CN102355018A - Lithium battery charging protection chip - Google Patents
Lithium battery charging protection chip Download PDFInfo
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- CN102355018A CN102355018A CN2011102716436A CN201110271643A CN102355018A CN 102355018 A CN102355018 A CN 102355018A CN 2011102716436 A CN2011102716436 A CN 2011102716436A CN 201110271643 A CN201110271643 A CN 201110271643A CN 102355018 A CN102355018 A CN 102355018A
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Abstract
The invention discloses a lithium battery charging protection chip. An OUT pin and a GATDRV pin are arranged on the chip. A mirror current source is connected between the OUT pint and the GATDRV pin, and comprises two metal oxide semiconductor (MOS) transistors. By the technical scheme, the mirror current source comprising the two MOS transistors are connected between the OUT pin and GATDRV pin of the lithium battery charging protection chip, and according to the principle of the mirror current source, the charging current Iout output by the OUT pin is proportional to the pull-down current Igatdrv output by the GATDRV pin, namely Iout is equal to the product of k and Igatdrv, wherein k is a width-to-length ratio. The width-to-length ratio k is the width-to-length ratio of the two MOS transistors in the mirror current source, is not influenced by temperature and current and has low discreteness, thereby improving the accuracy of the charging current Iout output by the OUT pin and further improving the accuracy of a lithium battery charging value.
Description
Technical field
The application relates to technical field of lithium batteries, particularly relates to a kind of lithium cell charging protection chip.
Background technology
Lithium battery is when charging; PMIC (Power Management IC, power management chip) detects the charging current Iout of the OUT pin output of lithium cell charging protection chip, according to detected charging current Iout numerical value; PMIC produces a pull-down current Igatdrv through internal arithmetic.The pin of PMIC links to each other with the GATDRV pin of lithium cell charging protection chip, so the electric current that the GATDRV pin of lithium cell charging protection chip goes out is pull-down current Igatdrv.Further, lithium cell charging protection chip is regulated the charging current Iout that the OUT pin is exported through internal circuit, to guarantee that charging current Iout is in the charging current scope of lithium battery.
At present, lithium cell charging protection chip adopts the positive-negative-positive triode usually, regulates the charging current Iout of OUT pin output, and is as shown in Figure 1.Among Fig. 1,10 is PMIC, and PMIC has GATDRV, VBAT and ISEN pin; 11 for lithium cell charging protection chip, has GATDRV, ACIN and OUT pin, and Iout is the charging current of OUT pin output; Igatdrv is the pull-down current of GATDRV pin output; 12 is resistance, and 13 is lithium battery, and the annexation between each parts sees also Fig. 1.As can be seen from Figure 1, Iout=β * Igatdrv, thus under the known situation of the parameter beta of positive-negative-positive triode, the pull-down current Igatdrv at the GATDRV pin place of adjustment lithium cell charging protection chip 11 can guarantee charging current Iout.But the parameter beta of positive-negative-positive triode changes along with temperature and change in current, and simultaneously, the discreteness of the parameter beta of positive-negative-positive triode is big, causes the charging current Iout accuracy of OUT pin output low, thereby causes lithium cell charging value accuracy to reduce.
Summary of the invention
In view of this, the application embodiment discloses a kind of lithium cell charging protection chip, improves charging current Iout accuracy, further improves lithium cell charging value accuracy.Technical scheme is following:
The application embodiment discloses a kind of lithium cell charging protection chip, has OUT pin and GATDRV pin on the chip, and the mirror current source that is connected with between said OUT pin and the GATDRV pin, said mirror current source comprise two metal-oxide-semiconductors.
Preferably, said mirror current source also comprises: operational amplifier, and said two metal-oxide-semiconductors are the P-channel enhancement type metal-oxide-semiconductor; Wherein:
The grid short circuit of two P-channel enhancement type metal-oxide-semiconductors, source shorted is to power supply, and the drain electrode of a P-channel enhancement type metal-oxide-semiconductor connects said OUT pin, and the drain electrode of another P-channel enhancement type metal-oxide-semiconductor connects said GATDRV pin;
The output of said operational amplifier connects the grid short circuit point of two P-channel enhancement type metal-oxide-semiconductors, and inverting input connects the drain electrode of a P-channel enhancement type metal-oxide-semiconductor, and normal phase input end connects the drain electrode of another P-channel enhancement type metal-oxide-semiconductor.
Preferably, said power supply is the internal electric source of said lithium cell charging protection chip.
Preferably, said metal-oxide-semiconductor is a N channel enhancement metal-oxide-semiconductor.
