Abstract: There is provided a charging apparatus that, even when an AC adapter is connected and there is heavy load, makes it possible to reduce heat produced due to the power loss of a control transistor, reduce cost and area for implementation, and improve safety. Charging apparatus 100 has: P-channel MOS transistors M1 and M2 that control charging current; current detecting resistance Rs that is connected to current output terminals of P-channel MOS transistors M1 and M2 and detects the charging current; switch 130 that is arranged on a path that bypasses current detecting resistance Rs; and load 300 that receives power supply from battery 200 without involving current detecting resistance Rs when switch 130 is closed.

Abstract: There is provided a charging apparatus that, even when an AC adapter is connected and there is heavy load, makes it possible to reduce heat produced due to the power loss of a control transistor, reduce cost and area for implementation, and improve safety. Charging apparatus 100 has: P-channel MOS transistors M1 and M2 that control charging current; current detecting resistance Rs that is connected to current output terminals of P-channel MOS transistors M1 and M2 and detects the charging current; switch 130 that is arranged on a path that bypasses current detecting resistance Rs; and load 300 that receives power supply from battery 200 without involving current detecting resistance Rs when switch 130 is closed.

Abstract: A pulse charger perform fine control of a charging current according to a battery voltage. The pulse charger includes a switch that turns a charging current from an external power supply on and off. A current detector detects charging current using a current detection resistor. An averaging section averages the output of the current detector. A reference voltage generator generates a reference signal. A comparison section compares an output voltage from the averaging section with the reference signal. A controller controls the switch section based on the output of comparison section. The comparison section includes a comparator that has a hysteresis width. The comparison section outputs an inverse signal between reference voltage and the hysteresis width. The controller performs on/off control of the switch section based on an inverse signal from the comparator and sets an average value of the charging current to a target constant value.