Virtual Ground Troubles
Oct 29, 2005 at 9:20 PM Thread Starter Post #1 of 1

maczrool

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Above is my test virtual ground circuit. I've got it set up on some solderless breadboard. I'm using an LT1970 CFB opamp because for my application I need high current drive. I have it set up like the CFB schematic on Tangent's virtual ground website. It works fine up to 10 volts and then very suddenly the idle current shoots through the roof and the voltage at the virtual ground drops substanially. C1 is 220 uF, C2 is .01 uF, R1 237K, R2 is 237K, R3 is 22K, R4 is 1K. I'm not using any of the current limiting features on the chip. I'm leaving those pins floating. I need to get this to function properly at 12 volts, but I can't figure out why it doesn't. Does anyone know why I am seeing this problem?

Thanks,
Stu
 

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