Diode Circuits

Voltage Regulation Rectifier Circuit

T in Half-Wave Rectifier Cause of ripple: the capacitor is discharged for almost an entire period.

inversion Ripple Reduction: Do not allow the capacitor to discharge so frequently

An Inverting Half-Wave Rectifier If V in >0, D1 and D2 are off. If V in 0.

An Non-Inverting Half-Wave Rectifier If V in >0, D1 and D2 are on, Vout>0. If V in <0, D1 and D2 are off.

Full-Wave Rectifier Inverting Non-Inverting

Full-Wave Rectifier Alternative Drawing Inverting Non-Inverting Full-Wave A.K.A. Bridge Rectifier

Using Constant Voltage Diode Model V out =-V in -2V D, on V out =V in -2V D, on

Input versus Output |V in |<2V D,on

Addition of the Smoothing Capacitor

Modification of Ripple Estimation Formula Modification: 1.Turn-on voltage 2.1/2 to account for inversion of negative peaks.

Maximum Reverse Voltage V B =V D,on V A =V P V AB =V P -V D,on Maximum reverse voltage is approximately V p V p is the amplitude of V in

Compare Maximum Reverse Bias Voltage to Half-Wave Rectifier A reverse diode voltage must sustain larger reverse bias voltage

Currents as a function of time

Application of Bridge Rectifier

Summary

Application of Limiting Circuits Limit the signal amplitude at a suitable point in the receiver

Characteristic of a Limiting Circuit

A Simple Limiter

General Limiter Circuit

Application of Voltage Doubler Electronic systems typically provide a global supply voltage: 3V Design of some circuits will be simplified if they from a higher supply voltage.

Voltage Doubler Floating CapacitorCapacitor Divider

Capacitor Diode Circuit Ideal diode. Vout pinned to 0 V Positive charges begin to leave the left Plate of C1, turning D1 off. C1 is now a floating capacitor

Generating 0 to 2Vp Waveform

Peak Detector

Voltage Doubler Peak Detector0 to 2Vp waveform

Diode as a Voltage Shifter Application: We may need to shift the average level of a signal up and down because the subsequent stage (e.g. an amplifier) may not operate properly with the present dc level.

A Simple Level Shift

Shift up the DC by 2 V D, On

A simple electronic switch CK is 1: I1=1, diodes are shorted, and Vin=Vout. CK is 0,diodes are off, charges are stored across C1.