External zero-crossing detection circuit for LED drivers
AssigneeErp Power, LLC
InventorsMichael Archer, Louis Chen
Life of this patent
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Abstract
A zero-crossing detection circuit coupled to a power factor correction (PFC) controller of a power supply system includes a zener diode configured to generate a zener reference signal, and an operational amplifier coupled to the zener diode and configured to receive the zener reference signal and a feedback signal corresponding to an output current of the power supply system, and to generate a zero-crossing signal to a zero-crossing input of the PFC controller.
Claims20
A zero-crossing detection circuit coupled to a power factor correction (PFC) controller of a power supply system, the zero-crossing detection circuit comprising:
- a zener diode configured to generate a zener reference signal;
- and
- an operational amplifier coupled to the zener diode and having an input terminal directly coupled to the PFC controller, the operational amplifier being configured to receive the zener reference signal and a feedback signal corresponding to an output current of the power supply system, and to generate a zero-crossing signal for transmission to a zero-crossing input of the PFC controller, the zero-crossing signal being configured to variably control an off-time of the PFC controller,
- wherein the PFC controller is configured to reduce a total harmonic distortion (THD) of the power supply system.
A power supply system comprising:
- a power factor correction (PFC) controller comprising a zero-crossing input, and configured to generate a gate control signal based on a zero-crossing signal received at the zero-crossing input to reduce a total harmonic distortion (THD) of the power supply system;
- and
- a zero-crossing detection circuit coupled to the PFC controller, the zero-crossing detection circuit comprising:
- a zener diode configured to generate a zener reference signal;
- and
- an operational amplifier coupled to the zener diode and having an input terminal directly coupled to the PFC controller, the operational amplifier being configured to receive the zener reference signal and a feedback signal corresponding to an output current of the power supply system, and to generate the zero-crossing signal to variably control an off-time of the PFC controller.
Dependencies are inferred from the claim text.