CN204068213U - A kind of li-ion cell protection system and over-current detection circuit thereof - Google Patents
A kind of li-ion cell protection system and over-current detection circuit thereof Download PDFInfo
- Publication number
- CN204068213U CN204068213U CN201420288951.9U CN201420288951U CN204068213U CN 204068213 U CN204068213 U CN 204068213U CN 201420288951 U CN201420288951 U CN 201420288951U CN 204068213 U CN204068213 U CN 204068213U
- Authority
- CN
- China
- Prior art keywords
- switch pipe
- link
- detector tube
- voltage
- current
- 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.)
- Withdrawn - After Issue
Links
Landscapes
- Charge And Discharge Circuits For Batteries Or The Like (AREA)
- Secondary Cells (AREA)
Abstract
The utility model provides a kind of li-ion cell protection system and over-current detection circuit thereof, and li-ion cell protection system comprises: battery protecting circuit; Discharge switch pipe, its first connection termination battery cathode, the second link is connected with charge switch pipe second link, controls the discharge prevention end of termination battery protecting circuit; Charge switch pipe, its first link is connected with load, controls the charge protection end of termination battery protecting circuit; Detector tube, its first link is connected with the current detecting end of battery protecting circuit, and the second link is connected with discharge switch pipe second link, and control end is connected with the control end of discharge switch pipe.Described over-current detection circuit also comprises constant-current source, and it is connected with detector tube first link, extracts reference current from detector tube first link; Comparator, the 1/N of detector tube first link voltage and detector tube second link voltage compares by it, to determine whether the overcurrent that discharges.Compared with prior art, the utility model can realize overcurrent protection and power consumption is lower accurately.
Description
[technical field]
The utility model relates to circuit design field, particularly a kind of li-ion cell protection system and over-current detection circuit thereof.
[background technology]
In li-ion cell protection field, Li battery protection IC needs to have over-current detection defencive function, current over-current detection circuit mainly comprises two classes: the operation principle of first kind over-current detection circuit is whether the electric current that the pressure drop on direct-detection power switch flows through power switch with judgement is excessive, once detect that the pressure drop on power switch exceedes protection threshold value, will the protection of triggering following or protection timing action; The operation principle of Equations of The Second Kind over-current detection circuit is that serial connection detects resistance on battery discharge path, judges that whether electric current is excessive by detecting this ohmically voltage.Because the conducting resistance deviation of power switch in first kind over-current detection circuit is very large, therefore, be difficult to accomplish overcurrent protection accurately; Although Equations of The Second Kind over-current detection circuit compensate for the former shortcoming, its detection resistance introduced to power and resistance precise requirements higher, and have electric current to flow through this detection resistance all the time in normal work, thus not only increase cost, also increase power consumption.
Therefore, be necessary to provide a kind of technical scheme of improvement to overcome the problems referred to above.
[utility model content]
The purpose of this utility model is to provide a kind of li-ion cell protection system and over-current detection circuit thereof, and it can realize overcurrent protection and power consumption is lower accurately.
In order to solve the problem, according to one side of the present utility model, the utility model provides a kind of li-ion cell protection system, it comprises: battery protecting circuit, it has power end, earth terminal, charge protection end, discharge prevention end and current detecting end, the positive pole of described power supply termination battery, the negative pole of described ground connection termination battery ground connection;
Charge switch pipe and discharge switch pipe, first of discharge switch pipe connects the negative pole of battery described in termination, second link of discharge switch pipe is connected with the second link of charge switch pipe, first link of charge switch pipe is connected with load as output, the control end of charge switch pipe connects the charge protection end of described battery protecting circuit, and the control end of discharge switch pipe connects the discharge prevention end of described battery protecting circuit; Detector tube, its first link is connected with the current detecting end of described battery protecting circuit, and its second link is connected with the second link of discharge switch pipe, and its control end is connected with the control end of described discharge switch pipe; Described battery protecting circuit also includes the current comparison circuit be connected with described current detecting end; described current comparison circuit comprises the constant-current source be connected between described current detecting end and earth terminal; described constant-current source extracts reference current via detector tube, described current comparison circuit by the voltage of more described current detecting end and the drain-source pressure drop of discharge switch pipe to determine whether the overcurrent that discharges.
