Patent ID: 8351166

Claim:
A capacitor tester comprising: a current mirror configured to selectively sense a leakage current of at least one capacitor; a comparison unit comprising a transimpedance amplifier and a voltage comparator configured to determine if the leakage current is above a threshold value; a timer unit configured to schedule sensing by the current mirror; a heater proximate to at least one of the plurality of capacitors, the heater configured to selectively heat at least one capacitor during sensing; and a switch unit to disconnect the at least one capacitor from a source if the leakage current is above the threshold value; wherein the current mirror comprises a first pFET including a first source, a first gate, and a first drain, the first source coupled to a supply voltage, the first gate coupled to a normal signal, and the first drain coupled to the at least one capacitor; wherein the current mirror further comprises a second pFET including a second source, a second gate, and a second drain, the second source coupled to the normal signal, and the second gate coupled to the timer unit; wherein the current mirror further comprises a third pFET including a third source, a third gate, and a third drain, the third source coupled to the first drain, the third gate coupled to the timer unit, and the third drain coupled to the first gate and the second source; and wherein the current mirror further comprises a secondary-side pFET including a secondary-side source, secondary-side gate, and secondary-side drain, the secondary-side source coupled to the supply voltage, the secondary-side gate coupled to the second drain, and the secondary-side drain coupled to the comparison unit.