CN205608161U - Be applied to full difference mould data acquisition appearance and converting circuit of battery monitoring chip - Google Patents

Abstract

The utility model provides a be applied to full difference mould data acquisition appearance and converting circuit of battery monitoring chip, a serial communication port, include: high pressure sampling module, low pressure processing module, comparator, digital process and control module and digital to analogue conversion, the battery connects high pressure sampling module, and low pressure processing module is given in high pressure signal output after the sampling of high pressure sampling module of battery, the comparator is given in low pressure processing module's output, digital process and control module are given to the result that the comparator will compare, digital process and control module control digital to analogue conversion module, the digital to analogue conversion module links to each other with high pressure sampling module and low pressure processing module respectively. The utility model has the advantages of it is following: the utility model discloses use high pressure and low tension switchgear to combine high -pressure electric capacity directly to gather cascade battery's voltage simultaneously, and do not need voltage conversion unit to carry out voltage conversion with group battery voltage conversion again for low pressure to improve sampling rate and sampling precision.

Description

A kind of fully differential modulus sampling being applied to battery cell monitoring chip and change-over circuit

Technical field

This utility model relates to the field of power management in electronic circuit, is specifically related to one and is applied to battery cell monitoring chip Fully differential modulus sampling and change-over circuit.

Background technology

Lithium battery monitoring chip is used for detecting the voltage of chargeable lithium cell, the information such as electric current and temperature, and these is believed Breath feeds back to central control unit, thus ensures safety and the life-span of lithium battery.400V electric automobile needs the dynamic of 96 joint series connection Power battery (single battery voltage 3.8V) is organized the composition electrokinetic cell bag that is simultaneously together in parallel and is produced the work for driving motor Voltage and enough driving electric currents.The single channel battery cell monitoring scheme of early stage, needs substantial amounts of discrete device, so that overall The area of system and reliability are said and are had a greatly reduced quality.

There is following defect in prior art:

Prior art all concentrates on the speed improving high voltage sampling switches, ignores the restriction of overall architecture speed, and existing The number having technology high voltage sampling switches is a lot, because the area that high voltage sampling switches needs is very big, causes whole chip face Long-pending very big, cost is high.The low pressure sample detecting symmetry of prior art is poor, and measurement result reliability is low.

Utility model content

For solving the problems referred to above, the utility model proposes a kind of fully differential modulus sampling being applied to battery cell monitoring chip And change-over circuit.

The technical solution of the utility model is:

A kind of fully differential modulus sampling being applied to battery cell monitoring chip and change-over circuit, including: high pressure sampling module, low Pressure processing module, comparator, digital processing and control module and D/A switch；Battery connects high pressure sampling module, the high pressure of battery Signal exports to low pressure processing module after high pressure sampling module is sampled；The output of low pressure processing module is to comparator；Comparator Result of the comparison is given digital processing and control module；Digital processing controls D/A switch module with control module；D/A Modular converter is connected with high pressure sampling module and low pressure processing module respectively.

Preferably, high pressure sampling module includes the submodule that two structures are the same: high pressure sampling module P and high pressure sampling mould Block N；Low pressure processing module includes the submodule that two structures are the same: low pressure processing module P and low pressure processing module N；D/A turns Die change block includes the submodule that two structures are the same: D/A switch P and D/A switch N；The positive and negative electrode of battery connects high pressure respectively The IN end of sampling module P and the IN end of high pressure sampling module N；The SW end of high pressure sampling module P and the SW end of high pressure sampling module N Between by switch S2 connect；The OUT terminal of high pressure sampling module P, the LSB end of low pressure processing module P and D/A switch P's LSB end links together；The OUT terminal of high pressure sampling module N, the LSB end of low pressure processing module N and the LSB of D/A switch N End links together；The MSB end of low pressure processing module P and the MSB end of D/A switch P connect；The MSB end of low pressure processing module N Connect with the MSB end of D/A switch N；The COMP end of low pressure processing module P is connected with the positive terminal of comparator；Low pressure processes mould The COMP end of block N is connected with the end of oppisite phase of comparator.

In order to make circuit overall work more stable, the noise etc. filtered in set of cells disturbs, and makes of the present utility model Circuit work is more stable reliably:

It is further preferred that also include filter module, wave filter is arranged between battery and high pressure sampling module.

