A fluorescent lamp drive power supply

Abstract

The disclosed drive power of fluorescent lamp comprises: multiple switch conversion circuits, a power transformer T1 with primary winding connecting the output of last circuits, a resonant inductor L1, a resonant capacitor C3 together with L1 connecting secondary winding of T1 through primary winding of T2, and a boost-up transformer T2 with secondary winding for output. This invention realizes regulating both frequency and voltage, and the soft switch function.

Description

technical field [0001] The invention relates to the field of electrical appliances, in particular to a fluorescent lamp driving power supply. Background technique [0002] The liquid crystal display device includes a backlight module and a liquid crystal panel, and the backlight module is used to provide a light source for the liquid crystal panel which itself does not emit light. Regardless of the backlight module or the liquid crystal panel, a power supply is required for it. [0003] In an existing application, as shown in FIG. 1 , it includes a power factor correction circuit, a power transformer T1, a step-up transformer T2, a first switch S1, a second switch S2, a third switch S3 and a fourth switch S4. The first switch S1 and the second switch S2 are connected in series to the input terminal Vin, the third switch S3 and the fourth switch S4 are connected in series to the input terminal Vin, and one end of the capacitor C2 is connected to the first switch S1 and the i...

AI Technical Summary

Problems solved by technology

(n is the number of step-up transformers, Lr' is the leakage inductance converted to the primary side) When the resonant inductance is too small, the Q value is low, and the frequency f1 changes to f2, the change of the voltage Δv on the lamp load Rlamp is too small to be Meet the requirements for adjusting the load voltage range

[0005] Disadvantages of the prior art: when multiple step-up transformers are connected in parallel to drive the load, the equivalent inductance of the leakage inductance of the secondary winding of the step-up transformer after parallel connection is greatly reduced, and the oscillation circuit formed by it and the capacitor C2 is due to the inductance Too small, the Q value is low, the loop cannot oscillate, and the frequency modulation cannot be realized to adjust the voltage on the load; in addition, because the inductance is small and the resonance frequency is high, the soft switching of the power circuit switch on the primary side of the power transformer cannot be realized in the specified operating frequency range Function

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