Method and device for short-circuit protection of current detection resistor of LED (Light Emitting Diode) driving circuit

Abstract

The embodiment of the invention discloses a method and a device for short-circuit protection of an LED (Light Emitting Diode) resistor. The method comprises the steps of: monitoring the changes of output voltages at a plurality of preset time points on a current detection resistor along the pulse starting time in a single pulse generation cycle of an LED driving circuit; when the output voltages at the preset time points do not increase along with the pulse starting time, judging that the current detection resistor is in short circuit; and starting short-circuit protection. According to the embodiment of the invention, by means of detecting and comparing the voltage values of the Rs (Resistor) at the preset time points in one cycle, the corresponding short-circuit protection is started when the Rs is judged to be in short circuit according to the condition whether the voltage on the Rs increases along with the increase of the starting time (inductive current), and the defects that short-circuit protection measures are in shortage when the current detection resistor Rs of the LED driving circuit is in short circuit and an integrated circuit board is burned down due to Rs short circuit are overcome.

Description

technical field [0001] The invention relates to the technical field of LED short-circuit protection, and more specifically, to a method and device for LED resistance short-circuit protection. Background technique [0002] Light-emitting diode (LED) is a solid-state semiconductor device that can convert electrical energy into visible light. LED can directly convert light energy into electrical energy. Due to its advantages of low energy consumption and high luminous efficiency, it is widely used in lighting and decoration. [0003] Such as figure 1 As shown in a typical LED drive circuit, when the output LED current detection resistor Rs is short-circuited, the flip-flop responsible for controlling the LED lamp is still sending out pulses to drive and light the LED lamp, and when the circuit corresponds to the maximum duty ratio pulse , the output current increases sharply and causes damage to line devices. [0004] However, the existing short-circuit protection methods onl...

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Problems solved by technology

[0003] like figure 1 As shown in a typical LED drive circuit, when the output LED current detection resistor Rs is short-circuited, the flip-flop responsible for controlling the LED lamp is still sending out pulses to drive and light the LED lamp, and when the circuit corresponds to the maximum duty ratio pulse , the output current increases sharply and causes damage to line devices

[0004] However, the existing short-circuit protection methods only take into account the short-circuit of the LED lamp, and lack short-circuit protection measures for the short-circuit of the current detection resistor Rs of the LED drive circuit, and the burning of the integrated circuit board due to the short-circuit of Rs occurs. Phenomenon

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