Overvoltage protective circuit in LED driving power supply without auxiliary winding

An overvoltage protection circuit and LED driving technology, applied in emergency protection circuit devices, electrical components, etc., can solve the problems of small size and low cost that are not suitable for LEDs

Active Publication Date: 2014-06-25
BCD (SHANGHAI) MICRO ELECTRONICS LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] It can be seen from this that the traditional LED overvoltage protection scheme increases the volume and cost of the entire LED drive power supply. In order to detect the overvoltage point, it is necess

Method used

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  • Overvoltage protective circuit in LED driving power supply without auxiliary winding
  • Overvoltage protective circuit in LED driving power supply without auxiliary winding
  • Overvoltage protective circuit in LED driving power supply without auxiliary winding

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Embodiment Construction

[0036] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

[0037] The embodiment of the present invention discloses an overvoltage protection circuit in an LED drive power supply without an auxiliary winding. It does not need a separate transformer winding to detect the output voltage, nor does it need to detect the pin position, so that the LED drive power produced can be Smaller size and lower cost.

[0038] In order to solve the problems of high cost and limited application in the prior art, the present in...

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PUM

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Abstract

The invention provides an overvoltage protective circuit in an LED driving power supply without an auxiliary winding. A sampling and holding unit detects a voltage Vcs flowing through a current sampling resistor of the driving power supply; a time detection unit detects conduction time of a secondary side diode of the driving power supply, and the conduction time is utilized to generate a voltage Vref via a current source and a charging capacitor; when the conduction time of the secondary side diode ends, a first comparator compares the voltage Vref and the voltage Vcs, and when the voltage Vref is less than the voltage Vcs, the first comparator outputs an overvoltage signal to a control logic unit; the control logic unit outputs a switching signal to a switching driving unit according to the overvoltage signal; and the switching driving unit turns off a power tube of the driving power supply according to the received switching signal. An independent transformer winding is not needed in detection of the output voltage, and detection of a pin bit is also not needed so that the manufactured LED driving power supply is smaller in volume and lower in cost.

Description

technical field [0001] The invention relates to the technical field of LED overvoltage protection, and more specifically relates to an overvoltage protection circuit in an LED driving power supply without auxiliary windings. Background technique [0002] With the continuous development of electronic technology, the application range of LED lights is becoming wider and wider. The working principle of the LED lamp is to provide a constant output current through the LED drive power supply to light the LED lamp. Therefore, when the output LED is open circuit or other circumstances make the output voltage higher, the LED drive power supply must take corresponding measures to keep the output voltage not exceeding the withstand voltage of the output capacitor, otherwise the output capacitor will be easily burned out. In the traditional LED drive power supply, a separate transformer winding is generally used to detect the output voltage, and then divided by resistors, input to a se...

Claims

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Application Information

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IPC IPC(8): H02H7/20
Inventor 张铮栋张炜周松明刘准朱亚江
Owner BCD (SHANGHAI) MICRO ELECTRONICS LTD
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