Power control circuit and electronic ballast with the same

Abstract

The invention relates to a power control circuit and an electric stabilizer with the same. the power control circuit, which can regulate power effectively, includes a load circuit, a power switch unit, a voltage detecting unit, an error amplifier, a current detecting unit, a comparator and a drive die set, wherein the load circuit being connected with loads and outputting an output voltage; the power switch unit receiving an input voltage to provide for the load circuit in switch; the voltage detecting unit detecting the output voltage and generating a first voltage signal; the error amplifier receiving the first voltage signal and a reference voltage, and outputting a second voltage signal; the current detecting unit detecting the current across the power switch unit and generating a third voltage signal; the comparator comparing the second and the third voltage signals; the drive die set generating a drive signal based on the comparative result of the comparator; the driver power switch unit switching, controlling and providing a load power. The electric stabilizer includes a power control circuit, a rectification circuit and a commutation circuit. The invention can regulate power instantly, and saves cost and is suitable for high illumination intensity air discharge lamp.

Description

technical field [0001] The invention relates to a power control circuit and an electronic ballast with the power control circuit, in particular to a power control circuit suitable for high-illuminance gas discharge lamps and an electronic ballast with the power control circuit. Background technique [0002] The equivalent impedance of high intensity discharge (HID) lamps will increase with time, so in order to maintain the stable lumen output of the lamp tube, the lamp tube needs to receive a stable power, so a power control is required A circuit is used to control the power supplied to the lamp. [0003] US Patent Publication No. 2006 / 0261746 A1, titled "Power control circuit for controlling rated power supplied to a load", proposes a power control circuit, and the power control circuit is suitable for use in an electronic ballast of a high-intensity gas discharge lamp . [0004] Please refer to FIG. 1 , which is a circuit diagram of a conventional electronic ballast. Th...

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Problems solved by technology

[0016] However, in the prior existing power control circuit 3, the current detection unit 34 detects once per cycle, and what the voltage detection unit 33 detects is the average value of the output voltage Vo, and the two detection units After the measurement results are added together, the response of the current detection will be slowed down, and the purpose of adjusting the power in real time cannot be achieved.

In addition, when the load R is open or short-circuited, the signal detected by the current detection unit 34 or the voltage detection unit 33 is zero, so the power switch unit 32 will be turned on, causing the output voltage Vo to be equal to the input voltage Vi, The output transient response is very poor, so that the voltage stress at the rear stage of the power control circuit 3 (such as: full bridge commutation circuit 4) is equal to the previous stage

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