Constant-current control circuit for isolated switching power supply

A technology of constant current control circuit and switching power supply, which is applied in the direction of control/regulation system, electrical components, and adjustment of electrical variables, etc. It can solve the problems of complex circuit structure, large PCB area, and large number of components, so as to reduce PCB area, The effect of cost reduction and simple structure

Active Publication Date: 2011-11-23
MAXIC TECHNOLOGY CORPORATION
View PDF2 Cites 5 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This kind of circuit structure is relatively complex, the number of components used is large, and the PCB

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
  • Constant-current control circuit for isolated switching power supply
  • Constant-current control circuit for isolated switching power supply
  • Constant-current control circuit for isolated switching power supply

Examples

Experimental program
Comparison scheme
Effect test

Example Embodiment

[0015] In the embodiment of the present invention, first discuss the principle of constant current control when the AC input voltage changes. figure 2 Shows the schematic diagram of the isolated switching power supply according to the related technology. In the isolated switching power supply, according to the conservation of energy, there are

[0016] Vo * Io * T = 1 2 * Lp * Idsp p 2 * eff T . . . . . . ( 1 )

[0017] Among them, Vo is the voltage of the output LED. Once the series-parallel relationship of the LEDs is determined, Vo is a certain value; Io is the average current of the output LED, which is a constant; T is the period of the switching power supply; Lp is the primary inductance of the transformer , Is also a constant; Idspp is the peak value of the primary current, which is also a constant for the constant off-time mode chip; eff T Is the transmission efficiency of the transformer, which is a constant, ...

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 constant-current control circuit for an isolated switching power supply. The isolated switching power supply comprises a primary part and a secondary part which are coupled by a transformer, wherein the primary part provides input voltages, and the secondary part provides output voltages; the primary part comprises an input voltage detection circuit, a turning-off time control circuit and a power switching tube; the input voltage detection circuit is used for detecting the input voltages; and the turning-off time control circuit is used for adjusting the turning-off time of a power switching tube in accordance with the changes of the input voltages relative to first reference voltages. The constant-current control circuit solves the problems that a circuit in theprior art is limited in some specific applications because the circuit structure is complicated, more components are used and the larger PCB (printed circuit board) area is occupied; and the cost is higher.

Description

technical field [0001] The invention relates to the field of switching power supplies, in particular to a constant current control circuit for an isolated switching power supply. Background technique [0002] According to the angle of use, switching power supply is divided into constant voltage, constant current, constant power and other types. From the perspective of electrical characteristics, it can be divided into two types: isolated type and non-isolated type. For some products with current sensitive characteristics, the switching power supply with isolation and constant current function is a better choice. [0003] In the prior art, the widely used constant current control methods are secondary sampling, feedback, primary control, figure 1 It shows the structure diagram of the constant current control circuit used in the isolated switching power supply in the related art, as figure 1 As shown, the secondary "current sampling circuit" realizes the detection of the ou...

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
IPC IPC(8): H02M3/335
Inventor 陈湛
Owner MAXIC TECHNOLOGY CORPORATION
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Try Eureka
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap