CN205280799U - Voltage detection circuit - Google Patents
Voltage detection circuit Download PDFInfo
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- CN205280799U CN205280799U CN201521099330.7U CN201521099330U CN205280799U CN 205280799 U CN205280799 U CN 205280799U CN 201521099330 U CN201521099330 U CN 201521099330U CN 205280799 U CN205280799 U CN 205280799U
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- transistor
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- bipolar transistor
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Abstract
The utility model discloses a voltage detection circuit, it includes: from bias current source production circuit, it includes a bipolar transistor and first resistance, based on bias current production offset voltage, the second circuit part, it includes: fourth, the 5th transistor, second, the 3rd bipolar transistor, second, third, fourth resistance, first, second, third, fourth, the 5th and the sixmo close, offset voltage is connected to the grid of fourth transistor, the 2nd bipolar transistor's projecting pole is connected to the third node through the fourth switch, the tertiary circuit part, it includes: operational amplifier, minion are closed and first electric capacity, and operational amplifier's first input end links to each other with the third node, and the second input closes through the minion and links to each other rather than the output through first capacity ground, second input. Like this, fuse band gap reference circuit, input imbalance compensating circuit, voltage comparison circuit together to the voltage detecting precision can be improved, the current detection precision is improved.
Description
[technical field]
This utility model relates to a kind of circuit design field, particularly relates to the voltage detecting circuit in battery protection chip.
[background technology]
Fig. 1 is the Organization Chart of existing battery protection system. Described battery protection system 100 includes battery Battery, battery protection chip and protection switch combination 110. The charging of described battery, electric discharge are protected by described battery protection chip. BP+ is the positive output end of battery, and BP-is the negative output terminal of battery. Described battery protection chip includes power end VCC, earth terminal VSS, discharge prevention controls end DOUT, charge protection controls end COUT, current detecting end VM. Described battery protection chip needs charging current and discharge current are detected, in order to avoid charged stream or the stream that discharged. Charged stream or the stream that discharged is determined whether by detecting the voltage of current detecting end VM. For over-current detection of discharging, whether described battery protection chip needs the difference of the voltage of the voltage ground end VSS of detection current detecting end VM higher than predetermined threshold VEDI, if it is, represent the stream that discharged, if it is not, then represent the stream that do not discharge.
Voltage detecting circuit is there is and carries out over-current detection in battery protection chip in (or claiming battery protecting circuit). Owing to over-current detection need to ensure temperature coefficient, it is therefore desirable to independent Bandgap Reference Voltage Generation Circuit and voltage comparator, there is bigger input offset voltage, accuracy of detection is substantially reduced.
It is necessary to propose a kind of new scheme to carry out over-current detection, improves curtage accuracy of detection.
[utility model content]
One of the purpose of this utility model is in that to provide a kind of voltage detecting circuit, and it can improve voltage detecting precision.
For achieving the above object, according to an aspect of the present utility model, this utility model provides a kind voltage detecting circuit, comprising: self-bias current source produces circuit, it includes the first bipolar transistor and the first resistance, base emitter voltage and the first resistance based on the first bipolar transistor produce bias current, and produce bias voltage based on this bias current, second circuit part, comprising: the 4th transistor, 5th transistor, second bipolar transistor, 3rd bipolar transistor, second resistance, 3rd resistance, 4th resistance, first switch, second switch, 3rd switch, 4th switch, 5th switch and the 6th switch, the grid of the 4th transistor connects described bias voltage, its source electrode connects input voltage, the base stage of its drain electrode and the second bipolar transistor and the 3rd bipolar transistor is commonly connected to secondary nodal point, second resistance and the 3rd switchs and is connected between secondary nodal point and primary nodal point, the drain electrode of the 5th transistor is connected to primary nodal point, its source electrode is connected with earth terminal, its grid is connected with detection voltage VM by second switch, first switch is connected between grid and the earth terminal of the 5th transistor, the colelctor electrode of the second bipolar transistor and the 3rd bipolar transistor is connected to input voltage, the emitter stage of the second bipolar transistor is connected to the 3rd node by the 4th switch, the emitter stage of the 3rd bipolar transistor is connected to the 3rd node by the 5th switch, 3rd resistance and the 4th resistant series are between the 3rd node and earth terminal, and the 6th switchs and the 4th resistor coupled in parallel, third circuit portion, comprising: operational amplifier, the 7th switch and the first electric capacity, the first input end of operational amplifier and the 3rd node are connected, and the second input is connected with earth terminal by the first electric capacity, and the second input is connected with its outfan by the 7th switch.
