SINGLE STAGE LED DRIVER SYSTEM, CONTROL CIRCUIT AND ASSOCIATED CONTROL METHOD

摘要

A light-emitting element driver system has a power conversion circuit, a second switch and a control circuit, the power conversion circuit has a primary circuit, a transformer, a first rectified circuit and a second rectified circuit, the second rectified circuit provides a first signal, the second switch has a first terminal coupled to an output terminal of the first rectified circuit and a second terminal to provide a second signal, when a dimming signal is in a first state, the control circuit provides a first control signal to control the power conversion circuit based on the first signal, and meanwhile provides a second control signal to control the second switch based on the second signal.

主权项

1. A light-emitting element driver system, comprising:
a power conversion circuit, configured to provide a first signal, wherein the power conversion circuit comprising:
a primary circuit, comprising a first switch, the primary circuit is configured to provide an AC signal;a transformer, comprising a primary winding, a first secondary winding and a second secondary winding, the primary winding is coupled to the primary circuit to receive the AC signal;a first rectified circuit, coupled to the first secondary winding and having an output terminal;a second rectified circuit, coupled to the second secondary winding and having an output terminal configured to provide the first signal; a second switch, having a first terminal and a second terminal, wherein the first terminal is coupled to the output terminal of the first rectified circuit and the second terminal is configured to provide a second signal; and a control circuit, configured to provide a first control signal to control the power conversion circuit and a second control signal to control the second switch; wherein when a dimming signal is in a first state, the first signal is regulated by turning ON and turning OFF the first switch, meanwhile the second signal is regulated by turning ON and turning OFF the second switch.