CN209298948U - A kind of metal-oxide-semiconductor driving circuit and li-ion cell protection IC - Google Patents
A kind of metal-oxide-semiconductor driving circuit and li-ion cell protection IC Download PDFInfo
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- CN209298948U CN209298948U CN201920153324.7U CN201920153324U CN209298948U CN 209298948 U CN209298948 U CN 209298948U CN 201920153324 U CN201920153324 U CN 201920153324U CN 209298948 U CN209298948 U CN 209298948U
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Abstract
The utility model relates to a kind of metal-oxide-semiconductor driving circuit and li-ion cell protection IC, the metal-oxide-semiconductor driving circuit includes current lens unit, current switch cell, output inverter module and dropping resistor；The input terminal of the current lens unit is connected to the reference circuit of li-ion cell protection IC, and output end is connected to the source of current switch cell；The control terminal of the current switch cell is connected to the end control signal cout of li-ion cell protection IC, and drain terminal is connected to output inverter module；The output inverter module includes metal-oxide-semiconductor NM1 and metal-oxide-semiconductor PM3; the grid of the metal-oxide-semiconductor NM1 is connected to the drain terminal of current switch cell; drain electrode is connected to the drain terminal of metal-oxide-semiconductor PM3; and the current detecting port of li-ion cell protection IC is connected to by current-limiting resistance, the grid of the metal-oxide-semiconductor PM3 is connected to the end control signal coutb of li-ion cell protection IC.Versatility is good, and manufacturing cost is low, good economy performance.
Description
Technical field
The utility model relates to the technical field of electronic technology, in particular to a kind of metal-oxide-semiconductor driving circuit and lithium battery are protected
Protect IC.
Background technique
Lithium battery is divided into lithium metal battery and lithium ion battery, and what the electronic products such as mobile phone and laptop used is all
Lithium battery is called in lithium ion battery, usual people's letter.Lithium ion battery energy density is high, and operating voltage is high, cycle charging
Number is more, and environmental-protecting performance is good, therefore lithium ion battery is widely used in current mancarried electronic aid.Lithium battery is in application process
In, because of the chemical property of lithium battery interior, its operating voltage and operating current will have certain limitation, if lithium battery
Occur overcharge, overdischarge, electric discharge overcurrent, short circuit situations such as, can to cause inside battery generate chemical side reactions, the side reaction
The performance and service life of battery can be seriously affected after generation, and there may be bulk gases, increase cell internal pressure rapidly
It explodes after big, leads to serious safety problem, therefore, in the battery pack of all lithium ion batteries, require to be equipped with lithium electricity
Pond protection board is effectively monitored come the charge and discharge state to battery, and turns off charge and discharge circuit under certain conditions, is prevented
Damage to lithium ion battery.The core devices of lithium battery protection board are li-ion cell protection IC, typical lithium battery as shown in Figure 1
Protection board, NM1, NM2 are respectively the power MOS pipes for controlling charging and discharging, and D1, D2 are the parasitic body diodes of metal-oxide-semiconductor,
R1, C1 constitute low-pass filter, for inhibiting the High-frequency Interference on chip VDD pin.It is li-ion cell protection in dotted line frame in Fig. 1
The internal circuit configuration schematic diagram of IC, it can be seen that li-ion cell protection IC is directly powered by lithium battery, by VDD and VSS pipe
The detection of voltage between foot, chip may determine that whether battery has occurred overcharge, over-discharge state；CS pin is chip
Current detecting port, the charge and discharge electric current that the voltage on CS pin is equal to battery switch the pressure drop formed on metal-oxide-semiconductors at two
When electric discharge (negative voltage when charging, positive voltage).OD and OC is control pin (OC, OD, CS etc. of electric discharge MOS and the MOS that charges respectively
The name of pin, different manufacturers will be different, but function is consistent).When the voltage and charging or discharging current of lithium battery are normal
Under state, OC, OD pin export high level, so that two metal-oxide-semiconductors are all connected；Once chip detects that battery generation is excessively put
Electricity or discharge current are excessive, and after continuing the regular hour, and the logic circuit control OD pin of chip interior exports low electricity
Flat (=VSS) then shuts off the discharge loop of lithium battery protection board so that NM1 is turned off；With should battery occur it is excessive
The case where charging and charging overcurrent, logic circuit controls OC pin output low level (equal to the voltage of CS pin), turns off NM2,
The charge circuit of tripping protection plate.
It will be seen from figure 1 that the logic control circuit of chip interior, there is no directly directly controlled by OC and OD pin
The switch of MOS, but joined a stage drive circuit between logic circuit and OC/OD pin, main cause has two o'clock:
(1) parasitic capacitance of the external metal-oxide-semiconductor of chip, grid would generally reach nanofarad rank, in order to make battery be abnormal charge and discharge
Afterwards, the parasitic capacitance discharge that OC/OD pin can rapidly to mos gate pole, is switched off, therefore OC/OD pin needs to be added
Driving circuit, to provide enough driving capabilities；(2) in order to guarantee that external MOS is thoroughly turned off under abnormality, MOS
Pressure difference VGS between the grid and source electrode of pipe is necessarily equal to zero, the unlatching threshold value of far smaller than MOS.
