A driver for a Light Emitting Diode (LED) comprises a main circuit of a Ringing Choke Converter (RCC), a driving circuit of the RCC, and a first adjustment module. The main circuit of the RCC comprises: an energy input terminal, an energy output terminal, and a control terminal. The energy input terminal is configured to receive an input voltage. The energy output terminal is coupled to the LED and configured to provide an output current to the LED. The control terminal is configured to receive a driving signal. The driving circuit comprises a driving signal output terminal coupled to the control terminal, and is configured to provide the driving signal to the main circuit via the driving signal output terminal. The first adjustment module is coupled between the energy input terminal and the driving signal output terminal, and is configured to adjust the driving signal according to the input voltage.

A two-stage driver supplies current to a light emitting diode (LED) load. The driver includes a first stage and a second stage. The second stage is configured to generate a desired current through the LED load. The second stage has a flyback converter having a flyback transformer with a primary winding and a secondary winding. The primary winding is turned on and off by a gating signal. An induced voltage in the secondary winding rings when a current in the secondary winding is discharged. The flyback converter is configured to turn on the primary winding only during a detected valley in the ringing of the secondary winding. If the primary winding is turned on during a detected valley different from the previous detected valley, a valley jump is detected and the switching frequency is adjusted.

A two-stage driver supplies current to a light emitting diode (LED) load. The driver includes a first stage and a second stage. The second stage is configured to generate a desired current through the LED load. The second stage has a flyback converter having a flyback transformer with a primary winding and a secondary winding. The primary winding is turned on and off by a gating signal. An induced voltage in the secondary winding rings when a current in the secondary winding is discharged. The flyback converter is configured to turn on the primary winding only during a detected valley in the ringing of the secondary winding. If the primary winding is turned on during a detected valley different from the previous detected valley, a valley jump is detected and the switching frequency is adjusted.

A display apparatus with a power supply circuit is provided. The power supply circuit is connected with a light emitting diode (LED) drive circuit, a filter circuit and a feedback circuit in the display apparatus. The power supply circuit includes a fixed-voltage power supply element and a variable-voltage power supply element, and the fixed-voltage power supply element is superposed on the variable-voltage power supply element and configured to supply power to the LED drive circuit in a stepped manner; and a controller is configured to control a voltage of the variable-voltage power supply element according to a variation of the output voltage feedback from the feedback circuit.

A display apparatus with a power supply circuit is provided. The power supply circuit is connected with a light emitting diode (LED) drive circuit, a filter circuit and a feedback circuit in the display apparatus. The power supply circuit includes a fixed-voltage power supply element and a variable-voltage power supply element, and the fixed-voltage power supply element is superposed on the variable-voltage power supply element and configured to supply power to the LED drive circuit in a stepped manner; and a controller is configured to control a voltage of the variable-voltage power supply element according to a variation of the output voltage feedback from the feedback circuit.

A power converter includes a primary winding and multiple output windings to provide multiple independently controlled and regulated outputs with a common return line. The outputs are coupled to independently regulate constant current, constant voltage, or both constant current and constant voltage outputs. A secondary control block is coupled to control a synchronous rectifier switch coupled to the common return line to synchronize switching with a primary side power switch to provide complementary conduction of the primary winding and the multiple output windings. A plurality of controlled power pulse switches is coupled to the multiple output windings. A request of a power pulse from each of the outputs is transferred through the secondary control block to a primary switch control block to turn on the primary side power switch to transfer a power pulse to the multiple output windings and through controlled power pulse switches to the outputs.

A power converter includes a primary winding and multiple output windings to provide multiple independently controlled and regulated outputs with a common return line. The outputs are coupled to independently regulate constant current, constant voltage, or both constant current and constant voltage outputs. A secondary control block is coupled to control a synchronous rectifier switch coupled to the common return line to synchronize switching with a primary side power switch to provide complementary conduction of the primary winding and the multiple output windings. A plurality of controlled power pulse switches is coupled to the multiple output windings. A request of a power pulse from each of the outputs is transferred through the secondary control block to a primary switch control block to turn on the primary side power switch to transfer a power pulse to the multiple output windings and through controlled power pulse switches to the outputs.

A power supply for an LED lighting unit. The power supply comprises two power converters, either of which may provide the power to be drawn by components of the LED lighting unit. In particular, a controller of the power supply controls which power converter converts a mains power supply to a power level for a connected LED lighting unit. The two power converters are designed to be efficient when providing different power levels.

A power supply for an LED lighting unit. The power supply comprises two power converters, either of which may provide the power to be drawn by components of the LED lighting unit. In particular, a controller of the power supply controls which power converter converts a mains power supply to a power level for a connected LED lighting unit. The two power converters are designed to be efficient when providing different power levels.

A solid-state light emitter power supply includes a first rectifier circuit, a second rectifier circuit, a power factor correction (PFC) stage, a first flyback converter, a second flyback converter, and a microcontroller. The rectifier circuits are configured to receive phase-cut signals from respective dimmer circuits as inputs and output respective phase-cut rectified power signals. The PFC stage is configured to receive a sum of the phase-cut rectified power signals as input and output a power-factor corrected electrical power to the flyback converters. The flyback converters are connected in parallel and are configured to power respective loads including a respective solid-state light emitter. The microcontroller is configured to receive signals derived from the phase-cut signals as inputs and to output respective pulse-width modulation (PWM) control signals to each of the flyback converters. Each flyback converter receives a respective power output portion of the power-factor corrected electrical power in accordance with the respective PWM control signals.