Device for controlling input surge current of LED module

Abstract

The invention discloses a device for controlling an input surge current of an LED module, and is used to control a current going through the LED module. The device comprises a power supply unit and a control unit; the power supply unit supplies power to the control unit; the control unit and the LED module are connected in series; and the control unit comprises a switch element which is connected in series with the LED module, a sampling circuit which is connected to the switch element, and also a current limiting unit; the LED module has a rated current; the sampling circuit samples the current going through the LED module; when the current flowing through the LED module is within a rated current range, the switch element of the control unit works in a saturated conduction state; when the current flowing through the LED module is greater than the rated current range, the current limiting unit starts limiting the current according to a signal sent by the sampling circuit, so that the switch element of the control unit works in a linear amplifying state; and accordingly, the current flowing through the LED module is controlled.

Description

【Technical field】 [0001] The invention relates to a control device, in particular to a control device for input surge current of an LED module. 【Background technique】 [0002] LED light source is more and more valued by the lighting industry due to its high luminous efficiency and long life. Different from traditional light sources, LED light sources require constant DC drive. Generally, a constant current drive power needs to be added between the input and the LED light source. Please refer to figure 1 As shown, the input voltage Vin can be an AC mains input or a DC input to provide power to the LED light source. The driving power supply is often a power conversion circuit, which can be a switching power supply or a linear constant current circuit, which is used to provide the DC signal required by the LED light source. The output terminal of the drive power supply is often connected with an output capacitor Co, which is mainly used to filter the output current ripple of ...

AI Technical Summary

Problems solved by technology

However, since the resistance value of the NTC changes in a relatively slow process, the current limiting effect on poor contact or fast hot-swapping is relatively limited, and the NTC itself will generate heat, which will affect the temperature characteristics of the module.

Moreover, if the NTC resistor is used to limit the current, the surge current flowing into the LED module will increase with the increase of the input surge voltage, and the upper limit of the current cannot be set well.

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