Further preferred, the positive and negative electrode of battery connects input INP and INN of wave filter respectively；The output of wave filter INP and INN connects IN end and the IN end of high pressure sampling module N of high pressure sampling module P respectively.

It addition, in order to measure the low-voltage signals such as the electric current of battery, temperature:

It is further preferred that also include low pressure sampling module；Low pressure sampling module is connected with D/A switch module.

Further preferred, low pressure sampling module is respectively the first low pressure sampling module and the second low pressure sampling module.

In order to measure the temperature of battery:

Further preferred, the first low pressure sampling module and the second low pressure sampling module are provided with critesistor.

In order to measure the electric current of battery:

Further preferred, the first low pressure sampling module and the second low pressure sampling module are provided with hall device.

It is further preferred that wave filter can be electric capacity C, inductance L, resistance R composition.

Further preferred, wave filter is RC wave filter；One end of port INP connecting resistance Rfi1, resistance Rfi1's is another One end of one termination capacitor Cfi1 and port OUTP；One end of port INN connecting resistance Rfi2, another termination electricity of resistance Rfi2 Hold the other end and the port OUTN of Cfi1.

It is further preferred that the structure of high pressure sampling submodule is: port IN connects one end of switch SW；Switch SW another One end of end, one end of switch Sgnd and electric capacity Cs is connected together as the port S of high pressure sampling submodule；Electric capacity Cs's Another terminates port OUT.

It is further preferred that the structure that low pressure processes submodule is: MSB end meets power vd DL by switch S3, by opening Close S6 and connect port COMP and one end of switch S5；Another termination voltage VCML of switch S5；Low pressure processes the LSB end of submodule and leads to Cross switch S4 ground connection VSSL, connect port COMP and one end of switch S5 by switch S7.

It is further preferred that D/A switch submodule includes the capacitor array module that two structures are identical, two electric capacity battle arrays Row module uses respectively as high-order capacitor array module and bit capacitor array module.The port SB of high-order capacitor array module Meet MSB, bit capacitor array module port SB and meet LSB.

Further preferred, capacitor array module is formed according to the electric capacity of binary weighting arrangement by m, all electric capacity A pole plate link together and meet port SB, the other end of electric capacity switched by switch can be alternatively coupled to respectively REF, TEMP or REFGND end, m is the positive integer more than or equal to 1.

This utility model has the advantage that

This utility model uses high pressure and low tension switch directly to gather the voltage of cascade battery in combination with high-voltage capacitance, Without voltage conversion unit, battery voltage is converted to low pressure and carries out voltage conversion again, thus improve sampling rate and adopt Sample precision.

High pressure pressure measures the structure using fully differential, can effectively eliminate common mode disturbances, have good common mode inhibition Than (CMRR, Common Mode Rejection Ratio).

For the measurement (temperature or electric current) of low pressure, this structure equally realizes perfect symmetry, presses down in common mode System ratio has advantage equally on (CMRR).

Accompanying drawing explanation

Fig. 1 this utility model is applied to the sampling of fully differential modulus and the general frame of change-over circuit of battery cell monitoring chip.

Fig. 2 this utility model is applied to the sampling of fully differential modulus and the concrete structure frame of change-over circuit of battery cell monitoring chip Figure.

Fig. 3 this utility model is applied to the sampling of fully differential modulus and the Filter Principle of change-over circuit of battery cell monitoring chip Figure.

Fig. 4 this utility model is applied to the fully differential modulus sampling of battery cell monitoring chip and high pressure sampling of change-over circuit Module principle figure.

The low pressure of the sampling of fully differential modulus and change-over circuit that Fig. 5 this utility model is applied to battery cell monitoring chip processes son Module principle figure.

Fig. 6 this utility model is applied to the sampling of fully differential modulus and the D/A switch of change-over circuit of battery cell monitoring chip Circuit module schematic diagram.

Fig. 7 this utility model is applied to the sampling of fully differential modulus and the D/A switch of change-over circuit of battery cell monitoring chip Capacitor array module schematic diagram in circuit module.

Fig. 8 this utility model is applied to the sampling of fully differential modulus and the overall schematic diagram of change-over circuit of battery cell monitoring chip One.

The battery voltage sampling process of Fig. 9 this utility model specific embodiment one.

