CS threshold is exceeded to /FAULT negative-going edge.
v. The amount of time when DST/CS threshold is exceeded, driver output VO is mute to LED input.
w. The amount of time when DST/CS mute time is expired, LED input must be kept Low for /FAULT status to return to High.
x. The TOUT output voltage is tested at TA = 25°C and TA = 125°C.
Parameter Symbol Min. Typ. Max. Units Test Conditions Note
Input-Output Momentary Withstand Voltage
VISO 5000 — — VRMS RH < 50%, t = 1 minute, TA = 25°C a, b, c
a. In accordance with UL1577, each optocoupler is proof tested by applying an insulation test voltage ≥ 6000 VRMS for 1 second.
b. The Input-Output Momentary Withstand Voltage is a dielectric voltage rating that should not be interpreted as an input-output continuous voltage rating. For the continuous voltage rating, refer to your equipment level safety specification or IEC/EN/DIN EN 60747-5-5 Insulation Characteristics Table.
c. The device is considered as a two-terminal device: pins 1 to 16 are shorted together and pins 17 to 32 are shorted together.
Resistance (Input – Output) RI-O — 1014 — Ω VI-O = 500Vdc c
Capacitance (Input – Output) CI-O — 1.3 — pF f = 1 MHz
Broadcom ACFH-3548T-DS10312
ACFH-3548T Data Sheet Automotive Gate Drive Optocoupler with Flyback DC-DC Controller, Adaptive Blanking,
Advance Short Circuit Protection and Isolated Analog Feedback for Temperature Sensing
Thermal Resistance Model for ACFH-3548T
The diagram for measurement is shown in Figure 4. This is a multi-chip package with four heat sources, the effect of heating of one die due to the adjacent dice are considered by applying the theory of linear superposition. Here, one die is heated first, and the temperatures of all the dice are recorded after thermal equilibrium is reached. Then, the second die is heated, and all the dice temperatures are recorded and so on until the fourth die is heated. With the known ambient temperature, the die junction temperature, and power dissipation, the thermal resistance can be calculated. The thermal resistance calculation can be cast in matrix form. This yields a 4 by 4 matrix for this case of four heat sources.
Figure 4: Diagram of ACFH-3548T for Thermal Resistance Model
Definitions
R11: Thermal Resistance of Die1 due to heating of Die1 (°C/W)R12: Thermal Resistance of Die1 due to heating of Die2 (°C/W)R13: Thermal Resistance of Die1 due to heating of Die3 (°C/W)R14: Thermal Resistance of Die1 due to heating of Die4 (°C/W)
R21: Thermal Resistance of Die2 due to heating of Die1 (°C/W)R22: Thermal Resistance of Die2 due to heating of Die2 (°C/W)R23: Thermal Resistance of Die2 due to heating of Die3 (°C/W)R24: Thermal Resistance of Die2 due to heating of Die4 (°C/W)
27
26
25
24
23
22
21
20
4
5
6
7
8
9
10
11
19
18
17
12
13
14
15
30
29
1
2
28
3
16
32
31
Die 1:Input IC
Die 3:Output IC
Die 2:LED1
Die 4:LED2
R11 R12 R13 R14
.P1 T1
R21 R22 R23 R24 P2 T2R31 R32 R33 R34 P3 T3
R41 R42 R43 R44 P4 T4
=
Broadcom ACFH-3548T-DS10313
ACFH-3548T Data Sheet Automotive Gate Drive Optocoupler with Flyback DC-DC Controller, Adaptive Blanking,
Advance Short Circuit Protection and Isolated Analog Feedback for Temperature Sensing
R31: Thermal Resistance of Die3 due to heating of Die1 (°C/W)R32: Thermal Resistance of Die3 due to heating of Die2 (°C/W)R33: Thermal Resistance of Die3 due to heating of Die3 (°C/W)R34: Thermal Resistance of Die3 due to heating of Die4 (°C/W)
R41: Thermal Resistance of Die4 due to heating of Die1 (°C/W)R42: Thermal Resistance of Die4 due to heating of Die2 (°C/W)R43: Thermal Resistance of Die4 due to heating of Die3 (°C/W)R44: Thermal Resistance of Die4 due to heating of Die4 (°C/W)
P1: Power dissipation of Die1 (W)P2: Power dissipation of Die2 (W)P3: Power dissipation of Die3 (W)P4: Power dissipation of Die4 (W)
T1: Junction temperature of Die1 due to heat from all dice (°C)T2: Junction temperature of Die2 due to heat from all dice (°C)T3: Junction temperature of Die3 due to heat from all dice (°C)T4: Junction temperature of Die4 due to heat from all dice (°C)
Ta: Ambient temperature (°C)
T1: Temperature difference between Die1 junction and ambient (°C)T2: Temperature deference between Die2 junction and ambient (°C)T3: Temperature difference between Die3 junction and ambient (°C)T4: Temperature deference between Die4 junction and ambient (°C)
T1 = (R11 × P1 + R12 × P2 + R13 × P3 + R14 × P4) + Ta ------ ---------------------------------------------- (1)
T2 = (R21 × P1 + R22 × P2 + R23 × P3 + R24 × P4) + Ta ---------------------------------------------------- (2)
T3 = (R31 × P1 + R32 × P2 + R33 × P3 + R34 × P4) + Ta ---------------------------------------------------- (3)
T4 = (R41 × P1 + R42 × P2 + R43 × P3 + R44 × P4) + Ta ---------------------------------------------------- (4)
Broadcom ACFH-3548T-DS10314
ACFH-3548T Data Sheet Automotive Gate Drive Optocoupler with Flyback DC-DC Controller, Adaptive Blanking,
Advance Short Circuit Protection and Isolated Analog Feedback for Temperature Sensing
Measurement is done on both low effective thermal conductivity test board (according to JESD51-3) and on high effective thermal conductivity test board (according to JESD51-7).
