Piecewise linear constant current LED drive circuit

Abstract

The invention discloses a piecewise linear constant current LED drive circuit. The piecewise linear constant current LED drive circuit comprises a rectifier bridge, a high voltage voltage-stabilizing voltage-reducing circuit, an output reference voltage circuit, and a linear constant current circuit, wherein the rectifier bridge performs full-wave rectification on sinusoidal voltage waveforms of 220V / 50Hz, and is connected to the high voltage voltage-stabilizing voltage-reducing circuit and an LED lamp string; the high voltage voltage-stabilizing voltage-reducing circuit uses a high-voltage LDMOS tube to charge an RC circuit, obtains a stable output voltage through a linear voltage stabilizing circuit, and is connected to the output reference voltage circuit; the output reference voltage circuit outputs a reference voltage and is connected to the linear constant current circuit, and the linear constant current circuit uses an integrated high-voltage power tube as a regulating tube, and achieves constant current output through feedback control over the regulating tube. According to the piecewise linear constant current LED drive circuit, the technical problems in the prior art are solved that a capacitor is ageing, the service life is sharply shortened, the service life of a driving power source is influenced, and further the service life of an LED whole lamp is shortened caused when an LED driving circuit is liable to the influence of an operating temperature and is thus prone to volatilization and leakage of electrolytic solution and lowing of capacitance capacity when an electrolytic capacitor is utilized.

Description

technical field [0001] The invention belongs to the technology of LED drive power supply, in particular to a segmented linear constant current LED drive circuit. Background technique [0002] In the 21st century, as a solid-state light source, LED is a typical green lighting source, which has the characteristics of long life, high luminous efficiency, and low power consumption. In LED lighting technology, the driving of the power supply is very important, which involves the service life of the LED lamp and various electrical properties. So far, LED driving power has been roughly developed into switching power supply and linear power supply. Switching power supply has the advantages of high efficiency and low power consumption. However, due to the circuit structure, the circuit has serious interference. These switching interferences may be connected to the power grid in series. Interfere with nearby electrical equipment and affect the normal operation of other electrical app...

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Problems solved by technology

[0003] The technical problem to be solved by the present invention: provide a piecewise linear constant current LED drive circuit to solve the problem that the LED drive circuit in the prior art uses electrolytic capacitors, which are easily affected by the working temperature, and the electrolyte volatilization and leakage occur, and the capacitance capacity Problems such as decline lead to aging of the capacitor and a greatly reduced service life, which affects the service life of the drive power supply, thereby reducing the service life of the LED lamp and other technical problems

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