Use technique scheme; The OUT pin of lithium cell charging protection chip is connected with the GATDRV pin; And the mirror current source that comprises two metal-oxide-semiconductors, according to the principle of mirror current source, the pull-down current Igatdrv of the charging current Iout of OUT pin output and the output of GATDRV pin is proportional; Be Iout=k * Igatdrv, k is a breadth length ratio.Compared with prior art; The accuracy of the charging current Iout of the OUT pin output of lithium cell charging protection chip is determined by breadth length ratio k; Breadth length ratio k is the breadth length ratio of two metal-oxide-semiconductors in the mirror current source, and it does not receive temperature and current affects, and discreteness is little; Thereby improved the charging current Iout accuracy of OUT pin output, further improved lithium cell charging value accuracy.
Description of drawings
In order to be illustrated more clearly in the application embodiment or technical scheme of the prior art; To do to introduce simply to the accompanying drawing of required use in embodiment or the description of the Prior Art below; Obviously, the accompanying drawing in describing below only is some embodiment that put down in writing among the application, for those of ordinary skills; Under the prerequisite of not paying creative work, can also obtain other accompanying drawing according to these accompanying drawings.
Fig. 1 is the partial schematic diagram of existing lithium cell charging protection chip;
Fig. 2 is the partial schematic diagram of the disclosed lithium cell charging protection of the application embodiment chip.
Embodiment
The inventor finds through practice; The charging current Iout that existing lithium cell charging protection chip provides is influenced by the parameter beta of positive-negative-positive triode; Owing to the parameter beta of positive-negative-positive triode along with temperature and change in current change, simultaneously, the discreteness of the parameter beta of positive-negative-positive triode is big; Cause the charging current Iout accuracy of OUT pin output low, thereby cause lithium cell charging value accuracy to reduce.In order to address the above problem, the application embodiment discloses a kind of lithium cell charging protection chip, and is as shown in Figure 1; Fig. 1 is the partial schematic diagram of the disclosed lithium cell charging protection of the application embodiment chip; Wherein: 21 are lithium cell charging protection chip, and OUT and GATDRV are the pin of lithium cell charging protection chip 21, and Iout is the charging current of OUT pin output; Igatdrv is the pull-down current of GATDRV pin output, and 22 is mirror current source.Wherein:
Mirror current source 22 is connected between the OUT pin and GATDRV pin of lithium cell charging protection chip 21, and mirror current source 22 comprises two metal-oxide-semiconductors 23 and 24.Two metal-oxide-semiconductors can be the P-channel enhancement type metal-oxide-semiconductor.For the charging current Iout accuracy that the OUT pin that guarantees lithium cell charging protection chip 21 is exported, mirror current source 22 also comprises operational amplifier 25.Wherein:
Two P-channel enhancement type metal-oxide- semiconductors 23 and 24 grid short circuit, source shorted like the internal electric source identical independent power supply of numerical value with lithium cell charging protection chip 21, also can directly be shorted to the internal electric source that lithium cell charging is protected chip 21 to power supply.The drain electrode of P-channel enhancement type metal-oxide-semiconductor 23 connects the OUT pin of lithium cell charging protection chip 21, and the drain electrode of P-channel enhancement type metal-oxide-semiconductor 24 connects the GATDRV pin of lithium cell charging protection chip 21.
The output of operational amplifier 25 connects the grid short circuit point of two P-channel enhancement type metal-oxide- semiconductors 23 and 24, and inverting input connects the drain electrode of P-channel enhancement type metal-oxide-semiconductor 23, and normal phase input end connects the drain electrode of P-channel enhancement type metal-oxide-semiconductor 24.
Above-mentioned P-channel enhancement type metal-oxide- semiconductor 23 and 24 grid short circuit, source shorted are to power supply, and drain electrode is the inverting input and the normal phase input end of concatenation operation amplifier 25 respectively.According to the characteristic of metal-oxide-semiconductor, when the grid of two metal-oxide-semiconductors, source electrode and drain potential were identical respectively, the electric current that flows through two metal-oxide-semiconductors was relevant with the breadth length ratio k of two metal-oxide-semiconductors.
The OUT pin that P-channel enhancement type metal-oxide- semiconductor 23 and 24 drain electrode are connected lithium cell charging protection chip 21 respectively and lithium cell charging are protected the GATDRV pin of chip 21; Therefore the charging current Iout of OUT pin output is the electric current that flows through the drain electrode of P-channel enhancement type metal-oxide-semiconductor 23; The pull-down current Igatdrv of GATDRV pin output is the electric current that flows through the drain electrode of P-channel enhancement type metal-oxide-semiconductor 24, i.e. Iout=k * Igatdrv.Breadth length ratio k is the breadth length ratio of two metal-oxide-semiconductors in the mirror current source, and it does not receive temperature and current affects, and discreteness is little, thereby has improved the charging current Iout accuracy of OUT pin output.
