Patent ID: 6385067
Filing Date: 2002-05-07
Classification: H02M

Abstract:
A feedback control circuit for current flowing in a load comprising a winding in series with a current sensing resistor, the feedback control circuit comprising:a full-bridge stage coupled to the load, and for being driven by first and second control signals; an amplifier having a noninverting input and an inverting input for respectively coupling to the sensing resistor, and for producing an amplified replica voltage of a voltage drop on the sensing resistor; a controller for receiving an output of said amplifier and a reference voltage representing a desired value of the current in the load, and for producing a correction signal; a pulse width modulating (PWM) converter for receiving the correction signal from said controller and a clock signal, and for generating the first and second control signals, said PWM converter comprising an up/down counter receiving the clock signal, and for producing a count value, a logic circuit for receiving the correction signal from said controller, and for producing a twos-complement signal based on the correction signal, first and second registers respectively receiving the correction signal from said controller and the two's-complement signal from the logic circuit, a first comparator coupled to said up/down counter and said first register for producing the first control signal when the count value exceeds a value stored in the first register, and a second comparator coupled to said up/down and said second register for producing the second control signal when the count value exceeds a value stored in the second register.