The cell voltage transformation process of Figure 10 this utility model specific embodiment one.

Figure 11 this utility model is applied to the sampling of fully differential modulus and the arrangement principle of change-over circuit of battery cell monitoring chip Figure two.

The battery voltage sampling process of Figure 12 this utility model specific embodiment two.

The cell voltage transformation process of Figure 13 this utility model specific embodiment two.

Detailed description of the invention

Below in conjunction with embodiment and accompanying drawing, this utility model is made the most in detail, intactly illustrated.

Main thought of the present utility model be the voltage to battery (battery here refers to: set of cells or single battery), The parameter such as temperature and electric current detects.Wherein detection high-pressure section and detection can be divided into low according to the concrete object of detection Laminate section.Detection high-pressure section refers mainly to detect cell voltage；Detection low-pressure section is primarily referred to as the temperature to battery, electric current etc. Detect.

In concrete detection, processed by high-pressure modular for relating to the part of high pressure；Part for low pressure is led to Cross low-voltage module to process.As Fig. 1 this utility model is applied to the sampling of fully differential modulus and the conversion electricity of battery cell monitoring chip Shown in the general frame on road, specifically include that high pressure sampling module, low pressure processing module, comparator, digital processing and control module And D/A switch.

Simultaneously can also include that low pressure is sampled mould to detect the low-voltage signal such as temperature, electric current (i.e. detecting low-pressure section) Block；In addition to circuit overall work can be made more stable, it is also possible to include wave filter.Here wave filter is primarily to filter Disturb except the noise in set of cells etc., make circuit of the present utility model work more stable reliably.

In Fig. 1 leftmost VCELL be battery to be detected (battery here refers to: set of cells or single battery, under With).Battery connects high pressure sampling module, and the high-voltage signal of battery exports to low pressure processing module after high pressure sampling module is sampled. The output of low pressure processing module is to comparator.Result of the comparison is given digital processing and control module by comparator.Digital processing D/A switch module is controlled with control module.D/A switch module respectively with high pressure sampling module and low pressure processing module phase Even.

After result of the comparison is given digital processing and control module by comparator, digital processing and control module by number/ The control and regulation electric charge distribution in D/A switch module, high pressure sampling module and low pressure processing module of mould modular converter, electric charge Redistribute rear comparator to compare again, by charge distributing repeatedly, compare, finally give the magnitude of voltage of set of cells.? The magnitude of voltage arrived is exported with control module by digital processing.Above-mentioned detection process of the present utility model can be understood as gradually forcing The work process of nearly register type (SAR) analog-digital converter (ADC).

In order to make circuit overall work more stable, wave filter is arranged between set of cells and high pressure sampling module, i.e. High pressure sampling module is given after the high-voltage signal filtered device filtering of set of cells.It addition, in order to measure the electric current of battery, temperature etc. Low-voltage signal, is provided with low pressure sampling module, and low pressure sampling module is connected with D/A switch module.

In order to illustrate further this utility model, as Fig. 2 this utility model is applied to the fully differential of battery cell monitoring chip Modulus sampling and shown in the concrete structure block diagram of change-over circuit: high pressure sampling module includes the submodule that two structures are the same: height Pressure sampling module P and high pressure sampling module N；Low pressure processing module includes the submodule that two structures are the same: low pressure processing module P With low pressure processing module N；D/A switch module includes the submodule that two structures are the same: D/A switch P and D/A switch N； The positive and negative electrode of battery connects input INP and INN of wave filter respectively；Output INP and INN of wave filter connects high pressure sampling respectively The IN end of module P and the IN end of high pressure sampling module N.Need exist for it is emphasised that: it has been observed that wave filter is not necessarily.As Fruit does not has the positive and negative electrode of wave filter battery to connect IN end and the IN end of high pressure sampling module N of high pressure sampling module P respectively.

Connected by switch S2 between SW end and the SW end of high pressure sampling module N of high pressure sampling module P；High pressure sampling mould The LSB end of the OUT terminal of block P, the LSB end of low pressure processing module P and D/A switch P links together；High pressure sampling module N The LSB end of OUT terminal, the LSB end of low pressure processing module N and D/A switch N link together；Low pressure processing module P The MSB end of MSB end and D/A switch P connects；The MSB end of low pressure processing module N and the MSB end of D/A switch N connect；Low pressure The COMP end of processing module P is connected with the positive terminal of comparator；The COMP end of low pressure processing module N and the end of oppisite phase phase of comparator Even.Switch in modules is also controlled by digital processing and control module, does not illustrate in Fig. 2.

