Shunted superimposed detection circuit and power protection device

Abstract

The application provides a shunt superposition detection circuit and a power protection device, the circuit comprising: a plurality of shunt branches, each shunt branch being connected between a total current input end and a total current output end, each shunt branch being connected in series with a current detection resistor, and the two ends of the current detection resistor of each shunt branch being connected in series with a voltage superposition resistor and then connected to the same voltage detection end; wherein the voltage value of the voltage detection end is the superposition value of the voltage drops formed by each shunt branch, the voltage value of the voltage detection end and the sum of the current values of the plurality of shunt branches are in a linear proportional relationship, and the current value of each shunt branch is an arbitrary proportion of the total current value. The shunt superposition detection circuit has low cost and simple scheme, and the output of the plurality of shunt branches can balance the heat generation and heat dissipation inside the power supply, and the reliability and safety are high.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of circuit, in particular to a shunt superimposed detection circuit and a power protection device. BACKGROUND

[0002] At present, the output end of the battery or other power supply device is the total current loop, and the total current can be obtained by directly detecting it. However, with the continuous increase of the power of the application device, the heat is concentrated in the internal of the battery or other power supply device and is not easy to dissipate, resulting in too high local temperature, which affects the user experience and the service life of the device.

[0003] In order to improve this problem, the battery or other power supply device has multiple input and output paths, and the current of each path is arbitrarily distributed, so that the detection of the total current will face severe challenges. The current solution is to design a current detection circuit for each branch to obtain the current of each branch, and then design a current collection detection circuit to collect the current of each branch, and finally obtain the total current. According to the total current, the power value can be calculated. However, this solution involves the comprehensive application of software and hardware, which is high in cost and low in efficiency. SUMMARY

[0004] The present application provides a shunt superimposed detection circuit and a power protection device to solve the problem of high cost and low efficiency of software and hardware involved in calculating the total current of each branch in the prior art.

[0005] In a first aspect, the present application provides a shunt superimposed detection circuit, which has a total current input end and a total current output end, both of which are connected to the internal or external of an external power supply device. The shunt superimposed detection circuit has a voltage detection end, and the shunt superimposed circuit comprises:

[0006] A plurality of shunt branches, each shunt branch being connected between the total current input end and the total current output end, each shunt branch being connected in series with a current detection resistor for detecting the current value of the branch, and each shunt branch being connected in series with a voltage superimposed resistor at both ends of the current detection resistor and being connected to the positive and negative electrodes of the voltage detection end, the voltage superimposed resistor being used to form a voltage drop at the voltage detection end;

[0007] Wherein, the voltage value of the voltage detection end is the superimposed value of the voltage drops formed by each shunt branch, the voltage value of the voltage detection end and the sum of the current values of the plurality of shunt branches are in linear proportional relationship, and the current value of each shunt branch is in arbitrary proportion to the total current value.

[0008] In an embodiment of the present application, if the resistance values of the current detection resistors of each shunt branch are equal, the linear proportional relationship is expressed by the following formula:

[0009] Uo=(1 / n)*R*(I1+I2+I3+I4+...+In);

[0010] Wherein, Uo represents the voltage value of the voltage detection end, n represents n shunt branches, R represents the resistance value of the current detection resistance, I1~In respectively represents the current value of the first to the n shunt branches, n is a natural number greater than 1.

[0011] In an embodiment of the present application, the shunt superposition detection circuit further comprises a plurality of loads, and the current detection resistance of each shunt branch is connected in series with a load and then connected to the total current output end.

[0012] In an embodiment of the present application, the plurality of shunt branches comprise a first shunt branch and a second shunt branch, the first shunt branch is connected in series with a first current detection resistance, the second shunt branch is connected in series with a second current detection resistance, the two ends of the first current detection resistance are connected in series with a voltage superposition resistance respectively and then connected in parallel to the positive and negative electrodes of the voltage detection end, and the two ends of the second current detection resistance are connected in series with a voltage superposition resistance respectively and then connected in parallel to the positive and negative electrodes of the voltage detection end.

[0013] In an embodiment of the present application, the voltage value of the voltage detection end and the sum of the current value of the first shunt branch and the current value of the second shunt branch are in a linear proportional relationship, and if the resistance value of the first current detection resistance is equal to the resistance value of the second current detection resistance, the linear proportional relationship is as follows:

[0014] Uo=0.5a*(I1+I2);

[0015] Wherein, Uo represents the voltage value of the voltage detection end, a represents the resistance value of the first current detection resistance or the second current detection resistance, I1 represents the current value of the first shunt branch, and I2 represents the current value of the second shunt branch.

[0016] In an embodiment of the present application, the resistance value of the current detection resistance is equal to the resistance value of the voltage superposition resistance.

