High accuracy low temperature drift high-side current sensing hardware and method

A circuit, comprising:

• a tank capacitor coupled between first and second nodes;
• a sense resistor having a first terminal coupled to the first node and a second terminal coupled to a regulator input;
• a switching circuit having first and second inputs respectively coupled to the first and second terminals of the sense resistor;
• a gain stage having first and second inputs capacitively coupled to first and second outputs of the switching circuit;
• an analog to digital converter (ADC) receiving the output of the gain stage, and first and second differential voltages;
• and
• a reference voltage generator comprising a temperature independent current source coupled to source current to a reference resistor, wherein the first differential reference voltage is formed across the reference resistor;
• wherein the switching circuit comprises:
• a first switch selectively coupling the first input of the switching circuit to the first output of the switching circuit in response to a logical OR of first and second switch control signals;
• a second switch selectively coupling the first input of the switching circuit to the second output of the switching circuit in response to a logical OR of the first switch control signal and a third switch control signal;
• a third switch selectively coupling the second input of the switching circuit to the second output of the switching circuit in response to the second switch control signal;
• a fourth switch selectively coupling the second input of the switching circuit to the first output of the switching circuit in response to the third switch control signal.