Analog/digital PWM control circuit of a winding

摘要

A feedback control circuit of the current in a load constituted by a winding in series to a current sensing resistor, coupled to a full-bridge output stage, an amplifier (SENSE_AMPL) coupled to the terminals of the sensing resistor, a controller fed with the output of the amplifier and with a voltage reference (VIN) and producing a correction signal, has a PWM converter for generating a pair of control signals (IN+, IN-) that comprises an up/down counter producing a count value and a logic circuitry that produces the complement to two of the correction signal. A pair of registers first (D_IN+) and second (D_IN-) are coupled to the outputs of the controller and of the logic circuitry. A first comparator (COMP_1) coupled to the outputs of the counter and of the first register (D_IN+) produces the first control signal (IN+) if the count signal exceeds the value stored in the first register (D_IN+) and a second comparator (COMP_2) coupled to the counter and to the second register (D_IN-), produces the second control signal (IN-) if the count signal overcomes the value stored in the second register (D_IN-). <IMAGE>