Diode Rectifier Circuits

Section 4.5

In this Lecture, we will:

Determine the operation and characteristics of diode rectifier circuits, which is the first stage of the process of converting an ac signal into a dc signal in an electronic power supply.

Full-wave and half-wave diode rectifier circuits will be discussed.

Block Diagram for an AC to DC Converter

(Power Supply)

Problem-Solving Technique: Diode Rectifier Circuits

1. Determine the input voltage condition such that the diode is conducting (on).

Then find the output signal for this condition.

2. Determine the input voltage such that the diode is not conducting (off).

Then find the output signal for this condition.

Half-Wave Real Diode Rectifier

Voltage Transfer Characteristics

vI

Half-Wave Rectifier

Voltage Transfer Characteristics

2

1

2

1

LL

NN

vv

S

I

Signals of Half Wave Rectifier

Input voltage Output voltage

Diode voltage

Load Line AnalysisLoad line when vS is at its maximum forward voltage.

Load line when vS is at its most negative value.

Load Line (con’t)

As vS varies with time, the load line also changes, which changes the Q-point (vD and iD) of the diode.

Full-Wave Rectifier

Voltage transfer characteristics

Input and output waveforms

Full-Wave Bridge Rectifier

In either case, current flows through R in the same direction, resulting in an output voltage, vO, shown in (c).

When vS is positive, D1 and D2 are turned on (a). When vS is negative, D3 and D4 are turned on (b).

Full-Wave Bridge Rectifier

Half-Wave Rectifier as a Battery Charger

Battery Charging Example

Battery Charging Example

Battery Charging Example

Another Battery Charging Example

Another Battery Charging Example

Another Battery Charging Example

DC Power Supply Circuit