Chopping control linear switch constant current constant power circuit

Abstract

The invention discloses a chopping control linear switch constant current constant power circuit. The chopping control linear switch constant current constant power circuit includes a rectification circuit and a current control circuit. The current control circuit includes a chopping comparison amplifier A, a constant comparison amplifier B and a constant current transistor Q1. The output terminal of the chopping comparison amplifier A is connected with a positive electrode input terminal of the constant current comparison amplifier B. A negative input terminal of the constant current comparison amplifier B is connected with a source electrode of the constant current transistor Q1. The output terminal of the constant current comparison amplifier B is connected with a grid electrode of the constant current transistor Q1. A drain electrode of the constant current transistor Q1 is connected with the negative electrode of an LED. The positive electrode of the LED is connected with an output terminal of the rectification circuit. A source electrode of the constant current transistor Q1 is in grounded connection via a current detecting resistor R4. A negative electrode input terminal of the chopping comparison amplifier A is connected with the output terminal of the rectification circuit via a resistor R1 and is in grounded connection via a resistor R2. According to the invention, by adopting chopping technology, constant power, dimming and overvoltage protection of the linear constant current circuit are achieved and the power consumption of the constant current transistor Q1 is also reduced.

Description

technical field [0001] The invention relates to the technical field of electronic drive circuit control, in particular to a chopping control linear switch constant current and constant power circuit. Background technique [0002] As an efficient new light source, LED is widely used in lighting in various fields due to its long life, low energy consumption, energy saving and environmental protection. [0003] When the LED is used as the light source of the lamp, the service life of the lamp not only depends on the LED lamp bead itself, but also includes the driving power. In the current application scheme, the life of the LED lamp mainly depends on the driving power. The main driving power types are: 1) switching power supply ; 2) linear constant current power supply; 3) RC power supply. [0004] The linear constant current drive power supply is cost-effective, but there are also some fatal shortcomings. When the grid voltage rises, the voltage drop of the regulating tube Q1...

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Problems solved by technology

[0004] The linear constant current drive power supply is cost-effective, but there are also some fatal shortcomings. When the grid voltage rises, the voltage drop of the regulating tube Q1 increases, causing serious heat generation, and the input power also fluctuates with the grid voltage fluctuation, which seriously affects the reliability of the linear power supply. sex

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