Further, when the first period, first switch, the 4th switch, the 7th switch conduction, second switch, the 3rd switch, the 5th switch cut-off, when the second period, first switch, the 4th switch, the 7th switch cut-off, second switch, the 3rd switch, the 5th switch conduction, the first period and the second period constantly replace.
Further, the 6th switch is in the conducting of the first period and the cut-off of the second period, or the 6th switch is in the conducting of the second period and the cut-off of the first period.
Further, described self-bias current source produces circuit and also includes: the first transistor, transistor seconds, third transistor, transistor seconds is connected with input voltage with the source electrode of third transistor, the grid of transistor seconds and the grid of third transistor, the drain electrode of transistor seconds, the source electrode of the first transistor is connected, the grid of the first transistor and the drain electrode of third transistor, the colelctor electrode of the first bipolar transistor is connected, the base stage of the first bipolar transistor and the drain electrode of the first transistor, one end of first resistance is connected, the emitter stage of the first bipolar transistor is connected with earth terminal, the other end of the first resistance is connected with earth terminal, the grid of transistor seconds is connected as the grid of outfan and the 4th transistor that described self-bias current source produces circuit.
Further, the gate source voltage of the 5th transistor when the gate source voltage of the 5th transistor approximated in the second period when the first period that selects the 5th suitable transistor to make.
Further, the first transistor, transistor seconds, third transistor, the 4th transistor are PMOS transistor, 5th transistor is nmos pass transistor, and the first bipolar transistor, the second bipolar transistor and the 3rd bipolar transistor are NPN bipolar transistor.
Compared with prior art, band-gap reference circuit, input offset compensation circuit, voltage comparator circuit are merged by this utility model, such that it is able to improve voltage detecting precision, and then improves current detection accuracy.
[accompanying drawing explanation]
In order to be illustrated more clearly that the technical scheme of this utility model embodiment, below the accompanying drawing used required during embodiment is described is briefly described, apparently, accompanying drawing in the following describes is only embodiments more of the present utility model, for those of ordinary skill in the art, under the premise not paying creative work, it is also possible to obtain other accompanying drawing according to these accompanying drawings. Wherein:
Fig. 1 is the Organization Chart of existing battery protection system;
Fig. 2 is the circuit diagram in one embodiment of the voltage detecting circuit in this utility model.
[detailed description of the invention]
Detailed description of the present utility model carrys out the running of direct or indirect simulation technical solutions of the utility model mainly through program, step, logical block, process or other symbolistic descriptions. For thorough explanation this utility model, following description set forth a lot of specific detail. And when not having these specific detail, this utility model is then likely to still can realize. Technical staff in art uses the work that these describe and statement effectively introduces them to the others skilled in the art in art herein essential. In other words, for the purpose of this utility model of avoiding confusion, owing to the methods and procedures known is easy to understand, therefore they are not described in detail.
" embodiment " or " embodiment " referred to herein refers to the special characteristic, structure or the characteristic that may be included at least one implementation of this utility model. Different local in this manual " in one embodiment " occurred not refer both to same embodiment, neither be independent or selective and that other embodiments are mutually exclusive embodiment.
Fig. 2 is the circuit diagram in one embodiment of the voltage detecting circuit 200 in this utility model. This voltage detecting circuit 200 can determine whether electric discharge or the stream that charged by the voltage of detection current detecting end VM.
Described voltage detecting circuit 200 includes self-bias current source and produces circuit 210, second circuit part 220 and Part III circuit 230.
Described self-bias current source produces circuit 210 and includes the first bipolar transistor Q1, the first resistance R1, the first transistor M1, transistor seconds M2, third transistor M3.