Further, described current comparison circuit also comprises comparator and a voltage sampling unit, the input of described voltage sampling unit is connected with the connected node of the second link of described discharge switch pipe with the second link of detector tube, its output is connected with the first input end of described comparator, described voltage sampling unit is for the drain-source pressure drop of described discharge switch pipe of sampling, its sampled voltage exported is the drain-source pressure drop of 1/N discharge switch doubly, and N is the numerical value pre-set; Second input of described comparator is connected with described current detecting end, its output is connected with the output of described current comparison circuit, when the voltage that the first input end of described comparator receives is greater than the voltage that its second input receives, the output of described current comparison circuit exports the first level, represent the overcurrent that do not discharge, when the voltage that the first input end of described comparator receives is less than the voltage that the second input receives, the output of described current comparison circuit exports second electrical level, represents electric discharge overcurrent.
Further, described current comparison circuit also comprises comparator and another voltage sampling unit, the input of another voltage sampling unit described is connected with described current detecting end, its output is connected with the second input of described comparator, another voltage sampling unit described is for described current detecting terminal voltage of sampling, its sampled voltage exported is N current detecting terminal voltage doubly, and N is the numerical value pre-set; The first input end of described comparator is connected with the connected node of the second link of described discharge switch pipe with the second link of detector tube, when the voltage that the first input end of described comparator receives is greater than the voltage that its second input receives, the output of described current comparison circuit exports the first level, represent the overcurrent that do not discharge, when the voltage that the first input end of described comparator receives is less than the voltage that the second input receives, the output of described current comparison circuit exports second electrical level, represents electric discharge overcurrent.
Further, charge switch pipe, discharge switch pipe, detector tube are nmos pass transistor, and the first link of nmos pass transistor is the source electrode of nmos pass transistor, and the second link is the drain electrode of nmos pass transistor, and control end is the grid of nmos pass transistor.
Further, described detector tube and discharge switch pipe are formed on same wafer, and drain electrode shared by detector tube and discharge switch pipe, and grid and lining body, the source electrode of discharge switch pipe and the source electrode of detector tube are independent separately.
Further, detector tube lining body and discharge switch pipe serve as a contrast the connected node of body and the source shorted of discharge switch pipe, or detector tube serves as a contrast body and discharge switch pipe serves as a contrast the connected node of body and the source shorted of detector tube.
Further, following formula (1) can be obtained according to circuit theory:
VS2＝VDS1-VDS2＝(ID-IREF)*Ron1-K*IREF*Ron1＝(ID-(K+1)*IREF)*Ron1(1)，
Wherein, VS2 is the voltage of current detecting end, IREF be constant-current source after testing pipe extract reference current value, VDS1 is the drain-source voltage of discharge switch pipe, and VDS2 is the drain-source voltage of detector tube, Ron1/Ron2=1/K, Ron1 is the conduction resistance value of discharge switch pipe, and Ron2 is the conduction resistance value of detector tube, and K is positive number, ID is the electric current of the connected node flowing into the second link of described discharge switch pipe and the second link of detector tube, and IREF is reference current; If VS2=VDS1/N, substitute into formula (1), can obtain:
ID=((K+1)+K/ (N-1)) * IREF, namely current protection threshold value is ((K+1)+K/ (N-1)) * IREF.
According to another aspect of the present utility model, the utility model provides a kind of over-current detection circuit, it comprises: power switch pipe, it has the first link, the second link and control end, detector tube, it has the first link, the second link and control end, and wherein the second link of detector tube is connected with the second end of power switch pipe, and the control end of detector tube is connected with the control end of described power switch pipe, constant-current source, it is connected with the first link of described detector tube, and it extracts reference current from the first link of described detector tube, comparator, the 1/N of the voltage of the voltage of the first link of detector tube and the second link of detector tube compares by it, when 1/N higher than the voltage of the second link of detector tube of the voltage of the first link of detector tube, the output of described comparator exports the first level, represent the electric current not overcurrent flowing through described power switch pipe, when 1/N lower than the voltage of the second link of detector tube of the voltage of the first link of detector tube, the output of described comparator exports second electrical level, represent the overcurrent flowing through described power switch pipe, N is the numerical value pre-set, when the voltage that the first input end of described comparator receives is greater than the voltage that its second input receives, the output of described current comparison circuit exports the first level, represent the overcurrent that do not discharge, when the voltage that the first input end of described comparator receives is less than the voltage that the second input receives, the output of described current comparison circuit exports second electrical level, represent electric discharge overcurrent.
