A flyback switching power supply with limited power supply protection function

A technology of switching power supply and protection function, which is applied in the field of flyback switching power supply, can solve the problems of increasing design cost and achieve the effect of easy implementation and overcoming the increase of design cost

Active Publication Date: 2021-04-20
TPV ELECTRONICS (FUJIAN) CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the flyback switching power supply with dual outputs is protected by LPS by connecting a fuse in series at the output end, which increases the design cost

Method used

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  • A flyback switching power supply with limited power supply protection function
  • A flyback switching power supply with limited power supply protection function
  • A flyback switching power supply with limited power supply protection function

Examples

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Embodiment Construction

[0029] Please refer to figure 2The flyback switching power supply of the present invention has an input terminal IN and an output terminal OUT. The input terminal IN receives AC mains power such as 90V-264V / 50Hz or 60Hz, and the output terminal OUT outputs 19V / 2A for power supply to the display. The flyback switching power supply includes a power switch Q1, a transformer T1, a resistor Rs, a feedback circuit and a controller U2. The power switch Q1 has a first terminal, a second terminal and a control terminal, and the control terminal controls the first terminal and the second terminal to be turned on or off; in this embodiment, the power switch Q1 is an N-channel metal oxide semiconductor field effect Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET), the first terminal, the second terminal and the control terminal are respectively a drain terminal (Drain), a source terminal (Source) and a gate terminal (Gate). The transformer T1 has a primary side winding Np and ...

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PUM

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Abstract

The invention discloses a flyback switching power supply with power-limited power supply protection function, which includes a controller with a feedback pin and a driving pin. The feedback pin is coupled to the output end of the flyback switching power supply through the feedback circuit. The driving pin outputs a pulse width modulation (PWM) square wave, and the working frequency of the PWM square wave in the heavy-load working mode is higher than that in the light-load working mode. The controller includes an LPS detection module, which is coupled to the feedback pin and the drive pin. The LPS detection module is used to detect whether the voltage of the feedback pin is lower than the voltage threshold. The voltage threshold is equal to the voltage of the feedback pin in light-load operation mode; if the feedback pin If the voltage is lower than the voltage threshold, it is detected whether the conduction time of the PWM square wave is greater than the time threshold; and if the conduction time of the PWM square wave is greater than the time threshold, the driving controller stops outputting the PWM square wave.

Description

technical field [0001] The present invention relates to a flyback switching power supply, and in particular to a flyback switching power supply with a Limit Power Source (LPS) protection function. Background technique [0002] When a switching power supply meets the requirement that the output is not greater than 8A / 100W under normal conditions and single fault conditions, the switching power supply is a limited power supply (LPS). In the safety standard IEC 60950, it is required that information products must provide a fireproof enclosure. However, when an information product is powered by a limited power supply (LPS), if the electronic components are placed in a printed circuit with a flame-retardant rating of V-1 or higher board, information products do not need to provide a fire-resistant casing, that is, a casing with a flame-retardant grade HB can be used. The shell material of flame retardant grade HB not only has low price, but also has good physical properties, and...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02M3/335H02H7/12
Inventor 余祚尚王舜弘
Owner TPV ELECTRONICS (FUJIAN) CO LTD
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