Power Suppliesvoltage converter

Virtual ground

Virtual ground: Often only a single power supply is available for an opamp circuit. Since such circuits normally require a double supply, this means that in some way the available supply has to be converted. This is normally done by a potential divider and capacitor across the single supply. sometimes followed by an ancillary opamp.

Nowadays, a more sophisticated way is the use of the TLE2426 from Texas Instruments. This IC is not only small and easy to use but, owing to the built-in opamp, also gives a better performance. This is particularly noticeable at low frequencies, where the impedance of the usual electrolytic capacitor across the potential divider may cause problems. In the TLE2426, a voltage follower takes the place of the capacitor, so that the impedance, even at low frequencies. remains low—typically 7.5 mΩ.
The quiescent current is only 170  μA, while the peak current that can be provided is 20 mA.

The device is available in two different enclosures: transistor-like, indicated by the suffix ‘LP’ in the type number, and S-pin DIL, suffixed D, P or JG. The LP model is eminently suitable as a replacement of a conventional potential divider and capacitor (and possibly, (Tamp). The D1L model has the advantage that a capacitor may be connected to its pin 8, which in some cases is desirable since each of the two output voltages is half the supply voltage, which may contain much noise.

There is also the Type TLE2425, which provides a fixed voltage of 2.5 V at a peak current of 20 mA. Pin 8 of this model is not connected.

Virtual ground Schematic diagram

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