Segmented led drive circuit

Abstract

The invention relates to a segmented LED driving circuit, which includes an LED module, which includes several strings of LED lamp strings connected end to end; a power tube module, which includes several power tube modules corresponding to the number of LED lamp strings. tube, and each power tube corresponds to only one string of LED lights; the power factor adjustment module includes several voltage comparison units corresponding to the number of power tubes, and each voltage comparison unit corresponds to only one power tube ; A reference source module, which includes several voltage output terminals and a reference signal output terminal corresponding in number to the voltage comparison unit, and the circuit also includes a constant current compensation module. Using the segmented LED drive circuit of the present invention, the LED drive current changes with the AC input voltage through the segmental conduction of the switch, thereby obtaining a higher power factor, and at the same time, a higher linear adjustment rate is obtained through the constant current compensation module. The structure is simple and the application range is wide.

Description

technical field [0001] The present invention relates to the field of electronic technology, in particular to a circuit, in particular to a segmented LED driving circuit. Background technique [0002] The common high power factor circuit is generally a switching power supply circuit integrated with a power factor correction circuit inside the controller. The circuit is more complicated. Compared with the switching power supply drive, the linear constant current drive has no EMI problems caused by high-frequency switching and does not require electrolytic capacitors. , without inductance and transformer, simple peripheral circuit, smaller size, and lower cost, but the linear constant current drive circuit in the prior art has a relatively low linear adjustment rate and has no power factor correction circuit. [0003] see figure 1 As shown, it is the LED driving circuit in the prior art, and VIN is the AC input voltage V AC Through the rectified half-wave signal, VIN>V TH...

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Problems solved by technology

[0005] (1) The current consistency is poor in the wide voltage input range, when the input AC signal V AC When changes occur, the time during which the current is constant within a half-wave cycle will change. When VIN1>VIN2, the time T1 during which VIN1 is greater than VTH within one cycle is greater than the time T2 during which VIN2 is greater than VTH. Output current I AV1 > I AV2

[0006] (2) When the number of LED lights is constant, the VIN will be lit at the same time when the VIN is high, so the utilization rate of LEDs is very low. If the number of LED lights is reduced, although the utilization rate can be increased, the power consumption of the line circuit will be reduced. greatly increases, thereby reducing the overall operating efficiency of the entire LED drive scheme

[0007] (3) Low PF (power factor) value and THD (total harmonic distortion)

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