Test Board TypeTest Board Conditions Thermal Resistance Power Dissipation Derating Chart
Low effective thermal conductivity board
Single layer board for signal.
Outer layer copper thickness: 2 oz.
Board size: 76.2 mm × 76.2 mm
R11: 44°C/W
R12: 40.3°C/W
R13: 24.5°C/W
R14: 37.2°C/W
R21: 28.5°C/W
R22: 145.2°C/W
R23: 27.8°C/W
R24: 34.5°C/W
R31: 26.7°C/W
R32: 43.4°C/W
R33: 39.5°C/W
R34: 44.7°C/W
R41: 28.6°C/W
R42: 39.9°C/W
R43: 32.2°C/W
R44: 101.4°C/W
Figure 5: Power Dissipation Derating Chart using Low Effective Thermal Conductivity Board
NOTE:
Input IC power dissipation is derated linearly above 105°C from 150 mW to 120 mW at 125°C.
Output IC power dissipation is derated linearly above 105°C from 600 mW to 400 mW at 125°C.
High effective thermal conductivity board
Four-layer board that embodies two signal layers, a power plane, and a ground plane.
Outer layer copper thickness: 2 oz.
Inner layers copper thickness: 1 oz.
Board size: 76.2 mm × 76.2 mm
R11: 34°C/W
R12: 20.3°C/W
R13: 15°C/W
R14: 22.2°C/W
R21: 16.2°C/W
R22: 119.2°C/W
R23: 17.5°C/W
R24: 19.5°C/W
R31: 15.1°C/W
R32: 22.3°C/W
R33: 30.4°C/W
R34: 29.3°C/W
R41: 16.3°C/W
R42: 18.9°C/W
R43: 22.2°C/W
R44: 91.5°C/W
Figure 6: Power Dissipation Derating Chart using High Effective Thermal Conductivity Board
NOTE:
Input IC power dissipation does not require derating for high effective thermal conductivity board.
Output IC power dissipation is derated linearly above 105°C from 600 mW to 550 mW at 125°C.
Broadcom ACFH-3548T-DS10315
ACFH-3548T Data Sheet Automotive Gate Drive Optocoupler with Flyback DC-DC Controller, Adaptive Blanking,
Advance Short Circuit Protection and Isolated Analog Feedback for Temperature Sensing
The application and environmental design for the ACFH-3548T must ensure that the junction temperature of the internal ICs and LED within the gate driver optocoupler do not exceed 150°C. The following examples are based on a typical circuit shown in Figure 23 for estimation of maximum power dissipation and corresponding effect on junction temperatures. This thermal calculation can only be used as a reference for thermal comparison between actual application board layout and PCB board according to JESD51-7. The actual power dissipation achievable will depend on the application environment (PCB layout, air flow, part placement, and so on).
Calculation of Input IC Power Dissipation, P1
Input IC Power Dissipation (P1) = PI(Static) + PIH(PGD) + PIL(PGD)
where
PI(Static) – Static power dissipated by the input IC = VCC1(MAX) × ICC1(MAX)PIH(PGD) – High side switching power dissipation at PGD pin
= (VCC1(MAX) × QG_ExtMOS × fPWM_DCDC(MAX)) × ROH_PGD(MAX) / (ROH_PGD(MAX) + RG_PGD) / 2PIL(PGD) – Low side switching power dissipated at PGD pin
= (VCC1(MAX) × QG_ExtMOS × fPWM_DCDC(MAX)) × ROL_PGD(MAX) / (ROL_PGD(MAX) + RG_PGD) / 2QG_ExtMOS – Gate charge of external MOSFET connected to PGD pin at supply voltagefPWM_DCDC(MAX) – Maximum DC-DC switching frequencyROH_PGD(MAX) – Maximum high side PGD pin output impedance = 0.5V/50 mA = 10ΩROL_PGD(MAX) – Maximum low side PGD pin output impedance = 0.4V/50 mA = 8ΩRG_PGD – Gate resistance connected to PGD pin
Example:
PI(Static) = 5.5V × 9.8 mA = 53.9 mWPIH(PGD) = (5.5V × 5 nC × 152 kHz) × 10Ω / (10Ω + 20Ω) / 2 = 0.70 mWPIL(PGD) = (5.5V × 5 nC × 152 kHz) × 8Ω / (8Ω + 20Ω) / 2 = 0.60 mWP1 = 53.9 mW + 0.70 mW + 0.60 mW = 55.2 mW
Calculation of Input LED Power Dissipation, P2
Input LED Power Dissipation (P2) = IF(LED) (Recommended Max) × VF(LED) (at 125°C) × Duty Cycle
Example:
P2 = 16 mA × 1.25V × 50% = 10 mW
Calculation of Output IC Power Dissipation, P3
Output IC Power Dissipation (P3) = PO(Static) + POH + POL
where:
PO(Static) – Static power dissipated by the output IC = (VCC2 – VEE2) × ICC2(MAX)(VCC2 – VEE2) – Total output power supply = Regulated VCC2(MAX) + Vz (Vz can be 0V if negative supply is not used)POH – High side switching power dissipation at VO pin
= (VCC2 – VEE2) × QG × fPWM × ROH(MAX) / (ROH(MAX) + RGH) / 2POL – Low side switching power dissipation at VO pin
= (VCC2 – VEE2) × QG × fPWM × ROL(MAX) / (ROL(MAX) + RGL) / 2QG – External buffer gate charge at supply voltage fPWM – Input LED switching frequencyROH(MAX) – Maximum high side VO pin output impedance at IOH(MIN) = 4Ω
Broadcom ACFH-3548T-DS10316
ACFH-3548T Data Sheet Automotive Gate Drive Optocoupler with Flyback DC-DC Controller, Adaptive Blanking,
Advance Short Circuit Protection and Isolated Analog Feedback for Temperature Sensing
RGH – Gate charging resistanceROL(MAX) – Maximum low side VO pin output impedance IOL(MIN) = 4ΩRGL - Gate discharging resistance
Example:
(VCC2 – VEE2) = 16.8V + 5.5V = 22.3VPO(Static) = 22.3V × 17.9 mA = 399.17 mWPOH = (22.3V × 200 nC × 10 kHz) × 4Ω / (4Ω + 20Ω) / 2 = 3.72 mWPOL = (22.3V × 200 nC × 10 kHz) × 4Ω / (4Ω + 20Ω) / 2 = 3.72 mWP3 = 399.17 mW + 3.72 mW + 3.72 mW = 406.61 mW
Calculation of LED2 Power Dissipation, P4
LED2 Power Dissipation (P4) = IF(LED2) (Design Max) × VF(LED2) (at 125°C) × Duty Cycle
Example:
P4 = 16mA × 1.25V × 50% = 10 mW
Calculation of Junction Temperature using High Effective Thermal Conductivity Board:
Input IC Junction Temperature = (37°C/W × P1 + 20.3°C/W × P2 + 15°C/W × P3 + 22.2°C/W × P4) + Ta Input LED Junction Temperature = (16.2°C/W × P1 + 119.2°C/W × P2 + 17.5°C/W × P3 + 19.5°C/W × P4) + Ta Output IC Junction Temperature = (15.1°C/W × P1 + 22.3°C/W × P2 + 30.4°C/W × P3 + 29.3°C/W × P4) + Ta LED2 Junction Temperature = (16.3°C/W × P1 + 18.9°C/W × P2 + 22.2°C/W × P3 + 91.5°C/W × P4) + Ta
Junction temperatures of the internal ICs and LEDs must not exceed 150°C.
