1. Diode Rectifier Circuits Section 4.5

2. 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.

3. Block Diagram for an AC to DC Converter (Power Supply)

4. 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.

5. Half-Wave Ideal Diode Rectifier Diode only allows current to flow through the resistor when v I ≥ 0V. Forward-bias equivalent circuit is used to determine v O under this condition.

6. Half-Wave Real Diode Rectifier Voltage Transfer Characteristics vIvI

7. Half-Wave Rectifier Voltage Transfer Characteristics

8. Signals of Half Wave Rectifier Input voltageOutput voltage Diode voltage

9. Load Line Analysis Load line when v S is at its maximum forward voltage. Load line when v S is at its most negative value.

10. Load Line (con’t) As v S varies with time, the load line also changes, which changes the Q-point (v D and i D ) of the diode.

11. Full-Wave Rectifier Voltage transfer characteristics Input and output waveforms

12. Full-Wave Bridge Rectifier In either case, current flows through R in the same direction, resulting in an output voltage, v O, shown in (c). When v S is positive, D 1 and D 2 are turned on (a). When v S is negative, D 3 and D 4 are turned on (b).

13. Full-Wave Bridge Rectifier

14. Half-Wave Rectifier as a Battery Charger

15. Battery Charging Example

18. Another Battery Charging Example

21. DC Power Supply Circuit