High speed PWM without linearity compromise at extreme duty cycles

U.S. Patent Number: 5379321

Abstract: A circuit for reducing the amount of instability in a pulse width modualtion circuit by providing a minimum amount of overdrive after the crossover point between a ramp and a voltage threshold level, and a constant amount of discharge time between the end on one ramp and the beginning of the next. Also, a feedback loop is privided to increase or decrease the slope to compensate for a decreasing or increasing amount of time between clock pulses, to maintain the duty cycle of the output when the clock frequency varies.

Inventors: Girmay; Girmay K. (Mirada, CA)

Assignee: Xerox Corporation (Stamford, CT)

Application Number: 07/966,912

Issued: 1995-01-03

Expired: 2007-01-03

Classes: 375/358 ; 327/172; 327/175; 370/212; 375/317

Field of search: 375/22-24,76 370/8-10 329/112 332/109 307/260-268 340/870.23,870.24

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