Bi-directional current sensor

摘要

A bidirectional current sensor circuit can be configured to generate a scaled version of a load current using a first transistor from a power regulator output stage and a second transistor that can be a mirror or scaled version of the first transistor. A trim circuit can be provided to correct gain errors under current sinking or current sourcing conditions. In an example, the bidirectional current sensor circuit can be configured to detect a polarity or a magnitude of a current signal that is used to operate a thermoelectric device.

主权项

1. A bidirectional current sensor circuit to sense a load current provided by a complementary output circuit, the complementary output circuit including first and second transistors coupled at an output node and configured to provide or receive the load current at the output node, the load current comprising respective first or second currents at respective first or second reference nodes through respective ones of the first or second transistors, the current sensor circuit comprising:
a first mirror transistor, coupled between the first reference node and a mirror node, the first mirror transistor comprising a scaled version of the first transistor; a second mirror transistor, coupled between the mirror node and the second reference node, the second mirror transistor comprising a scaled version of the second transistor; and a buffer circuit configured to drive a voltage at the mirror node to substantially match a voltage at the output node, wherein the buffer circuit provides a signal indicative of a magnitude or a polarity of the load current when the voltage at the output node and the voltage at the mirror node are about the same magnitude.