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High Speed Programmable Driver

IP.com Disclosure Number: IPCOM000091001D
Original Publication Date: 1969-Sep-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 28K

Publishing Venue

IBM

Related People

Celenza, N: AUTHOR

Abstract

The driver circuit is used where delays must be programmed. The individual time of rise or time of fall delay is changed by controlling the amount of forward bias on snap action diodes.

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High Speed Programmable Driver

The driver circuit is used where delays must be programmed. The individual time of rise or time of fall delay is changed by controlling the amount of forward bias on snap action diodes.

In the circuit, element 1 is a dual transistor current mode switch, a voltage divider, and a level shifter. The inputs can be either a zero to +3V or a +/-.4V voltage swing. The output is a +/-.7V swing around -6V. Device 2 is a single transistor current mode switch with an output voltage of +/- 3.5V. Element 3 is a voltage reference coupled with a snap diode. By varying the reference voltage with a potentiometer or an external supply, the fall time at the input of device 5 can be delayed from zero to 60 ns independently of the rise time. Device 4 is similar to element 3 but it changes the rise time delay only, and by the same amount as element 3. Device 5 divides the input voltage by one half and lowers the reference by -6V. Element 6 is a current mode switch. Element 7 is a temperature-compensated emitter-follower with programmable drive and load current limiting. Device 8 provides an SLT type output. Element 9 provides the uplevel reference voltage for the outputs of elements 6. This voltage reference can be either supplied externally and sensed or it can be adjusted with a potentiometer. The input +P overrides the potentiometer. Element 10 provides a constant current for element 6. This current can either be programmed through - P and sensed with...