[0017] In an embodiment of the present application, the resistance value of the current detection resistance is less than the resistance value of the voltage superposition resistance, the resistance value of the current detection resistance is in the order of milliohm, and the resistance value of the voltage superposition resistance is in the order of ohm.

[0018] In an embodiment of the present application, the current detection resistance or the voltage superposition resistance is an equivalent resistance using series-parallel resistance, series-parallel capacitance, series-parallel inductance or any one or more combinations of resistance, capacitance and inductance.

[0019] In an embodiment of the present application, the current detection resistance is a precision resistance.

[0020] In a second aspect, the present application also provides a power protection device comprising the shunt superposition detection circuit according to any one of the first aspect.

[0021] In an embodiment of the present application, the power protection device further comprises a battery body, a first connector, a second connector and a coulometer, the two shunt branches of the battery body are connected with the first connector and the second connector respectively, and the shunt superposition detection circuit is connected between the first connector and the second connector; the coulometer is connected with the positive and negative poles of the voltage detection end, used for measuring the voltage value of the voltage detection end, and calculating the total current according to the linear proportional relationship between the voltage value of the voltage detection end and the sum of the current values of each shunt branch to obtain the coulometer value of the voltage protection device, wherein the total current is the sum of the current values of each shunt branch.

[0022] The shunt superposition detection circuit and the power protection device provided by the present application can make the total current superimpose the voltage drops formed by each shunt branch after arbitrary shunting, and compared with the prior art, the shunt superposition detection circuit has low cost and simple scheme, and the multiple shunt branches can make the internal heating and heat dissipation of the power supply balanced, and the reliability and safety are high. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and for those skilled in the art, other embodiments can also be obtained without creative labor based on these drawings.

[0024] Figure 1 is a multi-path principle diagram of the shunt superposition detection circuit provided by the present application;

[0025] Figure 2 is Figure 1 is an equivalent circuit diagram in the first case;

[0026] Figure 3 is Figure 2 is a simplified circuit diagram of

[0027] Figure 4 is Figure 3 is an equivalent circuit diagram of

[0028] Figure 5 is Figure 4 is a simplified circuit diagram of

[0029] Figure 6 is Figure 1 is an equivalent circuit diagram in the second case;

[0030] Figure 7 is Figure 6 a circuit diagram of the equivalent circuit diagram of the application;

[0031] Figure 8 is Figure 7 a simplified circuit diagram of the equivalent circuit diagram of the application;

[0032] Figure 9 is Figure 8 a simplified circuit diagram of the equivalent circuit diagram of the application;

[0033] Figure 10 is a two-way principle schematic diagram of the shunt superposition detection circuit provided by the application;

[0034] Figure 11 is a multi-way application schematic diagram provided by the embodiment of the application;

[0035] Figure 12 is one of the two-way application schematic diagrams provided by the embodiment of the application;

[0036] Figure 13 is the second two-way application schematic diagram provided by the embodiment of the application. DETAILED DESCRIPTION

[0037] In order to make the objects, technical solutions and advantages of the application clearer, the technical solutions in the application will be described clearly and completely below in combination with the drawings in the application. Obviously, the described embodiments are only a part of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the application.

[0038] The terms "first", "second", and the like in the specification and claims of the application and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily have to be used to describe a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments described herein can be implemented in an order other than that illustrated or described herein.

[0039] The multi-way input and output of the battery cell inside or other power supply device can solve the problem of heat concentration and poor heat dissipation inside the battery cell or other power supply device, which leads to excessive local temperature. However, due to the multi-way input and output, the prior art calculates the current of each branch of the relevant software and hardware, and then obtains the total current by summarizing the current of each branch. The disadvantage of this method is high cost and low efficiency of software and hardware.

[0040] Therefore, the present application provides a shunt superimposed detection circuit and a power protection device, by symmetric design of current detection resistance and voltage superimposed resistance, the total current can be shunted according to any proportion, the voltage drop formed by each shunt branch is superimposed to obtain the voltage of the voltage detection end, and according to the linear relationship between the voltage of the voltage detection end and the sum of the current values of each shunt branch, the total current can be calculated.

[0041] Compared with the prior art, the shunt superimposed detection circuit has the advantages of low cost, simple scheme, balanced heating and heat dissipation in the power supply, high reliability and safety, etc.

[0042] The shunt superimposed detection circuit and the power protection device of the present application will be described below. Figures 1-13

[0043] Figure 1 The shunt superimposed detection circuit provided by the present application is a multi-channel principle diagram, as shown in Figure 1 A shunt superimposed detection circuit has a total current input end and a total current output end, both of which are connected to the inside or outside of an external power supply device, and the shunt superimposed detection circuit includes a plurality of shunt branches (I1-In, n is a natural number greater than 1), each shunt branch is connected between the total current input end and the total current output end. Exemplarily, in the circuit structure, in order to balance heating and heat dissipation, a plurality of shunt branches (I1-In) can be arranged to shunt according to any proportion. The total current Itotal is shunted through each shunt branch (I1-In), that is, Itotal=I1+I2+I3+...+In.

