Abstract: A switching circuit with reverse current prevention for use in a Buck converter includes a power switch coupled to a coupling node, which is an interconnection point of a power switch, an inductor and a freewheeling diode of the Buck converter. The inductor is coupled between the coupling node and an output of the Buck converter, and the freewheeling diode is coupled between coupling node and an output return of the Buck converter. A controller is coupled to receive a feedback signal to control switching of the power switch to regulate a transfer of energy from the input to the output of the Buck converter. A reverse current prevention circuit is coupled to detect a reverse current condition of the power switch to generate an inhibit signal to inhibit the power switch from receiving a drive signal to prevent a reverse current through the power switch.

Abstract: A bleeder circuit emulator for use in a power converter to compensate and increase the current demand from the Triac dimmer above its holding current. The circuit includes an input voltage modifier and a leading edge dimming detection circuit. The input voltage modifier receives an input voltage signal that is representative of a magnitude of an input voltage of the power converter and selectively provides a modified input voltage signal to an input of a controller in response to receiving a control signal. The modified input voltage signal is representative of a value that is less than the magnitude of the input voltage. The leading edge dimming detection circuit generates the control signal to engage the input voltage modifier to generate the modified input voltage signal in response to detecting leading edge dimming at an input of the power converter.

Abstract: A bleeder circuit for use with a driver circuit having input circuitry that receives an ac input signal and outputs a rectified voltage signal at a positive terminal. The driver circuit further including converter and output circuitry operably coupled to a plurality of light-emitting diodes (LEDs). The bleeder circuit including a first resistor having a first terminal coupled to the positive terminal, and a heat sensor positioned to detect an increase in temperature of the first resistor. The heat sensor produces a heat sense signal in response to the temperature increase. A bleeder heat controller is coupled to receive the heat sense signal and produce a heat control signal in response thereto. A switching device controls a bleeder current flowing through the first resistor. The switching device receives the heat sense signal, which turns the switching device off when the temperature of the first resistor exceeding a predetermined threshold.

Abstract: A switching circuit with reverse current prevention for use in a Buck converter includes a power switch coupled to a coupling node, which is an interconnection point of a power switch, an inductor and a freewheeling diode of the Buck converter. The inductor is coupled between the coupling node and an output of the Buck converter, and the freewheeling diode is coupled between coupling node and an output return of the Buck converter. A controller is coupled to receive a feedback signal to control switching of the power switch to regulate a transfer of energy from the input to the output of the Buck converter. A reverse current prevention circuit is coupled to detect a reverse current condition of the power switch to generate an inhibit signal to inhibit the power switch from receiving a drive signal to prevent a reverse current through the power switch.

Abstract: A power converter includes an energy transfer element, a power switch, a controller and a leading edge dimming detection circuit. The controller is coupled to control switching of the power switch to regulate the output of the power converter by controlling a transfer of energy through the energy transfer element. The leading edge dimming detection circuit is coupled to generate a control signal in response to detecting leading edge dimming at the input of the power converter. In one aspect, the leading edge dimming detection circuit detects the leading edge dimming and then generates a control signal to engage a compensator which maintains the input current of the power converter to be equal to or greater than a minimum current. In another aspect, the leading edge dimming detection circuit detects and reutilizes the turn-on current spike energy of a leading edge dimmer.

Abstract: Circuitry for damping transitions in an input current of a power converter includes a transistor with a control terminal coupled to receive an impedance control signal and main terminals coupled to variably impede the input current of the power converter in response to the impedance control signal. An impedance control circuit is coupled across input rails of the power converter to provide the impedance control signal. The impedance control circuit includes a first current conduction path coupling the control terminal to a first of the input rails of the power converter, and a second current conduction path coupling the control terminal to a second of the input rails of the power converter. The second of the input rails of the power converter is coupled to the main terminals of the transistor.

Abstract: A bleeder circuit for use in a power supply of a lighting system includes a first terminal to be coupled to a first input of the power supply. A second terminal is to be coupled to a second input of the power supply. An edge detection circuit is coupled between the first and second terminals of the bleeder circuit. The edge detection circuit is coupled to output an edge detection signal in response to an input signal between the first and second inputs. A variable current circuit is coupled to the edge detection circuit and coupled between the first and second terminals of the bleeder circuit. The variable current circuit is coupled to conduct a bleeder current between the first and second terminals of the bleeder circuit in response to the edge detection signal.

