Patent ID: 7755328
Filing Date: 2010-07-13
Classification: H02J

Abstract:
1. A charging circuit for charging a load component, the charging circuit comprising: a power supply unit comprising a pulse width modulation circuit and a power output terminal configured to output a direct current supply; a feedback circuit comprising an amplifier comparator, a constant voltage circuit, a transistor, and an optoelectrical coupler, the constant voltage circuit being configured to generate a reference voltage and apply the reference voltage to an inverting terminal of the amplifier comparator, an output terminal of the amplifier comparator being connected to a base of the transistor to control the transistor, an emitter of the transistor being grounded, a collector of the transistor being coupled to the optoelectrical coupler, the optoelectrical coupler being connected to the pulse width modulation circuit; and a sampling resistor comprising a current sampling terminal connected to a non-inverting terminal of the amplifier comparator, and a grounded terminal, the current sampling terminal also being connected to the power output terminal via the load component; wherein the charging circuit is configured such that when the load component is coupled to the direct current supply of the charging circuit and a direct current traveling through the load component changes, the amplifier comparator generates a feedback signal and applies the feedback signal to the pulse width modulation circuit via the transistor and the optoelectrical coupler, and the pulse width modulation circuit adjusts the direct current supply output from the power output terminal according to the feedback signal to stabilize the direct current traveling through the load component.