It will be seen from figure 1 that the source electrode of electric discharge metal-oxide-semiconductor NM1 and the cathode of battery connect, OD pin output VSS can make
The V of NM1GS=0, thoroughly shutdown electric discharge MOS, therefore the driving circuit design letter relatively between OD pin and control logic circuit
It is single, it is only necessary to driving capability to be provided, without level conversion function；And the driving circuit between OC pin and control logic is just
It is relative complex, it will be seen from figure 1 that charger is accessed between P+ and P- when battery is electrically charged, due to RCSWithout pressure on resistance
Drop, therefore the source potential for the metal-oxide-semiconductor NM2 that charges is equal to CS current potential (VCS) it is also equal to P- current potential, in order to make the V of charging MOSGS=
0V is complete switched off, and OC pin output voltage also is equal to VCS, and the logic circuit of chip interior, it can only provide equal to VDD or VSS
Logical signal, if output VSS low level, cannot thoroughly turn off charging metal-oxide-semiconductor.It is fixed according to the Kirchoff s voltage of circuit
Reason, when the MOS that charges is turned off, the voltage V of OC and CS pinOC=VCS=VDD-VCH, VCHIt is the open-circuit voltage of charger, at present
The li-ion cell protection IC of mainstream in the market, is required to be able to bear the charger voltage of 25V to 30V or so, and the mistake of lithium battery
It fills and protects voltage in 3.6~4.5V or so, therefore, the driving circuit of OC pin, it is desirable to be able to bear -25V or so high pressure.Cause
This, the MOS drive circuit that OC pin charges designs, need to take into account the performance requirement of driving capability, level conversion and resistance to negative high voltage, because
This is a difficult point in li-ion cell protection IC design.
In the prior art, charge driving circuit there are mainly two types of the structure of metal-oxide-semiconductor: 1. using thick grid oxygen BCD techniques
Level shifting circuit add output phase inverter structure；2. doing the output inverter structure of pull-down using big resistance.
The first existing charging metal-oxide-semiconductor foot driving circuit is as shown in Figure 2 as described above: cout is the control letter of the module
Number, phase inverter INV1, high voltage PMOS pipe PM1, PM2, high pressure NMOS pipe NM1, NM2 constitute level shifting circuit (level-
Shifter), high-voltage MOS pipe PM3 and NM3 constitutes output phase inverter.Cout is the control letter that chip interior logic circuit provides
Number, when the voltage and current of lithium battery is all normal, cout exports high level, and PM1 is connected at this time, and PM2 is disconnected, then the grid of NM2
Electrode potential is equal to VDD, then VGS,NM2=VDD-VCS, since under normal operating conditions, the voltage of CS pin is close to VSS, therefore
The conducting of NM2 pipe, this grid potential for allowing for NM1 pipe are equal to VCS, then its VGS,NM1=0, therefore the thoroughly shutdown of NM1 pipe, simultaneously
The V of PM3 pipeGS,PM3=VCS- VDD, PM3 conducting, OC export high level, and charging metal-oxide-semiconductor is opened；When battery occur overcharge or
When the case where overcurrent that charges, logic control circuit makes the overturning of cout signal be low level, and PM2 is connected at this time, then NM1 is connected, and makes
NM2 grid potential is equal to VCS, VGS, NM2=0, therefore the thoroughly shutdown of NM2 pipe, while PM2 conducting enables the V of NM3 againGS, NM3=
VDD-VCS, then NM3 is connected, therefore OC pin output voltage is equal to CS pin voltage, then just completes chip interior logic low
Level VSS to OC pin low level VCSLevel conversion function.
Second of existing charging metal-oxide-semiconductor foot driving circuit is as shown in Figure 3: the cout in coutb and Fig. 2 is a pair of of reverse phase
Signal.PM1 and R1 constitutes a kind of output inverter structure.PM2 is the ESD protection of GDPMOS (grid meets power supply PMOS) structure
Pipe, resistance R2 is current-limiting resistance.Its working principle is that: under chip normal operation, coutb output level, PM1 pipe is led at this time
It is logical, the voltage V of OC pinOC=VDD* [R1/ (R1+Ron,PM1)], Ron,PM1It is the conduction impedance of PM1, value is much smaller than R1, therefore
The output voltage of OC foot is just approximately equal to VDD, and the resistance value of R1 takes bigger, then OC pin voltage and the difference of VDD are smaller.Work as generation
Overcharge and charge overcurrent the phenomenon that when, logic circuit control coutb overturning be high level, at this time PM1 turn off, OC pin with
It is connected between CS pin by resistance R1, OC pin is defeated when after stabilization is equal to CS pin voltage, then also completes chip interior
Low level VSS to OC pin low level VCSConversion.
The disadvantage of the first above-mentioned charging metal-oxide-semiconductor foot driving circuit is more demanding to technique.By can be in Fig. 2
Find out, the first driving circuit is the level-shifter circuit of standard, realizes chip interior logic low VSS to OC
Pin low level VCSConversion, this structure is more demanding to the technique of the metal-oxide-semiconductor in circuit: (1) all in the circuit
NMOS tube all must be the isolated form high pressure NMOS pipe with individual substrate, i.e., its body end (end Bulk) needs to connect independent current potential.
This is because there is negative voltage in CS pin, and institute in the circuit after chip enters charging overcurrent protection or additives for overcharge protection state
There is the source electrode of NMOS tube to be all connected to CS, the substrate parasitics diode of NMOS occurs positively biased and generates big substrate electricity in order to prevent
Stream, causes chip can not work normally, therefore the body end (end BULK) of all NMOS tubes all allows for and source in the circuit
It is shorted, so that substrate-source bias etc. is zero；(2) circuit structure requires the V of NMOS and PMOS all in circuitGSWith resistance to
The ability of high pressure: any NMOS is in the state of conducting in the circuit, VGS, N=VDD-VCS, when any PMOS is connected, | VGS,P
|=VDD-VCS, by circuit analysis above it is found that VDD-VCS=VP+-VP-, equal to the open-circuit voltage of external charger.Due to
Mainstream lithium on the market protects IC product at present, requires that the voltage between VDD and CS can reach the high pressure of 30V or so, this is just
It is required that in the first metal-oxide-semiconductor driving circuit all metal-oxide-semiconductors VGSOperating voltage can reach 30V.For the isolated form in above-mentioned (1)
High pressure NMOS pipe, if only requiring its VDSWith high voltage bearing ability, then technical papers needed for circuit design are relatively easy
It finds, domestic many fabs can provide, and chip manufacturing cost is also easy control.But unfortunately the first drives
All MOS must satisfy the V of 30V described in (2) or so in dynamic circuitGSVoltage endurance capability, this requires generate in wafer
Need to make the mask plate of additional thick grid oxide layer before, it is also necessary to increase additional photo-mask process in chip manufacturing proces,
The production cost of chip is improved, and with substrate isolation features, VGSThe NMOS tube of high voltage, only a small number of wafer fabrications are all
It is capable of providing, therefore increases the limitation of process choice in circuit design.