Two metal-oxide-semiconductors in the above-mentioned image current source 22 can also be N channel enhancement metal-oxide-semiconductor; When the grid of two N channel enhancement metal-oxide-semiconductors, source electrode and drain potential are identical respectively; Can guarantee Iout=k * Igatdrv equally, wherein k is the breadth length ratio of two metal-oxide-semiconductors.
Use technique scheme; The OUT pin of lithium cell charging protection chip 21 is connected with GATDRV; And the mirror current source 22 that comprises two metal-oxide-semiconductors, according to the principle of mirror current source 22, the pull-down current Igatdrv of the charging current Iout of OUT pin output and the output of GATDRV pin is proportional; Be Iout=k * Igatdrv, k is a breadth length ratio.Compared with prior art; The accuracy of the charging current Iout of the OUT pin output of lithium cell charging protection chip is determined by breadth length ratio k; Breadth length ratio k is the breadth length ratio of two metal-oxide-semiconductors in the mirror current source, and it does not receive temperature and current affects, and discreteness is little; Thereby improved the charging current Iout accuracy of OUT pin output, further improved lithium cell charging value accuracy.
The above only is the application's a embodiment; Should be pointed out that for those skilled in the art, under the prerequisite that does not break away from the application's principle; Can also make some improvement and retouching, these improvement and retouching also should be regarded as the application's protection range.
Claims (4)
1. a lithium cell charging protection chip has OUT pin and GATDRV pin on the chip, it is characterized in that the mirror current source that is connected with between said OUT pin and the GATDRV pin, said mirror current source comprise two metal-oxide-semiconductors.
2. lithium cell charging protection chip according to claim 1 is characterized in that said mirror current source also comprises: operational amplifier, and said two metal-oxide-semiconductors are the P-channel enhancement type metal-oxide-semiconductor; Wherein:
The grid short circuit of two P-channel enhancement type metal-oxide-semiconductors, source shorted is to power supply, and the drain electrode of a P-channel enhancement type metal-oxide-semiconductor connects said OUT pin, and the drain electrode of another P-channel enhancement type metal-oxide-semiconductor connects said GATDRV pin;
The output of said operational amplifier connects the grid short circuit point of two P-channel enhancement type metal-oxide-semiconductors, and inverting input connects the drain electrode of a P-channel enhancement type metal-oxide-semiconductor, and normal phase input end connects the drain electrode of another P-channel enhancement type metal-oxide-semiconductor.
3. lithium cell charging protection chip according to claim 2 is characterized in that, said power supply is the internal electric source of said lithium cell charging protection chip.
4. lithium cell charging protection chip according to claim 1 is characterized in that said metal-oxide-semiconductor is a N channel enhancement metal-oxide-semiconductor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011102716436A CN102355018A (en) | 2011-09-14 | 2011-09-14 | Lithium battery charging protection chip |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011102716436A CN102355018A (en) | 2011-09-14 | 2011-09-14 | Lithium battery charging protection chip |
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| CN102355018A true CN102355018A (en) | 2012-02-15 |
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| CN2011102716436A Pending CN102355018A (en) | 2011-09-14 | 2011-09-14 | Lithium battery charging protection chip |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US11527883B2 (en) | 2017-09-23 | 2022-12-13 | Huawei Technologies Co., Ltd. | Power protection apparatus and terminal using the apparatus |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20080239603A1 (en) * | 2007-03-27 | 2008-10-02 | Eaglepicher Energy Products Corporation | Battery protection circuit for lithium cabon monofluoride battery |
| CN101702528A (en) * | 2009-11-19 | 2010-05-05 | 北京中星微电子有限公司 | Battery charging control device |
| CN202197129U (en) * | 2011-09-14 | 2012-04-18 | 开源集成电路(苏州)有限公司 | Lithium battery charging protection chip |
-
2011
- 2011-09-14 CN CN2011102716436A patent/CN102355018A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20080239603A1 (en) * | 2007-03-27 | 2008-10-02 | Eaglepicher Energy Products Corporation | Battery protection circuit for lithium cabon monofluoride battery |
| CN101702528A (en) * | 2009-11-19 | 2010-05-05 | 北京中星微电子有限公司 | Battery charging control device |
| CN202197129U (en) * | 2011-09-14 | 2012-04-18 | 开源集成电路(苏州)有限公司 | Lithium battery charging protection chip |
Non-Patent Citations (2)
| Title |
|---|
| 《万方学位论文》 20080625 胡清琮 基于恒流/恒压方式的锂离子电池充电保护芯片设计 , * |
| 胡清琮: "基于恒流/恒压方式的锂离子电池充电保护芯片设计", 《万方学位论文》 * |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US11527883B2 (en) | 2017-09-23 | 2022-12-13 | Huawei Technologies Co., Ltd. | Power protection apparatus and terminal using the apparatus |
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Application publication date: 20120215 |