GB1023801A - Voltage regulators - Google Patents

Abstract

1,023,801. Automatic voltage control. ROTAX Ltd. Jan. 7, 1963 [Feb. 6, 1962], No. 4463/62. Heading G3R. A direct voltage regulator comprises input terminals 1, 2, output terminals 4, 5, a series transistor 7, a square wave oscillator including a transformer 9 and transistors 21 and 22, a pair of switching circuits through which the output from the oscillator is applied to the base of transistor 7 which is thereby rendered conductive at the commencement of each half-cycle of the oscillator output, and means including controlled rectifiers 14,15 for interrupting the supply to the base of the transistor 7 at a time in each half cycle which is variable in accordance with the output voltage of the regulator. In operation, the output voltage is sensed by the resistance chain 29, 30 and is applied to the base of a transistor 33 the emitter voltage of which is held constant by a Zener diode 34. When the output voltage rises above a predetermined value, transistor 33 conducts to render a transistor 40 conductive thereby charging a capacitor 45 to a pre-determined level which then renders a uni-junction transistor 46 conductive; current then flows through winding 50 of transformer 51 to produce, in windings 52 and 53, pulses which render conductive either controlled rectifier 14 or controlled rectifier 15, whereby the base current is removed from transistor 7 so that no current flows to the terminal 4, and the output voltage falls. At the end of each half-cycle of the oscillator output the voltage across a resistor 27 renders a transistor 56 conductive to discharge capacitor 45; this regulating cycle continues so that the output voltage is maintained constant. To provide for protection against over-current faults, the base of transitor 33 is also connected to a circuit including a rectifier bridge 61 and a series transductor 60, which circuit is adjusted so that the output from the bridge 61 only renders transistor 33 conductive when the load current exceeds a predetermined value.