Broadcom ACFH-3548T-DS10317
ACFH-3548T Data Sheet Automotive Gate Drive Optocoupler with Flyback DC-DC Controller, Adaptive Blanking, Ad-
vance Short Circuit Protection and Isolated Analog Feedback for Temperature Sensing
Typical Performance PlotsFigure 7: PWM Duty Cycle vs. VCOMP Figure 8: ICOMP vs. Supply Voltage
0
10
20
30
40
50
60
0 1 2 3 4
D -
ELCYC YTUD
MWP
-%
VCOMP - COMPENSATION VOLTAGE - V-15
-10
-5
0
5
10
15
10 12 14 16 18 20 22
I COM
P-
TNERR
UC N
OITSNEP
MOC
-μA
VCC2 - SUPPLY VOLTAGE - V
Ta=-40°C
Ta=25°C
Ta=125°C
Figure 9: ICC1 vs. Temperature Figure 10: ICC2 vs. Temperature
6
6.5
7
7.5
8
8.5
-50 -25 0 25 50 75 100 125
I CC1
- T
NERRUC YLPP
US TUP
NI-m
A
TA - TEMPERATURE - C
12
12.5
13
13.5
14
14.5
15
-50 -25 0 25 50 75 100 125
i CC2
- T
NERRUC YLPP
US TUPT
UO
-mA
TA - TEMPERATURE - C
ICC2H
ICC2L
Figure 11: IE vs. Temperature Figure 12: IF vs. VF
-4.5
-4
-3.5
-3
-2.5
-50 -25 0 25 50 75 100 125
I E-
TNERR
UC YLPPUS EV T
UPTU
O-m
A
TA - TEMPERATURE - C
IEH
IEL
0.01
0.10
1.00
10.00
100.00
1.2 1.3 1.4 1.5 1.6
IF -
TNERRUC DRA
WROF DEL
-mA
VF - LED FORWARD VOLTAGE - V
Ta=25 C
Broadcom ACFH-3548T-DS10318
ACFH-3548T Data Sheet Automotive Gate Drive Optocoupler with Flyback DC-DC Controller, Adaptive Blanking, Ad-
vance Short Circuit Protection and Isolated Analog Feedback for Temperature Sensing
Figure 13: ITH vs. Temperature Figure 14: VOH vs. IOH
1
1.5
2
2.5
3
3.5
4
4.5
-50 -25 0 25 50 75 100 125
I TH-
DLOHSERHT T
NERRUC DEL
-mA
TA - TEMPERATURE - C
ITH+
ITH-
10
11
12
13
14
15
16
0 0.5 1 1.5 2 2.5 3
V OH
- EGATL
OV HGIH TUPT
UO
-V
IOH - OUTPUT HIGH CURRENT - A
Ta=-40°C
Ta=25°C
Ta=125°C
Figure 15: VOL vs. IOL Figure 16: VSSD vs. ISSD
0
1
2
3
4
5
6
0 0.5 1 1.5 2 2.5 3
V OL
- EGATL
OV W
OL TUPT
UO
-V
IOL - OUTPUT LOW CURRENT - A
Ta=-40°C
Ta=25°C
Ta=125°C
0
1
2
3
4
5
6
0 1 2 3 4
V SSD
- EGATL
OV DSS-V
ISSD - SOFT SHUTDOWN CURRENT- A
Ta=-40°C
Ta=25°C
Ta=125°C
Figure 17: TP vs. Temperature Figure 18: ICLAMP vs. VCLAMP
50
70
90
110
130
150
170
190
210
230
250
-50 -25 0 25 50 75 100 125
T P-
YALED N
OITAGAPORP T
UPTU
O-n
s
TA - TEMPERATURE - C
TPLH
TPHL
0
1
2
3
4
5
6
0 2 4 6 8
I MC
-T
NERRUC G
NIKNIS LEVEL
WOL P
MALC-A
VMC - CLAMP LOW LEVEL VOLTAGE - V
Ta=-40°C
Ta=25°C
Ta=125°C
Broadcom ACFH-3548T-DS10319
ACFH-3548T Data Sheet Automotive Gate Drive Optocoupler with Flyback DC-DC Controller, Adaptive Blanking, Ad-
vance Short Circuit Protection and Isolated Analog Feedback for Temperature Sensing
Figure 19: VDST vs. Temperature Figure 20: Propagation Delay Test Circuit
9
9.5
10
10.5
11
-50 -25 0 25 50 75 100 125
V DST
_TH
- DL
OHSERHT GNIS
NES TASED-V
TA - TEMPERATURE - C
27
26
25
24
23
22
21
20
LED2+
NC
VEE2
VCC2
CS
VE
DST4
5
6
7
8
9
10
11
PGDP_GND
/UVLO
/FAULT
TOUT
VCC1
VADJ
VEE1
19
18
17
VO12
13
14 CA
TOK
MC15 DNC
VEE2
30
29
1
2
28
3
SSD
TIN
NC
TB
TREF
ISEN
COMP
NC
AN
16 DNC
32
31
VEE2
DC+5V
260
5V0V
IF
Signal source
DC+16V
1μF
1μF
10 CLOAD
1nF
ACFH-3548T
10k
10k
10k
330pF
330pF
330pF
DC+4V
DC+2.8V0.1μF
0.1μF
Figure 21: CMR VO High Test Circuit Figure 22: CMR VO Low Test Circuit
27
26
25
24
23
22
21
20
LED2+
NC
VEE2
VCC2
CS
VE
DST4
5
6
7
8
9
10
11
PGDP_GND
/UVLO
/FAULT
TOUT
VCC1
VADJ
VEE1
19
18
17
VO12
13
14 CA
TOK
MC15 DNC
VEE2
30
29
1
2
28
3
SSD
TIN
NC
TB
TREF
ISEN
COMP
NC
AN
16 DNC
32
31
VEE2
DC+5V
165
16V
1μF
1μF
10 CLOAD
1nF
ACFH-3548T
5V +_
165
+_
+ _
High Voltage PulseVCM=1500V
10k
10k
10k
330pF
330pF
330pF
0.1μF
0.1μF 4V+_
2.8V+_
27
26
25
24
23
22
21
20
LED2+
NC
VEE2
VCC2
CS
VE
DST4
5
6
7
8
9
10
11
PGDP_GND
/UVLO
/FAULT
TOUT
VCC1
VADJ
VEE1
19
18
17
VO12
13
