CN102570408A - Over-discharge protection circuit for lithium battery - Google Patents
Over-discharge protection circuit for lithium battery Download PDFInfo
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- CN102570408A CN102570408A CN2011104581217A CN201110458121A CN102570408A CN 102570408 A CN102570408 A CN 102570408A CN 2011104581217 A CN2011104581217 A CN 2011104581217A CN 201110458121 A CN201110458121 A CN 201110458121A CN 102570408 A CN102570408 A CN 102570408A
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Abstract
The invention discloses an over-discharge protection circuit for a lithium battery. The over-discharge protection circuit comprises a switch, a first triode, a second triode and a light-emitting diode (LED), wherein an emitter of the first triode and one end of the switch are respectively connected with the input end of a lithium battery power supply, the collector electrode of the first triode serves as the output end of the lithium battery power supply, the positive electrode of the LED is connected with the other end of the switch, and the negative electrode of the LED is connected with the base electrode of the second triode through a first resistor. The over-discharge protection circuit provided by the invention has the beneficial effects that the over-discharge current value of the lithium battery connected into a circuit can be effectively lowered to improve the stability of the circuit, thus the life cycle of the lithium battery is effectively prolonged, the safety and reliability of charging devices, such as batteries, are guaranteed, and the circuit cost is lowered.
Description
Technical field
The present invention relates to a kind of discharge protection circuit, be specifically related to a kind of over circuit that is used for lithium battery.
Background technology
Because light-emitting diode has forward conduction, reverse by, the breakdown characteristics and the characteristics of luminescence, has been widely used in electronic instrument and the electronic equipment.As everyone knows, lithium battery can not be overcharged, cross and put, otherwise all can cause the inefficacy of lithium battery, also can cause the safety problem of lithium battery sometimes, puts protection and seems particularly important so carry out the mistake of lithium battery.Because also there is self discharge in lithium battery when storage; General self discharge electric current is a microampere order; Therefore the design objective of over was that the discharging current of putting when protecting voltage is controlled at necessarily below the mark; Traditional over circuit be with voltage stabilizing didoe as voltage-stabilizing device, utilize stabilized voltage characteristic to realize putting protection.The protection that battery perhaps is recharged device is accomplished in the overdischarge road under the situation of using voltage stabilizing didoe, thereby guarantees the fail safe of charging devices such as battery.The long-term work of overdischarge road is reliable and stable, can accomplish the protection to charging devices such as lithium batteries.But, receiving the restriction of factors such as voltage stabilizing didoe discharge stream and system cost, the overdischarge road is difficult to satisfy the protection to charging devices such as batteries.At present still do not have a kind of over circuit that is used for lithium battery, the overdischarge flow valuve of the lithium battery of place in circuit is effectively reduced, improving the stability of circuit, thereby effectively improve the discharge protection circuit of the life cycle of lithium battery.
Summary of the invention
The present invention provides a kind of over circuit that is used for lithium battery; The overdischarge flow valuve of the lithium battery of place in circuit is effectively reduced; To improve the stability of circuit; Thereby effectively improve the life cycle of lithium battery, guarantee the fail safe and the reliability of lithium battery, also reduced circuit cost.
In order to solve the problems of the technologies described above, the technical scheme that the present invention adopted is:
A kind of lithium battery over circuit; Comprise switch, first triode and second triode; It is characterized in that: also comprise Light-Emitting Diode; The emitting stage of said first triode is connected with the input of lithium battery power supply respectively with an end of switch; The collector electrode of said first triode is as the output of lithium battery power supply, and the positive pole of said light-emitting diode is connected with the other end of switch, and the negative pole of said light-emitting diode is connected through the base stage of first resistance with said second triode.
Aforesaid lithium battery over circuit is characterized in that: the base stage of described first triode is connected through the collector electrode of second resistance with second triode.
Aforesaid lithium battery over circuit is characterized in that: the emitter of said first triode is connected through the collector electrode of first biasing resistor with second triode.
Aforesaid lithium battery over circuit is characterized in that: the base stage of said second triode is connected with its emitter through second biasing resistor, and common ground.
Based on inventive concept of the present invention, the present invention can also adopt following technical scheme:
A kind of lithium battery over circuit; Comprise switch, first FET and second FET; It is characterized in that: also comprise light-emitting diode; The source electrode of said first FET is connected with the input of lithium battery power supply respectively with an end of switch, and the drain electrode of said first FET is as the output of lithium battery power supply, and the positive pole of said light-emitting diode is connected with the other end of switch; The negative pole of said light-emitting diode is connected through the grid of first resistance with said second FET.
Aforementioned a kind of lithium battery over circuit is characterized in that the grid of described first FET is connected through the drain electrode of second resistance with second FET.
Aforesaid a kind of lithium battery over circuit, it is characterized in that: the source electrode of said first FET is connected through the drain electrode of first biasing resistor with second FET.
Aforesaid a kind of lithium battery over circuit is characterized in that: the grid of said second FET is connected with its source electrode through second biasing resistor, and common ground.
