led drive circuit

Abstract

The invention relates to an LED drive circuit. The LED drive circuit comprises a protection unit, a rectifying and filtering unit, a control unit, an LED drive unit and a detected current feedback unit, wherein the protection unit is connected with an alternating current power supply, the rectifying and filtering unit is electrically connected with the protection unit, one end of the control unit is electrically connected with the rectifying and filtering unit, the LED drive unit is provided with a light emitting diode, a first capacitor and a transistor, the light emitting diode is in parallel connection with the first capacitor, the light emitting diode is provided with a positive electrode and a negative electrode, the positive electrode of the light emitting diode is electrically connected with the rectifying and filtering unit and the control unit, and the detected current feedback unit is arranged between the LED drive unit and the control unit. In this way, the detected current feedback unit forms the protection unit, and the situation that a power increase is caused by a too high input voltage of the alternating current power supply can be avoided.

Description

Technical field [0001] The present invention relates to an LED drive circuit, in particular to an LED drive circuit that uses a transistor to work in a linear region, does not switch the frequency, and does not need to use an electromagnetic interference filter, and the detection current feedback unit forms a high voltage feedback The compensated protection circuit can avoid the situation that the voltage input of the AC power supply is too high and the power rises. Background technique [0002] First, see figure 1 As shown, the existing LED driving circuit uses a flyback circuit 72 and a pulse width modulation (PWM) 71 to provide a DC power supply with constant current and power. The deficiency is that there are pulse width modulators and The high cost of the required parts of the electromagnetic interference filter. [0003] Moreover, the existing LED drive circuit does not use a high-voltage feedback compensation protection circuit. If it uses a linear power supply, although th...

AI Technical Summary

Problems solved by technology

[0002] First, see figure 1 As shown, the existing LED drive circuit provides a DC power supply with constant current and power in the form of a flyback circuit 72 and a pulse width modulation (PWM) 71. The disadvantage is that there will be a pulse width modulator and Expensive cost of required parts for EMI filter

[0003] Furthermore, the existing LED drive circuit does not use a protection circuit for high-voltage feedback compensation. If it uses a linear power supply, although there is no electromagnetic interference, the higher the input AC power voltage, the higher the voltage on the circuit. Transistor voltage is also higher, so that the AC power supply voltage input is too high, resulting in a rapid rise in power (W) (such as figure 2 shown), so it cannot protect the LED, and it is easy to overheat and cause damage to the LED

[0004] In view of this, the inventor of the present invention has devoted himself to research, design and assembly, hoping to provide an LED drive circuit that utilizes transistors to work in the linear region, without switching frequency, and does not require the use of electromagnetic interference filters. The protection circuit of high-voltage feedback compensation can avoid the situation that the voltage input of the AC power supply is too high and the power rises

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