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Differential Sense Switch

IP.com Disclosure Number: IPCOM000092626D
Original Publication Date: 1966-Dec-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 27K

Publishing Venue

IBM

Related People

Burke, RG: AUTHOR

Abstract

Transistors T3, T4, and T5 and resistors R6 and R7 are connected as a differential amplifier. The base of T3 is connected to an input terminal and the base of T4 is connected to a reference voltage. Thus, T3 turns on when the input voltage is higher than the reference. T4 turns on when the input voltage is lower than the reference voltage. Transistors T8 and T9 are connected with resistors R12...R15 to provide feedback to the base of T5. This feedback enhances the switching operation.

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Differential Sense Switch

Transistors T3, T4, and T5 and resistors R6 and R7 are connected as a differential amplifier. The base of T3 is connected to an input terminal and the base of T4 is connected to a reference voltage. Thus, T3 turns on when the input voltage is higher than the reference. T4 turns on when the input voltage is lower than the reference voltage. Transistors T8 and T9 are connected with resistors R12...R15 to provide feedback to the base of T5. This feedback enhances the switching operation.

The collector T3 is connected to the base of T9. T3 and T9 are of opposite conductivity type. Therefore T9 tends to conduct more heavily when T3 is on and to conduct less heavily when T3 is off. The collector of T4 is connected to the base of T8. T4 and T8 are of the same conductivity type. T8 tends to conduct more heavily when T4 is off and to conduct less heavily when T4 is on. Thus both T8 and T9 conduct in phase with T4. Diode D16 is connected to limit the reverse biasing voltages at the bases of T8 and T9 and thus provide faster operation when these transistors are turned on.

The collectors of T8 and T9 are connected to the base of T5. As T3, T8, and T9 turn on, T5 conducts more heavily and thus enhances the turn on operation of T3. Similarly when T3, T8, and T9 turn off, T5 conducts less heavily and thus enhances the turnoff operation of T3.

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