A discharge lamp ballast includes a DC-DC converter circuit configured to convert a voltage of a DC power supply by a switching operation of a switching element based on a PWM signal and to output a DC power, an inverter circuit configured to invert the DC power into an AC power, and a PWM ON-width control circuit configured to control switching conditions of the switching element in the DC-DC converter circuit immediately before a polarity of the AC power is reversed such that an ON-width of the PWM signal is increased from a start of a polarity reversal so as to increase the DC power in a predetermined period. The polarity of the AC power of the inverter circuit is reversed in synchronism with a switching timing of the switching element immediately after the control by the PWM ON-width control circuit to increase the ON-width.
Discharge lamp ballast, lighting unit, and vehicle
2015-11-17
Patent
Electronic Resource
English
IPC: | B60Q ARRANGEMENT OF SIGNALLING OR LIGHTING DEVICES, THE MOUNTING OR SUPPORTING THEREOF OR CIRCUITS THEREFOR, FOR VEHICLES IN GENERAL , Anordnung von Signal- oder Beleuchtungsvorrichtungen, deren Einbau oder Halterung oder deren Schaltkreise bei Fahrzeugen allgemein / H05B ELECTRIC HEATING , Elektrische Heizung |
Lamp unit, and lighting device and vehicle lamp using same
European Patent Office | 2019
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