Electronics- Controlling Power to Output Transducers

Basic Rule of ControlTypes of output transducers

Types of controlDevices for control

Other considerations

ElectronicsControlling Power to Output Transducers

Terry Sturtevant

Wilfrid Laurier University

November 10, 2016

Terry Sturtevant Electronics Controlling Power to Output Transducers




Basic Rule of Control

Control usually involves three things:1 a fixed power supply2 a load to which we want to control the power3 a control element to which we will send signals to control

the power to the load.These will be arranged in a voltage divider.






Control usually involves three things:

1 a fixed power supply2 a load to which we want to control the power3 a control element to which we will send signals to control







Control usually involves three things:1 a fixed power supply

2 a load to which we want to control the power3 a control element to which we will send signals to control







Control usually involves three things:1 a fixed power supply2 a load to which we want to control the power

3 a control element to which we will send signals to controlthe power to the load.

These will be arranged in a voltage divider.







the power to the load.

These will be arranged in a voltage divider.





Vsupply Vsupply

controlsignal

controlsignal

load

load

C.E.

C.E.

“C.E.” is the control element.“Load” could be a motor, solenoid, relay coil, etc.





Vsupply Vsupply

controlsignal

controlsignal

load

load

C.E.

C.E.

“C.E.” is the control element.

“Load” could be a motor, solenoid, relay coil, etc.





Vsupply Vsupply

controlsignal

controlsignal

load

load

C.E.

C.E.

“C.E.” is the control element.“Load” could be a motor, solenoid, relay coil, etc.





Produce “information”Produce “action”

Low power devices

These devices require low power. Low power is typically . 1W .meteroscilloscope

These devices produce information.






Low power devices

These devices require low power.

Low power is typically . 1W .meteroscilloscope







Low power devices

These devices require low power. Low power is typically . 1W .

meteroscilloscope







Low power devices

These devices require low power. Low power is typically . 1W .meter

oscilloscopeThese devices produce information.






Low power devices

These devices require low power. Low power is typically . 1W .meteroscilloscope







High power devices

These devices require high power. High power is typically & 1W .lightssolenoids

These devices produce action.An operational amplifier is a voltage device; it can’t produce morethan a few mW of power.






High power devices

These devices require high power.

High power is typically & 1W .lightssolenoids







High power devices

These devices require high power. High power is typically & 1W .

lightssolenoids







High power devices

These devices require high power. High power is typically & 1W .lights

solenoidsThese devices produce action.An operational amplifier is a voltage device; it can’t produce morethan a few mW of power.






High power devices








High power devices


These devices produce action.

An operational amplifier is a voltage device; it can’t produce morethan a few mW of power.






High power devices







Types of control

on/offlike a switchproportionallike a rheostat or potentiometer





Types of control

on/off

like a switchproportionallike a rheostat or potentiometer





Types of control

on/offlike a switch

proportionallike a rheostat or potentiometer





Types of control

on/offlike a switchproportional

like a rheostat or potentiometer





Types of control

on/offlike a switchproportionallike a rheostat or potentiometer





Control trade-offs

There are trade-offs involved in choosing a type of control.efficiencyon/off is 100% efficientproportional is less efficientnoiseon/off produces more noiseproportional produces less noise

There is a trade-off between efficiency and noise.





Control trade-offs

There are trade-offs involved in choosing a type of control.

efficiencyon/off is 100% efficientproportional is less efficientnoiseon/off produces more noiseproportional produces less noise






Control trade-offs

There are trade-offs involved in choosing a type of control.efficiency

on/off is 100% efficientproportional is less efficientnoiseon/off produces more noiseproportional produces less noise






Control trade-offs

There are trade-offs involved in choosing a type of control.efficiencyon/off is 100% efficient

proportional is less efficientnoiseon/off produces more noiseproportional produces less noise






Control trade-offs

There are trade-offs involved in choosing a type of control.efficiencyon/off is 100% efficientproportional is less efficient

noiseon/off produces more noiseproportional produces less noise






Control trade-offs

There are trade-offs involved in choosing a type of control.efficiencyon/off is 100% efficientproportional is less efficientnoise

on/off produces more noiseproportional produces less noise






Control trade-offs

There are trade-offs involved in choosing a type of control.efficiencyon/off is 100% efficientproportional is less efficientnoiseon/off produces more noise

proportional produces less noiseThere is a trade-off between efficiency and noise.





Control trade-offs

There are trade-offs involved in choosing a type of control.efficiencyon/off is 100% efficientproportional is less efficientnoiseon/off produces more noiseproportional produces less noise






RelayTransistorsMOSFETBJTTRIAC

As previously noted, any device used for control is basicallyused in a voltage divider using

the supply voltage,the control device,and the load.

The order of the control element and the load in the voltagedivider has some effects on the circuit operation.







the supply voltage,

the control device,and the load.








the supply voltage,the control device,

and the load.The order of the control element and the load in the voltagedivider has some effects on the circuit operation.







the supply voltage,the control device,and the load.