It addition, it has been observed that in order to measure the electric current of battery, temperature etc., it is low that the low pressure sampling module of setting is respectively first Pressure sampling module and the second low pressure sampling module.If for the temperature measuring battery, the first low pressure sampling module and second Low pressure sampling module is provided with critesistor；If for the electric current measuring battery, the first low pressure sampling module and second Low pressure sampling module is provided with hall device.

Below modules is described in detail.

Wave filter:

Wave filter can be electric capacity C, inductance L, resistance R composition.But wave filter according to actual needs, here is preferred For RC wave filter.As Fig. 3 this utility model is applied to the sampling of fully differential modulus and the filtering of change-over circuit of battery cell monitoring chip Shown in device schematic diagram: one end of port INP connecting resistance Rfi1, one end of another termination capacitor Cfi1 of resistance Rfi1 and port OUTP；One end of port INN connecting resistance Rfi2, the other end of another termination capacitor Cfi1 of resistance Rfi2 and port OUTN.

High pressure sampling submodule:

Here high pressure sampling submodule i.e. high pressure sampling module P or high pressure sampling module N, they are the same structures. As Fig. 4 this utility model be applied to battery cell monitoring chip fully differential modulus sampling and change-over circuit high pressure sampling submodule former Shown in reason figure: the port IN of high pressure sampling submodule connects one end of switch SW；Switch SW the other end, switch Sgnd one end with And one end of electric capacity Cs is connected together as the port S of high pressure sampling submodule；Another termination port OUT of electric capacity Cs.

Low pressure process submodule:

Same, low pressure here processes submodule i.e. low pressure processing module P and low pressure processing module N, as they are Structure.The sampling of fully differential modulus and the low pressure process of change-over circuit of battery cell monitoring chip it is applied to such as Fig. 5 this utility model Shown in submodule schematic diagram: low pressure processes the MSB end of submodule and met power vd DL by switch S3, connect port by switch S6 COMP and one end of switch S5；Another termination voltage VCML of switch S5；Low pressure is processed the LSB end of submodule and is connect by switch S4 Ground VSSL, by switch S7 connect port COMP and switch S5 one end.

D/A switch submodule:

D/A switch module includes the submodule that two structures are the same: D/A switch P and D/A switch N；Such as Fig. 6 originally Utility model is applied to the sampling of fully differential modulus and the D/A switch circuit module schematic diagram of change-over circuit of battery cell monitoring chip Shown in: D/A switch circuit module includes the capacitor array module that two structures are identical, two capacitor array module respectively as High-order capacitor array module and bit capacitor array module use.The port SB of high-order capacitor array module connects MSB, bit capacitor Array module port SB meets LSB.Three inputs of high-order capacitor array module and bit capacitor array module connect respectively VREF, VTEMP、VREFGND.Port VREF, VTEMP, VREFGND will be connected with control module with digital processing.

It is applied to the fully differential modulus sampling of battery cell monitoring chip such as Fig. 7 this utility model and the D/A of change-over circuit turns Change in circuit module shown in capacitor array module schematic diagram, capacitor array module mainly by m according to binary weighting arrangement Electric capacity forms, and a pole plate of all electric capacity links together and meets port SB, and the other end of electric capacity respectively can by switch switching To be alternatively coupled to REF, TEMP or REFGND end.Here, m is the positive integer more than or equal to 1.

Aforementioned comparator, digital processing are general module with control module, are the most just not described in detail.For first Low pressure sampling module and the second low pressure sampling module will be introduced explanation below in conjunction with specific embodiments.

Specific embodiment one (high pressure sample detecting):

As Fig. 8 this utility model is applied to the sampling of fully differential modulus and the overall principle of change-over circuit of battery cell monitoring chip Figure one.It should be noted that the concrete port title being the most specifically illustrate each submodule aforementioned in Fig. 8, but according to electricity What road connected may determine that each submodule and port thereof with earlier figures 2 corresponding relation.Fig. 8 does not comprise the first low pressure simultaneously Sampling module and the concrete structure of the second low pressure sampling module.In figure, VSSH is the ground of high pressure；VDDL, VSSL are low tension respectively Source and the ground of low pressure.It addition, port VREF, VTEMP, VREFGND of D/A switch P or D/A switch N and digital processing with The annexation of control module the most specifically illustrates.

