Overheating protection circuit, LED (light-emitting diode) drive circuit and lamp

Abstract

The invention relates to an overheating protection circuit, which is used for detecting the temperature of a key point of a lamp and regulating the output current of a working circuit, the overheating protection circuit comprises a first resistor, a second resistor, a third resistor, a controllable precision voltage source and a first switching transistor; the second resistor and the third resistor which are connected in series are connected in parallel with the controllable precision voltage source and then connected with an external driving power supply through the first resistor, and one end of the third resistor is grounded; the control end of the first switching transistor is connected with the common end of the second resistor and the third resistor, the high-potential end of the first switching transistor is connected with an LED (light-emitting diode) light source, and the low-potential end of the first switching transistor is grounded; the second resistor is a positive temperature coefficient thermistor. The invention also discloses an LED drive circuit and a lamp which apply the overheating protection circuit. By detecting the temperature of the lamp, the overheating protection circuit can automatically regulate the output current of the lamp, so that the heat produced by the lamp can be reduced. The service life of the lamp is long.

Description

technical field [0001] The invention relates to circuit protection, in particular to an overheating protection circuit, an LED driving circuit and a lamp. Background technique [0002] Since LED has the advantages of energy saving, environmental protection, and high efficiency, and basically does not require maintenance, and has high luminous efficiency, LED is more and more popular as a lighting source. However, when the temperature of traditional LED lamps is too high, it will cause serious light decay of the light source, resulting in a significant reduction in its service life. Contents of the invention [0003] Based on this, it is necessary to provide an overheating protection circuit for the problem that the service life of the LED lamp is reduced due to the high working temperature. [0004] In addition, an LED driving circuit is also provided. [0005] Finally, a light fixture is also provided. [0006] An overheating protection circuit, used to detect the temp...

AI Technical Summary

Problems solved by technology

[0003] Based on this, it is necessary to provide an overheating protection circuit for reducing the service life of LED lamps due to excessive operating temperature.

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