Patent ID: 7885361
Filing Date: 2011-02-08
Classification: H03L,H04L

Abstract:
1. A method for tuning a phase shifter, comprising: receiving a first signal having a 50% duty cycle at a first input of a first differential stage of the phase shifter and at a first input of a second differential stage of the phase shifter; receiving a second signal having a 50% duty cycle at a second input of the first differential stage of the phase shifter and at a second input of the second differential stage of the phase shifter; generating, using the first differential stage, an up-pulse; providing the up-pulse from the first differential stage to a first capacitor; generating, using the second differential stage, a down-pulse; and providing the down-pulse from the second differential stage to a second capacitor, wherein generating the up-pulse comprises generating the up-pulse to have 50% duty cycle if the second signal and the first signal are in phase with each other and wherein generating the down-pulse comprises generating the down-pulse to have a 50% duty cycle if the second signal and the first signal are in phase with each other, wherein generating the up-pulse comprises generating the up-pulse to have greater than a 50% duty cycle if the second signal lags the first signal by increasing a duration of the up-pulse by an amount proportional to a phase difference between the first signal and the second signal and wherein generating the down-pulse comprises generating the down-pulse to have a 50% duty cycle if the second signal lags the first signal, and wherein generating the down-pulse comprises generating the down-pulse to have greater than a 50% duty cycle if the second signal leads the first signal by increasing the duration of the down-pulse by an amount proportional to a phase difference between the first signal and the second signal and wherein generating the up-pulse comprises generating the up-pulse to have a 50% duty cycle if the second signal leads the first signal.