Patent ID: 7170266
Filing Date: 2007-01-30
Classification: H03F

Abstract:
1. A circuit for pulse width modulation, comprising: a first impedance circuit that is arranged to provide a first current from an input voltage; a second impedance circuit that is arranged to provide a feedback current from a feedback voltage that is based, in part, on a pulse width modulation output signal, wherein the first and second impedance circuits are coupled together at a first node such that an amplifier input current is provided at the first node; an amplifier circuit that is arranged receive the amplifier input current and a reference voltage, to provide a comparator input voltage such that a rate of change of the comparator input voltage is based on the amplifier input current, and to adjust a voltage at the first node such that the voltage at the first node is substantially equal to the reference voltage; and a comparator circuit that is arranged to provide the pulse modulation output signal in response to a comparison of a threshold signal and the comparator input voltage.