The process of high pressure sample detecting will be introduced below on the basis of shown in Fig. 8.Including battery voltage sampling and battery Voltage transformation process two parts.

Battery voltage sampling process:

Battery voltage sampling process such as Fig. 9 this utility model specific embodiment one: during battery voltage sampling, SW, S3 and S4 close, and other switches are opened.At this moment cell voltage is stored on sampling capacitance CS, and the common-mode voltage of comparator sets Being set to VCML (S5 Guan Bi), a high position of DAC and bit capacitor store different initial charges respectively.It should be noted that in Fig. 9 Distinguish and the connection status (following identical) in illustrative circuitry with the gray scale light and shade of line.

In this stage, the electric charge with VINP and VINN as reference point is:

Q_P1=V_DDL(C_MSBP)+V_SSL(C_LSBP)-A_INP(2C_S)-V_REF(C_MSBPF+C_LSBPF)-V_REFGND(C_MSBP+C_LSBP-C_MSBPF- C_LSBPF)

Q_N1=V_DDL(C_MSBN)+V_SSL(C_LSBN)-A_INN(2C_S)-V_REF(C_MSBNF+C_LSBNF)-V_REFGND(C_MSBN+C_LSBN-C_MSBNF- C_LSBNF)

Wherein for reference port VINP, CMSBP and CLSBP is that in D/A switch P, high-order total capacitance and low level are the most electric Holding, CMSBPF and CLSBPF is the high-order electric capacity being connected to VREF with low level respectively.For reference port VINN, CMSBN and CLSBN is high-order total capacitance and low level total capacitance in D/A switch N, CMSBNF and CLSBNF is high-order respectively and low level connects Electric capacity to VREF.CS is sampling capacitance.

Cell voltage transformation process:

As shown in the cell voltage transformation process of Figure 10 this utility model specific embodiment one: at cell voltage transformation process In, S2, S6 and S7 Guan Bi, other switches are opened.The capacitive switch array of D/A switch module (DAC) is by sampling capacitance Electric charge carries out charge distributing.In this stage, the electric charge with VINP and VINN as reference point is:

$\begin{array}{c}{Q}_{P2}=V_{INP}(2C_S+C_{MSBP}+C_{LSBP})-\frac{A_{INP}+A_{INN}}{2}\left(2C_S\right)-V_{REF}({C_{MSBPF}}^{,}+{C_{LSBPF}}^{,})-\\ V_{REFGND}(C_{MSBP}+C_{LSBP}-{C_{MSBPF}}^{,}-{C_{LSBPF}}^{,})\end{array}$

$\begin{array}{c}{Q}_{N2}=V_{INN}(2C_S+C_{MSBN}+C_{LSBN})-\frac{A_{INP}+A_{INN}}{2}\left(2C_S\right)-V_{REF}({C_{MSBNF}}^{,}+{C_{LSBNF}}^{,})-\\ V_{REFGND}(C_{MSBN}+C_{LSBN}-{C_{MSBNF}}^{,}-{C_{LSBNF}}^{,})\end{array}$

Wherein for reference port VINP, CMSBPF ' and CLSBPF ' is to be connected to opening of VREF in D/A switch P respectively Close array capacitor；It is that D/A switch N is connected to opening of VREF respectively for reference port VINN, CMSBNF ' and CLSBNF ' Close array capacitor.

According to principle of charge conservation, the voltage of QP2=QP1, QN2=QN1, VINP and VINN can be derived as:

$V_{INP}=\frac{(A_{INN}-A_{INP})C_S+V_{DDL}\left(C_{MSBP}\right)+V_{SSL}\left(C_{LSBP}\right)+(V_{REF}-V_{REFGND})({C_{MSBPF}}^{,}-C_{MSBPF}+{C_{LSBPF}}^{,}-C_{LSBPF})}{(2C_S+C_{MSBP}+C_{LSBP})}$