Beneficial effect of the present invention: a kind of over circuit that is used for lithium battery is provided; The overdischarge flow valuve of the lithium battery of place in circuit is effectively reduced; To improve the stability of circuit; Thereby effectively improve the life cycle of lithium battery, guarantee the fail safe and the reliability of lithium battery, also reduced circuit cost.
Description of drawings
Fig. 1 is the schematic diagram of a kind of lithium battery over circuit of the present invention.
The Reference numeral implication is following:
SW1: switch; Q1: first triode; Q2: second triode, BAT+: the input of lithium battery power supply; VDD: the output of lithium battery power supply; R2: second resistance; R3: first resistance; R1: first biasing resistor; R4: second biasing resistor; D1: light-emitting diode; I1, discharging current; I2, supply current.
Embodiment
To combine Figure of description below, the present invention will be further described.
With reference to Fig. 1; A kind of lithium battery over circuit; Comprise switch SW 1, the first triode Q1 and the second triode Q2; The emitter of the first triode Q1 is connected with the input BAT+ of lithium battery power supply respectively with an end of switch SW 1, and the collector electrode of the first triode Q1 is as the output VDD of lithium battery power supply.
In order to realize putting the effect of protection, the present invention also comprises light-emitting diode D1, and the positive pole of light-emitting diode D1 is connected with the other end of switch SW 1; The negative pole of light-emitting diode D1 is connected with the base stage of the second triode Q2 through first resistance R 3, and the base stage that first resistance R 3 is used for limiting the second triode Q2 electric current of flowing through is protected the second triode Q2; The base stage of the first triode Q1 be connected with the collector electrode of the second triode Q2 through second resistance R 2.
As a kind of preferred version, the emitter of the first triode Q1 is connected with the collector electrode of the second triode Q2 through the first biasing resistor R1; The base stage of the second triode Q2 is connected with its emitter through the second biasing resistor R4; And common ground; First biasing resistor R1 here and the effect of the second biasing resistor R4 all are for separately triode forward bias voltage to be provided, to protect the PN junction in the corresponding triode.
On the basis of the foregoing description; Can adopt corresponding FET also can realize; Be that above-mentioned first triode Q1 and the two or three pipe Q2 can use corresponding first FET and second FET to substitute, corresponding annexation corresponds to grid, source electrode, drain electrode by original base stage, emitter, collector electrode.
The present invention utilizes light-emitting diode D1 to realize the deep-discharge protection of lithium battery, and different with the traditional scheme that utilizes the voltage stabilizing didoe reverse characteristic is, the present invention utilizes the forward conduction voltage drop of light-emitting diode D1 to realize that the mistake of single-unit lithium battery puts protection.After switch SW 1 is pressed conducting; The second triode Q2 conducting, thereby the first triode Q1 conducting, the input BAT+ of lithium battery power supply just can be to the output VDD power supply of lithium battery power supply; Supply current is I2, and VDD just can provide a metastable voltage to connecing load; After if the mistake that lithium battery voltage reaches lithium battery is put protection voltage; When switch SW 1 is pressed always, to keep certain voltage on the light-emitting diode D1, make that the base voltage of the second triode Q2 is not enough; Be difficult to keep the second triode Q2 conducting; The second triode Q2 also can and then end by the back first triode Q1, and the current value of supply current I2 at this moment is 0, and the power consumption of lithium battery power supply input BAT+ has only discharging current I1 like this; At this moment require discharging current I1 below 10 microamperes (μ A), could satisfy the design objective of over.
Above-mentioned operation principle be equally applicable to above-mentioned first triode replace with the scheme of corresponding first FET and second FET with the second triode Q2 position equivalence; Also can under identical principle, realize the effect that is equal to; This can beyond all doubtly obtain on the basis of above-mentioned explanation for persons skilled in the art, does not add at this and gives unnecessary details.
Table 1 is embodiment shown in Figure 1; Discharging current I1 size of current when the position of light-emitting diode D1 is adopted 2V voltage stabilizing didoe, 2.7V voltage-stabiliser tube with itself respectively when lithium battery power supply input BAT+ loads different voltage (wherein, the following first biasing resistor R1 resistance of each resistance parameter is that 20 kilo-ohms, the second biasing resistor R4 resistance are that 51 kilo-ohms, first resistance R, 3 resistances are that 20 kilo-ohms, second resistance R, 2 resistances are 620 Europe)
Table 1
Can find out from form; Cross at the single-unit lithium battery and to put near protection voltage range (2.1V-2.5V); Voltage stabilizing didoe is the design standard that is difficult to make below the current value to 10 microampere of discharging current I1, but scheme of the present invention obviously can realize effectively reducing discharging current I1.
Among the present invention in the lithium battery over circuit, through switch SW 1, first triode and the second triode Q2, light-emitting diode D1 and first resistance R 3 between interconnected relationship reach the purpose of lithium battery over.
