ADA4622-2ARZ-R7 datasheet(31/34 Pages) AD

31 / 34 page

Data Sheet

ADA4622-1/ADA4622-2

Rev. B | Page 31 of 34

FULL WAVE RECTIFIER

Figure 101 shows the circuit of a full-wave rectifier using two

ADA4622-1 op amps in single-supply operation. The circuit is

composed of a voltage follower (U1) and a second stage amplifier

(U2) that combine the output of the first stage amplifier and the

inverted version of the input signal. U1 follows the input during

the positive half cycle and clamps the negative going input

signal to ground giving a half wave signal at VHW. The following

equation defines the circuit transfer function:

VFW = (1+ R3/R2)VHW − (R3/R2) × VIN

where:

VFW is the full wave output from U1.

R3 and R2 are the feedback resistors shown in Figure 101.

VHW is half wave output from U1.

VIN is the input voltage.

2V p-p

1kHz

0°

30kΩ

VFW

VCC

GND

50kΩ

Figure 101. Full Wave Rectifier Circuit

During the input positive half cycle, U1 follows the input so that

VHW = VIN; therefore, VFW = VIN. During the negative half cycle,

U1 clamps the signal to ground so that VHW = 0 V; therefore,

VFW = −(R3/R2) × VIN = −VIN because R3/R2 = 1. Figure 102

shows the input and outputs waveforms from the circuit. The

input is 2 V p-p, 1 kHz sine wave while the circuit is running on

a 5 V single supply.

INPUT

HALF

WAVE

FULL

WAVE

TIME

Figure 102. Full Wave and Half Wave Rectifier Input and Output Waveforms

ADA4622-2ARZ-R7 Datasheet(PDF) 31 Page - Analog Devices