From figure 3, it can be seen that the circuit structure of second of driving circuit is very simple, there is no NMOS tube, high pressure in circuit
The grid of PMOS tube PM1 is directly controlled by the logic circuit of chip interior, and therefore, PM1 does not have VGSHigh voltage bearing requirement, Ji Huke
To be realized with arbitrary BCD technique.But second of circuit have the shortcomings that it is several obvious: firstly, under chip normal operating conditions,
The circuit needs to consume quiescent current.In Fig. 3, when PM1 is connected, and OC pin exports high level (VDD), there is quiescent current to flow through
R1, quiescent current size are approximately equal to VDD/R1.It is low since the operating voltage of li-ion cell protection IC design is directly provided by lithium battery
Power consumption is the performance requirement of a certainty, and the overall work electric current of IC need to be controlled in 3uA or so, therefore, for an I/O mouthfuls of electricity
Road, quiescent current must control the rank in Naan.Assuming that the quiescent current I of the driving circuit of OC pinstat=360nA, VDD
=3.6V can obtain R1=VDD/Istat=10M Ω, therefore in order to guarantee it with lower quiescent current, then the resistance value of R1 must
What must be arranged is very big, needs to occupy biggish chip area；Secondly, the OC fall time of the circuit structure is very long, it can be serious
Reduce the reliability of charging overcurrent protection function.The delay time T of the charging overcurrent protection of li-ion cell protection ICCIPGenerally setting
It sets in 8ms~20ms or so, when chip detects abnormal charging current, and the duration is more than TCIPAfterwards, it is desirable that OC pin electricity
Pressure is rapidly decreased to VCS, shutdown charging MOS.It can be seen from the above, R1 is the other big resistance of mega-ohms, it is assumed that OC pipe is foot-powered outer
Meet the parasitic gate capacitor C of MOSP,OC=2nF, then in Fig. 3 OC terminal timeconstantτOC=R1*CP,OC=20ms.Assuming that electric
Cell voltage is equal to 3.6V, and the open-circuit voltage of charger is 5V, then when the shutdown of OC pin, the voltage V of CS pinCS=-1.4V,
If assuming, the threshold voltage of charging MOS is 0.8V, and the voltage of OC pin drops to -0.6V in requiring a very short time,
Can be by charging MOS shutdown, the calculation formula of the fall time of OC pin is as follows:
V in above formulaOC,1=3.6V, VOC,final=-1.4V enables VOC(t)=- 0.6V is substituted into after above formula it can be concluded that Tfall
=1.8* τOC=36ms.Calculated result shows that only external 5V charger, the fall time of OC pin will be up to 36ms, if
Battery pack accesses the higher charger of voltage, and the fall time of OC pin can also be longer, this is for lithium battery and protection board right and wrong
Often unsafe, high current duration in MOS is too long, it is easy to which burning MOS leads to protection board disabler；Third,
In test process, the failing edge waveform of OC pin, it is necessary to be observed with oscillograph, improve the difficulty of test of chip.Such as Fig. 4
Shown, general oscilloprobe has the internal resistance (R of M Ω magnitudeIt is interior), and have a ground terminal, when chip enters charging overcurrent
After guard mode, it is assumed that oscilloprobe and OC pins contact, OC pin voltage VOC[V can be essentially pulled up toCS+(VSS-VCS)*R1/
(R1+RIt is interior)], it is assumed that R1=10*RIt is interior, VCS=-1.4V, then VOC=-0.12V, i.e. OC voltage can be drawn high by oscilloprobe, shadow
The accuracy of observation is rung, more seriously, the V for the metal-oxide-semiconductor that charges at this timeGS=-0.12V- (- 1.4V)=1.28V, this results in original
The MOS that should be turned off is opened, it is possible to MOS be caused to be burned out.
Utility model content
For this reason, it may be necessary to provide a kind of metal-oxide-semiconductor driving circuit and li-ion cell protection IC, existing metal-oxide-semiconductor driving circuit pair is solved
The technique of metal-oxide-semiconductor requires high or needing to consume quiescent current and shutdown slowly causes metal-oxide-semiconductor to be easy the problem of burning out.
To achieve the above object, a kind of metal-oxide-semiconductor driving circuit, including current lens unit, current switch are inventor provided
Unit, output inverter module and dropping resistor；
The input terminal of the current lens unit is connected to current source I1, and output end is connected to the source of current switch cell；
The control terminal of the current switch cell is connected to the end control signal cout of li-ion cell protection IC, and drain terminal is connected to
Export inverter module；
The output inverter module includes that metal-oxide-semiconductor NM1 and metal-oxide-semiconductor PM3, the grid of the metal-oxide-semiconductor NM1 are connected to electric current
The drain terminal of switch unit, drain electrode are connected to the drain terminal of metal-oxide-semiconductor PM3, and source electrode is connected to the current detecting port of li-ion cell protection IC,
The grid of the metal-oxide-semiconductor PM3 is connected to the end control signal coutb of li-ion cell protection IC, and drain electrode is connected by current-limiting resistance R3
Pin is controlled in the charging MOS of li-ion cell protection IC, source electrode is connected to the VDD pin of li-ion cell protection IC；
The dropping resistor is connected across between the grid and source electrode of metal-oxide-semiconductor NM1.