Abstract: A bleeder circuit emulator for use in a power converter to compensate and increase the current demand from the Triac dimmer above its holding current. The circuit includes an input voltage modifier and a leading edge dimming detection circuit. The input voltage modifier receives an input voltage signal that is representative of a magnitude of an input voltage of the power converter and selectively provides a modified input voltage signal to an input of a controller in response to receiving a control signal. The modified input voltage signal is representative of a value that is less than the magnitude of the input voltage. The leading edge dimming detection circuit generates the control signal to engage the input voltage modifier to generate the modified input voltage signal in response to detecting leading edge dimming at an input of the power converter.

Abstract: A power converter includes an energy transfer element, a power switch, a controller and a leading edge dimming detection circuit. The controller is coupled to control switching of the power switch to regulate the output of the power converter by controlling a transfer of energy through the energy transfer element. The leading edge dimming detection circuit is coupled to generate a control signal in response to detecting leading edge dimming at the input of the power converter. In one aspect, the leading edge dimming detection circuit detects the leading edge dimming and then generates a control signal to engage a compensator which maintains the input current of the power converter to be equal to or greater than a minimum current. In another aspect, the leading edge dimming detection circuit detects and reutilizes the turn-on current spike energy of a leading edge dimmer.

Abstract: A bleeder circuit for use in a power converter of a lighting system includes a current sense circuit coupled between first and second terminals of an input of a driver circuit to be coupled to drive a load. The current sense circuit is coupled to output a current sense signal in response to an input current through an input of the power converter coupled to the input of the driver circuit. An edge detection circuit is coupled between the first and second terminals to output an edge detection signal in response to an input signal between the first and second terminals. A variable current circuit is coupled between the first and second terminals to conduct a bleeder current between the first and second terminals in response to current sense signal and further in response to the edge detection signal.

Abstract: A surge protection module is disclosed. An example surge protection module includes a first terminal coupled to a first output terminal of a rectifier of a power supply. A second terminal is coupled to a first input terminal of a switching converter of the power supply. A third terminal is coupled to a second output terminal of the rectifier and a second input terminal of the switching converter. A variable resistance circuit is coupled between the first and second terminals. A control circuit is coupled between the first and third terminals and coupled to control the variable resistance circuit. A resistance of the variable resistance circuit is responsive to a magnitude of a voltage between the first and third terminals.

Abstract: A bleeder circuit for use in a power converter of a lighting system includes a current sense circuit coupled between first and second terminals of an input of a driver circuit to be coupled to drive a load. The current sense circuit is coupled to output a current sense signal in response to an input current through an input of the power converter coupled to the input of the driver circuit. An edge detection circuit is coupled between the first and second terminals to output an edge detection signal in response to an input signal between the first and second terminals. A variable current circuit is coupled between the first and second terminals to conduct a bleeder current between the first and second terminals in response to current sense signal and further in response to the edge detection signal.

Abstract: A bleeder circuit for use in a power supply of a lighting system includes a first terminal to be coupled to a first input of the power supply. A second terminal is to be coupled to a second input of the power supply. An edge detection circuit is coupled between the first and second terminals of the bleeder circuit. The edge detection circuit is coupled to output an edge detection signal in response to an input signal between the first and second inputs. A variable current circuit is coupled to the edge detection circuit and coupled between the first and second terminals of the bleeder circuit. The variable current circuit is coupled to conduct a bleeder current between the first and second terminals of the bleeder circuit in response to the edge detection signal.

Abstract: A surge protection module is disclosed. An example surge protection module includes a first terminal coupled to a first output terminal of a rectifier of a power supply. A second terminal is coupled to a first input terminal of a switching converter of the power supply. A third terminal is coupled to a second output terminal of the rectifier and a second input terminal of the switching converter. A variable resistance circuit is coupled between the first and second terminals. A control circuit is coupled between the first and third terminals and coupled to control the variable resistance circuit. A resistance of the variable resistance circuit is responsive to a magnitude of a voltage between the first and third terminals.