Koninklijke Philips Corporation N.V.

Philips Electronics North America Corporation

Jerzy Janczak

Naveed Majid

Robert Alexander Erhardt

Ronald Hans Van Der Voort

Hendrik Anton Van Esveld

Fernand Raphael Antheunes

Oscar Jan Deurloo

Jerry Martin Kramer

William Lawrence Keith

Johannes M Van Meurs

Winston Donald Couwenberg

Raman Nair Harish Gopala Pillai

Srinivasa M Baddela

Ningliang Mi

Patrick E Smeets

An electronic ballast with dimming circuit including an electronic ballast dimming circuit receiving an analog dimming signal, the electronic ballast dimming circuit including an input dimming circuit () operable to receive the analog dimming signal () at an analog dimming signal input (); and an output dimming circuit () operably connected to the input dimming circuit (), the output dimming circuit () being operable to receive a fixed frequency signal () having a variable duty cycle and to generate an analog dimming control signal () in response to the analog dimming signal (). Output voltage at the analog dimming signal input () is a function of the variable duty cycle of the fixed frequency signal () when the analog dimming signal () is not present at the analog dimming signal input ().

Electronic ballast with dimming circuit

An electric circuit for igniting a discharge lamp includes a voltage source, and at least one condenser electrically connected to the voltage source. Further, a series chain is provided, electrically connected in parallel with the condenser, of at least one ignition and at least one inductor. A discharge lamp is electrically connected in parallel with the ignition.

Electric circuit for igniting a discharge lamp, and electric component module and discharge lamp incorporating such an electric circuit

A method and ballast for driving a high intensity discharge (HID) lamp include generating a very high frequency driving signal for the HID lamp, generating a low frequency modulating signal, amplitude modulating the driving signal with the modulating signal at a predetermined low initial modulation level, measuring a lamp voltage across the HID lamp, determining a standard deviation of the lamp voltage, comparing the standard deviation with a predetermined minimum level, if the standard deviation is above the predetermined minimum level, incrementally increasing the modulation level and repeating the amplitude modulating step, the measuring step, the determining step and the comparing step, and if the standard deviation is below the predetermined minimum level, maintaining the amplitude modulation at the determined level.

High frequency electronic ballast

An improved high frequency ballast is disclosed. The high frequency ballast establishes a lamp current for a gas discharge lamp during a starting operation of the gas discharge lamp wherein an operating ampere level of the lamp current facilitates a substantial achievement by the gas discharge lamp of a color specification associated with the gas discharge lamp. Thereafter, during a stable operation of the gas discharge lamp, the high frequency ballast applies a frequency modulation to an operating frequency of the lamp current and/or an amplitude modulation of the lamp current.

A resonant mode power supply includes a soft-start circuit for, at start-up, for sweeping the frequency of the power supply from a maximum value to a minimum value. The soft-start circuit performs this frequency sweep using the function

Soft start scheme for resonant converters having variable frequency

A resonant mode power supply includes a d.c. voltage source and switching elements for alternatively connecting an oscillating circuit, including the primary winding of a transformer, to the d.c. voltage source and to ground. In order to detect faults in the load on a secondary side of the transformer which would cause the resonant mode power supply to attempt to supply and inordinate amount of power, the power on the primary side is detected and if this primary power exceeds a predetermined threshold value, the frequency of oscillation is increased to reduce the power. If the fault condition persists, the switching of the switching elements is discontinued.

Resonant mode power supply having over-power and over-current protection

A resonant mode power supply includes a D.C. voltage source and switching elements for alternatively connecting an oscillating circuit, including a primary winding of a transformer, to the D.C. voltage source and to ground. A first secondary winding supplies the main output voltage of the power supply and a second secondary winding provides a control output voltage. An opto-coupler is included and has a light emitter connected to the second secondary winding, and a light sensor connected to a controller for controlling the switching of the switching elements, wherein the higher the frequency of the switching, the lower the power being supplied by the power supply. Burst mode stand-by is started by the first secondary winding being shunted to the second secondary winding causing the light emitter to emit a maximum amount of light. The controller increases the switching frequency until it exceeds a predetermined maximum frequency. The controller then stops the switching of the switching elements until the voltage across the light emitter falls below a predetermined value, and the controller then re-starts the switching.

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Eindhoven, Netherlands

Jerzy Janczak