$V_{INN}=\frac{(A_{INP}-A_{INN})C_S+V_{DDL}\left(C_{MSBN}\right)+V_{SSL}\left(C_{LSBN}\right)+(V_{REF}-V_{REFGND})({C_{MSBNF}}^{,}-C_{MSBNF}+{C_{LSBNF}}^{,}-C_{LSBNF})}{(2C_S+C_{MSBN}+C_{LSBN})}$

Due to:

CMSBP=CMSBN=CMSB；

CLSBP=CLSBN=CLSB；

CMSBPF=CMSB-CMSBNF；

CLSBPF=CLSB-CLSBNF；

CMSBPF '=CMSB-CMSBNF '；

CLSBPF '=CLSB-CLSBNF '；

Thus it is as follows with the relational expression of input cell voltage to derive comparator both end voltage:

$V_{INP}-V_{INN}=\frac{\left(2\right(A_{INN}-A_{INP})C_S+2(V_{REF}-V_{REFGND}\left)\right({C_{MSBPF}}^{,}-C_{MSBPF}+{C_{LSBPF}}^{,}-C_{LSBPF}\left)\right)}{(2C_S+C_{MSBP}+C_{LSBP})}$

From above formula it will be seen that this structure shows good symmetry, thus there is the highest common mode rejection ratio (CMRR, Common Mode Rejection Ratio).

Specific embodiment two (low pressure sample detecting):

As aforementioned: in order to measure the electric current of battery, temperature etc., the low pressure sampling module of setting is respectively the first low pressure sampling Module and the second low pressure sampling module.If for the temperature measuring battery, the first low pressure sampling module and the second low pressure are adopted Original mold block is provided with critesistor；If for the electric current measuring battery, the first low pressure sampling module and the second low pressure are adopted Original mold block is provided with hall device.

The process of low pressure detection is the most specifically described as a example by the temperature measuring battery.Measure the main thought of battery temperature It is by attaching critesistor on battery, critesistor being connected as partial-pressure structure, by critesistor by the temperature of battery Be converted to voltage signal, voltage signal detected it is thus possible to obtain the temperature information of battery.

It is applied to the fully differential modulus sampling of battery cell monitoring chip such as Figure 11 this utility model and the arrangement of change-over circuit is former Shown in reason figure two: add the first low pressure sampling module and the second low pressure sampling module unlike Fig. 8.First low pressure sampling Although the internal structure of module and the second low pressure sampling module is different, but it is the first low pressure sampling module and in connection Two low pressure sampling modules can exchange.In figure, resistance RNTC is critesistor.

It should be noted that the concrete port title being the most specifically illustrate each submodule aforementioned in Figure 11, but root Each submodule and port thereof can be specified with earlier figures 2 corresponding relation according to what circuit connected.In figure, VSSH is the ground of high pressure； VDDL, VSSL are the ground of low-tension supply and low pressure respectively.It addition, the port VREF of D/A switch P or D/A switch N, VTEMP, VREFGND the most specifically illustrate with the annexation of digital processing with control module.

The mistake of low pressure sample detecting (being specially temperature acquisition process here) will be introduced below on the basis of shown in Figure 11 Journey.Including battery temperature sampling process and battery temperature transformation process two parts.

Battery temperature sampling process:

As shown in the battery voltage sampling process of Figure 12 this utility model specific embodiment two: in battery temperature sampling process Middle Sgnd, SVT, S3 and S4 close, and other switches are opened.At this moment during battery temperature is stored in D/A switch P and D/A switch N Two capacitor array module high-order electric capacity on, the common-mode voltage of comparator is set to VCML (S5 Guan Bi), D/A switch P With two capacitor array module in D/A switch N a high position and bit capacitor store different initial charges respectively.

In this stage, the electric charge with VINP and VINN as reference point is:

Q_P1=V_DDL(C_MSBP)+V_SSL(C_LSBP)-V_TP(C_MSBPT)-V_REF(C_MSBPR+C_LSBPF)-V_REFGND(C_MSBP+C_LSBP- C_MSBPT-C_LSBPF-C_MSBPR)

Q_N1=V_DDL(C_MSBN)+V_SSL(C_LSBN)-V_TN(C_MSBNT)-V_REF(C_MSBNR+C_LSBNF)-V_REFGND(C_MSBN+C_LSBN- C_MSBNT-C_LSBNF-C_MSBNR)

Wherein for reference port VINP, CMSBP and CLSBP is that in D/A switch P, high-order total capacitance and low level are the most electric Holding, CMSBPR and CLSBPR is the high-order electric capacity being connected to VREF with low level in D/A switch P respectively.