[0044] Exemplarily, each shunt branch is connected in series with a current detection resistance, and the current detection resistance is used to detect the current value of the branch. For example, the first shunt branch I1 is connected in series with a current detection resistance R1, the second shunt branch I2 is connected in series with a current detection resistance R2, the third shunt branch I3 is connected in series with a current detection resistance R3, and the fourth shunt branch I4 is connected in series with a current detection resistance R4. The nth shunt branch In is connected in series with a current detection resistance Rn.

[0045] Exemplarily, the input end of the total current Itotal is connected to the negative electrode of the external power supply, and the positive electrode of the external power supply is connected to the output end of the total current Itotal. The shunt superimposed detection circuit I1-In also includes a plurality of loads, for example Figure 1 ​The load 1 to the load n are shown, and the current detection resistor of each shunt branch is connected in series with a load and then connected to the output end of the total current Itotal. For example, the first shunt branch I1 is connected in series with a current detection resistor R1, and then connected in series with a load 1 and then connected to the output end of the total current Itotal. The second shunt branch I2 is connected in series with a current detection resistor R2, and then connected in series with a load 2 and then connected to the output end of the total current Itotal. Similarly, the nth shunt branch In is connected in series with a current detection resistor Rn, and then connected in series with a load n and then connected to the output end of the total current Itotal.

[0046] Exemplarily, the external power supply is composed of array battery cells, which can be composed of n*n array battery cells in series and parallel, that is, the battery cells can be divided into n paths to make the battery cells internally balanced in heating and cooling, thereby improving reliability and safety. It can be understood that the external power supply can also be composed of multiple battery cells in parallel, and therefore the number and arrangement of the battery cells are not limited in the present application.

[0047] Exemplarily, the two ends of the current detection resistor of each shunt branch are connected in series with a voltage superposition resistor and then connected to the positive and negative electrodes of the same voltage detection end, and the voltage superposition resistor is used to form a voltage drop at the voltage detection end.

[0048] For example, the first shunt branch I1 is connected in series with a current detection resistor R1, and then connected in series with a voltage superposition resistor r1 and a voltage superposition resistor r2 at the two ends of the current detection resistor R1 and then connected to the positive and negative electrodes (+, -) of the voltage detection end Uo.

[0049] The second shunt branch I2 is connected in series with a current detection resistor R2, and then connected in series with a voltage superposition resistor r3 and a voltage superposition resistor r4 at the two ends of the current detection resistor R2 and then connected to the positive and negative electrodes (+, -) of the same voltage detection end Uo.

[0050] The third shunt branch I3 is connected in series with a current detection resistor R3, and then connected in series with a voltage superposition resistor r5 and a voltage superposition resistor r6 at the two ends of the current detection resistor R3 and then connected to the positive and negative electrodes (+, -) of the same voltage detection end Uo.

[0051] The fourth shunt branch I4 is connected in series with a current detection resistor R4, and then connected in series with a voltage superposition resistor r7 and a voltage superposition resistor r8 at the two ends of the current detection resistor R4 and then connected to the positive and negative electrodes (+, -) of the same voltage detection end Uo.

[0052] The nth shunt branch In is connected in series with a current detection resistor Rn, and then connected in series with a voltage superposition resistor r(2n-1) and a voltage superposition resistor r(2n) at the two ends of the current detection resistor Rn and then connected to the positive and negative electrodes (+, -) of the same voltage detection end Uo.

[0053] Exemplarily, the current detection resistors (R1~Rn) or the voltage superposition resistors (r1~r(2n)) can be equivalent resistors, for example, can be equivalent to a certain current detection resistor or a certain voltage superposition resistor through series-parallel resistors, series-parallel capacitors, series-parallel inductors, or the like, or can be equivalent to a certain current detection resistor or a certain voltage superposition resistor through any one or a combination of resistors, capacitors, and inductors. Because theoretically, for example, an inductor is an inductor, but actually, it can be equivalent to a resistor + an inductor, because the copper wire of the inductor itself has a resistance value. Generally, the current detection resistor needs to pass a large current, for example, the current value of 10A is required for the current of the current fast charging, so the resistance value of the current detection resistor is generally small, for example, basically within 5 milliohms. Therefore, it is also acceptable to use the inductor as the resistor in the application. The equivalent resistor of the application is not limited to the resistor.

[0054] For example, a certain resistor Rx and a certain capacitor Cx in parallel are equivalent to a certain resistor Ry in series, because the capacitor Cx is for passing alternating current and blocking direct current, and generally the battery is direct current, so the role of the capacitor Cx is small, so the two forms are basically equivalent. Figure 1 It can be seen that the voltage value of the voltage detection end Uo is the superposition value of the voltage drops formed by each shunt branch, and through the following theoretical calculation, it can be seen that the voltage value of the voltage detection end Uo is in a linear proportional relationship with the sum of the current values of each shunt branch (i.e. I1+I2+I3+I4+...+In), and the current values of each shunt branch can be shunted according to any proportion of the total current value, so as to facilitate setting the current value of a certain proportion according to the actual shunt branch.

