SUPPLY_VOLTAGE_SPLITTER

Published:2009/7/9 4:02:00 Author:May | From:SeekIC

This simple circuit can convert a single supply voltage, such as a battery, into a bipolar supply. Sense resistors R1 and R2 establish relative magnitudes for the resulting positive and negative voltages. Their rail-to-rail value, of course, equals VSUPPLY. R4 and R5 represent the load impedances. For example, equalvalue sense resistors produce 1/2 VSUPPLY across each of the load resistors, R4 and R5. The op amp maintains these equal voltages by sinking or sourcing current through R3; the op amp's action is equivalent to that of variable conductances G1 and G2 in shunt with each load resistor. Choose a value for R3 so that the largest voltage across it, the greatest load-current mismatch, won't exceed the op amp's output-voltage capability for the application. You can add a buffer amplifier at the op amp's output to provide greater load currents. If you need bypass capacitors across the load resistors as well, connect a capacitor (dashed lines) to ensure that the amplifier remains stable.



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