ISOLATED POWER SUPPLY CIRCUIT WITH PROGRAMMABLE FUNCTION AND CONTROL METHOD THEREOF

摘要

The present invention provides an isolated power supply circuit with a programmable function and a control method thereof. The isolated power supply circuit includes: a transformer circuit, a power switch circuit, a control circuit, and a discharge circuit. The control circuit generates an operation signal and a bleeding signal according to a setting signal. The discharge circuit is coupled to an output node, for generating a discharging current. When the programmable output voltage at the output node switches between different predetermined levels, in a transition period, the bleeding signal adjusts the discharging current to discharge the output node, such that the transition period is shortened.

主权项

1. An isolated power supply circuit with a programmable function, comprising:
a first transformer circuit, which includes a primary winding and a secondary winding, wherein the primary winding receives an input voltage and the secondary winding generates a programmable output voltage at an output node; a power switch circuit, which is coupled to the primary winding, the power switch circuit operating according to an operation signal to convert the input voltage to the programmable output voltage; a discharge circuit, which is coupled to the output node, for generating a discharging current according to a bleeding signal; and a control circuit, which is coupled to the power switch circuit and the discharge circuit, for generating the operation signal and the bleeding signal at least according to a setting signal; wherein the control circuit adjusts the operation signal according to the setting signal, such that the programmable output voltage switches from a first predetermined level to a second predetermined level, and in a transition period when the programmable output voltage switches from the first predetermined level to the second predetermined level, the control circuit determines the bleeding signal whereby the discharge circuit adjusts the discharging current, so that the discharging current discharges the programmable output voltage.