[0055] Exemplarily, assuming that the resistance values of the current detection resistors of each shunt branch are equal, i.e. R1=R2=R3=R4=...=Rn=R, the linear proportional relationship is expressed by the following formula:

[0056] Uo=(1 / n)*R*(I1+I2+I3+I4+...+In);

[0057] Wherein, Uo represents the voltage value of the voltage detection end, n represents n shunt branches, R represents the resistance value of the current detection resistor, I1~In respectively represent the current values of the 1st~nth shunt branch, and n is a natural number greater than 1.

[0058] The above linear proportional relationship is derived through theoretical calculation as follows.

[0059] Wherein, Itotal=I1+I2+I3+I4+…+In;

[0060] Assume:

[0061] r = r1 = r2 = r3 = r4 =... = r(2n-1) = r(2n);

[0062] R = R1 = R2 = R3 = R4 =... = Rn;

[0063] Figure 1 The current arrow shown in the middle is the reference direction, and if the current arrow is opposite to the direction shown, the current value is negative. The following formula derivation is divided into two cases: Figure 1

[0064] The first case:

[0065] Assume that the resistance values of resistors R1, R2, R3, R4...Rn are much smaller than the resistance values of resistors r1, r2, r3, r4...r(2n), so the current f1 = f2 = f3 = f4 =... = f(2n) = 0 (very close to 0, and set to 0), that is, the resistance values of current detection resistors R1, R2, R3, R4...Rn are preferably in the order of milliohms; the resistance values of voltage superposition resistors r1, r2, r3, r4...r(2n) are preferably in the order of ohms, even K ohms.

[0066] Figure 2 is Figure 1 the equivalent circuit diagram as shown in Figure 2 . Assume that currents I1, I2, I3, I4...In form voltage drops U1, U2, U3, U4...Un at resistors R1, R2, R3, R4...Rn, respectively.

[0067] Simplify Figure 2 to get Figure 3 , and according to the Thevenin theorem and the Norton theorem, get the equivalent Figure 4 . And further simplify Figure 4 to get Figure 5 . Among them, the Thevenin theorem and the Norton theorem are commonly used circuit simplification methods.

[0068] Let Is = Is1 + Is2 + Is3 + Is4 +... + Isn;

[0069] rs = (r1 + r2) / / (r3 + r4) / / ... / / (r(2n-1) + r(2n));

[0070] Then:

[0071] Uo = Is * rs.

[0072] Comprehensive Figures 2-5 above, we get:

[0073] U1 = I1 * R1, U2 = I2 * R2, U3 = I3 * R3, U4 = I4 * R4,..., Un = In * Rn;​

[0074] Is1=U1 / (r1+r2), Is2=U2 / (r3+r4),..., Isn=Un / (r(2n-1)+r(2n)).

[0075] Then:

[0076]

[0077]

[0078] According to the following assumptions:

[0079] r=r1=r2=r3=r4=…=r(2n-1)=r(2n);

[0080] R=R1=R2=R3=R4=…=Rn;

[0081] It can be obtained:

[0082] Is=(I1+I2+I3+I4+…+In)*R / (2*r);

[0083] rs=(2*r) / n;

[0084] Then:

[0085] Uo=Is*rs=(1 / n)*R*(I1+I2+I3+I4+…+In).

[0086] Therefore, it can be known from the above theoretical derivation that the voltage value Uo of the detection voltage end of the shunt superposition detection circuit and I1+I2+I3+I4+…+In are in a linear relationship, that is:

[0087] Uo=(1 / n)*R*(I1+I2+I3+I4+…+In).

[0088] The above formula is transformed to obtain:

[0089] I total=I1+I2+I3+I4+…+In=Uo*n / R.

[0090] Wherein, the value of I total is required, and the value of the voltage Uo can be directly detected by the electric energy meter. Since the electric energy meter itself has a coefficient n / R, the electric energy meter can correct the voltage Uo to obtain the value of I total. According to the value of I total, the electric energy value can be calculated.

[0091] Therefore, in the above formula, when R = R1 = R2 = R3 = R4 =... = Rn = 2mΩ, the precision resistance actually detected by the coulometer is (2 / n)mΩ, but at the same time, the coulometer detects I1 + I2 + I3 + I4 +... + In.

[0092] Preferably, in order to facilitate theoretical derivation and calculation, the present application assumes that the current detection resistance of each shunt branch is equal, and the voltage superposition resistance of each shunt branch is equal, i.e.

