Constant-current control method of power switch type LED (Light-Emitting Diode) drive circuit and circuit thereof

A technology of LED drive and power switch, applied in the direction of energy-saving control technology, lamp circuit layout, electric light source, etc., can solve the problems of reducing system reliability, increasing system cost, application customer obstacles, etc., and achieve good load regulation rate and current control The effect of high precision and small number of components

Inactive Publication Date: 2010-08-18
王桂兰
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, these schemes are often complex
Due to the need for more peripheral devices, the system cost is increased and the reliability

Method used

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  • Constant-current control method of power switch type LED (Light-Emitting Diode) drive circuit and circuit thereof
  • Constant-current control method of power switch type LED (Light-Emitting Diode) drive circuit and circuit thereof
  • Constant-current control method of power switch type LED (Light-Emitting Diode) drive circuit and circuit thereof

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[0030] image 3 The schematic diagram of the circuit principle of the non-peak current detection LED driving circuit of the present invention is shown. The non-peak current detection LED driving circuit 1 of the present invention is used to drive an LED lamp group 2, which consists of one LED or multiple LEDs connected in series. The LED drive circuit 1 includes a freewheeling diode 3, an energy storage inductor 4, a power switch 5, a current detection circuit 6, a power switch control circuit 7 and a power supply 8. The anode of the LED lamp group 2 is connected to the anode of the power supply 8, and the cathode is connected to the energy storage The first end of the inductor 3 is connected, and the second end of the energy storage inductor 3 is connected to the drain of the power switch 5. The anode of the freewheeling diode 3 is connected to the drain D of the power switch 5, and the cathode is connected to the anode of the LED lamp group 2. The input terminal of the curre...

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Abstract

The invention relates to a constant-current control method of a power switch type LED drive circuit and a circuit thereof. The method comprises the following steps of: setting a reference voltage value corresponding to the constant average current value of an LED lamp group and the sustainable turn-off time T2 of a power switch; opening the power switch to acquire an induced voltage corresponding to the working current of the LED lamp group, and comparing the induced voltage and the reference voltage value; accumulating the sustainable opening time Ta of the power switch since the power switch is opened until the induced voltage reaches the reference voltage value; accumulating the sustainable opening time Tb of the power switch since the induced voltage of the LED lamp group reaches the induced voltage value, when Tb is equal to Ta, turning off the power switch; and since the power switch is turned off, timing the sustainable turn-off time of the power switch, and after the set sustainable turn-off time T2 is reached, opening the power switch. The invention realizes the direct control on average current and improves the control precision on the current.

Description

technical field [0001] The invention relates to a constant current control method and a circuit of a power switch type LED drive circuit. Background technique [0002] As we all know, with the rapid development of light-emitting diode (LED) manufacturing technology, LED light source has been widely used in various fields such as backlight, automotive lighting and general lighting because of its high efficiency, reliability, durability, energy saving and environmental protection. The LED itself is a constant current device, which means that it needs a constant current to drive to maintain stable and reliable light. In practical applications, most of the power supply sources are constant voltage sources, so a specific LED drive circuit is required to extract power from the power supply in the form of constant current and supply it to the LED. [0003] At present, the mainstream LED drive circuits are mainly divided into two categories: linear current type and switching curren...

Claims

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Application Information

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IPC IPC(8): H05B37/02
CPCY02B20/42Y02B20/40
Inventor 王桂兰
Owner 王桂兰
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