Constant current output control device for LED drive circuit
A technology for driving circuits and circuits, which is applied in the layout of electric lamp circuits, lighting devices, electric light sources, etc., can solve the problems of the influence of circuit output current, and achieve the effect of facilitating precise control, improving stability, and saving chip area.
Inactive Publication Date: 2014-08-27
UNIV OF ELECTRONICS SCI & TECH OF CHINA
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Problems solved by technology
[0005] This basic constant current control structure is simple, but the circuit has the inherent disadvantage that the output current is affected by the parameters of the peripheral circuit
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[0020] Such as image 3 As shown, this example includes a drive circuit, a BUCK circuit, a time balance module, a time control module, and an average current sampling module; the time balance module is connected to the drive circuit, the time control module, and an average current sampling module; the BUCK circuit is connected to the drive circuit and the average current sampling module respectively. The average current sampling module is connected; the time balance module is used to output the conduction signal through the drive circuit, and the time for controlling the current in the BUCK circuit from the minimum value to the current average value is equal to the time from the current average value to the peak current; the time control module is used to pass The drive circuit outputs a shutdown signal; where,
[0021] The BUCK circuit is composed of a switch tube Q1, an inductor L1, a capacitor C1 and a diode D1; wherein, the drain of the switch tube Q1 is connected to the p...
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The invention relates to an electronic circuit technology, in particular to a constant current output control device for an LED drive circuit. The constant current output control device comprises a drive circuit and a BUCK circuit and is characterized by further comprising a time balancing module, a time control module and an average current sampling module; the time balancing module is connected with the drive circuit, the time control module and the average current sampling module; the BUCK circuit is connected with the drive circuit and the average current sampling module; the time balancing module is used for outputting breakover signals through the drive circuit, and controlling time for making currents in the BUCK circuit change from the minimum value to a current average value to be equal to time for making currents change from the current average value to a peak value. The time control module is used for outputting turn-off signals through the drive circuit. The constant current output control device has the advantages that the problem that output currents in the drive circuit are affected by parameters of input voltages, output voltages and inductance is solved, and constant current output stability is greatly improved. The constant current output control device is especially suitable for the LED drive circuit.
Description
technical field [0001] The invention belongs to electronic circuit technology, and in particular relates to a constant current output digital control device for an LED drive circuit based on a Buck circuit (the Buck circuit is a DC-DC step-down topology). Background technique [0002] LED has become the green lighting technology in today's society due to its long life, high brightness, stable performance, and no pollution. For the LED drive circuit, if the LED is driven by an ordinary regulated source, when the voltage fluctuates slightly, the current through the LED lamp fluctuates greatly, and it is easy to cause unstable brightness or even over-current phenomenon and burn the LED. Drive with constant current. [0003] Such as figure 1 Shown is a schematic diagram of an output constant current circuit based on the BUCK topology in a traditional way. The circuit mainly includes a freewheeling diode D, a switch tube Q, an energy storage inductor L, a load LED lamp, a dete...
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IPC IPC(8): H05B37/02
Inventor 方健马佳佳杜世才胥林江伍滔赵帅
Owner UNIV OF ELECTRONICS SCI & TECH OF CHINA