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US 8,913,360 B2Granted
Controllers, power supplies and control methods
AssigneeLeadtrend Technology Corp.
InventorsKuo-Chien Huang, Ren-Yi Chen
Life of this patent
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Abstract
Power supplies together with related over voltage protection methods and apparatuses. A power supply has a transformer including a primary winding and an auxiliary winding. A power switch is coupled to the primary winding and a sensing resistor coupled between the power switch and a grounding line. A multi-function terminal of a controller is coupled to the sensing resistor. A diode and a first resistor is coupled between the auxiliary winding and the multi-function terminal.
Claims2
A controller for controlling a power switch of a power supply providing an output voltage, the controller comprising:
- a multi-function terminal;
- a delay time generator for providing a delay time after the power switch is turned off;
- an over voltage detection circuit for comparing a voltage of the multi-function terminal with a reference voltage after the delay time in order to trigger an over voltage signal indicating the output voltage is over a predetermined value;
- and
- a gate controller for turning off the power switch according to the voltage of the multi-function terminal when the power switch is turned on;
- wherein when the power switch is turned on, the voltage of the multi-function terminal corresponds to a current through the power switch;
- wherein the over voltage detection circuit comprises:
- a comparator for comparing the voltage of the multi-function terminal with the reference voltage to trigger a relay signal;
- and
- a blocking unit for blocking the relay signal during the delay time and for taking the relay signal as the over voltage signal in a predetermined time after the delay time.
7 more elements
Dependencies are inferred from the claim text.