It advanced optimizes, further includes current-limiting resistance R2, the source electrode and lithium electricity of metal-oxide-semiconductor NM1 is arranged in the current-limiting resistance R2
It protects between the current detecting port of IC in pond.
It advanced optimizes, further includes antistatic unit, the static protective unit includes metal-oxide-semiconductor PM4, the metal-oxide-semiconductor PM4
Grid and source electrode be connected to the VDD pin of li-ion cell protection IC, drain electrode is connected to the charging MOS control pipe of li-ion cell protection IC
Foot.
It advanced optimizes, the current switch cell is high-voltage MOS pipe PM5.
Advanced optimize, the current lens unit includes metal-oxide-semiconductor PM1 and metal-oxide-semiconductor PM2, the source electrode of the metal-oxide-semiconductor PM1 and
The source electrode of metal-oxide-semiconductor PM2 is connected to the VDD pin of li-ion cell protection IC, the drain electrode of the grid and metal-oxide-semiconductor PM1 of the metal-oxide-semiconductor PM1
Current source I1 is met with the grid of metal-oxide-semiconductor PM2, the drain electrode of the metal-oxide-semiconductor PM2 is connected to the source of current switch cell PM5.
Inventor additionally provides another technical solution: a kind of li-ion cell protection IC, including metal-oxide-semiconductor driving circuit, described
Metal-oxide-semiconductor driving circuit is metal-oxide-semiconductor driving circuit described above.
It is different from the prior art, above-mentioned technical proposal, when the normal charge and discharge of lithium battery, cout=VDD, coutb=
VSS, current switch cell is closed at this time, and dropping resistor R1 no current passes through, pressure drop zero, while the electricity at the both ends dropping resistor R1
Pressure is equal to the V of metal-oxide-semiconductor NM1GS,NM1, therefore metal-oxide-semiconductor NM1 is turned off；Metal-oxide-semiconductor PM3 conducting makes the high electricity of MOS control pin output that charges
Flat VDD.And when lithium battery is there is a phenomenon where when charging over-voltage or charging overcurrent, cout=VSS, coutb=VDD, metal-oxide-semiconductor at this time
PM3 shutdown, and current switch cell is connected, current source I1 is that current mirror introduces a bias current I1, at this point, there is current mirror list
Member output electric current I2 flows through resistance R1, wherein electric current I2=N*I1, the V of metal-oxide-semiconductor NM1GS,NM1=I2*R1, it is therefore desirable to I2*R1
Conduction threshold V greater than NM1TH, NM1, so that it may so that metal-oxide-semiconductor NM1 is connected, the MOS control pin voltage that charges at this time is pulled down to
VCS, by charging MOS shutdown；In the state of lithium battery normal charge and discharge, without quiescent current consumption, the RC of circuit output node
Time constant is small, can be by the parasitic gate for the MOS that charges in the state that chip needs to enter charging overcurrent or additives for overcharge protection
The voltage repid discharge of capacitor is to VCS, charging MOS control pin fall time reach microsecond rank, can effectively ensure that electricity
The trouble free service in pond and battery protecting plate, for chip design technique it is of less demanding, versatility is good, manufacturing cost
It is low, good economy performance.
Detailed description of the invention
Fig. 1 is a kind of circuit diagram of typical lithium battery protection board described in background technique；
Fig. 2 is a kind of circuit diagram of the first existing charging metal-oxide-semiconductor foot driving circuit described in background technique；
Fig. 3 is a kind of circuit diagram of existing second of charging metal-oxide-semiconductor foot driving circuit described in background technique；
Fig. 4 is second of existing charging metal-oxide-semiconductor foot driving circuit is contacted with oscilloprobe described in background technique one
Kind circuit diagram；
Fig. 5 is a kind of circuit diagram of charging metal-oxide-semiconductor driving circuit described in specific embodiment.
Specific embodiment
Technology contents, construction feature, the objects and the effects for detailed description technical solution, below in conjunction with specific reality
It applies example and attached drawing is cooperated to be explained in detail.
Referring to Fig. 5, the metal-oxide-semiconductor driving circuit in li-ion cell protection IC described in the present embodiment, including current lens unit
110, current switch cell 120, output inverter module 130 and dropping resistor R1；
The input terminal of the current lens unit 110 is connected to current source I1, and output end is connected to current switch cell 120
Source；
The control terminal of the current switch cell 120 is connected to the end control signal cout of li-ion cell protection IC, and drain terminal connects
It is connected to output inverter module；Wherein, current switch cell 120 uses high-voltage MOS pipe PM5, by using high-voltage P-type MOS transistor
Realization current switch is carried out, and can realize current switch using other forms in other embodiments, such as transmission gate circuit.This
In li-ion cell protection IC be this circuit can be used as li-ion cell protection IC (integrated circuit) use, each end li-ion cell protection IC
Perhaps interface can be the detection or driving for being arranged when use as IC and circuit may be implemented at pin to mouth.This Shen
Circuit please can also be used as individual circuit and use, i.e. each component of circuit is made of independent original part.
