Abstract: LED driving circuit includes a first current source, a second current source, a current sensing circuit, and a control circuit. The first current source, coupled in series with a heat dissipation resistor, provides a first current path to the LED string. The second current source, coupled in parallel with the serially coupled first current source and the heat dissipation resistor, provides a second current path to the LED string. The current sensing circuit is configured to sense a current sense signal representing a current flowing through the LED string. The control circuit is configured to control a current distribution of the first current path and a second current path in response to the current sense signal. When the current sense signal is greater than a threshold, a current flowing through the first current path is larger than a current flowing through the second current path.

Abstract: An LED driving system for synchronizing two LED driving integrated circuits to drive LED strings. The LED driving system sequentially activates the LED strings driven by the first LED driving integrated circuit and then outputs a downstream enabling signal from the first LED driving integrated circuit to the second LED driving integrated circuit to activate the LED strings driven by the second LED driving integrated circuit.

Abstract: A feedback control circuit in an LED driving circuit for driving a plurality of LED strings. Each LED string provides a headroom detecting voltage. The feedback control circuit has a status detecting circuit, a counting circuit and a modulating circuit. The status detecting circuit compares each headroom detecting voltage with a low headroom threshold voltage and a high headroom threshold voltage and generates an up self-status signal and a down self-status signal. The counting circuit counts or keeps unchanged and then generates a counting signal based on the up self-status signal and the down self-status signal. The modulating circuit generates a modulating signal based on the counting signal. And based on the modulating signal, the feedback control circuit generates a feedback control signal to regulate a bias voltage supplying the plurality of LED strings.

Abstract: An LED driving system with a master-slave architecture. The LED driving system has at least two LED driving circuits which both have a first status detecting circuit, a second status detecting circuit and a first feedback control circuit. The first status detecting circuit receives a plurality of headroom detecting voltages provided by a plurality of LED strings and generates at least one self-status signal. The second status detecting circuit receives a downstream feedback signal and generates at least one downstream status signal. The first feedback control circuit generates a first feedback control signal based on the at least one self-status signal and the at least one downstream status signal. The second status detecting circuit of one LED driving circuit is coupled to the first feedback control circuit of the other LED driving circuit.

Abstract: A DC-to-DC converting apparatus with communication function for a vehicle is applied to an electric vehicle or a hybrid vehicle. The electric vehicle or the hybrid vehicle includes a vehicle control system. The DC-to-DC converting apparatus with communication function for a vehicle includes a DC-to-DC converter, a control circuit is electrically connected to the DC-to-DC converter, and a system communication interface is electrically connected to the control circuit and the vehicle control system. The working status of the DC-to-DC converter is detected by the control circuit and is informed to the vehicle control system through the system communication interface. The control circuit is controlled to control the DC-to-DC converter by the vehicle control system through the system communication interface.

Abstract: A power conversion circuit includes a flyback DC-to-DC converter, a capacitor and a DC-to-AC converter. The flyback DC-to-DC converter is used for receiving an input DC voltage and converting the input DC voltage into a constant high DC voltage. The capacitor is connected to the flyback DC-to-DC converter for filtering the high DC voltage. The DC-to-AC converter is connected to the capacitor for converting the filtered high DC voltage into an output AC voltage.