GB831511A - Regulated power supply system using transistors - Google Patents

Abstract

831,511. Automatic voltage-control systems. STANDARD TELEPHONES & CABLES Ltd. Dec. 21, 1956 [Dec. 29, 1955], No. 39001/56. Class 38 (4). A D.C. voltage regulator comprises a series transistor between input and output circuits which is controlled by the amplified, detected output of an H.F. oscillator, modulated in accordance with output voltage variations. A rectified A.C. supply 1, 2 feeds a load 3 through transistor T 1 . Across the load, resistor 7, reference tube 6 and potentiometer 8 form a bridge circuit, the output being applied to the baseemitter circuit of transistor T 2 , to control the conduction of the emitter-collector circuit. The latter circuit is in parallel with the output, across resistor 9, of transistor H.F. oscillator T 3 and, acting as a variable shunt, effectively modulates the signal fed to transistor amplifier T 4 , T 2 , T 3 and T 4 are N-P-N-type transistors and have a separate, isolated power supply from transistors T 1 , T 5 and T 6 which are of P-N-P type. These supplies are derived respectively from generator, transformer and bridge rectifier arrangements 31 &c. and 27, 28, &c. T 4 output is coupled to T 5 through isolating transformer 18; T 5 amplifies and detects the signal. T 5 output is D.C. modulated by the supply voltage ripple and output voltage variations and is applied to the base of D.C. amplifier T 5 . T 6 controls the conduction of T 1 and varies its impedance to compensate output voltage changes.