The source electrode of transistor seconds M2 and third transistor M3 is connected with input voltage VCC, the grid of transistor seconds M2 and the grid of third transistor M3, the drain electrode of transistor seconds M2, the first transistor M1 source electrode be connected. The grid of the first transistor M1 is connected with the colelctor electrode of the drain electrode of third transistor M3, the first bipolar transistor Q1. The base stage of the first bipolar transistor Q1 is connected with one end of the drain electrode of the first transistor M1, the first resistance R1. The emitter stage of the first bipolar transistor Q1 is connected with earth terminal VSS, and the other end of the first resistance R1 is connected with earth terminal. The grid of transistor seconds M2 produces the outfan of circuit 210 as described self-bias current source.
Described self-bias current source produces circuit 210 and produces bias current Ibias, particularly as follows:
Wherein, VBE1 is the base emitter voltage of the first bipolar transistor Q1, and R1 is the resistance of the first resistance R1.
Transistor seconds M2, third transistor M3 form current mirror.
Second circuit part 220 includes: the 4th transistor M4, the 5th transistor M5, the second bipolar transistor Q2, the 3rd bipolar transistor Q3, the second resistance R2, the 3rd resistance R3, the 4th resistance R4, the first switch S1, second switch S2, the 3rd switch S3, the 4th switch S4, the 5th switch S5 and the six switch S6.
The outfan that the grid of the 4th transistor M4 produces circuit 210 with described self-bias current source is connected, and its source electrode meets input voltage VCC, and the base stage of its drain electrode and the second bipolar transistor Q2 and the 3rd bipolar transistor Q3 is commonly connected to secondary nodal point 1. Wherein the 4th transistor M4 and transistor seconds M2 forms current mirror, and it replicates described bias current. Second resistance R2 and the 3rd switch S3 is also connected between secondary nodal point 1 and primary nodal point 0, the drain electrode of the 5th transistor M5 is connected to primary nodal point 0, its source electrode is connected with earth terminal VSS, its grid is connected with detection voltage VM by second switch S2, and the first switch S1 is connected between grid and the earth terminal VSS of the 5th transistor M5; The colelctor electrode of the second bipolar transistor Q2 and the three bipolar transistor Q3 is connected to input voltage VCC, the emitter stage of the second bipolar transistor Q2 switchs S4 by the 4th and is connected to the 3rd node 2, the emitter stage of the 3rd bipolar transistor Q3 switchs S5 by the 5th and is connected to the 3rd node 2,3rd resistance R3 and the 4th resistance R4 is series between the 3rd node 2 and earth terminal VSS, and the 6th switch S6 and the four resistance R4 is in parallel.
Third circuit portion 230 includes operational amplifier OP, the 7th switch S7 and the first electric capacity C1, first input end and the 3rd node 2 of operational amplifier OP are connected, second input 4 is connected with earth terminal VSS by the first electric capacity C1, and the second input 4 is connected with its outfan by the 7th switch S7. Described operational amplifier OP is equivalent to an input deviation power supply Vos and operational amplifier OP_AMPout without input deviation, and this input imbalance power supply Vos is connected between the 3rd node 2 and an input of operational amplifier OP_AMPout. Wherein the first input end of operational amplifier OP_AMPout is fourth node 3, and second input of operational amplifier OP_AMPout is the 5th node 4.
The first transistor, transistor seconds, third transistor, the 4th transistor are PMOS transistor, and the 5th transistor is nmos pass transistor, and the first bipolar transistor, the second bipolar transistor and the 3rd bipolar transistor are NPN bipolar transistor.
The control signal Phi of each switch is?Time, the first switch S1, the 4th switch S4, the 6th switch S6, the 7th switch S7 conducting, second switch S2, the 3rd switch S3, the 5th switch S5 cut-off. Now, operational amplifier OP works in operation amplifier state, and described first electric capacity C1 stores described input offset voltage Vos. ?Time, the first switch S1, the 4th switch S4, the 6th switch S6, the 7th switch S7 cut-off, second switch S2, the 3rd switch S3, the 5th switch S5 conducting. Now, described operational amplifier OP works in and compares state, and it compares the size of voltage of two inputs, thus the comparison of the difference realized between detection voltage VM and the voltage of earth terminal VSS and predetermined threshold VEDI.Period can be referred to as the first period,Period can be referred to as the second period, the first period and the second period constantly replace.