For reference port VINN, CMSBN and CLSBN is high-order total capacitance and low level total capacitance in D/A switch N, CMSBNF and CLSBNF is the high-order electric capacity being connected to VREF with low level in D/A switch N respectively.CMSBPT is temperature sampling electricity Hold.

Battery temperature transformation process:

As shown in the cell voltage transformation process of Figure 13 this utility model specific embodiment two: at battery temperature transformation process In, S6 and S7 closes, and other switches are opened.Capacitive switch array in D/A switch P and D/A switch N is by sampling capacitance Electric charge carry out charge distributing.

In this stage, the electric charge with VINP and VINN as reference point is:

Q_P2=V_INP(C_MSBP+C_LSBP)-V_REF(C_MSBPF’+C_LSBPF’)-V_REFGND(C_MSBP+C_LSBP-C_MSBPF’-C_LSBPF’)

Q_N2=V_INN(C_MSBN+C_LSBN)-V_REF(C_MSBNF’+C_LSBNF’)-V_REFGND(C_MSBN+C_LSBN-C_MSBNF’-C_LSBNF’)

Wherein for reference port VINP, CMSBPF ' and CLSBPF ' is to be connected to opening of VREF in D/A switch P respectively Close array capacitor.

It is the switch arrays being connected to VREF in D/A switch N respectively for reference port VINN, CMSBNF ' and CLSBNF ' Column capacitance.

According to principle of charge conservation:

QP2=QP1, QN2=QN1；

The voltage of VINP and VINN can be derived as:

$V_{INP}=\frac{V_{DDL}\left(C_{MSBP}\right)+V_{SSL}\left(C_{LSBP}\right)+(V_{REF}-V_{REFGND})({C_{MSBPF}}^{,}-C_{MSBPF}+{C_{LSBPF}}^{,}-C_{LSBPF})-V_{TN}\left(C_{MSBPT}\right)}{(C_{MSBP}+C_{LSBP})}$

$V_{INN}=\frac{V_{DDL}\left(C_{MSBN}\right)+V_{SSK}\left(C_{LSBN}\right)+(V_{REF}-V_{REFGND})({C_{MSBNF}}^{,}-C_{MSBNF}+{C_{LSBNF}}^{,}-C_{LSBNF})-V_{TP}\left(C_{MSBNT}\right)}{(C_{MSBN}+C_{LSBN})}$

Due to:

CMSBP=CMSBN=CMSB；

CLSBP=CLSBN=CLSB；

CMSBPT=CMSBNT=CT=CMSB/2；

CLSBPF=CLSB CLSBNF；

CMSBNR=CMSB-CMSBPT CMSBPR；

CMSBPF '=CMSB-CMSBNF '；

CLSBPF '=CLSB-CLSBNF '；

Thus it is as follows with the relational expression of input cell voltage to derive comparator both end voltage:

$V_{INP}-V_{INN}=\frac{(V_{TP}-V_{TN})\frac{C_{MSB}}{2}+2(V_{REF}-V_{REFGND})({C_{MSBPF}}^{,}-C_{MSBPF}+{C_{LSBPF}}^{,}-C_{LSBPF}-\frac{C_{MSB}}{4})}{(C_{MSBP}+C_{LSBP})}$

Whereby it can be detected that voltage.

Compared with prior art:

This utility model uses high pressure and low tension switch directly to gather the voltage of cascade battery in combination with high-voltage capacitance, Without voltage conversion unit, battery voltage is converted to low pressure and carries out voltage conversion again, thus improve sampling rate and adopt Sample precision.

High pressure pressure measures the structure using fully differential, can effectively eliminate common mode disturbances, have good common mode inhibition Than (CMRR, Common Mode Rejection Ratio).

For the temperature survey of low pressure, structure of the present utility model equally realizes perfect symmetry, presses down in common mode System ratio has advantage equally on (CMRR).