14 CA
TOK
MC15 DNC
VEE2
30
29
1
2
28
3
SSD
TIN
NC
TB
TREF
ISEN
COMP
NC
AN
16 DNC
32
31
VEE2
DC+5V
165
16V
1μF
1μF
10 CLOAD
1nF
ACFH-3548T
165
+_
+ _
High Voltage PulseVCM=1500V
1μF
10k
10k
10k
330pF
330pF
330pF
0.1μF
0.1μF 4V+_
2.8V+_
Broadcom ACFH-3548T-DS10320
ACFH-3548T Data Sheet Automotive Gate Drive Optocoupler with Flyback DC-DC Controller, Adaptive Blanking,
Advance Short Circuit Protection and Isolated Analog Feedback for Temperature Sensing
Figure 23: ACFH-3548T Typical Gate Driver Circuit with IGBT Desaturation/Emitter Over-Current Sensing, Temperature Sensing, and Negative Gate Bias Set by VZ
NOTE: The values of the components are subjected to change with various application requirements.
adcom Limited Proprietary and Confidential. © 2016 Broadcom Limited. All rights reserved.
uC
PWM_BOT
PWM_TOP
5V
Digital I/O
Digital I/O
VBAT + VCC2 - VE = 16V (Default)
VZ**
Flyback Transformerturn ratio 3.5
DC+5V
VBAT -
GND
IGBT
S
A
G
K
E
A/D
ACFH-3548T
27
26
25
24
23
22
21
20
LED2+
NC
VEE2
VCC2
CS
VE
DST4
5
6
7
8
9
10
11
PGD
P_GND
/UVLO
/FAULT
TOUT
VCC1
VADJ
VEE1
19
18
17
VO12
13
14 CA
TOK
MC15 DNC
VEE2
30
29
1
2
28
3
SSD
TIN
NC
TB
TREF
ISEN
COMP
NC
AN
16 DNC
32
31
VEE2
6.5V – 24V
VSE
VF
+
-
20μF20μF
1.8k220nF
100pF470k
22nF
>110V
>60V
Lp Ls
VDS > 60V
Rsense50m
20
Digital I/O
100pF
1.8k *
10k
200
15k *
19.1k * 5.9k *
4.7 *
12 *
Notes:* to be tuned to IGBT** to be shorted if negative
supply is not needed
1k *
RADJ1
RADJ2
10k 10k 10k
MOSFET
130
130
MURA160T3G
20 10uF
10uF
1μF
Broadcom ACFH-3548T-DS10321
ACFH-3548T Data Sheet Automotive Gate Drive Optocoupler with Flyback DC-DC Controller, Adaptive Blanking,
Advance Short Circuit Protection and Isolated Analog Feedback for Temperature Sensing
Description of Operations and Functions
Operation of Integrated DC-DC Flyback Controller
The ACFH-3548T integrated DC-DC flyback controller operates in a discontinuous conduction mode (DCM) at a fixed average switching frequency of 120 kHz. It converts a wide 6.5V to 24V input range to default 16V positive output supply (VCC2 – VE) when the VADJ pin is connected to ground of left open and programmable negative output voltage (VEE2 – VE) can be set by the Zener diode.
The primary control block implements direct duty cycle control logics for line and load regulation. Primary winding current is sensed and limited to VISEN_TH to prevent transformer short-circuit failure from damaging the primary switch. The sense resistor (Rsense) is selected based on the maximum primary winding current limit and maximum power dissipation requirement. Secondary output voltage, VCC2, is sensed and feedback to the primary control circuits. The closed loop control circuits always regulates VCC2 with reference to VE, based on the configurations set at the primary side of IC VADJ pin. The voltage ratio of VADJ over VCC1 determines (VCC2 – VE) voltage:
is defaulted at 0.4125 if the VADJ pin is left floating or tied to ground. VCC2 is approximated to the following:
Figure 24: Regulated Positive Supply Voltage (VCC2 – VE) vs (VADJ / VCC1) Ratio
= =+
21.48 ( 0.4125) + 16
Broadcom ACFH-3548T-DS10322
ACFH-3548T Data Sheet Automotive Gate Drive Optocoupler with Flyback DC-DC Controller, Adaptive Blanking,
Advance Short Circuit Protection and Isolated Analog Feedback for Temperature Sensing
The sum of the resistors used in the voltage divider for setting VADJ is to be less than 10 kΩ to avoid interference from the internal default voltage divider. The following table shows the typical resistor values for setting VCC2.
