US Patent 11506696 Hold-up capacitance health measurement with current leakage detection

Circuits for measuring a leakage current of one or more capacitors coupled to a power supply line that powers an apparatus, such as a storage device, are disclosed. In one embodiment, the circuit includes first and second resistors between the power supply line, and first and second respective switches to ground. A controller may charge the voltage line to a first voltage. Thereafter, the controller discharges the first voltage to a second voltage via the first resistor during a first identified time. After recharging the voltage line, the controller then discharge the first voltage to the second voltage via at least the second resistor during a second identified time. The controller determines the parasitic resistance using the first and second identified times, and then the leakage current from the parasitic resistance. Removing the leakage current factor from subsequent measurements can greatly improve testing accuracy and can avoid false positives in the testing process that would otherwise require removal of drives or other systems that are working properly.