Electrical ballast and driving method thereof
AssigneeDelta Electronics, Inc.
InventorsYung-Chuan Lu, Ching-Ho Chou
Life of this patent
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Abstract
An electrical ballast includes an inverter circuit and a detection circuit. The inverter circuit is configured to receive a dc voltage and provide an output voltage to a lighting module. The detection circuit is electrically coupled to the inverter circuit and a voltage source, and configured to detect an ac voltage signal in the inverter circuit, and pull down the voltage source from a supply level to an under voltage locking level to shut down the inverter circuit on the condition that the ac voltage signal is greater than a threshold value, and restart the inverter circuit after a delay period.
Claims20
An electrical ballast, comprising:
- an inverter circuit configured to receive a dc voltage and provide an output voltage to a lighting module;
- and
- a detection circuit electrically coupled to the inverter circuit and a voltage source, and configured to detect an ac voltage signal in the inverter circuit, and pull down the voltage source from a supply level to an under voltage locking level to shut down the inverter circuit on the condition that the ac voltage signal is greater than a threshold value, and restart the inverter circuit after a delay period;
- wherein the detection circuit comprises a delay unit electrically coupled between the voltage source and a ground terminal, wherein on the condition that the voltage source is pulled down to the under voltage locking level, the delay unit is configured to conduct during a delay period.
An electrical ballast driving method comprising:
- converting, by an inverter circuit, a dc voltage to an output voltage to a lighting module;
- detecting, by an detection circuit, an ac voltage signal on the inverter circuit;
- pulling down, by the detection circuit, a voltage source from a supply level to an under voltage locking level to shut down the inverter circuit on the condition that the ac voltage signal is greater than a threshold value;
- restarting, by the detection circuit, the inverter circuit being shutting down after a delay period;
- and
- configuring a delay unit in the detection circuit to conduct during a delay period on the condition that the voltage source is pulled down to the under voltage locking level, wherein the delay unit is electrically coupled between the voltage source and a ground terminal.
The electrical ballast driving method of claim further comprising:
- configuring the delay unit to be interrupted after the delay period, in order to recover the voltage source from the under voltage locking level to the supply level such that the inverter circuit is restarted.
Dependencies are inferred from the claim text.