Further, the first link ground connection of described power switch pipe, detector tube and power switch pipe are formed on same wafer.
Further, power switch pipe and detector tube are nmos pass transistor, first link of nmos pass transistor is the source electrode of nmos pass transistor, second link is the drain electrode of nmos pass transistor, control end is the grid of nmos pass transistor, detector tube and power switch pipe share drain electrode, grid and lining body, the source electrode of power switch pipe and the source electrode of detector tube are independent separately, detector tube lining body and power switch pipe serve as a contrast the connected node of body and the source shorted of discharge switch pipe, or detector tube serves as a contrast body and power switch pipe serves as a contrast the connected node of body and the source shorted of detector tube, the current protection threshold value flowing through the electric current of described power switch pipe is: ((N* (K+1)-1)/(N-1)) * IREF, wherein Ron1/Ron2=1/K, Ron1 is the conduction resistance value of power switch pipe, Ron2 is the conduction resistance value of detector tube, K is positive number, IREF is reference current.
Compared with prior art, over-current detection circuit in the utility model uses the detector tube matched with power switch pipe, and a reference current is set flows through this detector tube, current detecting is realized by the drain-source pressure drop of the drain-source pressure drop and power switch pipe of comparing detector tube, due to detector tube and power switch pipe conducting resistance ratio great disparity and matching degree is very high, therefore the electric current flowing through power switch pipe can be accurately detected very much, like this, not only can realize overcurrent protection accurately, and also omit the detection resistance adopted in prior art, reduce power consumption.
[accompanying drawing explanation]
In order to be illustrated more clearly in the technical scheme of the utility model embodiment, below the accompanying drawing used required in describing embodiment 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 prerequisite not paying creative work, other accompanying drawing can also be obtained according to these accompanying drawings.Wherein:
Fig. 1 shows the circuit diagram of the utility model li-ion cell protection system in one embodiment;
Fig. 2 is the circuit diagram of discharge switch pipe MD in Fig. 1 and detector tube Msense and current comparison circuit.
[embodiment]
For enabling above-mentioned purpose of the present utility model, feature and advantage become apparent more, are described in further detail the utility model below in conjunction with the drawings and specific embodiments.
Alleged herein " embodiment " or " embodiment " refers to special characteristic, structure or the characteristic that can be contained at least one implementation of the utility model.Different local in this manual " in one embodiment " occurred not all refers to same embodiment, neither be independent or optionally mutually exclusive with other embodiments embodiment.Unless stated otherwise, connection herein, be connected, word that the expression that connects is electrically connected all represents and is directly or indirectly electrical connected.
Fig. 1 is the circuit diagram of the utility model li-ion cell protection system in one embodiment, and Fig. 2 is the circuit diagram of discharge switch pipe MD in Fig. 1 and detector tube Msense and current comparison circuit.Shown in composition graphs 1 and Fig. 2, described li-ion cell protection system comprises battery protecting circuit 100, charge switch pipe MC, discharge switch pipe MD (also can be called as power switch pipe) and detector tube Msense.
Described battery protecting circuit 100 comprises power end VDD, earth terminal VSS, charge protection end COUT, discharge prevention end DOUT and current detecting end IL, and described power end VDD connects the positive pole of battery BAT, and described earth terminal VSS connects the negative pole of battery BAT and ground connection.First of described discharge switch pipe MD connects the negative pole of battery BAT described in termination; second link of discharge switch pipe MD is connected with second link of charge switch pipe MC; first link of charge switch pipe MC is connected with load (or claiming load resistance) RL as output; the control end of charge switch pipe MC connects the charge protection end COUT of described battery protecting circuit 100, and the control end of discharge switch pipe MD connects the discharge prevention end DOUT of described battery protecting circuit 100.
