Overcurrent/overpower protection method of switching power supply, protection circuit and switching power supply

A technology of over-power protection and switching power supply, which is applied in the direction of output power conversion devices and electrical components, which can solve the problems of switching power supply sub-harmonic oscillation and failure to start normally, and achieve the effect of suppressing sub-harmonic oscillation

Inactive Publication Date: 2014-04-02
BCD SEMICON MFG
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] In view of this, the present invention provides an over-current / over-power protection method, protection circuit and switching power supply of a switching power supply, so as to overcome the sub-harmonic oscillation of the switching power supply in the prior art under the condition of low line voltage and heavy load , so that the problem of not being able to start normally

Method used

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  • Overcurrent/overpower protection method of switching power supply, protection circuit and switching power supply
  • Overcurrent/overpower protection method of switching power supply, protection circuit and switching power supply
  • Overcurrent/overpower protection method of switching power supply, protection circuit and switching power supply

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Embodiment 1

[0058] Please refer to the attached Figure 4 , an overcurrent / overpower protection circuit 400 for a switching power supply provided by the present invention is applied to a switching power supply, including: a sample & hold circuit 460 and an overcurrent / overpower protection module 410 . Wherein, the overcurrent / overpower protection module 410 includes: a logic controller 420 , a voltage-current converter R440 , a compensation resistor R415 , a driving circuit 425 , and an overcurrent comparator 426 .

[0059] combine Figure 4 , to describe the connection relationship of the above-mentioned circuit components: the diode rectifier bridge 401 converts the AC voltage Vac into a DC voltage, and its output positive terminal is respectively connected to the first terminal of the filter capacitor C411 and the opposite end of the primary side inductance Lp3 of the transformer. The second end of the capacitor C411 is connected to the negative output end of the diode rectifier bridg...

Embodiment 2

[0080] Please refer to the attached Figure 9 , an overcurrent / overpower protection circuit 800 for a switching power supply provided by the present invention is applied to a switching power supply, including: a sample & hold circuit 850 and an overcurrent / overpower protection module 810 . Wherein, the overcurrent / overpower protection module 810 includes: a logic control circuit 620 , a driving circuit 625 , a voltage-voltage converter 830 , and a current comparator 833 .

[0081] Among them, the diode rectifier bridge 801 converts the AC voltage Vac into a DC voltage, and its positive output terminal is respectively connected to the first terminal of the filter capacitor C811 and the opposite end of the primary side inductance Lp8 of the transformer, and the second terminal of the filter capacitor C811 is connected to the diode rectifier The negative output terminals of bridge 801 are connected to ground. The terminal with the same name of the primary inductor Lp8 of the tra...

Embodiment 3

[0086] The circuit is described in detail in the above embodiments provided by the present invention. Based on the above-mentioned overcurrent / overpower protection circuit of the switching power supply, the present invention also provides an overcurrent / overpower protection method of the switching power supply, such as Figure 10 As shown, specific examples are given below for detailed description.

[0087] The overcurrent / overpower protection method of the switching power supply is based on the overcurrent / overpower protection circuit of the switching power supply provided in Embodiment 1 or Embodiment 2. The overcurrent / overpower protection circuit of the switching power supply is applied to a switching power supply, including : Diode rectifier bridge, filter capacitor, transformer primary inductance, oscillator, logic controller, voltage-current converter, compensation resistor, power transistor, drive circuit, overcurrent comparator, sampling resistor and sample & hold circ...

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PUM

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Abstract

The invention discloses an overcurrent / overpower protection method of a switching power supply. The protection method is applied to the switching power supply. The switching power supply comprises a control circuit used for controlling breakover and cut-off of a power tube, wherein the control circuit comprises an overcurrent / overpower protection module. The protection method comprises the following steps: a first signal is collected and kept to form a line voltage compensation signal which is constant in a preset time range, and the line voltage compensation signal is loaded to the overcurrent / overpower protection module, and the first signal is matched with the duty cycle of a PWM (Pulse-Width Modulation) signal, so that a line voltage compensation value is kept constant in a certain time range by the method, and is not timely changing along with the PWM signal, so that the sub-harmonic oscillation is effectively restrained from the source.

Description

technical field [0001] The invention relates to the field of switching power supplies, and more specifically, relates to an overcurrent / overpower protection method, a protection circuit and a switching power supply of a switching power supply. Background technique [0002] With the rapid development of the electronic information industry, switching power supplies are widely used in computers, electrical equipment, instruments, LED lighting, medical equipment, military equipment and other fields. Usually, a switching power supply converts an external alternating current (such as mains 220V, 380V, etc.) into a stable direct current to supply the load. [0003] Switching power supply has many protection functions, such as over-voltage and under-voltage protection, over-temperature protection, over-current protection, over-power protection, etc. These protection functions avoid damage to the power integrated IC and the entire switching power supply. [0004] However, in the ca...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02M1/32
Inventor 赵安东应征李冬超
Owner BCD SEMICON MFG
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