The output inverter module 130 includes that metal-oxide-semiconductor NM1 and metal-oxide-semiconductor PM3, the grid of the metal-oxide-semiconductor NM1 are connected to
The drain terminal of current switch cell, drain electrode are connected to the drain terminal of metal-oxide-semiconductor PM3, and source electrode is connected to the current detecting of li-ion cell protection IC
Port CS, the grid of the metal-oxide-semiconductor PM3 are connected to the end control signal coutb of li-ion cell protection IC, and drain electrode passes through current-limiting resistance
R3 is connected to the O current detecting port OC of li-ion cell protection IC, and source electrode is connected to the VDD pin of li-ion cell protection IC；
The dropping resistor R1 is connected across between the grid and source electrode of metal-oxide-semiconductor NM1.
Current source I1 can be the reference current source either reference circuit of li-ion cell protection IC, be electricity by current source I1
It flows mirror unit and introduces bias current I1, then export an electric current I2；Wherein, the current lens unit in the present embodiment includes MOS
The VDD that pipe PM1 and metal-oxide-semiconductor PM2, the source electrode of the metal-oxide-semiconductor PM1 and the source electrode of metal-oxide-semiconductor PM2 are connected to li-ion cell protection IC draws
Foot, the grid connection of the grid and metal-oxide-semiconductor PM2 of the metal-oxide-semiconductor PM1, the drain electrode of the metal-oxide-semiconductor PM1 and the grid of metal-oxide-semiconductor PM1
Current source I1 is met, the drain electrode of the metal-oxide-semiconductor PM2 is connected to the source of current switch cell, in other embodiments, current mirror list
Member can be realized using different current mirroring circuit structures；Wherein the leakage current of metal-oxide-semiconductor PM1 is equal to bias current I1, metal-oxide-semiconductor
The leakage current of PM2 is equal to I2, wherein I2=N*I1, and N is the ratio of the metal-oxide-semiconductor channel width of metal-oxide-semiconductor PM2 and metal-oxide-semiconductor PM1；
Cout and coutb is a pair of of inversion signal, and metal-oxide-semiconductor PM3 and metal-oxide-semiconductor NM1 constitute a pair of of output phase inverter.When lithium battery normally fills
When electric discharge, cout=VDD, coutb=VSS, current switch cell is closed at this time, and dropping resistor R1 no current passes through, and pressure drop is
Zero, while the voltage at the both ends dropping resistor R1 is equal to the V of metal-oxide-semiconductor NM1GS,NM1, therefore metal-oxide-semiconductor NM1 is turned off；Metal-oxide-semiconductor PM3 conducting,
OC pin is set to export high level VDD.And when lithium battery there is a phenomenon where charging over-voltage or charging overcurrent when, cout=VSS,
Coutb=VDD, metal-oxide-semiconductor PM3 is turned off at this time, and current switch cell is connected, and the reference circuit of li-ion cell protection IC is current mirror
A bias current I1 is introduced, at this point, there is current lens unit output electric current I2 to flow through dropping resistor R1, wherein electric current I2=N*
I1, the V of metal-oxide-semiconductor NM1GS,NM1=I2*R1, it is therefore desirable to which I2*R1 is greater than the conduction threshold V of NM1TH, NM1, so that it may so that metal-oxide-semiconductor
NM1 conducting, OC pin voltage pulled down to V at this timeCS, by charging MOS shutdown.
It wherein, further include current-limiting resistance R2, the current-limiting resistance in order to protect the source electrode of metal-oxide-semiconductor NM1 not by electrostatic breakdown
R2 is arranged between the source electrode of metal-oxide-semiconductor NM1 and the current detecting port CS of li-ion cell protection IC, can be protected by current-limiting resistance R2
The source electrode of metal-oxide-semiconductor NM1 is protected not by electrostatic breakdown.
It in the present embodiment, further include antistatic unit 140 in order to carry out electrostatic protection to metal-oxide-semiconductor driving circuit, it is described
Static protective unit 140 includes metal-oxide-semiconductor PM4, and the VDD that the grid and source electrode of the metal-oxide-semiconductor PM4 is connected to li-ion cell protection IC draws
Foot, drain electrode are connected to the charging MOS control pin OC of li-ion cell protection IC.ESD is constituted by current-limiting resistance R3 and metal-oxide-semiconductor PM4
(Electro-Staticdischarge, Electro-static Driven Comb) protection circuit is realized and carries out electrostatic protection to metal-oxide-semiconductor driving circuit.
