AD8510/AD8512/AD8513

Rev. E | Page 16 of 20

PRECISION RECTIFIERS

TIME (1ms/DIV)

Rectifying circuits are used in a multitude of applications. One

of the most popular uses is in the design of regulated power

supplies, where a rectifier circuit is used to convert an input

sinusoid to a unipolar output voltage. There are some potential

problems for amplifiers used in this manner.

voltage can exceed the power supply voltage, which would dam-

age some amplifiers permanently. The op amp must come out of

because the amplifier requires time to enter its linear region.

The AD8510/AD8512/AD8513 have a very fast overdrive

recovery time, which makes them great choices for the

rectification of transient signals. The symmetry of the positive

and negative recovery times is also important in keeping the

output signal undistorted.

Figure 51. Half-Wave Rectifier Signal (Out A)

TIME (1ms/DIV)

Figure 50 shows the test circuit of the rectifier. The first stage of

the circuit is a half-wave rectifier. When the sine wave applied at

the input is positive, the output follows the input response.

During the negative cycle of the input, the output tries to swing

negative to follow the input, but the power supply restrains it to

zero. In a similar fashion, the second stage is a follower during

the positive cycle of the sine wave and an inverter during the

negative cycle.

8

4

2

1

3

1/2

AD8512

4

8

5

7

6

2/2

AD8512

R2

10k

Ω

R3

10k

Ω

R1

1k

Ω

OUT A

(HALF WAVE)

OUT B

(HALF WAVE)

5V

5V

3V p-p

Figure 52. Full-Wave Rectifier Signal (Out B)

Figure 50. Half-Wave and Full-Wave Rectifier