Patent ID: 8796998

Claim:
A method for sensing a bidirectional current without requiring an external sense resistor, comprising the following steps: (1) providing of a power transistor, a first sense transistor, a second sense transistor, a first control circuit, a second control circuit, and an analog-to-digital converter (ADC); (2) mirroring to the first sense transistor a small fraction of a current to be sensed flowing in a first direction through the power transistor; (3) regulating a voltage drop of the current flowing in the first direction over the power transistor and over the first sense transistor to be the same by the first control circuit; (4) measuring a feedback current of the voltage drop regulation of the current flowing in the first direction by the analog-to digital converter; (5) mirroring to the second sense transistor a small fraction of a current to be sensed flowing in a second direction through the power transistor; (6) regulating a voltage drop of the current flowing in the second direction over the power transistor and over the second sense transistor to be the same by the second control circuit; and (7) measuring a feedback current of the voltage drop regulation of the current flowing in the second direction by the analog-to digital converter.