Simple circuit for implementing constant currents

Abstract

The invention relates to a simple circuit for implementing constant currents. The simple circuit comprises a first resistor, a second resistor, a voltage stabilizer and a transistor. One end of the first resistor is connected with a cathode of the voltage stabilizer and a base electrode of the transistor, the other end of the first resistor is used as a current output end, an anode of the voltagestabilizer is connected with one end of the second resistor, the other end of the second resistor is parallelly connected with a voltage input end of the voltage stabilizer and an emitting electrode of the transistor, and a collecting electrode of the transistor is used as a current output end. The simple circuit has the advantages that values of the constant currents in the simple circuit are related to Vref and additional resistors, and the simple circuit can be applied to circuits with requirements on constant currents and also can be applied to LED lamps.

Description

technical field [0001] The invention relates to a constant current circuit, in particular to a simple circuit for realizing constant current. Background technique [0002] A constant current source is a current source whose output current remains constant, and an ideal constant current source does not change due to changes in load or ambient temperature, and its internal resistance is infinite. It can be used in circuits that require constant current, and can also be used in LED lights. [0003] Most of the traditional AC constant current power supply adopts the form of AC-AC power conversion. The mains power is converted into an AC voltage with an appropriate amplitude through an autotransformer, and the output voltage of the autotransformer is converted into the required AC current through a step-down and step-up transformer. , the output current value is collected at the output terminal and fed back to the control system. The control system adjusts the change of the cent...

AI Technical Summary

Problems solved by technology

[0003] Most of the traditional AC constant current power supply adopts the form of AC-AC power conversion. The mains power is converted into an AC voltage with an appropriate amplitude through an autotransformer, and the output voltage of the autotransformer is converted into the required AC current through a step-down and step-up transformer. , the output current value is collected at the output terminal and fed back to the control system. The control system adjusts the change of the center tap of the autotransformer according to the return current value and the input current value to adjust its output voltage. Due to the autotransformer and step-down step-up transformer Due to the limitation of its own characteristics, the traditional high-current AC constant current source has disadvantages such as complex circuit, large volume, low precision, and high cost.

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