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US 6,472,829 B2Granted
Discharge lamp lighting circuit
AssigneeKoito Manufacturing Co., Ltd.
InventorsMasayasu Ito, Hitoshi Takeda
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AssigneeKoito Manufacturing Co., Ltd.
InventorsMasayasu Ito, Hitoshi Takeda
Estimating the term…
In a discharge lamp lighting circuit, there are provided a DC power supply portion for receiving a supply voltage from a DC power supply though an overcurrent protecting means, a DC-AC converter portion for converting an output voltage of the DC power supply portion into an AC voltage to supply the AC voltage to a discharge lamp, a starter circuit for starting the discharge lamp by applying a high voltage pulse to it, and a control circuit for detecting at least one of a voltage applied to the discharge lamp or to decide whether or not a failure occurs in a lighting state of the discharge lamp. Thus, a voltage is obtained from at least one of a position that is located between the DC power supply and the overcurrent protecting means or from another DC power supply different from the DC power supply, and the obtain voltage is supplied to the control circuit as the power supply voltage.
A discharge lamp lighting circuit comprising:
Dependencies are inferred from the claim text.
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From the US filing history. Foreign family members aren’t listed.
For protecting the circuit against abnormal operating conditions: against abnormal power supply conditions
Arrangements for protecting lamps or circuits against abnormal operating conditions: for protecting the circuit against abnormal operating conditions
Energy efficient lighting technologies
Electric heating
Term ended 30 May 2021 (estimated)
The present invention relates to a technology to adopt a sufficient measure for safety by assuring the supply voltage to the control circuit even when the supply of the power supply voltage to the discharge lamp or the lighting circuit is cut off because of the operation of the overcurrent protecting means.
As the lighting circuit for the discharge lamp (the metal halide lamp, etc.), the configuration having the DC power supply circuit, the DC-AC converter circuit, and the starting circuit (so-called starter circuit) is well known.
FIG. 8 shows a circuit configuration 50 of the discharge lamp lighting circuit according to the prior art. The power is supplied from the DC power supply 52 to the lighting circuit 51 via the overcurrent protecting element c and the lighting switch 55.
FIG. 1 is a block circuit diagram showing a basic configuration of a discharge lamp lighting circuit according to the present invention;
FIG. 2 is a block circuit diagram showing a pertinent portion of the basic configuration shown in FIG. 1;
FIG. 3 is a block circuit diagram showing an example of a power-supply voltage generating circuit using a three-terminal regulator;
FIG. 1 shows a basic configuration of a discharge lamp lighting circuit 1 according to the present invention.
The discharge lamp lighting circuit 1 comprises a DC power supply 2; overcurrent protecting means 3; a DC power supply portion 4; a DC-AC converter portion 5; a starter circuit 6; and a control circuit 7.
In this circuit, the DC power supply portion 4 is constructed to receive the supply of power from the DC power supply 2 via the overcurrent protecting means 3. That is, the voltage supplied from the DC power supply 2 via the overcurrent protecting means 3 (the overcurrent protecting element such as the fuse, etc., or the braker, etc.) is supplied to the DC power supply portion 4 as the input voltage. The DC power supply portion 4 converts the input voltage into a desired DC voltage in response to a control signal from the control circuit 7 and then outputs the DC voltage. For example, the DC-DC converter (fly-back type, chopper type, etc.) having a configuration of the switching regulator is employed.