First link of detector tube Msense is connected with the current detecting end IL of described battery protecting circuit 100, and its second link is connected with second link of discharge switch pipe MD, and its control end is connected with the control end of described discharge switch pipe MD.
In the embodiment shown in Fig. 1 and Fig. 2, described charge switch pipe MC, discharge switch pipe MD and detector tube Msense is NMOS (N-channel Metal Oxide Semiconductor) transistor, first link of nmos pass transistor is the source electrode of nmos pass transistor, second link of nmos pass transistor is the drain electrode of nmos pass transistor, the control end of nmos pass transistor is the grid of nmos pass transistor, preferably, detector tube Msense and discharge switch pipe MD is made in two twin TR tubes (i.e. power tube MDS) with on a die material (or same wafer), as shown in Figure 2, detector tube Msense and discharge switch pipe MD shares drain D, grid G and lining body B (the i.e. source electrode of detector tube Msense and the Source interconnect of discharge switch pipe MD, the grid of detector tube Msense and the gate interconnection of discharge switch pipe MD, the lining body of detector tube Msense and the lining body interconnection of discharge switch pipe MD), the source S 1 of discharge switch pipe MD and the source S 2 of detector tube Msense are independent separately, and detector tube Msense serves as a contrast the connected node B of lining body and source S 1 short circuit of discharge switch pipe MD of body and discharge switch pipe MD, in other embodiments, detector tube Msense serve as a contrast the lining body of body and discharge switch pipe MD connected node B also can with source S 2 short circuit of detector tube Msense.
It should be noted that, detector tube Msense and discharge switch pipe MD this feature of twin TR tube is both conducting resistance ratios great disparity and matching degree is very high, simultaneously, as long as the driving voltage of the connected node G of the grid of detector tube Msense grid and discharge switch pipe MD is enough high, the source S 1 of discharge switch pipe MD and the small impact of voltage differences on discharge switch pipe MD and detector tube Msense conducting resistance ratio of the source S 2 of detector tube Msense are insignificant in engineering, here the conducting resistance defining discharge switch pipe MD is Ron1, the conducting resistance Ron2 of detector tube Msense, and Ron1/Ron2=1/K, K is positive number.
Shown in Fig. 1 and Fig. 2; described battery protecting circuit 100 also comprises current comparison circuit 110; described current comparison circuit 110 is provided with the reference current flowing through detector tube Msense, and the drain-source pressure drop of its voltage and discharge switch pipe MD that pass through more described current detecting end IL is to determine whether the overcurrent that discharges.In the embodiment shown in Figure 2, the described current comparison circuit 110 constant-current source IREF that comprises comparator CMP, voltage sampling unit 112 and be connected between current detecting end IL and earth terminal.Described constant-current source IREF extracts reference current IREF via detector tube Msense; The input of described voltage sampling unit 112 is connected with the connected node D of the drain electrode of detector tube Msense with the described drain electrode of discharge switch pipe MD, its output is connected with the first input end of described comparator CMP, described voltage sampling unit 112 is for the drain-source pressure drop (i.e. the voltage of node D) of the described discharge switch pipe MD that samples, its sampled voltage exported is the drain-source pressure drop of 1/N discharge switch pipe MD doubly, and N is the numerical value pre-set; Second input of described comparator CMP is connected with described current detecting end IL; its output is connected with the output OUT of described current comparison circuit 110; when the voltage that the first input end of described comparator CMP receives is greater than the voltage that its second input receives; output OUT exports the first level; represent the overcurrent that do not discharge; when the voltage that the first input end of described comparator CMP receives is less than the voltage that the second input receives; output OUT exports second electrical level; represent electric discharge overcurrent, need to carry out discharge prevention.
Below the principle that the li-ion cell protection system in the utility model is so arranged specifically is introduced.