[0093] R = R1 = R2 = R3 = R4 =... = Rn; r = r1 = r2 = r3 = r4 =... = r(2n-1) = r(2n), the resistance R1, R2, R3, R4,..., Rn is much smaller than r1, r2, r3, r4,..., r(2n).

[0094] It should be noted that the above resistances R1, R2, R3, R4,..., Rn can also be unequal, for example, assuming that R1 is n times the resistance of other current detection resistances, and the resistance of other current detection resistances is R, if n is 3, then the above formula can be expressed as:

[0095] U1 = I1 * R1, U2 = I2 * R2, U3 = I3 * R3, U4 = I4 * R4,..., Un = In * Rn;

[0096] It is obtained that:

[0097] U1 = I1 * 3R, U2 = I2 * R2, U3 = I3 * R3, U4 = I4 * R4,..., Un = In * Rn;

[0098] It can be obtained that:

[0099] Is1 = U1 / (r1 + r2), Is2 = U2 / (r3 + r4),..., Isn = Un / (r(2n-1) + r(2n));

[0100] Let r = r1 = r2 = r3 = r4 =... = r(2n-) = r(2n);

[0101] R = 3 * R = R2 = R3 = R4... = Rn;

[0102] It is obtained that:

[0103] Is = (3 * I1 + I2 + I3 + I4 +... + In) * R / (2 * r);

[0104] rs = (2 * r) / n;

[0105] Then:

[0106] Uo = (1 / n) * R * (3 * I1 + I2 + I3 + I4 +... + In).

[0107] Therefore, when the current detection resistors of each shunt branch are different, a coefficient is multiplied on the current value of each shunt branch, for example, the current I1 is multiplied by the coefficient 3 to represent whether the current of the shunt branch is amplified or reduced.

[0108] In practical applications, the resistance R of the current detection resistor Rx of one of the shunt branches can be taken as a reference, and the resistance Ry of the current detection resistor of other shunt branches is a multiple of the resistance Rx, for example, 0.1 times (i.e. 0.1R), 0.007 times (i.e. 0.007R), 5 times (i.e. 5R), etc.

[0109] The second case is:

[0110] Suppose the resistances R1, R2, R3, R4……Rn and r1, r2, r3, r4……r(2n) are similar, so f1=f2=f3=f4=…=f(2n) is not 0.

[0111] Using the superposition theorem of circuit analysis, suppose that I1, I2, I3, I4……In only one is not 0, that is, load 1, load 2, load 3, load 4, …… load n only one is always on, and the rest are all off with current 0.

[0112] Let I1 be not 0, I2=I3=I4=…=In=0, then get Figure 6 The circuit shown.

[0113] Figure 6 In which r4, r6, r8……r(2n) are in parallel, and after simplification, we get Figure 7 The circuit shown, where Z1=r4 / / r6 / / r8 / / ...... / / r(2n).

[0114] Figure 7 In which (R2+r3), (R3+r5), (R4+r7)……(Rn+r(2n-1)) are in parallel, and after simplification, we get Figure 8 The circuit shown, where,

[0115] G1+H1=(R2+r3) / / (R3+r5) / / (R4+r7) / / ...... / / (Rn+r(2n-1)).

[0116] The above Figure 8 After arrangement, we get Figure 9 The circuit shown.

[0117] Suppose that I1, I2, I3……In only one is not 0, that is, load 1, load 2, load 3, …… load n only one is always on, and the rest are all off with current 0.

[0118] Let I1 be not 0, I2=I3=I4=…=In=0, get: Uo1=I1*x1+J1*y1;

[0119]

[0120] Let x1, x2, x3…xn and y1, y2, y3…yn be constant coefficient, I1, I2, I3…In and J1, J2, J3…Jn be current, similarly get the following form:

[0121] Let I1 be not 0, I2=I3=I4=…=In=0, get: Uo1=I1*x1+J1*y1;

[0122] Let I2 be not 0, I1=I3=I4=…=In=0, get: Uo2=I2*x2+J2*y2;

[0123] Let I3 be not 0, I1=I2=I4=…=In=0, get: Uo3=I3*x3+J3*y3; …;

[0125] Let In be not 0, I1=I2=I3=…=I(n-1)=0, get: Uon=In*xn+Jn*yn;

[0126] Superposition theorem: Uo total = Uo1+Uo2+Uo3+…Uon;

[0127] Practical application suggestions:

[0128] r=r1=r2=r3=r4=…=r(2n-1)=r(2n), R=R1=R2=R3=R4=…=Rn;

[0129] Finally get the following form:

[0130] Uo total = (1 / n)*R*(I1+I2+I3+I4+…+In).

[0131] The following describes the shunt superposition detection circuit according to the present application through an embodiment with two shunt branches.

[0132] Figure 10 is a two-way principle schematic diagram of the shunt superposition detection circuit provided by the present application, as Figure 10 shown. It should be noted that the circuit diagram shown in Figure 9 is equivalent to the circuit diagram shown in Figure 10 .

