Koninklijke Philips Corporation N.V.

Ykm Technologies, LLC

Young-Kee Min

Bernd Clauberg

Ajay Tripathi

Raghuram Narasimhan

Rohit Khetarpal

Bertrand J E Hontel&eacute;

The power supply () for LEDs provides power to a LED light source () having a variable number of LEDs wired in series and/or in parallel. The power supply () uses current and voltage feedback to adjust power to the LEDs and provides protection to the LED light source (). A feedback controller () compares sensed current and sensed voltage to a reference signal and generates a feedback signal, which is processed by a power factor corrector () to adjust the current flow through the transformer supplying current to the LEDs. A LED control switch () clamps a peak of the current to the LEDs to provide further protection to the LED light source (). A short/open detection circuit () indicates any detection of a 'LED outage' of the LED light source ().

LEDS driver

A circuit and method measures main motor winding voltage and detects points in the electromagnetic wave cycle where this voltage 'crosses' zero. It also measures auxiliary motor winding voltage. Phase shifts measured in the auxiliary winding are compared as a means for starting and restarting the auxiliary winding. The points in the electromagnetic wave cycle where the current in the auxiliary winding 'crosses' zero are detected and compared with a first window pulse that is generated when the main voltage crosses zero. When the zero current crossing points fall outside the first window pulse, the auxiliary winding is disconnected. The points where the voltage in the auxiliary winding &#x201c;crosses&#x201d; zero are also detected and compared with a second window pulse that is generated when the main voltage crosses zero. When the zero voltage crossing points fall within the second window pulse, the auxiliary winding is switched back into the circuit.

Load and speed sensitive motor starting circuit and method

A circuit and method measures the voltage at the main motor winding () and detects the points in the electromagnetic wave cycle at which this voltage 'crosses' zero. The method and circuit also measures the voltage at the auxiliary motor winding (). The voltages measured in the main winding () and in the auxiliary winding () are compared by the circuit () as a means for starting and restarting the auxiliary winding (). The circuit and method also detects the points in the electromagnetic wave cycle where the current in the auxiliary winding 'crosses' zero and compares the phase of these current zero crossing points with a window pulse () that is generated when the main voltage crosses zero. When the zero current crossing points fall within the window pulse, the auxiliary winding () is up to proper operating speed and the auxiliary winding () is disconnected by the starting circuit. If the load on the main motor winding () increases or the main motor winding () speed decreases below a certain predetermined speed, the auxiliary winding () is switched back into the circuit to boost the speed of the main motor winding ().

The driver circuit for light emitting diodes (LEDs) of the present invention provides power to LEDs using pulse width modulation (PWM). The driver circuit uses current feedback to adjust power to LED arrays and provides a full light and a dim mode.

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Elm Grove, WI, United States of America

Young-Kee Min