Target of the present utility model detects electric current (it equals to flow through the electric current sum of detector tube Msense and discharge switch pipe MD) the whether overcurrent flowing into D port.In the embodiment shown in Fig. 1 and Fig. 2, reference current IREF is extracted from the source S 2 of detector tube Msense by constant-current source IREF, the constant-current source IREF that side circuit is formed is also imperfect, when the undercurrent of inflow D port is to be supplied to constant-current source IREF by detector tube Msense, voltage (i.e. the voltage of current detecting end IL) the meeting closely level of the source S 2 of detector tube Msense; When the electric current flowing into D port is enough large so that be supplied to constant-current source IREF by detector tube Msense, detector tube Msense drain-source voltage difference constant be VDS2=IREF*Ron2=K*IREF*Ron1 and, along with the electric current flowing into D port continues to increase, the current potential of D port rises, and source S 2 current potential (i.e. the current potential of current detecting end IL) of detector tube Msense also can synchronously rise thereupon.Definition ID is the electric current flowing into D port, can obtain:
VS2＝VDS1-VDS2＝(ID-IREF)*Ron1-K*IREF*Ron1＝(ID-(K+1)*IREF)*Ron1 (1)，
Wherein, VS2 is the voltage (it equals the voltage of current detecting end IL) of the source S 2 of detector tube Msense, IREF be constant-current source IREF after testing pipe Msense extract reference current value, VDS1 is the drain-source voltage of discharge switch pipe MD, VDS2 is the drain-source voltage of detector tube Msense, and Ron1/Ron2=1/K, K are positive number, Ron1 is the conduction resistance value of discharge switch pipe MD, and Ron2 is the conduction resistance value of detector tube Msense.
When the overturn point of comparator CMP, VS2=VDS1/N, substitutes into formula (1), can obtain:
(ID-IREF)*Ron1/N＝(ID-(K+1)*IREF)*Ron1
＝>ID*Ron1-IREF*Ron1＝N*ID*Ron1-N*(K+1)*IREF*Ron1
＝>ID-IREF＝N*ID-N*(K+1)*IREF
＝>(N-1)*ID＝(N*(K+1)-1)*IREF
＝>ID＝((N*(K+1)-1)/(N-1))*IREF
＝>ID＝((K+1)+K/(N-1))*IREF
Thus; can know by the ratio N of the voltage VS2 of the drain-source voltage VDS1 of discharge switch pipe MD and current detecting end IL the electric current I D flowing into D port by inference, described comparator CMP achieves the comparison of ID to current protection threshold value ((N* (K+1)-1)/(N-1)) * IREF.Due to detector tube Msense and discharge switch pipe MD conducting resistance ratio great disparity and matching degree is very high, and this current protection threshold value is only relevant with IREF in N, K, and therefore, the over-current detection circuit in the utility model can realize overcurrent accurately and detect.
In the embodiment shown in Figure 2, VS2 and VDS1/N is compared by comparator CMP, the first input end of this comparator CMP is normal phase input end, its second input is negative-phase input, when (VDS1/N) > VS2 (time, output OUT is high level, represent that the electric current I D flowing into D port does not exceed current protection threshold value, as (VDS1/N) < VS2, output OUT is low level, represent that the electric current I D flowing into D port exceedes current protection threshold value, need to carry out overcurrent protection, thus overcurrent protection accurately can be realized.In another embodiment, the first input end of described comparator CMP can be negative-phase input, and its second input is normal phase input end.
In another embodiment, also the described voltage sampling unit 112 in Fig. 2 can be saved, another voltage sampling unit is set up between current detecting end IL and second input of described comparator CMP, this voltage sampling unit is for the voltage of the described current detecting end IL that samples, its sampled voltage exported is N current detecting end IL voltage doubly, thus N VS2 and VDS1 is doubly compared by comparator CMP, to judge the electric current I D whether overcurrent of inflow D port.Be specially, the input of another voltage sampling unit described is connected with described current detecting end IL, its output is connected with second input of described comparator CMP, another voltage sampling unit described is for described current detecting end IL voltage of sampling, its sampled voltage exported is N current detecting end IL voltage doubly, the first input end of described comparator CMP is connected with the connected node D of second link of detector tube Msense with described second link of discharge switch pipe MD, when the voltage that the first input end of described comparator CMP receives is greater than the voltage that its second input receives, output OUT exports the first level, represent the overcurrent that do not discharge, when the voltage that the first input end of described comparator CMP receives is less than the voltage that the second input receives, output OUT exports second electrical level, represent electric discharge overcurrent.
