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High Speed Low Power Transistor Switch

IP.com Disclosure Number: IPCOM000052712D
Original Publication Date: 1981-Jul-01
Included in the Prior Art Database: 2005-Feb-11
Document File: 2 page(s) / 31K

Publishing Venue

IBM

Related People

Heimeier, HH: AUTHOR [+4]

Abstract

A circuit is described permitting saturated transistors controlled in parallel to be rapidly switched on or off with low power.

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High Speed Low Power Transistor Switch

A circuit is described permitting saturated transistors controlled in parallel to be rapidly switched on or off with low power.

To achieve high switching speeds in monolithic, integrated semiconductor circuits in spite of a low supply voltage, certain switching transistors must be operated in the saturation mode. To permit such transistors to be rapidly switched on or off, the above circuit is provided.

To rapidly switch on transistors T5, which are operated in the saturation mode and of which only one transistor is shown in the circuit diagram, they are strongly overdriven by transistor T1 via the current-limiting base resistors R1. To switch off transistors T5 as rapidly as possible, their bases must be discharged equally rapidly. This is done by transistors T4 operated in the saturation mode and forming a low-impedance path between the bases of transistors T5 and the collector of transistor T2.

After their bases have been discharged, transistors T5 are switched off. Then, the base currents of transistors T4 can also be switched off to reduce the power dissipation. For this purpose, a control circuit, which consists of transistor T6, resistor R2 and transistor T7, common to all transistors T4 is used. After transistor T5 has been switched off, its collector potential rises, and transistor T6 becomes conductive. As a result, the base current supply to transistor T7 is stopped, so that the latter is switched off. This, in tu...