When VCC2 is greater than the specified VCC2 over-voltage threshold (VOV2_TH+), VCC2 over-voltage protection is triggered. The PGD pin on the primary side of gate driver is shut down to protect secondary over-voltage failure and the DC-DC flyback conversion will cease. When VCC2 reduces to VOV2_TH–, the PGD pin is released and DC-DC regulation resumes its normal operations.
While designing the flyback transformer for DCM controller, the maximum PWM duty cycle must be limited to 50% or less at the minimum input voltage (for example, VBAT+ = 6.5V) under full load conditions. A discrete flyback transformer should be connected to ACFH-3548T according to Figure 23 for complete isolated DC-DC converter. The input LED should be kept off while powering up the VCC1. To ensure proper operation of the DC-DC converter, fast VCC1 rise time (≤ 5 ms) is preferred for soft start function to control the inrush current. If VCC2 fails to rise above 6V at the end of the soft start period (about 20 ms), the primary switch is turned off to prevent a possible VCC2 short-circuit event during start-up. The DC-DC controller can be restarted by power reset VCC1.
The average PWM switching frequency of primary gate drive (PGD) is dithered ± 6% typically from center frequency of 120 kHz. Frequency dithering feature helps to achieve better EMI performance by spreading the switching and its harmonics over a wider band.
Soft Start Operation
ACFH-3548T is designed with built-in soft start feature. When VCC1 is higher than VCC1_TH+, the built-in soft start circuit starts to function. Typical soft start timing is 20 ms, where a typical soft start current profile steps up from 3 µA, then 6 µA, and finally 10 µA charges up the compensation network through the VCOMP pin and gradually increases the VCOMP voltage to the correct working level. Figure 25 shows the typical DC-DC start up waveforms.
Table 2: Typical Resistor Values for Setting VCC2
RADJ1 (kΩ) RADJ2 (kΩ) (V/V) VCC2 (V)
4.70 2.40 0.3380 14.4
4.70 3.32 0.4140 16.0
4.70 4.22 0.4731 17.3
Broadcom ACFH-3548T-DS10323
ACFH-3548T Data Sheet Automotive Gate Drive Optocoupler with Flyback DC-DC Controller, Adaptive Blanking,
Advance Short Circuit Protection and Isolated Analog Feedback for Temperature Sensing
Figure 25: Typical DC-DC Start Up Waveforms
NOTE:
VSAW is IC internal saw waveform and cannot be measured externally. VSAW frequency is not drawn to scale.
Typical DC-DC switching frequency at the PGD pin is 120 kHz. VPGD frequency is not drawn to scale.
Status Flags
The status flags at the input side reflect the state of the circuit operation. Figure 26 exemplifies how the status flags react when VCC2 ramps up and down when VCC1 is ready.
Normal operation: All of the status flags (/UVLO, /FAULT, and TOK) are in Hi-Z state. These pins are pulled high through the external resistors.
Under-voltage Fault: When VCC1 is below the VCC1 turn-on threshold (VCC1_TH+) or VCC2 falls below the UVLO2 threshold (VUVLO2_TH–), both of the /UVLO and TOK flags are pulled low.
VCC2 Over-voltage Fault: When VCC2 is over the VCC2 over-voltage protection threshold (VOV2_TH+), only the TOK flag is pulled low.
DC-DC Flyback Over-current Fault: When ISEN voltage exceeds the threshold VISEN_TH, the /UVLO flag is pulled low. It is reset to high upon next PGD switching cycle. If the DC-DC over-current fault persists, the /UVLO pulses at the PGD PWM frequency. In the case that /UVLO has a large filter capacitor, the short upward /UVLO pulses are filtered, resulting in a persistent low /UVLO for the affected PGD PWM cycles. See Figure 27.
IGBT Short-circuit Fault: If a short-circuit fault occurs by triggering at DST pin or CS pin, the IGBT gate is turned off adaptively according to the voltage sensed at the DST pin and the CS pin. The /FAULT flag is pulled low.
1.25
4.0
2.625VCOMP (V)
Time
5VCC1_TH+
VCC1 (V)
Time
VUVLO2_TH+
VCC2 – VEE2 (V)
Time
VSAW (V)
VPGD (V)5
(Note a)
(Note b)
Broadcom ACFH-3548T-DS10324
ACFH-3548T Data Sheet Automotive Gate Drive Optocoupler with Flyback DC-DC Controller, Adaptive Blanking,
Advance Short Circuit Protection and Isolated Analog Feedback for Temperature Sensing
LED2 Fault: When VCC2 – VEE2 supply voltage is greater than typical 6V, the secondary side LED2 starts to pulse to inform the primary IC that the feedback channel is working normally. If the primary IC detects no signal from LED2, it is presumed that LED2 is faulty and all the status flags (/UVLO, /FAULT, and TOK) are pulled low. The primary IC stops the DC-DC regulation by pulling the PGD pin and the COMP pin low. The driver IC’s power (VCC1) then needs to be recycled for IC reset. Figure 28 shows a typical gate driver circuit with low-dropout linear regulator (LDO) for primary IC (VCC1) reboot during LED2 fault condition.
TOUT Invalid: The TOUT reading is invalid with the indicator TOK pulled low, during UVLO fault, VCC2 over-voltage fault and IGBT short-circuit fault.