[0133] Exemplarily, a shunt superposition detection circuit is connected with a power supply Us. Wherein the positive pole of the power supply Us is connected with the output end of the total current, the negative pole of Us is connected with the input end of the total current, Figure 10Two shunt branches are shown, each of which is in series with a load, i.e. the first shunt branch I1 is in series with a load 1, and the second shunt branch I2 is in series with a load 2.

[0134] Exemplarily, the power supply Us can represent the power supply of the battery, the loads 1 and 2 can represent a mobile phone or other electrical equipment, and the shunts I1 and I2 represent discharging of large current through the two branches.

[0135] Figure 10 Two shunt branches are shown, i.e. the first shunt branch I1 and the second shunt branch I2, the output end of the total current Itotal is connected with the first shunt branch I1 and the second shunt branch I2 respectively, the first shunt branch I1 is in series with a current detection resistor R1, the second shunt branch I2 is in series with a current detection resistor R2, the two ends of the current detection resistor R1 of the first shunt branch I1 are connected in series with a voltage superposition resistor RS1 and a voltage superposition resistor RS3 respectively, and then are connected in parallel to the positive and negative poles of a voltage detection end Uo, the two ends of the current detection resistor R2 of the second shunt branch I2 are connected in series with a voltage superposition resistor RS2 and a voltage superposition resistor RS4 respectively, and then are connected in parallel to the positive and negative poles of the voltage detection end Uo. The current detection resistor R1 is used for detecting the current value of the first shunt branch I1, and the current detection resistor R2 is used for detecting the current value of the second shunt branch I2. The voltage superposition resistors RS1 and RS3 are used for forming a voltage drop at the voltage detection end Uo, and the voltage superposition resistors RS2 and RS4 are also used for forming a voltage drop at the voltage detection end Uo. The voltage detection end Uo has positive and negative poles.

[0136] From Figure 10 It can be seen that the first shunt branch I1 is shunted into currents I3 and I4 after passing through the voltage superposition resistors RS1 and RS3, so as to form a voltage drop at the voltage detection end Uo.

[0137] Exemplarily, Figure 10 In the formula, RI1, RI2, RI3 and RI4 represent the wire resistance, the current detection resistors R1 and R2 are precision resistors, and the voltage superposition resistors RS1 to RS4 are ordinary detection resistors. The voltage detection end Uo is a voltage that can be output to a coulometer to calculate the total current.

[0138] From Figure 10 It can be seen that the voltage value of the voltage detection end Uo is the superposition value of the voltage drops formed by the first shunt branch I1 and the second shunt branch I2. Through theoretical calculation, it can be known that the voltage value of the voltage detection end Uo is in linear proportional relationship with the sum of the current values of the first shunt branch I1 and the second shunt branch I2 (i.e. I1+I2), and the current values of the first shunt branch I1 and the second shunt branch I2 can be shunted according to any proportion of the total current value, so as to facilitate setting of a specific proportional current value according to the actual shunt branch.

[0139] Exemplarily, assuming that the resistance values of the current detection resistors of the first and second shunt branches I1 and I2 are equal, i.e. R1=R2=a, the linear proportional relationship is expressed by the following formula:

[0140] Uo=0.5a*(I1+I2);

[0141] wherein Uo represents the voltage value of the voltage detection end, a represents the resistance value of the current detection resistor, I1 represents the current value of the first shunt branch, and I2 represents the current value of the second shunt branch.

[0142] The above linear proportional relationship is derived by theoretical calculation as follows.

[0143] wherein Us, load 1, load 2, R1, R2, and RS1, RS2, RS3, RS4 are known values, and the relationship between Uo and I1, I2 is solved.

[0144] Let R1=R2=R and RS1=RS2=RS3=RS4=b, and the following is obtained according to Kirchhoff's law:

[0145] I1*Rl1+I3*(RS1+RS2)=I2*Rl2;---------------------------------------①

[0146] I3*(RS1+RS2)+(I2+I3)*R2=(I1-I3)*R1+I4*(RS3+RS4);---------②

[0147] Uo+I3*RS1=(I1-I3)*R1+I4*RS3;-------------------------------------③

[0148] From ①, we have:

[0149]

[0150] From ②, we have:

[0151]

[0152] Substitute I3 into I4 to obtain:

[0153]

[0154]

[0155] Substitute ④ and ⑤ into ③ to obtain:

[0156] After arrangement, we have:

[0157]

[0158]

[0159]

[0160]

[0161]

[0162]

[0163]

[0164] Finally, the coefficients of I1 and I2 are constant values, and Uo and I1 and I2 are in linear proportional relationship:

[0165] If 1: Rl1 = Rl2;

[0166] If 2: Rl1 and Rl2 are the inner resistances of the conductors, and the inner resistances are very small, and are set as 0;

[0167] If 1 or If 2, then:

[0168]

[0169] If 3: R1 = R2 = a, RS1 = RS2 = RS3 = RS4 = b, then:

[0170] Uo = 0.5a(I1 + I2).

