Other

Linfinity Microelectronics

Minhui Wang

Dean A Wallace

A Norton equivalent implementation of a fail safe bias circuit drives a bus to provide a stable bias voltage which is not affected by an output impedance of a current source. The Norton equivalent implementation has first current source, a bias resistor and a current sink in series. The bias resistor is connected across a pair of differential bus lines so that the current flowing through the bias resistor causes a bias voltage to be generated between the bus lines. The current to the bias resistor is selectively switched on and off to control the bias voltage so that the bias voltage can be turned off during high speed data transfers on the bus.

Fail safe bias system for a tri-state bus

A monolithic electronic circuit breaker having an input terminal, an output terminal, and a controllable impedance connected between the input and output terminals. A current sensor generates a current magnitude signal indicative of the current flowing between the input and output terminals. In one embodiment, an over-current circuit generates an over-current signal when the current magnitude signal exceeds a threshold. In response to at least a first occurrence of the over-current signal, a control circuit controls the controllable impedance so as to reduce current through the controllable impedance for a period of time, and then automatically increase current through the controllable impedance. Further, in response to an N.sup.th (N&gt;1) occurrence of the over-current signal, the control circuit controls the controllable impedance so as to reduce current through the controllable impedance and does not thereafter automatically increase current through the controllable impedance. In another embodiment, an over-current and control circuit controls the controllable impedance so as to reduce current through the controllable impedance when the current magnitude signal exceeds a threshold. A first time period after current through the controllable impedance is reduced, the over-current and control circuit automatically increases current through the controllable impedance by gradually reducing the impedance of the controllable impedance over a second time period. Thus, the impedance at the output terminal slowly transitions from a high impedance state to a low impedance state.

Growing community of inventors

Diamond Bar, CA, United States of America

Minhui Wang