Switching mode power supply
AssigneeFairchild Korea Semiconductor Ltd.
InventorsJin-Ho Choi, Dong-Young Huh, Yong-Chul Ryu
Life of this patent
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Abstract
A switching mode power supply (SMPS) is presented to compensate for variations of maximum output power caused by variations of input power. The output power varies according to variations of input power because of a propagation delay of the SMPS. To compensate for the propagation delay, a reference voltage for turning off a switching MOS transistor is differently established depending on the input voltage. The variation of maximum output power according to the input voltage is prevented by differentiating the turned-off time of the reference voltage for turning off a main switch, such as a switching MOS transistor according to the input voltage.
Claims20
A switching mode power supply (SMPS), comprising:
- a power supply including a main switch coupled to a primary coil of a transformer, configured to supply power to a secondary coil of the transformer according to an operation of the main switch;
- an input voltage sensor, configured to sense a level of an input voltage;
- and
- a switching controller, configured to compare a first voltage, combined from the sensed input voltage and a feedback voltage, with a second voltage which corresponds to the current flowing through the main switch, and to output a corresponding control signal for controlling a duty of the main switch.
A switching mode power supply (SMPS) comprising:
- a power supply including a main switch coupled to a primary coil of a transformer, and supplying power to a secondary coil of the transformer according to an operation of the main switch;
- an input voltage sensor, configured to sense a level of an input voltage;
- a feedback circuit, configured to generate a feedback voltage which corresponds to a voltage output by the secondary coil of the transformer;
- and
- a switching controller, configured to compare a first voltage, combined from the sensed input voltage and the feedback voltage, and a second voltage which corresponds to the current flowing through the main switch, and to output a corresponding control signal for controlling a duty of the main switch.
A switching mode power supply (SMPS) comprising:
- a power supply including a main switch coupled to a primary coil of a transformer, configured to supply power to a secondary coil of the transformer according to an operation of the main switch;
- an input voltage sensor configured to sense an input voltage;
- and
- a switching controller configured to control a peak current flowing through the main switch to be constant irrespective of the sensed input voltage and a delay time, wherein the power supply has a delay time.
Dependencies are inferred from the claim text.