Hi Friends,
I needed 8mA of current for driving an op-Amp TL084 in my circuit. The TL084 is being used for precision rectification of the current feedback signal coming from CT. This rectified and properly amplified signal is then fed to PCF8591 ADC which is an I2C ADC connected to my P89V51RD2 micro. For this TL084 I needed a +9V -9V supply, Earlier I used linear regulators 78xx and 79xx series for the simmilar applications, but this time I used two ICL7660 with first one being used for voltage doubler and second for negative voltage. Given below is the schematic of the circuit I am using.


The Vcc input shown is +5V. I constructed the circuit as per above schematic and the measured the output voltage without any load on outputs. It measured exactly +9.08V and -9.08V. Then I connected this circuit with TL084 and I was surprised to see that the voltage at ICL7660 outputs have dropeed to +8.06V and -7.74V I also measured the current being consumed by opAmp it was consuming no more than 7.82mA. Have you guys ever come across such problem. If yes please tell me what should I do get +9V -9V exact for my application.

Thank you very much.

Regards,
Prahlad Purohit