In sum, li-ion cell protection system in the utility model comprises battery protecting circuit 100, charge switch pipe MC, discharge switch pipe MD and detector tube Msense, detector tube Msense and discharge switch pipe MD is made in two twin TR tubes with on a die material (or same wafer), detector tube Msense and discharge switch pipe MD shares drain D, grid G and lining body B, first link of detector tube Msense is connected with the current detecting end IL of described battery protecting circuit 100, its second link is connected with second link of discharge switch pipe MD, its control end is connected with the control end of described discharge switch pipe MD, described current comparison circuit 110 is provided with the constant-current source IREF be connected between current detecting end IL and earth terminal, described constant-current source IREF extracts reference current IREF via detector tube Msense, the drain-source pressure drop of voltage and discharge switch pipe MD that described current comparison circuit 110 passes through more described current detecting end IL is to determine whether the overcurrent that discharges.Like this, due to detector tube Msense and discharge switch pipe MD conducting resistance ratio great disparity and matching degree is very high, not only can realize overcurrent protection accurately, and also omit the detection resistance adopted in prior art, reduce power consumption.
In the utility model, " connection ", be connected, word that " companys ", the expression such as " connecing " are electrical connected, if no special instructions, then represent direct or indirect electric connection.
It is pointed out that the scope be familiar with person skilled in art and any change that embodiment of the present utility model is done all do not departed to claims of the present utility model.Correspondingly, the scope of claim of the present utility model is also not limited only to previous embodiment.
Claims (9)
1. a li-ion cell protection system, is characterized in that, it comprises:
Battery protecting circuit, it has power end, earth terminal, charge protection end, discharge prevention end and current detecting end, the positive pole of described power supply termination battery, the negative pole of described ground connection termination battery ground connection;
Charge switch pipe and discharge switch pipe, first of discharge switch pipe connects the negative pole of battery described in termination, second link of discharge switch pipe is connected with the second link of charge switch pipe, first link of charge switch pipe is connected with load as output, the control end of charge switch pipe connects the charge protection end of described battery protecting circuit, and the control end of discharge switch pipe connects the discharge prevention end of described battery protecting circuit;
Detector tube, its first link is connected with the current detecting end of described battery protecting circuit, and its second link is connected with the second link of discharge switch pipe, and its control end is connected with the control end of described discharge switch pipe;
Described battery protecting circuit also includes the current comparison circuit be connected with described current detecting end; described current comparison circuit comprises the constant-current source be connected between described current detecting end and earth terminal; described constant-current source extracts reference current via detector tube, described current comparison circuit by the voltage of more described current detecting end and the drain-source pressure drop of discharge switch pipe to determine whether the overcurrent that discharges.
2. li-ion cell protection system according to claim 1, is characterized in that, described current comparison circuit also comprises comparator and a voltage sampling unit,
The input of described voltage sampling unit is connected with the connected node of the second link of described discharge switch pipe with the second link of detector tube, its output is connected with the first input end of described comparator, described voltage sampling unit is for the drain-source pressure drop of described discharge switch pipe of sampling, its sampled voltage exported is the drain-source pressure drop of 1/N discharge switch doubly, and N is the numerical value pre-set;
Second input of described comparator is connected with described current detecting end, its output is connected with the output of described current comparison circuit, when the voltage that the first input end of described comparator receives is greater than the voltage that its second input receives, the output of described current comparison circuit exports the first level, represent the overcurrent that do not discharge, when the voltage that the first input end of described comparator receives is less than the voltage that the second input receives, the output of described current comparison circuit exports second electrical level, represents electric discharge overcurrent.
