Linear light-emitting diode driving circuit with voltage-lowering serial capacitor

Abstract

A linear light-emitting diode (LED) driving circuit with a voltage-lowering serial capacitor has a rectification unit, an LED unit, a constant current controller, a series and parallel voltage divider and a controller. The controller is built in with a safe voltage threshold, controls the series and parallel voltage divider to be connected in series to the LED unit when an output voltage of the rectification unit exceeds the safe voltage threshold, ensuring that an average voltage across the LED unit and the constant current controller is stable, and controls the series and parallel voltage divider to be parallelly connected across the LED unit and the ground when the output voltage of the rectification unit does not exceed the safe voltage threshold. Accordingly, a safety standard of voltage for LED driving circuit can be secured and users' safety can be ensured.

Description

technical field [0001] The invention relates to a linear LED driving circuit, in particular to a linear LED driving circuit using capacitors in series to reduce voltage. Background technique [0002] Light Emitting Diode (LED; Light Emitting Diode) is a common lighting appliance on the market. Compared with traditional incandescent bulbs, it has the characteristics of high luminous efficiency, low power consumption and low pollution; , so it is difficult to use the widely used alternating current; for this reason, the industry has developed a linear LED drive circuit; please refer to Figure 8 As shown, the linear LED drive circuit includes: [0003] A rectification unit 50, connected to an AC power supply AC / IN, and converting the AC power supply AC / IN into a pulsating DC power supply; [0004] An LED unit 51 is connected in series with the rectifying unit 50 and includes a plurality of LED light sources; and [0005] A constant current controller 52 is connected in serie...

AI Technical Summary

Problems solved by technology

Therefore, manufacturers of AC LED drive circuits must prepare AC LED drive circuits for AC power supply AC / IN with different voltages. In addition, they use transformers for step-down, and the volume of transformers is larger than that of ordinary electronic components, causing manufacturers Correspondingly, consumers must also confirm that the purchased AC LED drive circuit meets the household mains voltage specifications when purchasing. When the purchased low-voltage AC LED drive circuit is plugged into the high-voltage AC power supply, it will cause damage.

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