Claims (10)

1. the fully differential modulus sampling being applied to battery cell monitoring chip and change-over circuit, it is characterised in that including: high pressure is adopted Original mold block, low pressure processing module, comparator, digital processing and control module and D/A switch；Battery connects high pressure sampling module, The high-voltage signal of battery exports to low pressure processing module after high pressure sampling module is sampled；The output of low pressure processing module is compared Device；Result of the comparison is given digital processing and control module by comparator；Digital processing controls D/A switch mould with control module Block；D/A switch module is connected with high pressure sampling module and low pressure processing module respectively.

Being applied to the sampling of fully differential modulus and the change-over circuit of battery cell monitoring chip the most as claimed in claim 1, its feature exists The submodule that two structures are the same is included: high pressure sampling module P and high pressure sampling module N in: high pressure sampling module；Low pressure processes Module includes the submodule that two structures are the same: low pressure processing module P and low pressure processing module N；D/A switch module includes two The submodule that individual structure is the same: D/A switch P and D/A switch N；The positive and negative electrode of battery connects high pressure sampling module P's respectively IN end and the IN end of high pressure sampling module N；By opening between SW end and the SW end of high pressure sampling module N of high pressure sampling module P Close S2 to connect；The LSB end of the OUT terminal of high pressure sampling module P, the LSB end of low pressure processing module P and D/A switch P is connected to Together；The LSB end of the OUT terminal of high pressure sampling module N, the LSB end of low pressure processing module N and D/A switch N is connected to one Rise；The MSB end of low pressure processing module P and the MSB end of D/A switch P connect；The MSB end of low pressure processing module N and D/A turn The MSB end changing N connects；The COMP end of low pressure processing module P is connected with the positive terminal of comparator；The COMP of low pressure processing module N End is connected with the end of oppisite phase of comparator.

3. the fully differential modulus sampling being applied to battery cell monitoring chip as described in as arbitrary in claim 1 and 2 and change-over circuit, its It is characterised by: also include that filter module, wave filter are arranged between battery and high pressure sampling module.

Being applied to the sampling of fully differential modulus and the change-over circuit of battery cell monitoring chip the most as claimed in claim 3, its feature exists In: the positive and negative electrode of battery connects input INP and INN of wave filter respectively；Output INP and INN of wave filter connects high pressure respectively and adopts The IN end of original mold block P and the IN end of high pressure sampling module N.

Being applied to the sampling of fully differential modulus and the change-over circuit of battery cell monitoring chip the most as claimed in claim 2, its feature exists In: also include low pressure sampling module；Low pressure sampling module is connected with D/A switch module.

Being applied to the sampling of fully differential modulus and the change-over circuit of battery cell monitoring chip the most as claimed in claim 5, its feature exists In: low pressure sampling module is respectively the first low pressure sampling module and the second low pressure sampling module.

Being applied to the sampling of fully differential modulus and the change-over circuit of battery cell monitoring chip the most as claimed in claim 2, its feature exists In: the structure of high pressure sampling submodule is: port IN connects one end of switch SW；The other end of switch SW, one end of switch Sgnd And one end of electric capacity Cs is connected together as the port S of high pressure sampling submodule；Another termination port OUT of electric capacity Cs.

Being applied to the sampling of fully differential modulus and the change-over circuit of battery cell monitoring chip the most as claimed in claim 2, its feature exists In: low pressure processes the structure of submodule and is: MSB end is met power vd DL by switch S3, met port COMP by switch S6 and opened Close one end of S5；Another termination voltage VCML of switch S5；Low pressure process submodule LSB end by switch S4 ground connection VSSL, Port COMP and one end of switch S5 is met by switch S7.

Being applied to the sampling of fully differential modulus and the change-over circuit of battery cell monitoring chip the most as claimed in claim 2, its feature exists In: D/A switch submodule includes the capacitor array module that two structures are identical, and two capacitor array module are respectively as a high position Capacitor array module and bit capacitor array module use；The port SB of high-order capacitor array module connects MSB, bit capacitor array Module port SB meets LSB.

Being applied to the sampling of fully differential modulus and the change-over circuit of battery cell monitoring chip the most as claimed in claim 9, its feature exists In: capacitor array module is formed according to the electric capacity of binary weighting arrangement by m, and a pole plate of all electric capacity links together Meeting port SB, the other end of electric capacity is switched by switch can be alternatively coupled to REF, TEMP or REFGND end respectively, and m is big In the positive integer equal to 1.