CN103746345A - Discharge over-current protection device - Google Patents
Discharge over-current protection device Download PDFInfo
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- CN103746345A CN103746345A CN201310749710.XA CN201310749710A CN103746345A CN 103746345 A CN103746345 A CN 103746345A CN 201310749710 A CN201310749710 A CN 201310749710A CN 103746345 A CN103746345 A CN 103746345A
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Abstract
The invention discloses a discharge over-current protection device which has an over-current protection function and guarantees the working safety of a product. The discharge over-current protection device comprises a battery, a main board and a motor which are connected with one another in sequence, wherein an N-MOS (N-channel metal oxide semiconductor) transistor, a driving circuit, a singlechip microcomputer, a battery voltage detection circuit, a motor resetting circuit, a reference circuit and a temperature detection circuit which are connected in parallel with one another are arranged on the main board; the main board is also connected in parallel with a temperature, voltage and over-current protection circuit and an over-current detection circuit. The discharge over-current protection device has the advantages that the temperature, voltage and over-current protection circuit and the over-current detection circuit are used for preventing a series of problems caused by over-current. A milliohm-level resistor is used as the over-current detection circuit, so that a current over-discharge protection function can be realized, and the power consumption of the circuit cannot be increased; the battery, the motor and power elements on the circuits are protected, and the service lives of the battery and a tool are prolonged.
Description
Technical field
The present invention relates to a kind of discharge over-current protective device.
Background technology
Existing Household handheld electric tool is generally to adopt MCU(single-chip microcomputer) to control, circuit comprises following module: battery provides reference voltage circuit by voltage stabilizing IC for MCU; Temperature detection circuit; Motor inverse electromotive force reset circuit; Cell voltage circuit for detecting, motor-drive circuit.Possess foregoing circuit control very ripe, no problem when instrument normally uses.Because battery capacity is limited; in order to reduce loss; this control module is without overcurrent protection at present, and after tool work a period of time, in circuit, switch element metal-oxide-semiconductor temperature raises; along with uprising element characteristic, temperature rise declines rapidly; if saw blade blocks, cause motor lock-rotor, excessive metal-oxide-semiconductor and the motor of easily burning out of electric current, causes tool failures; seriously can cause that battery is crossed puts burning, the phenomenons such as blast.
Summary of the invention
Technical problem to be solved by this invention is: thus a kind of discharge over-current protective device with the work of overcurrent protection function guarantee product safety is provided.
For solving the problems of the technologies described above; the technical solution used in the present invention is: a kind of discharge over-current protective device; comprise connected successively battery, mainboard and motor; on mainboard, be provided with N-MOS pipe parallel with one another, drive circuit, single-chip microcomputer, cell voltage circuit for detecting, reset motor circuit, reference circuit and temperature detection circuit, on mainboard, be also parallel with temperature-voltage-current foldback circuit and overcurrent circuit for detecting.
On described mainboard, be also parallel with voltage-stabiliser tube and resistance.
In described overcurrent circuit for detecting, contain overcurrent detecting resistance, this overcurrent detecting resistance is 0.002 ohm.
The invention has the beneficial effects as follows, utilize temperature-voltage-current foldback circuit and overcurrent circuit for detecting to prevent the generation of the series of problems that overcurrent brings.Adopt Milliohm resistance to do overcurrent circuit for detecting, both increased electric current Cross prevention function, do not increase again the power consumption of circuit.Protected battery, motor, the power component on circuit, the useful life of prolongation battery and instrument.
Accompanying drawing explanation
Fig. 1 is the structure chart of discharge over-current protective device of the present invention.
In figure: 1, battery, 2, drive circuit, 3, motor, 4, single-chip microcomputer, 5, cell voltage circuit for detecting; 6, reset motor circuit, 7, reference circuit, 8, temperature detection circuit; 9, temperature-voltage current foldback circuit, 10, overcurrent circuit for detecting, 11, N-MOS pipe.
Embodiment
Below in conjunction with accompanying drawing, describe specific embodiment of the invention scheme in detail.
As shown in Figure 1; a kind of discharge over-current protective device; comprise connected successively battery 1, mainboard and motor 3; on mainboard, be provided with N-MOS pipe 11, drive circuit 2, single-chip microcomputer 4, cell voltage circuit for detecting 5, reset motor circuit 6, reference circuit 7 and temperature detection circuit 8 parallel with one another, on mainboard, be also parallel with temperature-voltage-current foldback circuit 9 and overcurrent circuit for detecting 10.On described mainboard, be also parallel with voltage-stabiliser tube and resistance (not shown in FIG.).In described overcurrent circuit for detecting 10, contain overcurrent detecting resistance, this overcurrent detecting resistance is 0.002 ohm.
