LED protecting chip based on PWM shunt

A technology for protecting chips and generating units, which is applied in the direction of protection against overvoltage, emergency protection device for automatic disconnection, emergency protection circuit device, etc., and can solve the problems that the switch cannot be reset automatically and the shutdown is uncontrollable, etc. Achieve the effects of complete protection functions, easy integration, and simple power supply

Active Publication Date: 2010-05-26
CHONGQING UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Since the silicon controlled rectifier SCR is a semi-controlled device, its shutdown is unco

Method used

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  • LED protecting chip based on PWM shunt
  • LED protecting chip based on PWM shunt
  • LED protecting chip based on PWM shunt

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Embodiment Construction

[0026] The present invention will be described in further detail below in conjunction with the accompanying drawings and specific embodiments.

[0027] figure 1 It is the working principle diagram used on the LED of the present invention, as shown in the figure: in the figure, three LEDs are connected in series, respectively in the LED 1 ,LED 2 and LED 3 A PWM shunt switch is connected in parallel at both ends of each, and by adjusting the parallel PWM shunt switch (S 1 , S 2 , S 3) duty cycle to achieve constant temperature overvoltage circuit breaker protection for each LED. The control signal that controls the duty cycle of the PWM shunt switch is based on changes in sensed LED temperature, overvoltage and open circuit signals. When the LED is working normally and the temperature is lower than the temperature protection point, the duty ratio of the PWM shunt switch is 0, and the switch is always in the off state, which does not affect the normal operation of the LED. ...

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Abstract

The invention discloses an LED protecting chip based on PWM shunt, which comprises a PWM shunt switch, a power supply unit, a voltage detecting unit, a temperature detecting unit and a PWM control signal generating unit, wherein the PWM shunt switch is connected with two ends of an LED in parallel, and the current passing through the LED is controlled by controlling the working duty ratio of the PWM shunt switch; the power supply of the chip is taken from the two ends of the LED and supplies power for other units after being processed by the power supply unit; the grounding terminals of the power supply unit, the temperature detecting unit and the PWM control signal generating unit are connected with the cathode of the LED; the voltage detecting unit and the temperature detecting unit respectively detect the voltages at the two ends of the LED and the junction temperature of the LED, and detecting signals output by the voltage detecting unit and the temperature detecting unit are connected with the PWM control signal generating unit; and PWM signals generated by the PWM control signal generating unit are connected with the control terminal of the PWM shunt switch to realize constant temperature, overvoltage and shut-off protection of the LED. The LED protecting chip has the advantages of complete protecting functions, low power loss, simple power supply and easy integration.

Description

technical field [0001] The invention relates to the field of LED protection, in particular to an LED protection chip based on PWM shunting. Background technique [0002] LED has the advantages of high light quality, energy saving, green environmental protection, etc., and its application is more and more extensive. Because the photoelectric conversion efficiency of LED is not high, only about 15%-20% of the electrical energy is converted into light output, and the rest is converted into heat energy, which will increase the junction temperature of the LED. The relative luminous efficiency of LED will decrease linearly with the increase of temperature, and the light attenuation is serious; the luminous wavelength of LED will drift significantly with the increase of temperature when the temperature exceeds 50°C, which will reduce the quality of light; the junction of LED The temperature rise will also significantly shorten the working life of the LED. According to the data, if...

Claims

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Application Information

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IPC IPC(8): H02H5/04H02H3/20H05B37/02
Inventor 周雒维孙明坤罗全明杜雄
Owner CHONGQING UNIV
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