Charging control circuit

摘要

The present invention discloses a charge control circuit for supplying power from an external power source to a first common node and charging a second common node from the first common node. A regulator circuit is coupled between the external power source and the first common node, and a transistor is coupled between the first common node and the second common node. The present invention detects an operation parameter of the transistor and controls an internal voltage source to generate a non-predetermined voltage difference accordingly. When the sum of the voltage at the second common node and the non-predetermined voltage is equal to or higher than the reference voltage, the voltage at the first common node is regulated to a level higher than the voltage at the second common node, and the transistor is in an optimum conductive state.

主权项

1. A charge control circuit for supplying power from an external power source to a first common node and charging a second common node from the first common node, a regulator circuit being coupled between the external power source and the first common node, and a first transistor being coupled between the first common node and the second common node, the charge control circuit comprising:
a detecting device for detecting an operation parameter of the first transistor and controlling an internal voltage source to generate a non-predetermined voltage difference accordingly; a charge control unit for controlling a conductive state of the first transistor; and a first error amplifier circuit for generating and transmitting a control signal to the regulator circuit according to a voltage at the first common node, a sum of a voltage at the second common node and the non-predetermined voltage difference, and a reference voltage; whereby when the sum of the voltage at the second common node and the non-predetermined voltage difference is smaller than the reference voltage, the voltage at the first common node is regulated to a predetermined level; and when the sum of the voltage at the second common node and the non-predetermined voltage difference is equal to or higher than the reference voltage, the voltage at the first common node is regulated to a level higher than the voltage at the second common node, and the first transistor is in an optimum conductive state.