Patent ID: 8362750

Claim:
An apparatus for controlling a charging circuit to charge a capacitor, the apparatus comprising: a first detector coupled to the charging circuit, the first detector for detecting a voltage level at a first time during charging the capacitor and generating a first indication value corresponding to the voltage level at the first time, wherein the voltage level corresponds to an output voltage of the charging circuit; a second detector coupled to the charging circuit, the second detector for detecting the voltage level at a second time after the first time and generating a second indication value corresponding to the voltage level at the second time during charging the capacitor; and a controller coupled to the charging circuit, the first detector, and the second detector, the controller for receiving the first and second indication values, and further for generating a control signal according to the first and second indication values for turning the charging circuit off, wherein the controller generates the control signal to disable the charging circuit when the first indication value is greater than the second indication value.