Figure 26: Status Indicators During VCC2 Ramp Up and Ramp Down
Table 3: Status Flags
Conditions
Status Flags
/UVLO /FAULT TOK
Normal operation Hi-Z Hi-Z Hi-Z
VCC1 under-voltage/VCC2 UVLO fault Low Hi-Z Low
VCC2 over-voltage fault Hi-Z Hi-Z Low
DC-DC over-current fault Pulsed Hi-Z Hi-Z
IGBT short-circuit fault High Low Low
LED2 fault Low Low Low
TOUT invalid Don’t Care Don’t Care Low
VCC2
TOK
/UVLO
/FAULT
LED2 fault UVLO fault Normal LED2 faultUVLO faultNormalOV fault
~6V
VUVLO2_TH+VOV2_TH+ VOV2_TH-
VUVLO2_TH-
~5V
Broadcom ACFH-3548T-DS10325
ACFH-3548T Data Sheet Automotive Gate Drive Optocoupler with Flyback DC-DC Controller, Adaptive Blanking,
Advance Short Circuit Protection and Isolated Analog Feedback for Temperature Sensing
Figure 27: DC-DC Flyback Over-Current Fault Reporting
Figure 28: Typical Gate Driver Circuit with Low-Dropout Linear Regulator (LDO) for VCC1 Reboot
PGD
ISEN
Case 1: /UVLO with small capacitor: /UVLO will follow PGD frequency
Case 2: /UVLO with large capacitor: /UVLO will be kept low due to large capacitor
ISEN over current thresholdOver-current event occurs
Broadcom Limited Proprietary and Confidential. © 2016 Broadcom Limited. All rights reserved.
uC
PWM_BOT
PWM_TOP
5V
Digital I/O
Digital I/O
VBAT + VCC2 - VE = 16V (Default)
VZ**
Flyback Transformerturn ratio 3.5
DC+5V
VBAT -
GND
IGBT
S
A
G
K
E
A/D
ACFH-3548T
27
26
25
24
23
22
21
20
LED2+
NC
VEE2
VCC2
CS
VE
DST4
5
6
7
8
9
10
11
PGD
P_GND
/UVLO
/FAULT
TOUT
VCC1
VADJ
VEE1
19
18
17
VO12
13
14 CA
TOK
MC15 DNC
VEE2
30
29
1
2
28
3
SSD
TIN
NC
TB
TREF
ISEN
COMP
NC
AN
16 DNC
32
31
VEE2
6.5V – 24V
VSE
VF
+
-
20μF20μF
1.8k220nF
100pF470k
22nF
>110V
>60V
Lp Ls
VDS > 60V
Rsense50m
20
Digital I/O
100pF
1.8k *
10k
200
15k *
19.1k * 5.9k *
4.7 *
12 *
Notes:* to be tuned to IGBT** to be shorted if negative
supply is not needed
1k *
RADJ1
RADJ210k 10k 10k
MOSFET
130
130
MURA160T3G
20 10uF
10μF
1uF
INEN
OUT
GND
5V LDO
Control
Broadcom ACFH-3548T-DS10326
ACFH-3548T Data Sheet Automotive Gate Drive Optocoupler with Flyback DC-DC Controller, Adaptive Blanking,
Advance Short Circuit Protection and Isolated Analog Feedback for Temperature Sensing
Description of Gate Driver and Miller Clamping
The gate driver is directly controlled by the LED current. When the LED current is driven high, the main output driver (VO) of the ACFH-3548T delivers 1.5A sourcing current to output buffer to drive the IGBT’s gate. While LED is switched off, it provides 1.5A sinking current to the output buffer to switch the gate off fast.
When UVLO is not active (VCC2 – VE > VUVLO2_TH+), VO of the ACFH-3548T is allowed to go high. IGBT desaturation fault detection (by the DST pin) and over-current detection (by the CS pin) of the ACFH-3548T is the primary source of IGBT protection. When VCC2 exceeds the VUVLO2_TH+ threshold, DST and CS detections remain functional, until VCC2 crosses below the VUVLO2_TH– threshold. Thus, the DST/CS detection and UVLO features of the ACFH-3548T work in conjunction to ensure constant IGBT protection.
The Miller clamping transistor (MC pin) and all pull-down drivers are activated when the gate voltage drops below VMC_TH voltage, to provide low impedance path to the Miller current.
Description of Under Voltage Lock Out
Insufficient gate voltage to IGBT can increase turn-on resistance of IGBT, resulting in large power loss and IGBT damage due to high heat dissipation. The ACFH-3548T monitors the output power supply constantly. When the output power supply is lower than under voltage lockout (UVLO) threshold, the gate driver output shuts off to protect IGBT from low voltage bias. During power up, the UVLO feature forces the ACFH-3548T’s output low to prevent unwanted turn-on at low voltage. When power supply (VCC2) voltage increases more than VUVLO2_TH+ threshold, the /UVLO fault status is cleared and the gate driver resumes its normal function automatically.
Figure 29: Circuit Behavior During Power Up, Power Down, and UVLO
VCC1
VCC2
LED IF
VO tUVLO_OFF
VUVLO2_TH-
/UVLO
VCC1_TH+
tUVLO_ON
tPHL_UVLO2 tPLH_UVLO2
VUVLO2_TH+
UVLO2UVLO2UVLO1
Low
UVLO2
VUVLO2_TH-VUVLO2_TH+VUVLO2_TH+
VCC1_TH-
Low
UVLO1UVLO2
High Z
/FAULT High Z
VUVLO2_TH-
Broadcom ACFH-3548T-DS10327
ACFH-3548T Data Sheet Automotive Gate Drive Optocoupler with Flyback DC-DC Controller, Adaptive Blanking,
Advance Short Circuit Protection and Isolated Analog Feedback for Temperature Sensing
Description of IGBT Short-circuit Protection and Shutdown Sequence
1. ACFH-3548T monitors the DST pin and the CS pin for IGBT short-circuit conditions.
2. Short-circuit detection on the DST pin and the CS pin is only active when the voltage at the TB pin is greater than the VTB_TH threshold. This corresponds to the period when the IGBT is in conduction mode.