Operation principle of the present invention is: battery 1 is first by voltage-stabiliser tube, and electric resistance partial pressure is to single-chip microcomputer 4, and single-chip microcomputer 4 is detected input voltage by cell voltage circuit for detecting 5, and protection battery 1 mistake is put and damaged battery.Above circuit set up errorless after, single-chip microcomputer 4 is exported PWM and is controlled N-MOS pipe 11, motor 3 starts normal work.Overcurrent is detected to resistance and is placed on source electrode and the battery 1 negative pole two ends of N-MOS pipe 11, due to battery 1 finite capacity, during motor 3 normal work, electric current is at 3-8A, during stall, electric current reaches tens amperes, so overcurrent detecting resistance should not be obtained too large, resistance too during large work loss very large, cause 1 operating time of battery to shorten, 1 life-span of battery shortens.This circuitous resistance adopts 0.002 ohm, the Chip-R sampling that precision is 0.1%, 5 watt; increase hardly circuit power consumption, when motor 3 is worked, the voltage of sampling is in high speed operation amplifier; the amplification voltage obtaining is input to single-chip microcomputer 4; abnormal once the work short circuit that causes of battery 1 or motor 3, single-chip microcomputer 4 can turn-off input in time, stops exporting PWM; N-MOS pipe 11 is closed; protective circuit element is not burnt, and protects battery 1 can not burn because crossing to put simultaneously, and the accidents such as blast occur.That is to say; overcurrent circuit for detecting 10, cell voltage circuit for detecting 5 and temperature detection circuit 8 pass to temperature-voltage-current foldback circuit 9 by the signal detecting; temperature-voltage-current foldback circuit 9 compares this signal and reference circuit 7; signal is relatively issued to single-chip microcomputer 4, by single-chip microcomputer 4, control corresponding element and make corresponding safeguard measure.Adopt Milliohm resistance to do overcurrent circuit for detecting, both increased electric current Cross prevention function, do not increase again the power consumption of circuit.Protected battery, motor, the power component on circuit, the useful life of prolongation battery and instrument.
Claims (3)
1. a discharge over-current protective device; comprise connected successively battery, mainboard and motor; on mainboard, be provided with N-MOS pipe parallel with one another, drive circuit, single-chip microcomputer, cell voltage circuit for detecting, reset motor circuit, reference circuit and temperature detection circuit, it is characterized in that: on mainboard, be also parallel with temperature-voltage-current foldback circuit and overcurrent circuit for detecting.
2. discharge over-current protective device according to claim 1, is characterized in that: on described mainboard, be also parallel with voltage-stabiliser tube and resistance.
3. discharge over-current protective device according to claim 1, is characterized in that: in described overcurrent circuit for detecting, contain overcurrent detecting resistance, this overcurrent detecting resistance is 0.002 ohm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310749710.XA CN103746345A (en) | 2013-12-31 | 2013-12-31 | Discharge over-current protection device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310749710.XA CN103746345A (en) | 2013-12-31 | 2013-12-31 | Discharge over-current protection device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN103746345A true CN103746345A (en) | 2014-04-23 |
Family
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201310749710.XA Pending CN103746345A (en) | 2013-12-31 | 2013-12-31 | Discharge over-current protection device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN103746345A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105448260A (en) * | 2015-12-29 | 2016-03-30 | 深圳市华星光电技术有限公司 | Overcurrent protection circuit and liquid crystal display |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20010017238A1 (en) * | 2000-02-28 | 2001-08-30 | Shinobu Tajima | Controller of elevator |
| CN101257273A (en) * | 2008-03-07 | 2008-09-03 | 张志贤 | DC electric machine drive apparatus with power supply by second lithium batteries |
| CN102035168A (en) * | 2009-09-30 | 2011-04-27 | 富士通天株式会社 | Overcurrent protection circuit and in-vehicle display device |
-
2013
- 2013-12-31 CN CN201310749710.XA patent/CN103746345A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20010017238A1 (en) * | 2000-02-28 | 2001-08-30 | Shinobu Tajima | Controller of elevator |
| CN101257273A (en) * | 2008-03-07 | 2008-09-03 | 张志贤 | DC electric machine drive apparatus with power supply by second lithium batteries |
| CN102035168A (en) * | 2009-09-30 | 2011-04-27 | 富士通天株式会社 | Overcurrent protection circuit and in-vehicle display device |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105448260A (en) * | 2015-12-29 | 2016-03-30 | 深圳市华星光电技术有限公司 | Overcurrent protection circuit and liquid crystal display |
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| C06 | Publication | ||
| PB01 | Publication | ||
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| WD01 | Invention patent application deemed withdrawn after publication | ||
| WD01 | Invention patent application deemed withdrawn after publication |
Application publication date: 20140423 |