Constant current controller and BUCK constant current circuit

Abstract

The invention provides a constant current controller and a BUCK constant current circuit. The constant current controller is applied to the BUCK constant current circuit. A DC power supply is connected to the constant current controller, and the constant current controller outputs constant current power to a load. The BUCK constant current circuit comprises a first resistor, a first capacitor, a fly-wheel diode and a first inductor. The constant current controller comprises a switching tube, a peak limiting module and a demagnetization detection module. The peak limiting module is used for detecting the magnitude of a current flowing through the first resistor through a voltage sampling end and controlling the switching tube to be switched off according to the magnitude of the current. The demagnetization detection module is used for detecting the demagnetization time of the first inductor through a demagnetization detection end and controlling the switching tube to be switched on according to the demagnetization time. Through the constant current controller and the BUCK constant current circuit, an existing current detection and demagnetization detection mode is changed, the circuit does not need a current detection port or a feedback circuit, an external divider resistor is omitted, adverse effects caused by the damp resistors are avoided, and the cost is lowered.

Description

technical field [0001] The invention belongs to the technical field of constant-current driving power supply, and in particular relates to a BUCK constant-current circuit and a constant-current controller applied to the BUCK (step-down conversion) constant-current circuit. Background technique [0002] LED lighting source has the advantages of environmental protection, energy saving, long life, etc., and is regarded as the most promising lighting source in the 21st century. In recent years, with the development of LED lighting technology, LED lighting sources have begun to replace traditional light sources and are widely used in various lighting fixtures. In order to obtain ideal lighting effects, LEDs require constant current drive power. [0003] At present, the commonly used BUCK constant current circuit structure with FB (FeedBack) feedback on the market is as follows: figure 1 As shown, this structure requires the FB feedback port to sample the output voltage informati...

AI Technical Summary

Problems solved by technology

[0004] Based on this, it is necessary to provide a constant current controller that eliminates the current detection port, the feedback port, and the external voltage-dividing resistor for the problems that the external voltage-dividing resistor is easily affected by moisture and the output overvoltage protection threshold cannot be adjusted flexibly.

Images