[0171] In application, preferably, R1 = R2, RS1 = RS2 = RS3 = RS4, when a = R1 = R2 = 2mΩ, the precision resistance actually detected by the electric quantity meter IC or other current-voltage detection IC is 1mΩ, and the detection of the electric quantity meter on I1 and I2 is satisfied.

[0172] The shunt superposition detection circuit can be applied to any power protection device, for example, a lithium battery protection device in a mobile phone.

[0173] The following is an embodiment of the shunt superposition detection circuit applied to the field of mobile phones.

[0174] Figure 11 is a multi-path application schematic diagram provided by the embodiment of the application, as shown in Figure 11 . Figure 11The left power supply is an n*n matrix battery cell, and the voltage detection end is detected by a power gauge IC or other current and voltage detection IC to obtain the corresponding voltage value, and then the voltage value of the voltage detection end is linearly related to the total current according to the formula deduced above, so as to calculate the value of the total current. The rectangular dashed box in the figure is a protection circuit, for example, a large current circuit can increase overcharge, over-discharge, over-current, short circuit and other protection circuits with disconnection protection function.

[0175] Figure 12 is one of the two-way application schematic diagrams provided by the embodiment of the application, Figure 13 is the second application schematic diagram provided by the embodiment of the application, as shown in Figure 12 , Figure 13 . Figure 12 The power supply protection device shown includes a battery cell body, in order to prevent and avoid the temperature inside the battery cell body from being too high, so Figure 12 The battery cell body is shown to be divided into left and right two-way current output, that is, I1 and I2 represent the large current of the left and right two-way.

[0176] Figure 12 The large current charging and discharging connector J1 and the connector J2 shown correspond to Figure 13 the connector J1 and the connector J2 in Figure 12 the current summary detection line corresponds to Figure 13 the current summary detection line in

[0177] Exemplarily, the power supply protection device provided by the application includes the shunt superposition detection circuit as described above.

[0178] Exemplarily, the power supply protection device further includes a battery cell body, a first connector, a second connector and a power gauge, two shunt branches of the battery cell body are connected with the first connector and the second connector respectively, the shunt superposition detection circuit is the two shunt branches, including current detection resistors R1 and R2, voltage superposition resistors RS1, RS2, RS3 and RS4, and the connection relationship of the current detection resistors and the voltage superposition resistors can refer to the above Figure 10 , which will not be described here again.

[0179] Exemplarily, the power supply protection device further includes a current overcurrent detection module, two ends of the current detection resistor R1 are connected with a current overcurrent detection module, for detecting whether the shunt branch is overcurrent to realize overcurrent protection; two ends of the current detection resistor R2 are also connected with a current overcurrent detection module, also for detecting whether the shunt branch is overcurrent to realize overcurrent protection.

[0180] Exemplarily, the electric quantity meter is connected to the positive and negative electrodes of the voltage detection end Uo, used for measuring the voltage value of the voltage detection end Uo, and calculating the total current according to the linear proportional relationship between the voltage value of the voltage detection end Uo and the sum of the current values of each shunt branch, the total current being the sum of the current values of each shunt branch.

[0181] For example, according to the above, Uo=0.5a*(I1+I2), then the current value of I1+I2 can be obtained according to the voltage Uo measured by the electric quantity meter, that is, I1+I2=Uo / 0.5a, since the electric quantity meter itself has a coefficient of 1 / 0.5a, the electric quantity meter can correct Uo by itself, thereby obtaining the total current Itotal=I1+I2, and calculating the power value of the mobile phone battery according to the current value of I1+I2.

[0182] It should be noted that the shunt branches of the shunt superposition detection circuit can be arranged at different positions according to different circuit structures, and can be arranged with any number of input and output, not limited to the mode provided in the above embodiment.

[0183] Further, the shunt superposition detection circuit can also be applied to other power protection devices, and the other power protection devices are not limited to the two shunt branches, but can also be multiple shunt branches, and the multiple shunt branches can be shunted according to any proportion.

[0184] Moreover, the shunt superposition detection circuit can also be integrated into a PCB protection board, which can reduce the design space required by the protection board and reduce the complexity of the multi-layer PCB design, for example, it is beneficial to avoid positive and negative overlaps between PCB layers, reduce the risk of positive and negative short circuits, and improve the reliability and safety of the product.

[0185] In summary, the shunt superposition detection circuit provided by the present application can balance the heat generation and dissipation inside the power supply through multiple shunt branches, avoid focused heat generation, improve the reliability and safety of the power supply and the power protection board, and prolong the service life of the power supply.

