CN202204865U - Charging current detecting circuit - Google Patents
Charging current detecting circuit Download PDFInfo
- Publication number
- CN202204865U CN202204865U CN2011202770120U CN201120277012U CN202204865U CN 202204865 U CN202204865 U CN 202204865U CN 2011202770120 U CN2011202770120 U CN 2011202770120U CN 201120277012 U CN201120277012 U CN 201120277012U CN 202204865 U CN202204865 U CN 202204865U
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- CN
- China
- Prior art keywords
- charging current
- resistance
- lithium battery
- connects
- operational amplifier
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
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Abstract
The utility model relates to a charging current detecting circuit in a lithium battery protection circuit. A current detecting resistor is serially connected between an overdischarge control tube and a battery negative electrode in the lithium battery protection circuit. When a lithium battery is charged, the charging current generates a negative voltage on the detecting resistor. The negative voltage is reversely amplified into a positive voltage by a reversing amplifier consisting of an operational amplifier, and in addition, the voltage amplitude is in direct proportion to the charging current value. The lithium battery protection circuit controls the charging current through the charging control tube according to the voltage.
Description
Technical field
The utility model relates to the charging current testing circuit in a kind of lithium battery protection circuit.
Background technology
The charging current testing circuit is the important component part in the lithium battery protection circuit.When the charging current testing circuit detects charging current when excessive, lithium battery protection circuit overcharges control tube and cuts off charge circuit through closing, thereby reaches the purpose of protection lithium battery.At present, the lithium battery protection circuit that has a charging current testing circuit mainly is some special ICs.These special ICs exist cost higher, detect the electric current problem of smaller.
Summary of the invention
In order to overcome the deficiency that charging current testing circuit cost is high in the existing lithium battery protection circuit, testing circuit is little; The utility model provides a kind of charging current testing circuit; This circuit adopts an operational amplifier; Cooperate suitable inspection leakage resistance, can detect up to tens of charging currents with extremely low cost to hundreds of amperes.
The utility model solves the technical scheme that its technical matters adopted: cathode of lithium battery connects power cathode and the balance resistance R 3 of inspection leakage resistance Rs, operational amplifier OPA.The other end of inspection leakage resistance Rs connects input resistance R1 and crosses the source electrode of putting control tube.The inverting input of operational amplifier OPA connects the other end of balance resistance R3, and in-phase input end connects the other end of feedback resistance R2 and input resistance R1, and output terminal connects the other end of feedback resistance R2.Operational amplifier OPA, input resistance R1, feedback resistance R2 and balance resistance R 3 are formed an inverting amplifier.When lithium battery was recharged, inspection leakage resistance Rs went up and produces a negative voltage, because operational amplifier OPA is operated in the inverting amplifier state, therefore produced the voltage signal of a positive at its output terminal OUT.The amplitude of this signal is proportional to the size of charging current.
The beneficial effect of the utility model is, only adopts an operational amplifier in the circuit, cooperates suitable inspection leakage resistance, can detect up to tens of charging currents to hundreds of amperes with extremely low cost.
Description of drawings
Below in conjunction with accompanying drawing and embodiment the utility model is further specified.
Fig. 1 is the circuit theory diagrams of the utility model.
Among the figure, the OPA. operational amplifier, Rs. examines leakage resistance, R1. input resistance; R2. feedback resistance, R3. balance resistance, OUT. charging current signal output part, VDD. operational amplifier cathode power supply; DCH. cross and put control end, CH. overcharges control end, and the P+. power brick is anodal, P-. power brick negative pole.
Embodiment
In Fig. 1, the anodal P+ of power brick, lithium battery, inspection leakage resistance Rs, mistake are put control tube, are overcharged control tube and power brick negative pole P-series connection formation power brick.The negative pole of lithium battery connects the power cathode of inspection leakage resistance Rs, balance resistance R3 and operational amplifier OPA.The other end of inspection leakage resistance Rs connects input resistance R1 and crosses the source electrode of putting control tube.The inverting input of operational amplifier OPA connects the other end of balance resistance R3, and in-phase input end connects the other end of feedback resistance R2 and input resistance R1, and output terminal connects the other end of feedback resistance R2.
When to lithium cell charging the time, charging current will flow through the anodal P+ of power brick, lithium battery, inspection leakage resistance Rs in order, put control tube excessively, overcharge control tube and power brick negative pole P-.Therefore, will produce negative voltage signal on the tie point of inspection leakage resistance Rs and input resistance R1, the amplitude of this voltage signal is proportional to the size of charging current.Because operational amplifier OPA, resistance R 1, resistance R 2 and resistance R 3 are formed an inverting amplifier, the negative voltage signal on the inspection leakage resistance Rs is outputed to charging current signal output part OUT by the anti-phase amplification.The voltage signal of charging current signal output part OUT output is for just, and its amplitude is proportional to the size of charging current.Whether lithium battery protection circuit can close or open and overcharge control tube with the control charging current through overcharging control end CH according to the decision of the size of this signal.
Claims (3)
1. a charging current testing circuit is characterized in that: power cathode and the balance resistance R 3 of cathode of lithium battery connection inspection leakage resistance Rs, operational amplifier OPA.
2. charging current testing circuit according to claim 1 is characterized in that: the other end of inspection leakage resistance Rs connects input resistance R1 and crosses the source electrode of putting control tube.
3. charging current testing circuit according to claim 1; It is characterized in that: the inverting input of operational amplifier OPA connects the other end of balance resistance R3; In-phase input end connects the other end of feedback resistance R2 and input resistance R1, and output terminal connects the other end of feedback resistance R2.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011202770120U CN202204865U (en) | 2011-08-02 | 2011-08-02 | Charging current detecting circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011202770120U CN202204865U (en) | 2011-08-02 | 2011-08-02 | Charging current detecting circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN202204865U true CN202204865U (en) | 2012-04-25 |
Family
ID=45968983
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2011202770120U Expired - Fee Related CN202204865U (en) | 2011-08-02 | 2011-08-02 | Charging current detecting circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN202204865U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106058960A (en) * | 2016-05-31 | 2016-10-26 | 天津市三源电力设备制造有限公司 | Charging current detection circuit |
-
2011
- 2011-08-02 CN CN2011202770120U patent/CN202204865U/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106058960A (en) * | 2016-05-31 | 2016-10-26 | 天津市三源电力设备制造有限公司 | Charging current detection circuit |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20120425 Termination date: 20120802 |