Unlock instant, AI-driven research and patent intelligence for your innovation.

Secondary overpower protection circuit and switching power supply

An over-power protection, switching power supply technology, applied in the direction of emergency protection circuit devices, circuit devices, output power conversion devices, etc., can solve the problems of over-power use of power supply, reduce power supply life, low cost performance of power supply, etc., to avoid life attenuation. , The effect of reducing after-sales maintenance costs

Active Publication Date: 2016-04-27
深圳茂硕电子科技有限公司
View PDF8 Cites 0 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

When the output current changes, if you want to keep the maximum output voltage of the power supply unchanged, there are generally two design options: (1) The maximum output power of the power supply is designed at the maximum output voltage point, and the maximum output current is equal to the maximum output power divided by the maximum Output voltage, the disadvantage of this solution is that when the actual application voltage of LED products is smaller than the maximum output voltage of the power supply, the actual maximum output power of the power supply is smaller, and its value may be far less than the full-load output power of the power supply design. The higher the full-load output power, the higher the general price, so the power supply is less cost-effective; (2) The designed power supply can output the maximum power within a certain output voltage range, that is, the maximum allowable output current varies with the output voltage, and the output The allowable output current is higher when the voltage is lower. The disadvantage of this scheme is that the power supply may be used by overpower, and long-term overpower use will reduce the life of the power supply.

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Secondary overpower protection circuit and switching power supply
  • Secondary overpower protection circuit and switching power supply
  • Secondary overpower protection circuit and switching power supply

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] The secondary overpower protection circuit of the present invention is applied to a switching power supply, refer to figure 1 As shown, the secondary overpower protection circuit in Embodiment 1 includes a voltage follower circuit 100 and a voltage error amplifier circuit 200, wherein:

[0031]The voltage follower circuit 100 includes a PNP transistor Q1 and an NPN transistor Q2. The base of the PNP transistor Q1 is connected to the voltage sampling signal terminal Vref_I, its collector is grounded, and its emitter is connected to the power supply terminal Vcc through a bias resistor R2. The emitter is also connected to the base of the NPN transistor Q2; the collector of the NPN transistor Q2 is connected to the power supply terminal Vcc, its emitter is grounded through the bias resistor R3, and its emitter is also connected to an input end of the voltage error amplifier circuit. The voltage follower circuit 100 outputs a voltage follower signal equal to the voltage sam...

Embodiment 2

[0054] In the second embodiment, the voltage follower circuit 100 can also be designed with other structures. refer to figure 2 As shown, the voltage follower circuit includes an NPN transistor Q'1, the base of which is connected to the voltage sampling signal Vref_I through the bias resistor R'1, the collector of the NPN transistor Q'1 is connected to the power supply terminal Vcc, and the NPN transistor Q The emitter of '1 is grounded through a bias resistor R'2, and the emitter is also connected to the input end of the voltage error amplifier circuit 200. in:

[0055] V2=Vref_I-Vbe_Q'1(9)

[0056] V2 represents the voltage of the node V2, Vbe_Q'1 represents the be junction voltage of the NPN transistor Q'1, and Vref_I represents the voltage of the voltage sampling signal Vref_I terminal. When the voltage sampling signal Vref_I is much larger than the be junction voltage of the NPN transistor Q'1, for example, Vref_I When ≥10×Vbe_Q'1, the be junction voltage of NPN trans...

Embodiment 3

[0060] In the third embodiment, refer to image 3 As shown, the voltage follower circuit 100 may further include an operational amplifier U2, the non-inverting input terminal of which is connected to the voltage sampling signal Vref_I terminal through a resistor R'3, the inverting input terminal of the operational amplifier U2 is connected to its output terminal, the operational amplifier The output terminal of U2 is connected to the input terminal of the voltage error amplifier circuit 200 . in:

[0061] V2=Vref_I(11)

[0062] V2 represents the voltage of the node V2, and Vref_I represents the voltage at the terminal of the voltage sampling signal Vref_I, which is proportional to the output current of the switching power supply. It can be understood by those skilled in the art that the reverse changes of the maximum output voltage and output current allowed by the switching power supply can still be obtained through derivation.

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

The invention discloses a secondary overpower protection circuit, which comprises a voltage follower circuit and a voltage error amplifier circuit, wherein the voltage follower circuit outputs a voltage follower signal which is equal to a voltage sampling signal to the voltage error amplifier circuit; the voltage error amplifier circuit is used for carrying out summation on the voltage follower signal and an output voltage signal of a switching power supply and comparing the summation signal with a reference voltage signal to output a voltage signal to achieve closed-loop control of the switching power supply; and when the summation signal is equal to the reference voltage signal, the voltage error amplifier circuit is free of an output and a preset reference voltage limits reverse change of the voltage follower signal and the maximum allowable output voltage of the switching power supply, so that the maximum allowable output power of the switching power supply is limited; lifetime attenuation caused by overload use of the switching power supply is avoided; and reduction of the after-sales maintenance cost of a power supply product is facilitated.

Description

technical field [0001] The invention relates to the technical field of switching power supplies, in particular to a secondary overpower protection circuit and a switching power supply. Background technique [0002] A constant current source circuit is often set in the switching power supply to ensure that the switching power supply can still work normally under the condition of wide voltage input. Taking the LED driving power supply as an example (hereinafter referred to as the power supply), in order to match the volt-ampere characteristics of the LED, the power supply generally uses a constant current driving method. Due to the diversity of LED products, most power supplies are designed to be programmable, that is, to set the output current in a programmable way to meet the needs of different output parameters. When the output current changes, if you want to keep the maximum output voltage of the power supply unchanged, there are generally two design schemes: (1) The maxi...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Applications(China)
IPC IPC(8): H02H3/42H02M3/335
CPCH02H3/42H02M3/33523H02M1/0038
Inventor 邓勇丁华王华轶
Owner 深圳茂硕电子科技有限公司