Method and apparatus for conserving energy stored in bypass capacitors during dynamic power collapse

Abstract

Energy stored in bypass capacitors in a portable device may be conserved when a power supply voltage is collapsed reducing the need to recharge the bypass capacitors and thereby saving power. A bypass charge saving circuit includes a bypass capacitor, a power source having an output supply voltage that is switchable, a load circuit of the portable device coupled to the output supply voltage, and the bypass capacitor operable to filter the output supply voltage. Also, a transistor switch is operable to decouple a discharge path of the bypass capacitor through the load circuit when the transistor switch is disabled. Further, a controller is operable to turn off the output supply voltage and the transistor switch in order to conserve energy stored in the bypass capacitor.