DC-Spannungsverdoppler (12 V auf 22 V bei 20 mA, braucht 10-kHz-Takt, 2NPN + 3 Dioden + 2 C)

It is sometimes necessary to provide a nega- tive supply voltage in a circuit that otherwise uses all positive supply voltages, for example to provide a symmetrical supply for an op- amp in a circuit that is otherwise all logic ICs. Providing such a supply can be a problem, especially in battery operated equipment.