Regulated inverting power supply

PCT No. PCT/US93/12178 Sec. 371 Date Jun. 11, 1996 Sec. 102(e) Date Jun. 11, 1996 PCT Filed Dec. 14, 1993 PCT Pub. No. WO95/17036 PCT Pub. Date Jun. 21, 1995An inverting power supply (10) having first and second charging capacitors (22, 24) that are alternately connected to a positive power source (12) and a negative output terminal (18) which is to be maintained at a negative voltage with respect to a common ground for the power source and the power supply. Switches (34, 36) connect a positive plate of each charging capacitor to the power supply positive terminal during alternate half cycles of a two-phase clock (20) and charge is bled from the positive plates by switching transistors (46, 50) during the other half cycle to enable charge to be transferred via diodes (52, 54) from the negative output terminal to negative plate of the charging capacitors during the other half cycle. The base-emitter currents of the switching transistors are controlled by a charge transfer control circuit (56) in relation to the voltage at the negative output terminal to regulate the voltage at the negative output terminal by controlling the rate of charge transfer to the negative output terminal. Additional regulation can be provided by a current control circuit (106) that adjusts the switching transistor base-emitter currents in relation the collector currents of the switching transistors.