More than show and described basic principle of the present invention, principal character and advantage.The technical staff of the industry should understand; The present invention is not restricted to the described embodiments; That describes in the foregoing description and the specification just explains principle of the present invention; Under the prerequisite that does not break away from spirit and scope of the invention, the present invention also has various changes and modifications, and these variations and improvement all fall in the scope of the invention that requires protection.It is the boundary by appending claims and equivalence thereof that the present invention requires protection range.
Claims (8)
1. lithium battery over circuit; Comprise switch, first triode and second triode; It is characterized in that: also comprise light-emitting diode; The emitter of said first triode is connected with the input of lithium battery power supply respectively with an end of switch, and the collector electrode of said first triode is as the output of lithium battery power supply, and the positive pole of said light-emitting diode is connected with the other end of switch; The negative pole of said light-emitting diode is connected through the base stage of first resistance with said second triode.
2. a kind of lithium battery over circuit according to claim 1, it is characterized in that: the base stage of described first triode is connected through the collector electrode of second resistance with second triode.
3. a kind of lithium battery over circuit according to claim 2, it is characterized in that: the emitter of said first triode is connected through the collector electrode of first biasing resistor with second triode.
4. a kind of lithium battery over circuit according to claim 3 is characterized in that: the base stage of said second triode is connected with its emitter through second biasing resistor, and common ground.
5. lithium battery over circuit; Comprise switch, first FET and second FET; It is characterized in that: also comprise light-emitting diode; The source electrode of said first FET is connected with the input of lithium battery power supply respectively with an end of switch, and the drain electrode of said first FET is as the output of lithium battery power supply, and the positive pole of said light-emitting diode is connected with the other end of switch; The negative pole of said light-emitting diode is connected through the grid of first resistance with said second FET.
6. a kind of lithium battery over circuit according to claim 5, it is characterized in that: the grid of described first FET is connected through the drain electrode of second resistance with second FET.
7. a kind of lithium battery over circuit according to claim 6, it is characterized in that: the source electrode of said first FET is connected through the drain electrode of first biasing resistor with second FET.
8. a kind of lithium battery over circuit according to claim 7 is characterized in that: the grid of said second FET is connected with its source electrode through second biasing resistor, and common ground.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011104581217A CN102570408A (en) | 2011-12-31 | 2011-12-31 | Over-discharge protection circuit for lithium battery |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011104581217A CN102570408A (en) | 2011-12-31 | 2011-12-31 | Over-discharge protection circuit for lithium battery |
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| CN102570408A true CN102570408A (en) | 2012-07-11 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN2011104581217A Pending CN102570408A (en) | 2011-12-31 | 2011-12-31 | Over-discharge protection circuit for lithium battery |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106786927A (en) * | 2016-12-29 | 2017-05-31 | 洛阳宝盈智控科技有限公司 | A kind of passive balanced fail-safe circuit and a kind of battery pack |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
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| JPH03145934A (en) * | 1989-10-31 | 1991-06-21 | Sanyo Electric Co Ltd | Accumulator battery pack |
| CN1533006A (en) * | 2003-03-18 | 2004-09-29 | 阳 魏 | Battery discharge protective regulating circuit |
| CN1674402A (en) * | 2004-03-25 | 2005-09-28 | 美国凹凸微系有限公司 | Circuits capable of trickle precharge and/or trickle discharge |
| CN101026316A (en) * | 2006-02-17 | 2007-08-29 | 新电源***株式会社 | Charging apparatus for capacitor storage type power source and discharging apparatus for capacitor storage type power source |
| CN201866678U (en) * | 2010-05-10 | 2011-06-15 | 艾晓峰 | Infrared-induction solar garden lamp |
| CN201976333U (en) * | 2011-04-03 | 2011-09-14 | 阮雪芬 | Full-bridge oscillating electrodeless lamp with solar power supply |
-
2011
- 2011-12-31 CN CN2011104581217A patent/CN102570408A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH03145934A (en) * | 1989-10-31 | 1991-06-21 | Sanyo Electric Co Ltd | Accumulator battery pack |
| CN1533006A (en) * | 2003-03-18 | 2004-09-29 | 阳 魏 | Battery discharge protective regulating circuit |
| CN1674402A (en) * | 2004-03-25 | 2005-09-28 | 美国凹凸微系有限公司 | Circuits capable of trickle precharge and/or trickle discharge |
| CN101026316A (en) * | 2006-02-17 | 2007-08-29 | 新电源***株式会社 | Charging apparatus for capacitor storage type power source and discharging apparatus for capacitor storage type power source |
| CN201866678U (en) * | 2010-05-10 | 2011-06-15 | 艾晓峰 | Infrared-induction solar garden lamp |
| CN201976333U (en) * | 2011-04-03 | 2011-09-14 | 阮雪芬 | Full-bridge oscillating electrodeless lamp with solar power supply |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106786927A (en) * | 2016-12-29 | 2017-05-31 | 洛阳宝盈智控科技有限公司 | A kind of passive balanced fail-safe circuit and a kind of battery pack |
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Application publication date: 20120711 |