Relay

A relay is based on a solenoid, and has four types of pins:coilcommonNO; normally open (possibly)NC; normally closed (possibly)






Relay

A relay is based on a solenoid, and has four types of pins:

coilcommonNO; normally open (possibly)NC; normally closed (possibly)






Relay

A relay is based on a solenoid, and has four types of pins:coil

commonNO; normally open (possibly)NC; normally closed (possibly)






Relay

A relay is based on a solenoid, and has four types of pins:coilcommon

NO; normally open (possibly)NC; normally closed (possibly)






Relay

A relay is based on a solenoid, and has four types of pins:coilcommonNO; normally open (possibly)

NC; normally closed (possibly)






Relay

A relay is based on a solenoid, and has four types of pins:coilcommonNO; normally open (possibly)NC; normally closed (possibly)






Relay OFF

NO

commonNC






Relay ON

NO

commonNC






An internal spring returns the solenoid to its original position whenpower is removed from the coil.






Since a relay is inductive, all of the precautions for an inductivedevice must be taken.

Vin






The relay can be inserted on either side of the load in a voltagedivider.

Vout

VsupplyVin






The relay can be inserted on either side of the load in a voltagedivider.

Vout

Vsupply

Vin






Transistors

There are several types of transistor; each is a three terminaldevice.The most common types of transistors are BJTs and FETs.Transistors are often used in voltage dividers to act as variableresistors.






Transistors

There are several types of transistor; each is a three terminaldevice.

The most common types of transistors are BJTs and FETs.Transistors are often used in voltage dividers to act as variableresistors.






Transistors

There are several types of transistor; each is a three terminaldevice.The most common types of transistors are BJTs and FETs.

Transistors are often used in voltage dividers to act as variableresistors.






Transistors

There are several types of transistor; each is a three terminaldevice.The most common types of transistors are BJTs and FETs.Transistors are often used in voltage dividers to act as variableresistors.






Metal Oxide Semiconductor Field Effect Transistors

A MOSFET (or Metal Oxide Semiconductor Field EffectTransistor) is a three terminal device.

drainsourcegate








drain

sourcegate








drainsource

gate








drainsourcegate






FET symbol






FET symbol

drain






FET symbol

drain

source






FET symbol

drain

sourcegate






FET operation

FETS are voltage amplifiers; a small gate voltage controls amuch larger drain/source current.

Actually it’s the voltage between the gate and the source whichmatters.






D and E MOSFETs

There are two kinds of MOSFETenhancement mode (E type)When Vgs is below Vth, ID = 0As Vgs increases above Vth,ID increases.depletion mode (D type)To get ID to zero, a negative Vgsoff must be applied.

Actually, all MOSFETs operate in enhancement mode. It’s justthat some only operate in that mode. Which kind you wantdepends on whether or not you want some current to flow with noapplied gate-source voltage.






D and E MOSFETs

There are two kinds of MOSFET

enhancement mode (E type)When Vgs is below Vth, ID = 0As Vgs increases above Vth,ID increases.depletion mode (D type)To get ID to zero, a negative Vgsoff must be applied.







D and E MOSFETs

There are two kinds of MOSFETenhancement mode (E type)

When Vgs is below Vth, ID = 0As Vgs increases above Vth,ID increases.depletion mode (D type)To get ID to zero, a negative Vgsoff must be applied.







D and E MOSFETs

There are two kinds of MOSFETenhancement mode (E type)When Vgs is below Vth, ID = 0

As Vgs increases above Vth,ID increases.depletion mode (D type)To get ID to zero, a negative Vgsoff must be applied.







D and E MOSFETs

There are two kinds of MOSFETenhancement mode (E type)When Vgs is below Vth, ID = 0As Vgs increases above Vth,

ID increases.depletion mode (D type)To get ID to zero, a negative Vgsoff must be applied.







D and E MOSFETs

There are two kinds of MOSFETenhancement mode (E type)When Vgs is below Vth, ID = 0As Vgs increases above Vth,ID increases.

depletion mode (D type)To get ID to zero, a negative Vgsoff must be applied.







D and E MOSFETs

There are two kinds of MOSFETenhancement mode (E type)When Vgs is below Vth, ID = 0As Vgs increases above Vth,ID increases.depletion mode (D type)

To get ID to zero, a negative Vgsoff must be applied.Actually, all MOSFETs operate in enhancement mode. It’s justthat some only operate in that mode. Which kind you wantdepends on whether or not you want some current to flow with noapplied gate-source voltage.






D and E MOSFETs








D and E MOSFETs


Actually, all MOSFETs operate in enhancement mode. It’s justthat some only operate in that mode.

Which kind you wantdepends on whether or not you want some current to flow with noapplied gate-source voltage.






D and E MOSFETs








D (depletion mode) MOSFET






D (depletion mode) MOSFET output






E (enhancement mode) MOSFET






E (enhancement mode) MOSFET output






E (enhancement mode) MOSFET output zoomed in






Vsupply

Vo

I ≈ 0 if Vgs . Vth

Vgs

E (enhancement mode) FET






Vsupply

Vo = VDS

Vgs







Vsupply

Vo ≈ Vsupply if Vgs < Vth

Vgs = 0gate







Vsupply

Vo = VDS < Vsupply if Vgs & Vth

Vgs & Vthgate







Vsupply

Vo = VDS → 0 if Vgs >> Vth

Vgs >> Vthgate







FETS are voltage amplifiers; a small gate-source voltagecontrols a much larger drain/source current.

