Patent ID: 8698472
Filing Date: 2014-04-15
Classification: H02M,H03K,Y02B

Abstract:
1. An adjustable driver voltage source for a switching power supply including a power switch and a driver for providing a control signal to switch the power switch, the adjustable voltage source comprising: a linear regulator providing a driver voltage to the driver that determines a voltage level of the control signal, the linear regulator comprising: a transistor connected to a voltage output terminal of the linear regulator; an operational amplifier connected to the transistor, controlling a current of the transistor according to a feedback signal to determine the driver voltage; and a feedback loop connected to the operational amplifier and the voltage output terminal of the linear regulator, generating the feedback signal according to the driver voltage; and a modulator connected to the linear regulator, responsive to a loading change of the switching power supply to change the feedback signal to adjust the driver voltage; wherein the feedback loop comprises: a resistor serially connected to the transistor; and a feedback terminal between the resistor and the transistor, for providing the feedback signal; wherein the modulator comprises: a current sensor sensing a load current of the switching power supply to generate a current sense signal; and a transconductance amplifier connected to the current sensor and the linear regulator, for sinking a current from the feedback terminal according to a difference value between the current sense signal and a setting value so as to adjust the driver voltage.