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High Speed Bidirectional Driver Circuit

IP.com Disclosure Number: IPCOM000085995D
Original Publication Date: 1976-Jul-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 2 page(s) / 29K

Publishing Venue

IBM

Related People

Hoyt, ES: AUTHOR

Abstract

This circuit, which has a low number of components and low-power consumption, receives low-level signals to produce at very high speeds low and high voltages with positive and negative offsets.

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High Speed Bidirectional Driver Circuit

This circuit, which has a low number of components and low-power consumption, receives low-level signals to produce at very high speeds low and high voltages with positive and negative offsets.

With a voltage of 0 volts at input A, transistors Q1 and Q3 conduct and the output is a +V volts. Q3 is kept out of saturation by hot carrier or Schottky diode D1. To switch the output to -V volts, the voltage at input A is raised to +3 volts to turn off Q1 and Q3, and turn on transistors Q2 and Q4. Since the bases of Q1 and Q2 have a common bias voltage, for example, +1.6 volts, Q1 and Q3 turn off before Q2 and Q4 turn on. In one embodiment, Q1 turned off at +1.2 volts and Q2 turned on at +2.2 volts.

With input A at +3 volts the voltage at the output is maintained at -V volts, with Q4 kept out of saturation by hot carrier or Schottky diode D2. If less time is desired in the switching time from a +V volt output to a -V volt output and vice versa, separate bias voltages may be provided for the bases of Q1 and Q2. The adjustment of these biases must be such that both Q3 and Q4 are not conducting at the same time.

Very little power is dissipated in this circuit, since each of the transistors Q3 and Q4 is close to saturation when conducting and the other is turned off. This circuit may have a large output swing which is limited only by the breakdown voltage of the transistors and diodes. This circuit may be used as a current steering dev...