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Low Voltage Regulator with Zero Temperature Coefficient

IP.com Disclosure Number: IPCOM000075316D
Original Publication Date: 1971-Sep-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 25K

Publishing Venue

IBM

Related People

Driscoll, CD: AUTHOR [+3]

Abstract

In conventional low-voltage power supplies with regulation, it is conventional to use a low-voltage zener diode to raise the emitter voltage of a transistor amplifier to a substantial part of the desired output voltage and to regulate the output voltage by applying a corresponding part voltage to the base of the amplifier. The amplifier output is used to control the usual series regulator circuit. In this arrangement, the negative temperature coefficients of the base-emitter junction of the amplifier and that of the low-voltage zener diode are additive in their effect on the voltage output.

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Low Voltage Regulator with Zero Temperature Coefficient

In conventional low-voltage power supplies with regulation, it is conventional to use a low-voltage zener diode to raise the emitter voltage of a transistor amplifier to a substantial part of the desired output voltage and to regulate the output voltage by applying a corresponding part voltage to the base of the amplifier. The amplifier output is used to control the usual series regulator circuit. In this arrangement, the negative temperature coefficients of the base-emitter junction of the amplifier and that of the low-voltage zener diode are additive in their effect on the voltage output.

The circuit in the diagram uses a zener diode of a substantially higher voltage rating and such a diode will normally have a positive rather than a negative temperature coefficient. In the diagram, 1 is the usual ground or voltage reference connection and 2 is the input of an unregulated voltage. A regulator transistor 3 has its collector connected to input 2 and its emitter connected to terminal 4, the regulated voltage output. A control transistor 5 has its collector connected to the base of transistor 3 and both are connected to source 2 through a resistor 6. The emitter of transistor 5 is connected to line 1 and its base is connected to the junction of resistors 7 and 8. The upper end of resistor 7 is connected to the output line 4. A zener diode 9 has its cathode connected to line 1 and its anode connected through a...