Analyze in detail below, the operation principle of foregoing circuit.
?Time,
Namely
WhereinIt is that primary nodal point 0 existsTime voltage,It is that secondary nodal point 1 existsTime voltage,It is that the 3rd node 2 existsTime voltage,It is that fourth node 3 existsTime voltage,
It is that the 5th transistor M5 existsTime gate-source voltage, VBE2 is the base-emitter voltage of the second bipolar transistor Q2, and Vos is the input offset voltage of operational amplifier OP.
?Time,
Namely
WhereinIt is that primary nodal point 0 existsTime voltage,It is that secondary nodal point 1 existsTime voltage,It is that the 3rd node 2 existsTime voltage,It is that fourth node 3 existsTime voltage,
It is that the 5th transistor M5 existsTime gate-source voltage, VBE3 is the base-emitter voltage of the 3rd bipolar transistor Q3.
For third circuit portion 230,Time,?Time,And it is rightAndCompare.It is that the 5th node 4 existsTime voltage,It is that the 5th node 4 existsTime voltage.
WhenAndTime equal, have
Namely
Wherein VEDI is predetermined threshold voltage.
Wherein, VE is the voltage of NPN bipolar transistor emitter e (Emitter), VTCoefficient V for NPN bipolar transistorT=kT/q, Is are the saturation current of NPN bipolar transistor.
In summary, this utility model can select the 5th suitable transistor M5, it is ensured that
Regulate resistance R1, R2, R3, R4, to ensure the temperature characterisitic of predetermined threshold voltage VEDI, and the input offset voltage impact on predetermined threshold voltage VEDI can also be eliminated.
In another embodiment, the 6th switch S6 being parallel to the 4th resistance R4 also can be changed toConducting is used for regulating threshold value and temperature characterisitic.
" connection ", " being connected " or " connecting " in this utility model etc. represent that the word being electrically connected all represents electrical directly or indirectly connection. Described above has fully disclosed detailed description of the invention of the present utility model. It is pointed out that any change that detailed description of the invention of the present utility model done by one skilled in the art scope all without departing from claims of the present utility model. Correspondingly, scope of the claims of the present utility model is also not limited only to previous embodiment.
Claims (6)
1. a voltage detecting circuit, it is characterised in that comprising:
Self-bias current source produces circuit, and it includes the first bipolar transistor and the first resistance, and base emitter voltage and the first resistance based on the first bipolar transistor produce bias current, and produce bias voltage based on this bias current;
Second circuit part, comprising: the 4th transistor, 5th transistor, second bipolar transistor, 3rd bipolar transistor, second resistance, 3rd resistance, 4th resistance, first switch, second switch, 3rd switch, 4th switch, 5th switch and the 6th switch, the grid of the 4th transistor connects described bias voltage, its source electrode connects input voltage, the base stage of its drain electrode and the second bipolar transistor and the 3rd bipolar transistor is commonly connected to secondary nodal point, second resistance and the 3rd switchs and is connected between secondary nodal point and primary nodal point, the drain electrode of the 5th transistor is connected to primary nodal point, its source electrode is connected with earth terminal, its grid is connected with detection voltage VM by second switch, first switch is connected between grid and the earth terminal of the 5th transistor, the colelctor electrode of the second bipolar transistor and the 3rd bipolar transistor is connected to input voltage, the emitter stage of the second bipolar transistor is connected to the 3rd node by the 4th switch, the emitter stage of the 3rd bipolar transistor is connected to the 3rd node by the 5th switch, 3rd resistance and the 4th resistant series are between the 3rd node and earth terminal, and the 6th switchs and the 4th resistor coupled in parallel,
Third circuit portion, comprising: operational amplifier, the 7th switch and the first electric capacity, the first input end of operational amplifier and the 3rd node are connected, and the second input is connected with earth terminal by the first electric capacity, and the second input is connected with its outfan by the 7th switch.