You do not use a gate resistor with an FET!All FETs work in enhancement mode; some also work indepletion mode.






FETS are voltage amplifiers; a small gate-source voltagecontrols a much larger drain/source current.You do not use a gate resistor with an FET!

All FETs work in enhancement mode; some also work indepletion mode.






FETS are voltage amplifiers; a small gate-source voltagecontrols a much larger drain/source current.You do not use a gate resistor with an FET!All FETs work in enhancement mode; some also work indepletion mode.






Vsupply

Vo = VDS > 0 if Vgs = 0

Vgs = 0gate

D (depletion mode) FET






Vsupply

Vo

I ≈ 0 if Vgs . Vgsoff < 0

Vgs has to be negative to turn off.Xy

Vgs







Vsupply

Vo = VDS < Vsupply if Vgs & 0

Vgs & 0gate







Vsupply

Vo = VDS → 0 if Vgs >> 0

Vgs >> 0gate







The MOSFET, like the relay, can be placed in either position of avoltage divider.

The effects are the same as for the relay.

Vout

Vsupply

Vin






The MOSFET, like the relay, can be placed in either position of avoltage divider. The effects are the same as for the relay.

Vout

Vsupply

Vin






Bipolar Junction Transistors

A BJT (or Bipolar Junction Transistor) is a three terminal currentdevice.The terminals are

collectoremitterbase

The current from the collector to the emitter is controlled by thecurrent into the base.







A BJT (or Bipolar Junction Transistor) is a three terminal currentdevice.

The terminals arecollectoremitterbase









collector

emitterbase









collectoremitter

baseThe current from the collector to the emitter is controlled by thecurrent into the base.






collector






collector

emitter






collector

emitterbase






BJT operation

BJTS are current amplifiers; a small base current controls amuch larger collector/emitter current.You should always have a base resistor with a BJT!






BJT operation

BJTS are current amplifiers;

a small base current controls amuch larger collector/emitter current.You should always have a base resistor with a BJT!






BJT operation

BJTS are current amplifiers; a small base current controls amuch larger collector/emitter current.

You should always have a base resistor with a BJT!






BJT operation

BJTS are current amplifiers; a small base current controls amuch larger collector/emitter current.You should always have a base resistor with a BJT!






Vs

Ic ≈ 0 if Vi . 0.7

Vo ≈ Vs if Vi . 0.7Vi . 0.7






Vs

Ic ∝ Ib if Vi > 0.7

Vo = Vs − IcR if Vi > 0.7Vi > 0.7

≈ 0.7






Like the previous devices, either position in a voltage divider canbe used.

Vout

Vsupply

Vin






TRIAC

A TRIAC is a three terminal ac voltage device. The terminals aremain terminal 1main terminal 2gate

A triac will begin to conduct when it receives a voltage pulse onthe gate. It will continue to conduct until the current is zero.






TRIAC

A TRIAC is a three terminal ac voltage device.

The terminals aremain terminal 1main terminal 2gate







TRIAC

A TRIAC is a three terminal ac voltage device. The terminals are

main terminal 1main terminal 2gate







TRIAC

A TRIAC is a three terminal ac voltage device. The terminals aremain terminal 1

main terminal 2gate







TRIAC

A TRIAC is a three terminal ac voltage device. The terminals aremain terminal 1main terminal 2

gateA triac will begin to conduct when it receives a voltage pulse onthe gate. It will continue to conduct until the current is zero.






TRIAC








TRIAC


A triac will begin to conduct when it receives a voltage pulse onthe gate.

It will continue to conduct until the current is zero.






TRIAC








gate

MT1

MT2






It can operate in two modes.

burstdelayed trigger






It can operate in two modes.burst

delayed trigger






It can operate in two modes.burstdelayed trigger






In burst mode, trigger pulses are only given at the beginning ofhalf-cycles.






This is a typical circuit to control a triac in burst mode.






In delayed trigger mode, trigger pulses are delayed after thebeginning of half-cycles to produce power for only a part of eachhalf cycle.






This is a typical circuit to control a triac in delayed trigger mode.





Using TTL gates for control


“Extra” current from TTLsink instead of source0.4mA vs. 8 mA (LS)







“Extra” current from TTL

sink instead of source0.4mA vs. 8 mA (LS)







“Extra” current from TTLsink instead of source

0.4mA vs. 8 mA (LS)







“Extra” current from TTLsink instead of source0.4mA vs. 8 mA (LS)






Current sourcing






Current sourcing

IOH ≤ 0.4mA






Current sinking






Current sinking

VCC






Current sinking

VCC

IOL ≤ 8.0mA






Using a TTL gate to sink instead of source allows 20x the current!


Electronics- Controlling Power to Output Transducers

Documents

Transcript of Electronics- Controlling Power to Output Transducers