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# Rapid Recovery Single Shot

IP.com Disclosure Number: IPCOM000080752D
Original Publication Date: 1974-Feb-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 2 page(s) / 30K

IBM

## Related People

Scotto, VA: AUTHOR [+1]

## Abstract

The present circuit makes use of a transistor in a grounded-collector mode, to allow a rapid capacitor discharge and provide an increased cycle rate.

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Rapid Recovery Single Shot

The present circuit makes use of a transistor in a grounded-collector mode, to allow a rapid capacitor discharge and provide an increased cycle rate.

Referring to the circuit diagram, the input terminal is driven by an open- collector input transistor. When this transistor is turned off, transistors T1 and T2 are supplied base drive through resistors R1, R2 and R3. The capacitor C is discharged, the negative input to the differential amplifier DA is at approximately ground and its output is at an up level.

As the input transistor is turned on, transistors T1 and T2 turn off. Base current is pulled from transistor T3 and it turns on.

The negative input to the amplifier sees voltage V2 across resistance R and the output switches to a down level. As the capacitor C charges, the voltage across R decays toward ground. As it reaches the voltage V2/2 of the positive terminal, the amplifier output will switch to an up level. The timing equation for this cycle is given by: t = RC [ 1n(VR over Vi) ] where

VR is the voltage on the resistor,

Vi is V2 - (V(CE)((T3))) + Vci), where Vci is the

capacitors initial condition voltage.

When the input transistor turns off, transistor T3 turns off. Transistors T1 and T2 turn on discharging the capacitor C. This allows for a rapid recovery of the capacitor and hence the single-shot.

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