2. voltage detecting circuit according to claim 1, it is characterised in that:
When the first period, the first switch, the 4th switch, the 7th switch conduction, second switch, the 3rd switch, the 5th switch cut-off,
When the second period, the first switch, the 4th switch, the 7th switch cut-off, second switch, the 3rd switch, the 5th switch conduction,
First period and the second period constantly replace.
3. voltage detecting circuit according to claim 1, it is characterised in that: the 6th switch is in the conducting of the first period and the cut-off of the second period, or the 6th switch is in the conducting of the second period and the cut-off of the first period.
4. voltage detecting circuit according to claim 1, it is characterised in that: described self-bias current source produces circuit and also includes: the first transistor, transistor seconds, third transistor,
Transistor seconds is connected with input voltage with the source electrode of third transistor, the grid of transistor seconds and the grid of third transistor, the drain electrode of transistor seconds, the first transistor source electrode be connected,
The grid of the first transistor is connected with the colelctor electrode of the drain electrode of third transistor, the first bipolar transistor,
The base stage of the first bipolar transistor is connected with one end of the drain electrode of the first transistor, the first resistance,
The emitter stage of the first bipolar transistor is connected with earth terminal,
The other end of the first resistance is connected with earth terminal,
The grid of transistor seconds is connected as the grid of outfan and the 4th transistor that described self-bias current source produces circuit.
5. voltage detecting circuit according to claim 2, it is characterised in that:
The 5th suitable transistor is selected to make the gate source voltage of the 5th transistor when the first period be equal to the gate source voltage of the 5th transistor during in the second period.
6. voltage detecting circuit according to claim 4, it is characterised in that:
The first transistor, transistor seconds, third transistor, the 4th transistor are PMOS transistor,
5th transistor is nmos pass transistor,
First bipolar transistor, the second bipolar transistor and the 3rd bipolar transistor are NPN bipolar transistor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201521099330.7U CN205280799U (en) | 2015-12-25 | 2015-12-25 | Voltage detection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201521099330.7U CN205280799U (en) | 2015-12-25 | 2015-12-25 | Voltage detection circuit |
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| Publication Number | Publication Date |
|---|---|
| CN205280799U true CN205280799U (en) | 2016-06-01 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201521099330.7U Withdrawn - After Issue CN205280799U (en) | 2015-12-25 | 2015-12-25 | Voltage detection circuit |
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| CN (1) | CN205280799U (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105467193A (en) * | 2015-12-25 | 2016-04-06 | 无锡中感微电子股份有限公司 | Voltage detection circuit |
| CN106953605A (en) * | 2017-03-22 | 2017-07-14 | 中国电子科技集团公司第二十四研究所 | The high performance operational amplifier of JFET inputs |
| CN108594004A (en) * | 2018-07-09 | 2018-09-28 | 珠海市微半导体有限公司 | bidirectional current detection circuit and detection method |
-
2015
- 2015-12-25 CN CN201521099330.7U patent/CN205280799U/en not_active Withdrawn - After Issue
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105467193A (en) * | 2015-12-25 | 2016-04-06 | 无锡中感微电子股份有限公司 | Voltage detection circuit |
| CN105467193B (en) * | 2015-12-25 | 2018-02-27 | 无锡中感微电子股份有限公司 | Voltage detecting circuit |
| CN106953605A (en) * | 2017-03-22 | 2017-07-14 | 中国电子科技集团公司第二十四研究所 | The high performance operational amplifier of JFET inputs |
| CN106953605B (en) * | 2017-03-22 | 2020-01-31 | 中国电子科技集团公司第二十四研究所 | High-performance operational amplifier with JFET input |
| CN108594004A (en) * | 2018-07-09 | 2018-09-28 | 珠海市微半导体有限公司 | bidirectional current detection circuit and detection method |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| AV01 | Patent right actively abandoned |
Granted publication date: 20160601 Effective date of abandoning: 20180227 |
|
| AV01 | Patent right actively abandoned |