3. Short-circuit protection is triggered in either of the following situations.
– Voltage on the DST terminal exceeds VDST_TH threshold.
– Voltage on the CS terminal exceeds the VCS_TH threshold.
4. Shutdown is triggered by LED input turning-off or short-circuit events. ACFH-3548T executes an adaptive shutdown for any shutdown operation.
a. CS information is latched into memory cells at the start of every shutdown sequence.
b. DST is first checked to find out whether IGBT is in desaturation short condition. If VDST > VDST_TH, the SSD driver is selected to softly shut down the IGBT gate throughout the shutdown process (IGBT arm short circuit, Figure 30).
c. If VDST < VDST_TH, main driver VO is first used to minimize Miller plateau time. As the IGBT collector voltage rises, DST will rise above VDST_TH, which also means that Miller plateau is coming to its end. Then the next most appropriate driver is selected based on the latched CS information VCS.
d. If VCS > VCS_TH, the SSD driver is selected for slow soft shutdown (IGBT wire short circuit, Figure 31). If VCS < VCS_TH, the main driver VO continues to be used for a quick normal shutdown (normal operation, Figure 32).
5. In a short-circuit event, /FAULT status is always reported to MCU (see Figure 33).
6. ACFH-3548T starts an adaptive shutdown.
7. /FAULT output goes low, notifying the microcontroller of the short-circuit fault condition.
8. PWM commands at input LED will be ignored during mute time tSC(MUTE).
9. When tSC(MUTE) expires, LED input must be kept low for tSC(RESET) duration before the fault condition can be cleared.
10. After the fault condition is cleared, /FAULT flag will then return to high, and output starts to respond to LED input.
Broadcom ACFH-3548T-DS10328
ACFH-3548T Data Sheet Automotive Gate Drive Optocoupler with Flyback DC-DC Controller, Adaptive Blanking,
Advance Short Circuit Protection and Isolated Analog Feedback for Temperature Sensing
Figure 30: Adaptive Shutdown (IGBT Arm Short Circuit – Direct Soft Shutdown)
VCS_TH
Hi-Z
Hi-Z
Hi-Z
VDST_TH VCC2
VMC_TH
VCC2
Blanking time set by TB
MC
SSD
IF
DST
VSENSE
ICE
VGE
VO
VCE
Broadcom ACFH-3548T-DS10329
ACFH-3548T Data Sheet Automotive Gate Drive Optocoupler with Flyback DC-DC Controller, Adaptive Blanking,
Advance Short Circuit Protection and Isolated Analog Feedback for Temperature Sensing
Figure 31: Adaptive Shutdown (IGBT Wire Short Circuit – Hard then Soft Shutdown)
Hi-Z
Hi-Z
Hi-Z
MC
SSD
IF
VO
VCS_TH
VMC_THVGE
Miller Plateau
VCE VCC2
VDST_THDST VCC2
VSENSE
ICE
Blanking time set by TB
Broadcom ACFH-3548T-DS10330
ACFH-3548T Data Sheet Automotive Gate Drive Optocoupler with Flyback DC-DC Controller, Adaptive Blanking,
Advance Short Circuit Protection and Isolated Analog Feedback for Temperature Sensing
Figure 32: Adaptive Shutdown (Normal Operation – Hard Shutdown)
Figure 33: Status Report During a Short-Circuit Event
VCS_TH
Hi-Z
Hi-Z
VMC_TH
VDST_TH
MC
SSD
IF
DST
VSENSE
ICE
VGE
VO
VCE
Miller Plateau
VCC2
VCC2
Blanking time set by TB
Short Circuit Event
tSC_FLT
IFVCS_TH
VGE
VSENSE
Hi-Z
Hi-Z
Hi-Z
TOK
/FAULT
tSC(MUTE)
tSC(RESET)
Blanking time set by TB
/UVLO
Broadcom ACFH-3548T-DS10331
ACFH-3548T Data Sheet Automotive Gate Drive Optocoupler with Flyback DC-DC Controller, Adaptive Blanking,
Advance Short Circuit Protection and Isolated Analog Feedback for Temperature Sensing
Description of Blanking Time Control
ACFH-3548T monitors the DST pin and the CS pin for short-circuit conditions when the input LED is turned on. However, during operations, the initial states of the DST and CS pins when the LED turns on may trigger a false short-circuit alarm. It is necessary to ignore DST and CS pins for the initial “blanking time” period when the IGBT gate voltage is still around its Miller plateau.
By comparing IGBT gate voltage, VG, with the internal reference VTB_TH of the TB pin, the end of the turn-on Miller plateau can be determined. Blanking time is only released when the gate voltage, VG, presented at TB pin is higher than VTB_TH.
A simple circuit shown in Figure 34 is used to tune the effective VG threshold lower to release blanking time more quickly. The effective VG threshold with VO adjusted is as follows.
R2 and CTB provide low-pass filtering of the spikes at VG.
For example, if VCC2 is 16V and VTB_TH is 13V, setting R1 = 1.8 kΩ and R2 = 1 kΩ sets the effective VG threshold to 11.3V. VG_TH should be larger than the Miller plateau gate voltage Vmiller that corresponds to the designed IGBT short-circuit protection current Ishort.
Figure 34: Simple Circuit for Blanking Time Control
Description of Temperature Sensor
1. TIN takes input of the voltage across temperature sensor diodes to sense temperature information.
2. Enabled by superior optical coupling and advanced sigma-delta (S-D) modulation technology, TIN voltage is transmitted over to TOUT pin on the primary side, with low offset and high gain accuracy.