3. li-ion cell protection system according to claim 1, is characterized in that, described current comparison circuit also comprises comparator and another voltage sampling unit,
The input of another voltage sampling unit described is connected with described current detecting end, its output is connected with the second input of described comparator, another voltage sampling unit described is for described current detecting terminal voltage of sampling, its sampled voltage exported is N current detecting terminal voltage doubly, and N is the numerical value pre-set;
The first input end of described comparator is connected with the connected node of the second link of described discharge switch pipe with the second link of detector tube, when the voltage that the first input end of described comparator receives is greater than the voltage that its second input receives, the output of described current comparison circuit exports the first level, represent the overcurrent that do not discharge, when the voltage that the first input end of described comparator receives is less than the voltage that the second input receives, the output of described current comparison circuit exports second electrical level, represents electric discharge overcurrent.
4., according to the arbitrary described li-ion cell protection system of claim 1-3, it is characterized in that,
Charge switch pipe, discharge switch pipe, detector tube are nmos pass transistor,
First link of nmos pass transistor is the source electrode of nmos pass transistor, and the second link is the drain electrode of nmos pass transistor, and control end is the grid of nmos pass transistor.
5. according to li-ion cell protection system according to claim 4, it is characterized in that, detector tube and discharge switch pipe are formed on same wafer, and drain electrode shared by detector tube and discharge switch pipe, and grid and lining body, the source electrode of discharge switch pipe and the source electrode of detector tube are independent separately.
6., according to li-ion cell protection system according to claim 5, it is characterized in that,
Detector tube lining body and discharge switch pipe serve as a contrast the connected node of body and the source shorted of discharge switch pipe, or
Detector tube lining body and discharge switch pipe serve as a contrast the connected node of body and the source shorted of detector tube.
7. an over-current detection circuit, is characterized in that, it comprises:
Power switch pipe, it has the first link, the second link and control end,
Detector tube, it has the first link, the second link and control end, and wherein the second link of detector tube is connected with the second end of power switch pipe, and the control end of detector tube is connected with the control end of described power switch pipe;
Constant-current source, it is connected with the first link of described detector tube, and it extracts reference current from the first link of described detector tube;
Comparator, the 1/N of the voltage of the voltage of the first link of detector tube and the second link of detector tube compares by it, when 1/N lower than the voltage of the second link of detector tube of the voltage of the first link of detector tube, the output of described comparator exports the first level, represent the electric current not overcurrent flowing through described power switch pipe, when 1/N higher than the voltage of the second link of detector tube of the voltage of the first link of detector tube, the output of described comparator exports second electrical level, represent the overcurrent flowing through described power switch pipe, N is the numerical value pre-set.
8. over-current detection circuit according to claim 7, is characterized in that, the first link ground connection of described power switch pipe, detector tube and power switch pipe are formed on same wafer.
9. over-current detection circuit according to claim 7, is characterized in that, power switch pipe and detector tube are nmos pass transistor, first link of nmos pass transistor is the source electrode of nmos pass transistor, second link is the drain electrode of nmos pass transistor, and control end is the grid of nmos pass transistor
Detector tube and power switch pipe share drain electrode, grid and lining body, and the source electrode of power switch pipe and the source electrode of detector tube are independent separately,
Detector tube lining body and power switch pipe serve as a contrast the connected node of body and the source shorted of discharge switch pipe; or detector tube serves as a contrast body and power switch pipe serves as a contrast the connected node of body and the source shorted of detector tube; the current protection threshold value flowing through the electric current of described power switch pipe is: ((N* (K+1)-1)/(N-1)) * IREF