[0186] Moreover, the shunt superposition detection circuit provided by the present application has a simple circuit and low cost through symmetric design of pure resistance; after the total current is shunted according to any proportion, the voltage drops formed by the currents of each branch are superimposed, the total current can be calculated, and there is no need to provide complex software and hardware design.

[0187] Further, the shunt superposition detection circuit provided by the application can set multiple independent large-current input and output according to the actual circuit structure, can improve the charging efficiency of large-capacity power supply, and can reduce the charging time to meet the fast charging and endurance requirements of consumers. Finally, it should be pointed out that: the above examples are only used to illustrate the technical solutions of the application, but not to limit them; although the application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the application.

Claims

1. A shunt superposition detection circuit, comprising a total current input terminal and a total current output terminal, wherein the total current input terminal and the total current output terminal are both connected to the inside or outside of an external power supply device, characterized in that: The shunt superposition detection circuit has a voltage detection terminal, and the shunt superposition detection circuit includes: Multiple shunt branches, each shunt branch is connected between the total current input terminal and the total current output terminal, each shunt branch is connected in series with a current detection resistor for detecting the current value of the branch, and both ends of the current detection resistor of each shunt branch are connected in series with a voltage superposition resistor and then connected to the positive and negative electrodes of the voltage detection terminal, and the voltage superposition resistor is used to form a voltage drop at the voltage detection terminal; Among them, the voltage value of the voltage detection end is the superposition value of the voltage drop formed by each shunt branch, the voltage value of the voltage detection end and the sum of the current values ​​of the multiple shunt branches are in a linear proportional relationship, and the current value of each shunt branch is any proportion of the total current value.

2. The current shunting and superposition detection circuit according to claim 1, characterized in that: If the resistance of the current detection resistors in each shunt branch is equal, the linear proportional relationship can be expressed as follows: Uo=(1 / n)*R*(I1+I2+I3+I4+...+In); Among them, Uo represents the voltage value of the voltage detection end, n represents n shunt branches, R represents the resistance value of the current detection resistor, I1~In represent the current values ​​of the 1st to nth shunt branches respectively, and n is a natural number greater than 1.

3. The current shunting and superposition detection circuit according to claim 1, characterized in that: The shunt superposition detection circuit further includes a plurality of loads, and the current detection resistor of each shunt branch is connected in series with a load and then connected to the total current output end.

4. The current shunting and superposition detection circuit according to claim 1, characterized in that: The multiple shunt branches include a first shunt branch and a second shunt branch, the first shunt branch is connected in series with a first current detection resistor, the second shunt branch is connected in series with a second current detection resistor, both ends of the first current detection resistor are connected in series with a voltage superposition resistor and then connected to the positive and negative poles of the voltage detection terminal, and both ends of the second current detection resistor are connected in series with a voltage superposition resistor and then connected to the positive and negative poles of the voltage detection terminal.

5. The current shunting and superposition detection circuit according to claim 4, characterized in that: The voltage value of the voltage detection terminal is linearly proportional to the sum of the current value of the first shunt branch and the current value of the second shunt branch. If the resistance value of the first current detection resistor is equal to the resistance value of the second current detection resistor, the linear proportional relationship is expressed as follows: Uo=0.5a*(I1+I2); Wherein, Uo represents the voltage value of the voltage detection terminal, a represents the resistance value of the first current detection resistor or the second current detection resistor, I1 represents the current value of the first shunt branch, and I2 represents the current value of the second shunt branch.

6. The current shunting and superposition detection circuit according to claim 1, characterized in that: The resistance of the current detection resistor is equal to the resistance of the voltage superposition resistor.

7. The current shunting and superposition detection circuit according to claim 1, characterized in that: The resistance of the current detection resistor is smaller than the resistance of the voltage superposition resistor. The resistance of the current detection resistor is in the milliohm level, and the resistance of the voltage superposition resistor is in the ohm level.

8. The current shunting and superposition detection circuit according to claim 1, characterized in that: The current detection resistor or the voltage superposition resistor is an equivalent resistor using series-parallel resistors, series-parallel capacitors, series-parallel inductors, or any one or more combinations of resistors, capacitors, and inductors; the current detection resistor is a precision resistor.

9. A power supply protection device, comprising the shunt superposition detection circuit according to any one of claims 1 to 8.

10. The power protection device according to claim 9, characterized in that: The power protection device also includes a battery cell body, a first connector, a second connector and a power meter. The two shunt branches of the battery cell body are respectively connected to the first connector and the second connector, and the shunt superposition detection circuit is connected between the first connector and the second connector; the power meter is connected to the positive and negative poles of the voltage detection end, and is used to measure the voltage value of the voltage detection end, and calculate the total current based on the linear proportional relationship between the voltage value of the voltage detection end and the sum of the current value of each shunt branch to obtain the power value of the power protection device, and the total current is the sum of the current value of each shunt branch.

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