Microsemi Corporation

Xiaoping Jin

Simon Kahn

Yuji Yoshida

Ting-Hui Lin

Juan R Cendejas

A flyback converter is provided with a first output associated with a first secondary winding, a primary side controller arranged to maintain the first output at a predetermined voltage level and a second output associated with a second secondary windings; an LED controller. A first secondary electronically controlled switch is responsive to the LED controller; a first LED luminaire arranged to provide a first illumination responsive to a power signal on the second output when the first secondary electronically controlled switch is in a closed state and not provide the first illumination when the first secondary electronically controlled switch is in the open state, wherein the turns ratio of the first secondary winding and the second secondary winding is such that power is delivered to the first output via the first unidirectional electronic valve only when the first secondary electronically controlled switch is switched to the open state.

LED luminaire driving circuit and method

An arrangement wherein a plurality of LED strings are driven with a balanced drive signal, i.e. a drive signal wherein the positive side and negative side are of equal energy over time, is provided. In a preferred embodiment, the drive signal is balanced responsive to a capacitor provided between a switching network and a driving transformer. Balance of current between various LED strings is provided by a balancing transformer.

High efficiency LED driving method

A LED driving arrangement constituted of: a control circuitry; an inductance element having a primary side and a secondary side; the inductance element arranged, responsive to a switching circuit, to receive power at the primary side from a power source, and the inductance element further arranged, responsive to the received power at the primary side, to output at the secondary side a function of the received power; at least LED based luminaire; a parasitic capacitance between the at least one LED based luminaire and a chassis; and an electronically controlled switch coupled between the secondary side of the inductance element and the at least one LED based luminaire, wherein the electronically controlled switch and the secondary side of the inductance element and a discharge path of the parasitic capacitance are coupled in series.

LED driving arrangement with reduced current spike

A resonant converter is provided with a plurality of secondary transformer windings. A first secondary winding provides a fixed output, which is utilized to control the switching frequency of the resonant converter. A second secondary winding drives one or more LED luminaires, and is provided with a secondary side resonant circuit. When the feedback from the first output calls for a reduced frequency so as to increase the output, the reduced frequency results in an increased impedance of the secondary side resonant circuit so as to prevent any voltage rise for the LED luminaires. When the feedback from the first output calls for an increased frequency so as to reduce the output, the increased frequency results in an decreased impedance of the secondary side resonant circuit so as to prevent any voltage fall for the LED luminaires.

A multiple output power converter constituted of: an inductance element arranged, responsive to a switching circuit to receive power and arranged to output a function of the received power for a predetermined time period, the secondary side exhibiting a predetermined voltage during the predetermined time period; a control circuitry arranged to switch the switching circuit so as to maintain a first output at a predetermined level; a second output; and an electronically controlled switch arranged to be alternately in a closed state and an open state, the second output arranged to receive or not receive a portion of the output power responsive to the state, the switch set in synchronization with the switching circuit.

Multiple output synchronous power converter

A solid state lighting driver arrangement exhibiting a plurality of LED strings receiving power from a single power source, the single power source providing a discontinuous current, wherein a plurality of first windings are provided, each associated with a particular LED string and coupled to provide current balancing between the various LED strings. The discontinuous current resets the windings during the off time or during a reversal period. In one particular embodiment, a second winding is magnetically coupled to each of the first windings, and the second windings are connected in a closed in-phase loop. In another particular embodiment, at least two of the first windings are magnetically coupled to each other, thus ensuring a balance between current in each LED string.

LED string driver arrangement with non-dissipative current balancer

A light emitting diode (LED) based luminaire driving arrangement constituted of: a switched driver; a plurality of LED based luminaires arranged to receive power from the switched driver; at least one electronically controlled switch in series with at least one of the plurality of LED based luminaires and arranged to alternatively pass current through the at least one LED based luminaire when closed and prevent the flow of current through the at least one LED based luminaire when opened; and at least one synchronous driver in communication with the at least one electronically controlled switch, the at least one synchronous driver arranged to close the at least one electronically controlled switch only when the switched driver is actively supplying power.

Synchronous regulation for LED string driver

An apparatus for LED string short circuit detection constituted of: a constant current drive circuit; a plurality of LED strings, a first end of each of the plurality of LED strings coupled to a common output of the constant current drive circuit; a first sense resistor coupled between a second end of each of the plurality of LED strings and a chassis; a second sense resistor coupled between the chassis and a return of the constant current drive circuit; and a comparing circuit arranged to compare the amount of current flow through the first sense resistor with amount of current flow through the second sense resistor, the comparing circuit arranged to assert a fault signal in the event that the amount of current flow through the second sense resistor exceeds the current flow through the first sense resistor by a predetermined minimum value.

Method and apparatus for LED string short circuit detection and protection

A driving circuitry arranged to pass a dead time over an isolation transformer, the driving circuitry constituted of: a three-state driver arranged to output a first signal, the first signal selectively at one of two complementary voltage levels and a high impedance state; a first capacitor, a first end of the first capacitor coupled to receive the first signal; and a first isolation transformer, a first end of a first winding of the first isolation transformer coupled to a second end of the first capacitor.

Lips backlight control architecture with low cost dead time transfer

A light emitting diode (LED) based luminaire driving arrangement constituted of: a switched driver; a plurality of LED based luminaries arranged to receive power from the switched driver; at least one electronically controlled switch in series with at least one of the plurality of LED based luminaries and arranged to alternatively pass current through the at least one LED based luminaire when closed and prevent the flow of current through the at least one LED based luminaire when opened; and at least one synchronous driver in communication with the at least one electronically controlled switch, the at least one synchronous driver arranged to close the at least one electronically controlled switch only when the switched driver is actively supplying power.

High efficiency LED driving method for odd number of LED strings

A driving arrangement for light emitting diode (LED) based illumination constituted of: a comparison circuitry arranged to compare an integral of a target current over a target illumination time for at least one LED based luminaire with an integral of an illumination current over an illumination time for the at least one LED based luminaire, the comparison circuitry arranged to output a comparison signal; and a control circuitry in communication with the comparison circuitry and arranged to alternately: allow the flow of electrical current through the at least one LED based luminaire responsive to a first condition of the comparison signal; and prevent the flow of electrical current through the at least one LED based luminaire responsive to a second condition of the comparison signal, the second condition different from the first condition.

Brightness control for LED lighting

A lighting arrangement constituted of: a power factor correction circuit; a lighting controller operative at an electrical potential consonant with the electric potential of the output of the power factor correction circuit; a switching network, coupled to the output of the power factor correction circuit and to respective outputs of the lighting controller; a transformer, a primary winding of the transformer coupled to the output of the switching network; and at least one luminaire coupled to at least one secondary winding of the transformer and arranged to be driven by the at least one secondary winding, the lighting controller operative to control the switching network via the respective outputs to switchably pass current from the power factor correction circuit through the primary winding, thereby powering the at least one luminaire.

Integrated backlight control system

A ring balancer comprising a plurality of balancing transformers facilitates current sharing in a multi-lamp backlight system. The balancing transformers have respective primary windings separately coupled in series with designated lamps and have respective secondary windings coupled together in a closed loop. The secondary windings conduct a common current and the respective primary windings conduct proportional currents to balance currents among the lamps. The ring balancer facilitates automatic lamp striking and the lamps can be advantageously driven by a common voltage source.

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Orange, CA, United States of America

Xiaoping Jin