Koninklijke Philips Corporation N.v.

Dolf Henricus Jozef Van Casteren

Oscar Jan Deurloo

Robertus Leonardus Tousain

Winston Donald Couwenberg

Roy Hendrik Anna Maria Van Zundert

Thijs Oosterbaan

Markus Krijzer

Edwin Theodorus Maria De Koning

A driver () for driving a gas discharge lamp () comprises:&#x2014;a current source () generating lamp current, having a setpoint input () for receiving a setpoint signal;&#x2014;a controller () generating a current setpoint signal (SM);&#x2014;a controllable noise signal source () generating a pseudo random noise signal (SPRNS);&#x2014;an adder () adding the current setpoint signal (SM) from the controller and the pseudo random noise signal (SPRNS) from the noise signal source, and providing the result to the setpoint input of the current source;&#x2014;measuring means () measuring a characteristic lamp response of the lamp in response to the pseudo random noise signal (SPRNS), and providing to the controller a sense signal;&#x2014;a memory () associated with the controller, having stored therein at least one reference signal. The controller compares the measured lamp response with said predetermined reference signal in the memory, and may switch off the lamp.

Method and device for driving a gas discharge lamp

A lamp driver circuit for operating a gas discharge lamp (La) is proposed, which comprises a switched mode power supply circuit (SMPS) and a first and a second output terminal (OTT) for supplying a lamp current to the gas discharge lamp (La). The lamp driver circuit further comprises an output capacitor (CO) connected between the SMPS circuit and a ground terminal (GT) and comprises a resistive shunt (Rsh) connected between the ground terminal (GT) and the second output terminal (T) for determining the lamp current. An output current sensing circuit for determining a SMPS output current is comprised in the lamp driver circuit instead of a further resistive shunt, which would require a differential voltage measurement. The output current sensing circuit comprises a sensing resistor (RS) connected in series with a sensing capacitor (CS), the series connection being connected in parallel to the output capacitor.

Lamp driver for operating a gas discharge lamp

A circuit arrangement and a method for operating a high intensity discharge lamp driver, which assure long-lasting stable operation of a high intensity discharge lamp regardless of the type or the age of the lamp. This is achieved by the determination of a correctional setpoint signal for a given time period based on the a difference signal between a principal setpoint signal and the actual output current signal for a given time period. The principal setpoint signal is then adjusted by the determined correctional setpoint signal.

Robust driver for high intensity discharge lamp

A circuit arrangement for operating a high pressure discharge lamp comprises a down converter equipped with an output capacitor and a commutator equipped with lamp connection terminals. The amplitude of the DC current generated by the down converter is controlled by means of a control loop. Commutation of the DC current causes a periodical voltage to be present across the output capacitor. This periodical voltage can be an overshoot voltage and/or a voltage caused by resonance of the lamp with the output capacitor. To suppress the periodical voltage, the reference signal of the current control loop is adjusted in dependency of the amplitude of the periodical voltage.

Circuit arrangement for operating a high pressure discharge lamp

A circuit for a discharge lamp includes a first sub-circuit for connecting to mains voltage of a predetermined frequency for rectifying the mains voltage; and a second sub-circuit connected to the first sub-circuit for providing an alternating current, such as a square-wave current, required for the lamp. A control circuit is connected to the first and the second sub-circuit. The control circuit controls the frequency of the alternating current subject to a varying component of the mains voltage rectified by the first sub-circuit.

Circuit for a gas-discharge lamp

Circuit for driving a load, comprising: two input terminals for connection to a source of a supply voltage; a first and a second output terminal for connection to the load; at least one inductor coupled between one of the output terminals and a corresponding connection node; at least one arrangement comprising a switch coupled between one of said input terminals and one of said connection nodes, a diode being connected between said one connection node and the other input terminal; a control unit for controlling said one or more switches; wherein each arrangement and corresponding diode are designed to allow the voltage over the opened switch of said arrangement to return to substantially zero before said switch is closed, the control unit being designed to provide a signal for closing the switch when a substantially zero voltage over said opened switch is detected. Turning the switch on at a substantially zero voltage means that switching losses are greatly reduced, and this without complicating the circuit.

Circuit and method for driving a load, in particular a high-intensity discharge lamp, and a control unit for said circuit

An DC/AC converter for supplying two gas discharge lamps, includes a double bridge configuration of four switches and a controller. The controller controls the conducting periods of the switches with a duty cycle which is variable. By control of the conducting periods of the switches, a proper control of the energy supplied to the lamps is obtained.

DC/AC converter for supplying two gas discharge lamps

The invention relates to a device for operating a high-pressure discharge lamp, comprising: a switched-mode power supply circuit for supplying power to the high-pressure discharge lamp from a supply voltage, the power supply circuit comprising at least one power switching element, and control means for controlling the at least one power switching element in its switched-on and switched-off states for controlling the power or current supplied to the high-pressure discharge lamp. According to the invention the control means are adapted to control the power consumed by the lamp during its steady phase or the current consumed by the lamp during its run-up phase by controlling the on-time (Ton) of the switched-on state of the at least one power switching element.

