Current deep constant-current output driving circuit with load short circuit protection function

A technology of load short circuit and protection function, applied in the electronic field, can solve the problems of high cost of drive circuit chips, lower system reliability, easy to burn out drive circuits, etc., and achieve low cost, good versatility, and good reliability Effect

Inactive Publication Date: 2008-12-24
UNIV OF ELECTRONIC SCI & TECH OF CHINA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In this way, when the load is short-circuited, all the load voltage will be applied to the drive circuit, which will easily burn out the drive circuit and greatly reduce the reliability of the system.
H

Method used

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  • Current deep constant-current output driving circuit with load short circuit protection function
  • Current deep constant-current output driving circuit with load short circuit protection function
  • Current deep constant-current output driving circuit with load short circuit protection function

Examples

Experimental program
Comparison scheme
Effect test

Embodiment approach 1

[0017] Embodiment one (such as image 3 shown):

[0018] A current sink constant current output drive circuit with load short circuit protection function, including a drive unit and a load short circuit protection unit.

[0019] The drive unit is composed of an operational amplifier OP1, resistor R1, resistor R2, first selector SEL1 and NMOS power switch tube M3; the substrate of the NMOS power switch tube M3 is grounded, its source is grounded through resistor R1, and its gate is connected to the first The selection signal output terminal Y of a selector SEL1; the second selection signal input terminal B of the first selector SEL1 is grounded through a resistor R2, and the first selection signal input terminal A of the first selector SEL1 is connected to the output terminal of the operational amplifier OP1; When the selection terminal of the first selector is at a high level, its first selection signal input terminal A is connected to the selection signal output terminal Y; ...

Embodiment approach 2

[0022] Implementation mode two (such as Figure 4 shown):

[0023] A current sink constant current output drive circuit with load short circuit protection function, including a drive unit and a load short circuit protection unit.

[0024] The drive unit is composed of an operational amplifier OP1, resistor R1, resistor R2, first selector SEL1 and NMOS power switch tube M3; the substrate of the NMOS power switch tube M3 is grounded, its source is grounded through resistor R1, and its gate is connected to the first The selection signal output terminal Y of a selector SEL1; the second selection signal input terminal B of the first selector SEL1 is grounded through a resistor R2, and the first selection signal input terminal A of the first selector SEL1 is connected to the output terminal of the operational amplifier OP1; When the selection terminal of the first selector is at a high level, its first selection signal input terminal A is connected to the selection signal output te...

Embodiment approach 3

[0027] Implementation mode three (such as Figure 5 shown):

[0028] A current sink constant current output drive circuit with load short circuit protection function, including a drive unit and a load short circuit protection unit.

[0029] The drive unit is composed of an operational amplifier OP1, resistor R1, resistor R2, first selector SEL1 and NMOS power switch tube M3; the substrate of the NMOS power switch tube M3 is grounded, its source is grounded through resistor R1, and its gate is connected to the first The selection signal output terminal Y of a selector SEL1; the second selection signal input terminal B of the first selector SEL1 is grounded through a resistor R2, and the first selection signal input terminal A of the first selector SEL1 is connected to the output terminal of the operational amplifier OP1; When the selection terminal of the first selector is at a high level, its first selection signal input terminal A is connected to the selection signal output ...

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PUM

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Abstract

The invention belongs to the electronic technical field, and relates to a constant current outputting and driving circuit of a current sink, which has the load short circuit protecting function. The constant current outputting and driving circuit comprises a driving unit and a load short circuit protecting unit, wherein, the driving unit provides a drive working current for load; the load short circuit protecting unit comprises a sampling circuit, a comparing circuit and a control signal output/turn-off circuit; when the load normally works, the load short circuit protecting unit provides a control signal for the power switch tube of the driving unit; when the load has a short circuit, the load short circuit protecting unit outputs low level, thereby automatically cutting off the power switch tube of the driving unit, protecting the whole driving circuit, and avoiding the chip damage caused by the overlarge current during the load short circuit. As the source end of a sampling MOS tube is connected with the input end, the constant current outputting and driving circuit is high voltage resistant, and does not need an additional ESD structure; at the same time, the adopted circuit elements are basic circuit elements such as logic gates, selectors, MOS tubes, capacitors, etc., thereby having the advantages of low cost, simple structure, good reliability, etc. The constant current outputting and driving circuit can be not only applied to the LED drive.

Description

technical field [0001] The invention belongs to the field of electronic technology, and relates to a current sink constant current output drive circuit, in particular to a current sink constant current output drive circuit with a load short circuit protection function. Background technique [0002] At present, with the continuous development of electronic applications, there are more and more drive circuits with current sink constant current output. Among them, the large-screen LED display is a notable example. It has been widely used in sports venues, cities and public squares, transportation, corporate image promotion, commercial advertisements and other applications. The technical difficulties of LED display are basically overcome, the brightness and quality of light-emitting display devices are becoming more and more perfect, and the price is further reduced. The market development is becoming more and more mature, and the demand is increasing day by day. For the drive...

Claims

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Application Information

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IPC IPC(8): H02H7/122H02M3/156G09G3/32
Inventor 罗萍沈磊甄少伟李君阳邓雯君
Owner UNIV OF ELECTRONIC SCI & TECH OF CHINA
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