I need to power a TLO72 at +/- 2.5V using the 5V of the USB port.
Is there a simple way to do this without using a voltage converter IC?
IOW a divider that does not reduce the rail voltage.
Thank you,
Lucas
+/- 2.5V from USB
Mar 04, 2006
2 Replies
Look up virtual ground circuits.
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There are many issues to understand with virtual ground circuits.
Hope your analog design skills are up to date. ;-)
Donald
Hello L. Moore,
Commonly that is done by configuring one opamp as a follower and biasing its positive input at half VCC, via a hi-Z resistor divider. Then you have a low impedance virtual ground at the output of this opamp. But don't directly load that down with lots of capacitance or the thing might oscillate.
AFAIK the TL072 is not going to be happy with that little voltage. It might be better to make an oscillator with some free logic Schmitt inverter and then rectify its output so you obtain -5V in addition to your +5V.
Regards, Joerg
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