White-light LED (Light-Emitting Diode) constant-current driving power supply based on pulse width modulation circuit

Abstract

The invention discloses a white-light LED (Light-Emitting Diode) constant-current driving power supply based on a pulse width modulation circuit. The white-light LED constant-current driving power supply is characterized by mainly consisting of a voltage-stabilizing chip U, a transformer T, a diode D1, a polar capacitor C2, a polar capacitor C1, a diode D2, an operational amplification circuit, a second-order filtering circuit and the pulse width modulation circuit, wherein a P electrode of the diode D2 is connected with a non-dotted terminal of a secondary side inductance coil of the transformer T, and an N electrode of the diode D2 is connected with a negative electrode of the polar capacitor C1; the operational amplification circuit is connected with the N electrode of the diode D1 and the voltage-stabilizing chip U; the second-order filtering circuit is connected with the operational amplification circuit; and the pulse width modulation circuit is connected in series between the operational amplification circuit and the second-order filtering circuit. Through adoption of the white-light LED constant-current driving power supply, the voltage resistance of a voltage can be enhanced effectively, the dynamic range of the voltage can be extended effectively, and the middle null offset of current can be controlled within 0.5nA, so that the stability of an output voltage and output current is ensured, and the stability of the brightness of a white-light LED lamp is ensured effectively.

Description

technical field [0001] The invention relates to the field of electronics, in particular to a white LED constant current drive power supply based on a pulse width modulation circuit. Background technique [0002] As a new type of energy-saving light source, white LED lights have been widely accepted and adopted by people due to their environmental protection, energy saving, long life, and small size. Since the white light LED is a characteristic sensitive semiconductor device and has negative temperature characteristics, the white light LED power supply plays a very important role in promoting the white light LED to be in a stable working state during the application process. The currently used white LED power supply has the problem of unstable output voltage and current due to external electromagnetic wave interference, resulting in unstable brightness of the white LED lamp, thereby affecting the service life of the white LED lamp. [0003] Therefore, it is urgent to provid...

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Problems solved by technology

[0004] The purpose of the present invention is to overcome the defect of unstable output voltage and current in the white LED power supply in the prior art due to external electromagnetic wave interference, and provide a white LED constant current drive power supply based on pulse width modulation circuit

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