Browse Prior Art Database

Zero Quiescent Power Line Driver and Receiver

IP.com Disclosure Number: IPCOM000083039D
Original Publication Date: 1975-Mar-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 3 page(s) / 42K

Publishing Venue

IBM

Related People

Harr, JD: AUTHOR

Abstract

This circuitry overcomes the heavy power drain in battery operated transmission line driver systems, operating in relatively high radio-frequency noise environments.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 53% of the total text.

Page 1 of 3

Zero Quiescent Power Line Driver and Receiver

This circuitry overcomes the heavy power drain in battery operated transmission line driver systems, operating in relatively high radio-frequency noise environments.

For the purpose, low-impedance and high-current driving circuits are desired. The circuit arrangement shown in Fig. 1 has zero quiescent line current flowing in either the units (1) state or the naughts (phi) state. At the same time, it provides better noise rejection than conventional circuitry, because extremely low- impedances and high-current drive capability are had at both ends of the transmission line.

Digital data to be transmitted is applied to input terminals 10. A driver circuit 12 is connected between the input terminals 10 and one transmission line terminal 14 of a transmission line 16. The line 16 may be quite long. The other transmission line terminal 18 is connected to the input terminal of a conventional Schmitt trigger circuit 20, or other level triggering bistable circuit. One output terminal of the circuit 20 is connected to output terminals 22 and to an inverting line driver circuit 24. The output of the driver circuit 24 is connected by way of a resistor 26 to the input terminal of the Schmitt trigger circuit 20 and to the transmission line terminal 18.

The circuit operation is illustrated by the accompanying waveforms. Data is represented by curves 30 and 32. Initially both outputs of line drivers 12, 24 are low. Noise 36, occurring at time A attempts to pull up the line, but both line drivers sink the noise current and keep the line low.

At time B, the transmitting driver 12 turns on and supplies current into the line 16 and into the receiving driver 24, which sinks the current. Because there is a voltage drop across the input to the Schmitt trigger circuit 20 output starts to rise.

At time C the transmission line 16 has charged up to the point where the voltage at the terminal 18 crosses the upper threshold 39. This brings the...