3. High accuracy unity gain between TOUT and TIN is maintained for nominal temperature range.
4. No temperature information is transmitted during UVLO or short-circuit fault condition. The TOUT pin is pulled low for all fault conditions. The TOK flag is set to low as an indicator that TOUT reading is no longer valid during the fault conditions. See Table 3 for status flags information.
j
_ = _ ( _ )2
1 ×
TB 19
VO 21
CTBVEE2 17
IGBTGBuffer DriverVG
R2
R1
Broadcom ACFH-3548T-DS10332
ACFH-3548T Data Sheet Automotive Gate Drive Optocoupler with Flyback DC-DC Controller, Adaptive Blanking,
Advance Short Circuit Protection and Isolated Analog Feedback for Temperature Sensing
Figure 35: Transfer Function of Temperature Sensor (TIN and TOUT)
Description of Temperature Compensation Function
The input TREF is used to match the negative temperature coefficient of the temperature sensor diodes to the positive temperature coefficient of the IGBT emitter sense voltage, VSE.
The output of the temperature compensation block in Figure 1 gives the reference voltage, VCS_TH, for the comparator at the CS pin, providing the threshold for short-circuit detection.
TREF can be calculated using the following equation.
Where:
KVF: Normalized thermal co-efficient of temperature sensor voltage, VF
KVSE: Normalized thermal co-efficient of IGBT emitter current sensor voltage, VSE
VFTO: Temperature sensor voltage, VF at temperature T0 (for example: 25°C)
Where:
VFT1: Temperature sensor voltage, VF at temperature T1 (for example: 125°C)
Where:
VSET0: Emitter current sensor voltage, VSE at temperature T0 (for example: 25°C)
VSET1: Emitter current sensor voltage, VSE at temperature T1 (for example: 125°C)
3.5V0
3.5V
TIN
TOUT
= × 1
=
=
Broadcom ACFH-3548T-DS10333
ACFH-3548T Data Sheet Automotive Gate Drive Optocoupler with Flyback DC-DC Controller, Adaptive Blanking,
Advance Short Circuit Protection and Isolated Analog Feedback for Temperature Sensing
Printed Circuit Board Layout Considerations
Take care when designing the layout of printed circuit board (PCB) for optimum performance. Maintain adequate spacing between the high-voltage isolated circuitry and any input-referenced circuitry. Maintain the same minimum spacing between two adjacent high-side isolated regions of the printed circuit board as well. Insufficient spacing reduces the effective isolation and increases parasitic coupling that will affect CMR performance.
The placement and routing of supply bypass capacitors require special attention. During switching transients, the majority of the gate charge is supplied by the bypass capacitors. Maintaining short charging and discharging paths between capacitors and gate can help to achieve clean switching waveforms and low supply ripples. Have supply and ground planes for VCC2 and VEE2. Connect IC power pins, such as VCC2 (pin 22) and VEE2 (pins 17, 31, and 32) directly to these planes using multiple via holes right next to the pins. Figure 36 shows a good example of PCB layout arrangement in comparison with a bad one.
Figure 36: Good and Bad PCB Layout Example
Similar layout guidelines are applicable to input side circuitry, such as power supply VCC1 (pin 5), input side ground VEE1 (pin 4), and supply decoupling capacitors. Place the compensation network circuitry that connected to COMP (pin 7) next to IC with short traces. For thermal dissipation purposes, place the large copper area for top layer VEE2 (pins 17, 31, and 32) and connect the copper area with multiple via holes to VEE2 plane at the bottom layer of PCB as shown in Figure 37.
VCC2 plane
Pin 17, 31 and 32 are all connected to VEE2 plane.
VEE2
22VCC2
31VEE2
VEE2
32
17
VEE2 plane
Pin 17, 31 and 32 are all connected to VEE2 plane.
Bad Example: Decoupling capacitor is connected to VCC2 pin through a thin routing wire with no VCC2 plane
VEE2 planeLong Top layer VCC2 trace
Goode Example: Decoupling capacitor is connected between VCC2 and VEE2 planes
VEE2
22VCC2
31VEE2
VEE2
32
17
Broadcom ACFH-3548T-DS10334
ACFH-3548T Data Sheet Automotive Gate Drive Optocoupler with Flyback DC-DC Controller, Adaptive Blanking,
Advance Short Circuit Protection and Isolated Analog Feedback for Temperature Sensing
Figure 37: Example of Recommended Layout
VCC2 planeVEE2 planeVEE1 plane
VCC1 plane
ACFH-3548T
Large copper area for VEE2 at top layer with multiple via holes connected to bottom layer VEE2 plane for heat dissipation.
Bypass capacitor is connected between VCC2 and VEE2 planes.
Desat decoupling capacitor and schottky protection diode are placed right next to the DESAT and use kelvin connection to VE pin.
DC-DC compensation circuit is placed right next
to the IC COMP pin and grounded to VEE1 plane.
Connect P_GND to VEE1 plane directly.
Bypass capacitor is connected between VCC1
and VEE1 planes.27
26
25
24
23
22
21
20
LED2+
NC
VEE2
VCC2
CS
VE
DST4
5
6
7
8
9
10
11
PGDP_GND
/UVLO/FAULT
TOUT
VCC1VADJ
VEE1
19
18
17
VO12
13
14 CA
TOK
MC15 DNCVEE2
30
29
1
2
28
3
SSD
TIN
NC
TB
TREF
ISEN
COMP
NC
AN
16 DNC
32
31
VEE2
Broadcom ACFH-3548T-DS10335
Broadcom, the pulse logo, Connecting everything, Avago Technologies, Avago, the A logo, and the R2Coupler are among the trademarks of Broadcom and/or its affiliates in the United States, certain other countries, and/or the EU.
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The term “Broadcom” refers to Broadcom Inc. and/or its subsidiaries. For more information, please visit www.broadcom.com.
Broadcom reserves the right to make changes without further notice to any products or data herein to improve reliability, function, or design. Information furnished by Broadcom is believed to be accurate and reliable. However, Broadcom does not assume any liability arising out of the application or use of this information, nor the application or use of any product or circuit described herein, neither does it convey any license under its patent rights nor the rights of others.