In the present embodiment, the charging MOS control pin OC fall time of metal-oxide-semiconductor driving circuit calculates as follows: also assuming that
Charger voltage is equal to 5V, and the cell voltage of lithium battery is equal to 3.6V, and the parasitic gate capacitor for the MOS that charges is 2nF, limits in Fig. 5
Leakage resistance resistance value R2=R3=2k Ω, it is assumed that in order to save chip area, smaller, the metal-oxide-semiconductor of the breadth length ratio design of metal-oxide-semiconductor NM1
The conducting resistance R of NM1on,NM1Be approximately equal to 1k Ω, at this point, in Fig. 5 OC node timeconstantτOC=5k Ω * 2nF=10us, far
Less than the time constant of OC node in charging MOS drive circuit shown in Fig. 3, above-mentioned each value is brought into formula:Can drop in the hope of the voltage of OC pin from 3.6V-
The fall time of 0.6V=1.8* τOC=18us, can ignore the delay time of the charging overcurrent protection relative to chip completely
Disregard, in the moment that delay time reaches, the shutdown to charging MOS can be completed.In Fig. 5, metal-oxide-semiconductor PM1, metal-oxide-semiconductor PM2 are low
PMOS tube is pressed, the drain electrode of metal-oxide-semiconductor PM5 requires connect to CS, therefore PM5 | VDS| pressure-resistant size is VDD-VCS, it is equal to charger
The grid voltage of voltage, metal-oxide-semiconductor PM5 is controlled by logic circuit, therefore its VGSDemand without high voltage.Similarly metal-oxide-semiconductor PM3 and
Metal-oxide-semiconductor PM4 also only has | VDS| there is high voltage bearing demand.The pressure-resistant demand for seeing metal-oxide-semiconductor NM1 again, when chip works normally, MOS
Pipe PM5 shutdown, the grid and source electrode of metal-oxide-semiconductor NM1 is connected by R1, therefore the V of metal-oxide-semiconductor NM1GS,NM1=0, VDS,NM1=VDD-
VCS≈VDD；As metal-oxide-semiconductor PM5 conducting, the V of metal-oxide-semiconductor NM1GS,NM1=I2*R1, as long as therefore reasonably select I2 and R1 size,
I2*R1 can be made to be less than the supply voltage of chip.VDS, the NM1=VDD-VCS of metal-oxide-semiconductor NM1 is equal to charger voltage, with
The resistance to pressure request of PMOS tube is identical in circuit.For the value of I2 and R1, need to meet: VTH,NM1< I2*R1 < VDD-Vdsat,PM2-
VDS,PM5.In above formula, Vdsat,PM2It is minimum V of the metal-oxide-semiconductor PM2 work in saturation regionDSVoltage, VDS,PM5It is metal-oxide-semiconductor PM5 conducting pressure
Drop.The breadth length ratio of metal-oxide-semiconductor PM5 is bigger, the V of metal-oxide-semiconductor PM2dsat,PM2Smaller, then I2*R1 desirable value is bigger, metal-oxide-semiconductor NM1 conducting
When VGS, NM1Value will be bigger, and the conducting resistance of metal-oxide-semiconductor NM1 is with regard to smaller, and the time constant at the end OC is with regard to smaller, under OC pin
It is faster that time drops.
A novel output inverter structure is constituted by metal-oxide-semiconductor PM3 and metal-oxide-semiconductor NM1, in the normal charge and discharge of lithium battery
Under state, there is no current path in circuit, without quiescent current consumption, efficiently reduces the quiescent dissipation of circuit.Circuit is defeated
The RC time constant of egress is small, can be by the MOS that charges in the state that chip needs to enter charging overcurrent or additives for overcharge protection
Parasitic gate capacitor voltage quick pull-down to VCS, the fall time of OC signal reaches microsecond rank, can effectively ensure that
The trouble free service of battery and battery protecting plate.For chip design technique it is of less demanding, versatility is good, in the circuit
All high pressure NMOSs, PMOS tube, only VDSHigh voltage bearing requirement, without VGSHigh voltage bearing requirement, therefore the circuit can be
It is realized on the BCD technique platform of nearly all mainstream, increases the flexibility of circuit design.Due to the metal-oxide-semiconductor inside the circuit
Without VGSHigh voltage bearing requirement, therefore the mask plate for eliminating thick grid oxygen technique manufactures and additional photo-mask process, reduces
The manufacturing cost of chip.
In another embodiment, a kind of li-ion cell protection IC, including charging metal-oxide-semiconductor driving circuit, the charging metal-oxide-semiconductor
Driving circuit is charging metal-oxide-semiconductor driving circuit described in above-described embodiment.The metal-oxide-semiconductor driving circuit includes current lens unit, electricity
Flow switch unit, output inverter module and dropping resistor R1；
The input terminal of the current lens unit is connected to the reference circuit of li-ion cell protection IC, and output end is connected to electric current and opens
Close the source of unit；
The control terminal of the current switch cell is connected to the end control signal cout of li-ion cell protection IC, and drain terminal is connected to
Export inverter module；Wherein, current switch cell is realized using high-voltage MOS pipe PM5, and can be adopted in other embodiments
Current switch, such as transmission gate circuit are realized with other forms.
The output inverter module includes that metal-oxide-semiconductor NM1 and metal-oxide-semiconductor PM3, the grid of the metal-oxide-semiconductor NM1 are connected to electric current
The drain terminal of switch unit, drain electrode are connected to the drain terminal of metal-oxide-semiconductor PM3, and source electrode is connected to the current detecting port of li-ion cell protection IC
CS, the grid of the metal-oxide-semiconductor PM3 are connected to the end control signal coutb of li-ion cell protection IC, and drain electrode is connected to li-ion cell protection
The current detecting port OC of IC, source electrode are connected to the VDD pin of li-ion cell protection IC；
The dropping resistor R1 is connected across between the grid and source electrode of metal-oxide-semiconductor NM1.
Reference circuit by li-ion cell protection IC is that current lens unit introduces bias current I1, then exports an electric current
I2；Wherein, the current lens unit in the present embodiment includes metal-oxide-semiconductor PM1 and metal-oxide-semiconductor PM2, the source electrode and MOS of the metal-oxide-semiconductor PM1
The source electrode of pipe PM2 is connected to the VDD pin of li-ion cell protection IC, and the grid of the metal-oxide-semiconductor PM1 and the grid of metal-oxide-semiconductor PM2 connect
Ground, the grounded drain of the metal-oxide-semiconductor PM1, the drain electrode of the metal-oxide-semiconductor PM2 is connected to the source of current switch cell, in other realities
It applies in example, current lens unit can be realized using different current mirroring circuit structures；Wherein the leakage current of metal-oxide-semiconductor PM1 is equal to
The leakage current of bias current I1, metal-oxide-semiconductor PM2 are equal to I2, and wherein I2=N*I1, N are the metal-oxide-semiconductor ditch of metal-oxide-semiconductor PM2 Yu metal-oxide-semiconductor PM1
The ratio of road width；Cout and coutb is a pair of of inversion signal, and metal-oxide-semiconductor PM3 and metal-oxide-semiconductor NM1 constitute a pair of of output phase inverter.