Wherein Ron1/Ron2=1/K, Ron1 are the conduction resistance value of power switch pipe, and Ron2 is the conduction resistance value of detector tube, and K is positive number, and IREF is reference current.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420288951.9U CN204068213U (en) | 2014-05-30 | 2014-05-30 | A kind of li-ion cell protection system and over-current detection circuit thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420288951.9U CN204068213U (en) | 2014-05-30 | 2014-05-30 | A kind of li-ion cell protection system and over-current detection circuit thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN204068213U true CN204068213U (en) | 2014-12-31 |
Family
ID=52209660
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201420288951.9U Withdrawn - After Issue CN204068213U (en) | 2014-05-30 | 2014-05-30 | A kind of li-ion cell protection system and over-current detection circuit thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN204068213U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104022490A (en) * | 2014-05-30 | 2014-09-03 | 无锡中星微电子有限公司 | Lithium battery protection system and over-current direction circuit thereof |
| CN108063428A (en) * | 2017-09-23 | 2018-05-22 | 华为技术有限公司 | A kind of apparatus for protecting power supply and the terminal using described device |
-
2014
- 2014-05-30 CN CN201420288951.9U patent/CN204068213U/en not_active Withdrawn - After Issue
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104022490A (en) * | 2014-05-30 | 2014-09-03 | 无锡中星微电子有限公司 | Lithium battery protection system and over-current direction circuit thereof |
| CN104022490B (en) * | 2014-05-30 | 2017-03-15 | 无锡中感微电子股份有限公司 | A kind of li-ion cell protection system and its over-current detection circuit |
| CN108063428A (en) * | 2017-09-23 | 2018-05-22 | 华为技术有限公司 | A kind of apparatus for protecting power supply and the terminal using described device |
| US11527883B2 (en) | 2017-09-23 | 2022-12-13 | Huawei Technologies Co., Ltd. | Power protection apparatus and terminal using the apparatus |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN104022490B (en) | A kind of li-ion cell protection system and its over-current detection circuit | |
| CN204886403U (en) | External power and backup battery's seamless handover circuit | |
| CN105846493B (en) | Over-current detection, protection circuit and battery | |
| CN105372552B (en) | A kind of load open-circuit detection circuit and method for high side switches | |
| CN104319742B (en) | Battery protecting circuit | |
| CN204666703U (en) | The current detection circuit of quick charging battery fender | |
| CN102403756A (en) | Charge/discharge control circuit and battery device | |
| CN103091590A (en) | Series capacitor detection method and device | |
| CN110021992A (en) | A kind of main secondary power switching circuit and method | |
| CN104600963A (en) | Output voltage dual-mode detection circuit of switching power supply | |
| CN102270867A (en) | Battery state monitoring circuit and battery device | |
| CN102983556A (en) | Battery protection circuit with self-recovery function after discharge over-current protection | |
| CN109888855A (en) | Charge-discharge controller and cell apparatus | |
| CN203037745U (en) | Insulation resistance detection circuit of two ways of photovoltaic input | |
| CN204068213U (en) | A kind of li-ion cell protection system and over-current detection circuit thereof | |
| CN104821555B (en) | The battery protecting circuit of precision current sampling can be carried out | |
| CN204408184U (en) | A kind of Boost type dc-dc synchronizing power pipe current-limiting circuit | |
| CN106299180B (en) | The combination of electric tool and battery pack | |
| CN102983557B (en) | Battery protective circuit and charging power switch control signal producing circuit thereof | |
| CN205544488U (en) | Detection, protection circuit and battery overflow | |
| CN204144922U (en) | Battery protecting circuit | |
| CN202840563U (en) | Rechargeable battery protective circuit | |
| CN208461440U (en) | A kind of overcurrent protective switch circuit | |
| CN109085412B (en) | Reverse current detection circuit | |
| CN105743059A (en) | Output over-current protection circuit formed by reference source and resistor |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C56 | Change in the name or address of the patentee | ||
| CP03 | Change of name, title or address |
Address after: 214028 Jiangsu Province, Wuxi City District Qingyuan Road No. 18 Taihu International Science Park sensor network university science and Technology Park 530 building A1001 Patentee after: WUXI ZHONGGAN MICROELECTRONIC CO., LTD. Address before: A 530 Taihu international science and Technology Park building 214028 Qingyuan Road in Jiangsu province Wuxi City District 10 layer Patentee before: Wuxi Vimicro Co., Ltd. |
|
| AV01 | Patent right actively abandoned | ||
| AV01 | Patent right actively abandoned |
Granted publication date: 20141231 Effective date of abandoning: 20171114 |