Device and method for operating a discharge lamp

Driver () for a gas discharge lamp () comprises: an arrangement of two MOSFET switches () connected in series between two input terminals (); an inductor () connected in series with said lamp (), this series arrangement being coupled to a node (P) between said two switches; a control unit () providing control signals (S, S) to said two switches. During a first commutation interval (), a lamp circuit current (ILC) has only a first direction while during a second commutation interval () said lamp circuit current has only an opposite direction. In each commutation interval (), during a first operational phase () said lamp circuit current has a continuously increasing level while during a second operational phase () said lamp circuit current has a continuously decreasing level. The control unit () is designed to generate its control signals (S, S) such that said two switches are always, switched substantially simultaneously in counter-phase. The mosfets are used in reverse conduction m node also, to avoid body diode conduction (synchronous rectification).

Driver for a gas discharge lamp

In a bridge circuit for operating a high pressure discharge lamp an additional switching element, a control circuit for driving the additional switching element, a resonant inductor and a resonant capacitor are incorporated. The additional components together form a comparatively simple resonant igniter. The resonant inductor can be formed by part of a filter comprised in the bridge.

Circuit arrangement with a separate resonant igniter for a high-pressure discharge lamp

A DC-AC converter in a half bridge configuration is used for operation with high pressure discharge lamps as well as low pressure discharge lamps. The converter consists in two switches (T-T) serially connected through a first series of diodes (D, D) and a second series of diodes (D,D) to which at their middle points (N, N) a first and a second lamp loads (L,L,LA,LA) are connected. Furthermore, the second terminals of the lamp loads are connected to the middle point of a series of capacitors (C,C) which are also connected to the terminals (Ki,K) of the supply voltage source. The converter includes also four diodes (D,D,D,D) which shunt the switches (T,T) and their respective series of diodes (D,D,D,D). The switches (T,T) are controlled by a controller (CC) which renders alternatively conductive at low frequency the two switches (Ti,T). In the first operating state, the first switch (T) is rendered conductive and non-conductive at a high-frequency while the second switch (T) is maintained in a non-conductive state, in the second operating state the second switch (T) is rendered conductive and non-conductive at high-frequency while the first switch (T) is maintained in a non-conductive state. The series of two capacitors (C,C) can be replaced by a series of two switches (T,T) in order to obtain a full bridge configuration of the converter. The particular configuration of the network and its operating mode allow to drive the lamp loads in such a way that the difference in power consumed by the lamps is comparatively small.

Circuit arrangement for operating discharge lamps

In a ballast circuit for supplying a high pressure discharge lamp and comprising an up-converter and a bridge circuit, the output voltage of the up-converter is controlled at a higher level immediately after the ignition of the lamp and at a lower level during stationary operation. Stabilization of the discharge immediately after ignition of the lamp and a relatively small power dissipation are both realized in this ballast circuit.

Ballast for high pressure discharge lamp

A switch mode power supply for igniting and operating a high-pressure gas discharge lamp includes an ignition sub-circuit which is coupled via a transformer to the circuit. The ignition sub-circuit has at least an ignition capacitor, and a switching element for discharging the capacitor at a desired moment in time having a control electrode. The control electrode of the switching element is connected to the commutator of the lamp circuit via a control sub-circuit having substantially passive elements.

Switch mode power supply for a gas discharge lamp

The present invention relates to an Electronic ballast for operating a high-pressure discharge lamp, comprising a switched-mode power supply circuit (SMPS) for supplying a rail voltage Vrail to the high pressure discharge lamp, the power supply circuit comprising a half bridge commutating forward circuit including an inductance (Lhbcf), a capacitor circuit of a first capacitor (Cs) and a second capacitor (Cs) in series, the lamp (LA) being connectable between the inductance (Lhbcf) and a midpoint (M) between the first and second capacitor (Cs,Cs); a duty cycle control circuit, connected to the switched-mode power supply circuit, for controlling the duty cycle of the half bridge commutating forward circuit; and overvoltage protection means for protecting said capacitors against overvoltage, comprising&#x2014;a midpoint voltage detection circuit for detecting the voltage at the midpoint between the first and second capacitor, the midpoint voltage detection circuit providing a first signal representative of the detected midpoint voltage; voltage difference determining circuit for determining the difference between the first signal and a second signal, which is representative of half the rail voltage, wherein the voltage difference determining circuit is connected to the duty cycle control circuit and the duty cycle control circuit is operable to change the duty cycle of the half bridge commutating forward circuit if the determined difference exceeds a maximum voltage difference.

Device for operating a high-pressure discharge lamp

The present invention relates to a device for operating a high-pressure discharge lamp, comprising a switched mode power supply circuit (SMPS) for supplying power to the high pressure discharge lamp from a supply voltage, the power supply circuit comprising a half bridge commutating forward (HBCF) circuit including an inductancehbcf?), a capacitor circuit of a first capacitor (C) and a second capacitor (C) in series, the lamp (LA) being connectable between the inductance (L) and a point (M) between the first and second capacitor (C,C); wherein overvoltage protection means are connected parallel to the lamp, which switch from an off-state with a high resistance operation to an on-state with a low resistance operation when the voltage difference across the protection means exceeds a breakover voltage (V), the breakover voltage (V) being selected to correspond to a predetermined maximum voltage across the first or the second capacitor (C,C).

Growing community of inventors

Eindhoven, Netherlands

Dolf Henricus Jozef Van Casteren