When the normal charge and discharge of lithium battery, cout=VDD, coutb=VSS, current switch cell is closed at this time, and dropping resistor R1 is without electricity
Stream passes through, pressure drop zero, while the voltage at the both ends dropping resistor R1 is equal to the V of metal-oxide-semiconductor NM1GS,NM1, therefore metal-oxide-semiconductor NM1 is turned off；
Metal-oxide-semiconductor PM3 conducting, makes OC pin export high level VDD.And when lithium battery there is a phenomenon where charging over-voltage or charging overcurrent when,
Cout=VSS, coutb=VDD, metal-oxide-semiconductor PM3 is turned off at this time, and current switch cell is connected, the benchmark electricity of li-ion cell protection IC
Road is that current mirror introduces a bias current I1, at this point, having current lens unit output electric current I2 to flow through dropping resistor R1, wherein electricity
Flow I2=N*I1, the V of metal-oxide-semiconductor NM1GS,NM1=I2*R1, it is therefore desirable to which I2*R1 is greater than the conduction threshold V of NM1TH, NM1, so that it may
Metal-oxide-semiconductor NM1 is connected, OC pin voltage pulled down to V at this timeCS, by charging MOS shutdown.
It wherein, further include current-limiting resistance R2, the current-limiting resistance in order to protect the source electrode of metal-oxide-semiconductor NM1 not by electrostatic breakdown
R2 is arranged between the source electrode of metal-oxide-semiconductor NM1 and the current detecting port CS of li-ion cell protection IC, can be protected by current-limiting resistance R2
The source electrode of metal-oxide-semiconductor NM1 is protected not by electrostatic breakdown.
It in the present embodiment, further include antistatic unit in order to carry out electrostatic protection to metal-oxide-semiconductor driving circuit, it is described quiet
Electric protective unit includes metal-oxide-semiconductor PM4, and the grid and source electrode of the metal-oxide-semiconductor PM4 are connected to the VDD pin of li-ion cell protection IC, leakage
Pole is connected to the OC pin of li-ion cell protection IC.ESD (Electro-Static is constituted by current-limiting resistance R3 and metal-oxide-semiconductor PM4
Discharge, Electro-static Driven Comb) protection circuit, it realizes and electrostatic protection is carried out to metal-oxide-semiconductor driving circuit.
In the present embodiment, the charging MOS control pin OC fall time of metal-oxide-semiconductor driving circuit calculates as follows: also assuming that
Charger voltage is equal to 5V, and the cell voltage of lithium battery is equal to 3.6V, and the parasitic gate capacitor for the MOS that charges is 2nF, limits in Fig. 5
Leakage resistance resistance value R2=R3=2k Ω, it is assumed that in order to save chip area, smaller, the metal-oxide-semiconductor of the breadth length ratio design of metal-oxide-semiconductor NM1
The conducting resistance R of NM1on,NM1Be approximately equal to 1k Ω, at this point, in Fig. 5 OC node timeconstantτOC=5k Ω * 2nF=10us, far
Less than the time constant of OC node in charging MOS drive circuit shown in Fig. 3, above-mentioned each value is brought into formula:Can drop in the hope of the voltage of OC pin from 3.6V-
The fall time of 0.6V=1.8* τOC=18us, can ignore the delay time of the charging overcurrent protection relative to chip completely
Disregard, in the moment that delay time reaches, the shutdown to charging MOS can be completed.In Fig. 5, metal-oxide-semiconductor PM1, metal-oxide-semiconductor PM2 are low
PMOS tube is pressed, the drain electrode of metal-oxide-semiconductor PM5 requires connect to CS, therefore PM5 | VDS| pressure-resistant size is VDD-VCS, it is equal to charger
The grid voltage of voltage, metal-oxide-semiconductor PM5 is controlled by logic circuit, therefore its VGSDemand without high voltage.Similarly metal-oxide-semiconductor PM3 and
Metal-oxide-semiconductor PM4 also only has | VDS| there is high voltage bearing demand.The pressure-resistant demand for seeing metal-oxide-semiconductor NM1 again, when chip works normally, MOS
Pipe PM5 shutdown, the grid and source electrode of metal-oxide-semiconductor NM1 is connected by R1, therefore the V of metal-oxide-semiconductor NM1GS,NM1=0, VDS,NM1=VDD-
VCS≈VDD；As metal-oxide-semiconductor PM5 conducting, the V of metal-oxide-semiconductor NM1GS,NM1=I2*R1, as long as therefore reasonably select I2 and R1 size,
I2*R1 can be made to be less than the supply voltage of chip.The V of metal-oxide-semiconductor NM1DS,NM1=VDD-VCS, it is equal to charger voltage, with circuit
The resistance to pressure request of middle PMOS tube is identical.For the value of I2 and R1, need to meet: VTH,NM1< I2*R1 < VDD-Vdsat,PM2-
VDS,PM5.In above formula, Vdsat,PM2It is minimum V of the metal-oxide-semiconductor PM2 work in saturation regionDSVoltage, VDS,PM5It is metal-oxide-semiconductor PM5 conducting pressure
Drop.The breadth length ratio of metal-oxide-semiconductor PM5 is bigger, the V of metal-oxide-semiconductor PM2dsat,PM2Smaller, then I2*R1 desirable value is bigger, metal-oxide-semiconductor NM1 conducting
When VGS, NM1Value will be bigger, and the conducting resistance of metal-oxide-semiconductor NM1 is with regard to smaller, and the time constant at the end OC is with regard to smaller, under OC pin
It is faster that time drops.
