Emitter-coupled logic balanced signal transmission circuit
AssigneeFujitsu Limited
InventorHiroshi Matsunaga
Life of this patent
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Abstract
A signal transmission circuit which transmits a signal over a transmission line includes a line driver circuit comprising a differential amplifier and an emitter follower circuit connected thereto, and a metal oxide semiconductor field-effect transistor which provides a high impedance when power supply from a power supply source is turned off and, thereby, causes the line driver circuit to provide a high output impedance to the transmission line when power supply is turned off.
Claims7
An emitter-coupled logic balanced signal transmission circuit for transmitting an ECL signal over a transmission line, the signal transmission circuit comprising:
- a line driver circuit connected to the transmission line for driving the transmission line;
- a power supply connected to said line driver circuit to provide a power source thereto;
- and
- at least one resistor element included in said line driver circuit and constructed so as to provide a low impedance when the power supply is turned on and a high impedance when the power supply is turned off and thereby causing said line driver circuit to provide a high output impedance to the transmission line when the power supply is turned off,
- said line driver circuit comprising an emitter-coupled logic differential amplifier and an emitter-coupled logic emitter follower circuit connected thereto for outputting a signal to the transmission line through an output terminal, said at least one resistor element comprising a metal oxide semiconductor field-effect transistor, and
- wherein said at least one resistor element is connected between an output terminal of said emitter-coupled logic emitter follower circuit and the transmission line.
An emitter-coupled logic balanced signal transmission circuit for transmitting an ECL signal over a transmission line, the signal transmission circuit comprising:
- a line driver circuit connected to the transmission line for driving the transmission line;
- a power supply connected to said line driver circuit to provide a power source thereto;
- and
- at least one resistor element included in said line driver circuit and constructed so as to provide a low impedance when the power supply is turned on and a high impedance when the power supply is turned off and thereby causing said line driver circuit to provide a high output impedance to the transmission line when the power supply is turned off,
- said line driver circuit including a differential amplifier and an emitter follower circuit connected thereto for outputting a signal to the transmission line, said at least one resistor element being connected between an output terminal of said emitter follower circuit and the transmission line.
Dependencies are inferred from the claim text.