Light-emitting diode (LED) constant current drive circuit and LED lighting device

Abstract

The invention discloses a light-emitting diode (LED) constant current drive circuit and an LED lighting device, wherein the LED constant current drive circuit comprises a power source and an LED load, the power source is connected with the LED load, and the LED constant current drive circuit further comprises a boost-type constant current output circuit and a power control circuit. The boost-type constant current output circuit is used for outputting constant current to the LED load, and the power control circuit is connected with the power source, the LED load and the boost-type constant current output circuit and used for conducting power supply control and protecting power supply of the LED load. The LED constant current drive circuit serves as the boost-type constant current output circuit so that boosting and decompression control can be achieved by controlling the duty ratio of pulsing communication and pulsing closing of a metal oxide semiconductor (MOS) pipe in a constant current chip according to the value of the sampled voltage, and therefore the output current is controlled to a preset value so as to keep constant current output, the LED can be driven to work safely and reliably.

Description

technical field [0001] The invention relates to the field of LED lighting, in particular to an LED constant current drive circuit and an LED lighting device. Background technique [0002] As a new light source, LED has the characteristics of energy saving, environmental protection and high efficiency. The technology has matured and has been widely used as a lighting source, and various LED drive circuits have also appeared. As a constant current load, LED itself has strict requirements on the working voltage, too high or too low voltage will cause the LED to work abnormally, so the power supply quality of the power supply voltage directly affects the reliability of the LED. At present, DC low-voltage power supply, such as lithium battery power supply, lead-acid battery power supply, DC power supply, etc., all use step-down constant current technology to drive LED, which has low power consumption, high efficiency, small unit power volume, light weight, etc. advantage. [00...

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Problems solved by technology

[0003] However, the first condition for the operation of this step-down constant current output circuit is that its input voltage is required to be higher than the voltage sum of the LED lamp group. When the input voltage is lower than the voltage sum of the LED lamp group, the step-down constant current circuit cannot output The constant current guarantees the constant current operation of the LED, resulting in a decrease in the output luminous flux of the LED, and the LED cannot work at full load, which brings serious inconvenience to the user and has limitations.

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