Use AD8037 to make a Full-Wave Rectifier but failed

Thread Starter

PSIR

Joined Apr 23, 2008
29
Hello everyone :

Please see the attached file AD8036_37.doc. This is my circuit. I according to AD8036/37's datasheet page 19, Figure 12. Full-Wave Rectifier to made the same circuit.

But as soon as I input sinewave signal to the circuit. The AD8037 start to getting heat, and power voltage also drop, circuit current also to raise.

If I remove the input signal, everything turned to normal. I don't know why the reason is. Does anyone who has experience in AD8036 or 37?
Could you help me to make the Figure 12. Full-Wave Rectifier. Thanks.

Many Regards

PSIR
 

Attachments

bertus

Joined Apr 5, 2008
20,041
Hello,

The opamp is designed to use a maximum power supply of +/- 6 Volts.
How much are you giving at the input?
The schematic uses the lower clamping connection.

Greetings,
Bertus
 

Thread Starter

PSIR

Joined Apr 23, 2008
29
As the circuit shows. I gave +/- 5 Volts to the AD8037 and input signal is 1Vp-p.
 

SgtWookie

Joined Jul 17, 2007
22,201
Do you have bypass capacitors between ground and +Vs and -Vs as shown in the datasheet? If not, you may have some very high frequency oscillations going on that you can't see on your O-scope. You don't show these caps in your schematic.
 

Audioguru

Joined Dec 20, 2007
11,251
The datasheet recommends 140 ohm feedback and input resistors to avoid oscillation. Yours is much higher.
The datasheet says that an AC8037 is stable only with a gain of 2 or more. Your circuit has a gain that is less.
The schematic of the full-wave recitifer contradicts the above statements.
It shows two supply bypass capacitors for each supply.

I hope you didn't make this high frequency circuit on a breadboard.
 

Thread Starter

PSIR

Joined Apr 23, 2008
29
Dear SgtWookie and Audioguru:

I appreciate your help very much. I certainly not only didn't connect bypass capacitors(0.1uf and 10uf)between ground and +Vs and -Vs but also made this circuit on a breadboard.

Then I made this circuit with the essential component on a experiment board by soldering-iron. It works, it can rectified high frequency up to at least 1MHz.

Many Thanks
 
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