Patent ID: 8405407

Claim:
A current measurement circuit for measuring a current, comprising: a current integrating unit with a capacitor array, integrating the current on the capacitor array to obtain an input voltage; a comparator coupled to the current integrating unit, comparing the input voltage with a specific voltage to generate a compare output; and a control unit coupled to the comparator and the current integrating unit, generating a control signal to apply to the capacitor array of the current integrating unit according to the compare output, wherein a magnitude of the current is obtained according to the control signal and the capacitance of the capacitor array, wherein the capacitor array comprises a plurality of capacitors coupled between the comparator and the control unit, and capacitances of the capacitors are binary weighted, wherein the comparator comprises: a first inverter, receiving a reset signal; a second inverter coupled to an output of the first inverter; a third inverter coupled between the current integrating unit and the control unit; a switch connected with the third inverter in parallel, having a control terminal coupled to the output of the first inverter, and correcting offset of the third inverter when the switch is turned on by the reset signal during a reset state; and a transistor, having a gate coupled to an output of the second inverter, a drain coupled to an input of the third inverter and a source coupled to the input of the third inverter, wherein the specific voltage is a threshold voltage of the inverter.