A novel output inverter structure is constituted by metal-oxide-semiconductor PM3 and metal-oxide-semiconductor NM1, in the normal charge and discharge of lithium battery
Under state, there is no current path in circuit, without quiescent current consumption, efficiently reduces the quiescent dissipation of circuit.Circuit is defeated
The RC time constant of egress is small, can be by the MOS that charges in the state that chip needs to enter charging overcurrent or additives for overcharge protection
Parasitic gate capacitor voltage repid discharge to VCS, the fall time of OC signal reaches microsecond rank, can effectively ensure that
The trouble free service of battery and battery protecting plate.For chip design technique it is of less demanding, versatility is good, in the circuit
All high pressure NMOSs, PMOS tube, only VDSHigh voltage bearing requirement, without VGSHigh voltage bearing requirement, therefore the circuit can be
It is realized on the BCD technique platform of nearly all mainstream, increases the flexibility of circuit design.Due to the metal-oxide-semiconductor inside the circuit
Without VGSHigh voltage bearing requirement, therefore the mask plate for eliminating thick grid oxygen technique manufactures and additional photo-mask process, reduces
The manufacturing cost of chip.
Wherein, the li-ion cell protection IC in the present embodiment can not only be applied in the li-ion cell protection IC being individually encapsulated,
It can also apply and close the chip of envelope in li-ion cell protection IC and charging metal-oxide-semiconductor, and in the li-ion cell protection IC without peripheral circuit.
It should be noted that being not intended to limit although the various embodiments described above have been described herein
The scope of patent protection of the utility model.Therefore, based on the innovative idea of the utility model, embodiment described herein is carried out
Change and modification or equivalent structure or equivalent flow shift made based on the specification and figures of the utility model, directly
Or above technical scheme is used in other related technical areas indirectly, it is included in the patent protection model of the utility model
Within enclosing.
Claims (6)
1. a kind of metal-oxide-semiconductor driving circuit, which is characterized in that including current lens unit, current switch cell, output inverter module
And dropping resistor；
The input terminal of the current lens unit is connected to current source I1, and output end is connected to the source of current switch cell；
The control terminal of the current switch cell is connected to the end control signal cout of li-ion cell protection IC, and drain terminal is connected to output
Inverter module；
The output inverter module includes that metal-oxide-semiconductor NM1 and metal-oxide-semiconductor PM3, the grid of the metal-oxide-semiconductor NM1 are connected to current switch
The drain terminal of unit, drain electrode are connected to the drain terminal of metal-oxide-semiconductor PM3, and source electrode is connected to the current detecting port of li-ion cell protection IC, described
The grid of metal-oxide-semiconductor PM3 is connected to the end control signal coutb of li-ion cell protection IC, and drain electrode is connected to lithium by current-limiting resistance R3
The charging MOS of battery protection ic controls pin, and source electrode is connected to the VDD pin of li-ion cell protection IC；
The dropping resistor is connected across between the grid and source electrode of metal-oxide-semiconductor NM1.
2. metal-oxide-semiconductor driving circuit according to claim 1, which is characterized in that further include current-limiting resistance R2, the current-limiting resistance
R2 is arranged between the source electrode of metal-oxide-semiconductor NM1 and the current detecting port of li-ion cell protection IC.
3. metal-oxide-semiconductor driving circuit according to claim 1, which is characterized in that it further include antistatic unit, the electrostatic protection
Unit includes metal-oxide-semiconductor PM4, and the grid and source electrode of the metal-oxide-semiconductor PM4 are connected to the VDD pin of li-ion cell protection IC, drain electrode connection
Pin is controlled in the charging MOS of li-ion cell protection IC.
4. metal-oxide-semiconductor driving circuit according to claim 1, which is characterized in that the current switch cell is high-voltage MOS pipe
PM5。
5. metal-oxide-semiconductor driving circuit according to claim 1, which is characterized in that the current lens unit include metal-oxide-semiconductor PM1 and
Metal-oxide-semiconductor PM2, the source electrode of the metal-oxide-semiconductor PM1 and the source electrode of metal-oxide-semiconductor PM2 are connected to the VDD pin of li-ion cell protection IC, described
The drain electrode of grid and metal-oxide-semiconductor PM1 of metal-oxide-semiconductor PM1 and the grid of metal-oxide-semiconductor PM2 meet current source I1, and the drain electrode of the metal-oxide-semiconductor PM2 connects
It is connected to the source of current switch cell PM5.
6. a kind of li-ion cell protection IC, which is characterized in that including metal-oxide-semiconductor driving circuit, the metal-oxide-semiconductor driving circuit is above-mentioned power
Benefit requires 1 to 5 described in any item metal-oxide-semiconductor driving circuits.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109831001A (en) * | 2019-01-29 | 2019-05-31 | 福建省福芯电子科技有限公司 | A kind of metal-oxide-semiconductor driving circuit and li-ion cell protection IC |
| CN116896363A (en) * | 2023-09-08 | 2023-10-17 | 成都利普芯微电子有限公司 | NMOS control circuit and battery protection chip |
-
2019
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109831001A (en) * | 2019-01-29 | 2019-05-31 | 福建省福芯电子科技有限公司 | A kind of metal-oxide-semiconductor driving circuit and li-ion cell protection IC |
| CN109831001B (en) * | 2019-01-29 | 2024-06-04 | 福建省福芯电子科技有限公司 | MOS tube driving circuit and lithium battery protection IC |
| CN116896363A (en) * | 2023-09-08 | 2023-10-17 | 成都利普芯微电子有限公司 | NMOS control circuit and battery protection chip |
| CN116896363B (en) * | 2023-09-08 | 2023-12-05 | 成都利普芯微电子有限公司 | NMOS control circuit and battery protection chip |
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