Cascaded battery pack bus output drive circuit

Abstract

The present invention discloses a cascaded battery pack bus output drive circuit, comprising multiple batteries, a driving voltage module, a field-effect transistor (FET) switch circuit, a field-effect transistor (FET) drive circuit, and an energy output bus; the positive and negative electrodes of the multiple batteries connected in series are connected to the positive and negative electrodes of the driving voltage module; the positive or negative electrode of each battery is connected in series with the FET switch circuit and then connected to the energy output bus; each field-effect transistor drive circuit is connected in parallel with the gate of the field-effect transistor switch circuit and then connected to the positive or negative electrode of each battery and the energy output bus. In the present invention, the driving voltage module is a boost circuit that ensures that the driving voltage can drive the FET switch circuit of each level of batteries, including the highest string of batteries; the field-effect transistor switch array includes a pair of field-effect transistors between the positive and negative electrodes of each battery and the energy output bus, solving the problem that the source voltage platform of the field-effect transistors changes due to the series connection of batteries and cannot be uniformly driven using the same driving voltage, thereby significantly reducing the cost of the driving circuit.

Description

Technical Field

[0001] The present invention relates to the technical field of drive circuits, and in particular to a cascade battery pack bus output drive circuit. Background Art

[0002] When each stage of the series battery drives the field effect transistor, the source voltage platform changes. Generally, an isolated driving solution is adopted, which is costly and has a large circuit area. In addition, the source voltage platform of the field effect transistor changes due to the series connection of the batteries, so it is impossible to use the same driving voltage for unified driving. Summary of the Invention

[0003] In view of this, the main object of the present invention is to provide a cascade battery pack bus output drive circuit.

[0004] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0005] A first embodiment of the present invention provides a cascaded battery pack bus output drive circuit, comprising a plurality of batteries, a drive voltage module, a field effect transistor switch circuit, a field effect transistor drive circuit, and an energy output bus;

[0006] The positive and negative electrodes of the plurality of batteries connected in series are connected to the positive and negative electrodes of the driving voltage module;

[0007] The positive electrode or negative electrode of each battery is connected in series with a field effect transistor switch circuit and then connected to the energy output bus;

[0008] Each of the field effect transistor drive circuits is connected in parallel to the grid of the field effect transistor switch circuit and is correspondingly connected to the positive electrode or negative electrode of each battery and the energy output bus.

[0009] Preferably, the field effect transistor switch circuit includes a first field effect transistor and a second field effect transistor, the drain of the first field effect transistor is connected to the drain of the second field effect transistor, the source of the first field effect transistor is connected to the positive electrode or the negative electrode of the battery, and the gate of the first field effect transistor and the gate of the second field effect transistor are connected in series with the field effect transistor drive circuit.

[0010] Preferably, the driving voltage module includes a boost circuit, whose input voltage is the sum of the voltages of multiple batteries: ∑Vi, and outputs a fixed driving voltage: Vd, and the driving voltage is:

[0011] Vd=Max(∑Vi)+Vgs;

[0012] Wherein Max(∑Vi) is the sum of the battery's charge cut-off voltages, and Vgs is the gate drive voltage of the first field-effect transistor and the second field-effect transistor.

[0013] Preferably, in the present invention, the field effect transistor driving circuit includes a driving voltage switching circuit and a Vgs voltage stabilizing protection circuit, and the driving voltage switching circuit and the Vgs voltage stabilizing protection circuit are connected in series and then connected to the control signal terminal.

[0014] Preferably, the present invention, the driving voltage switching circuit includes a first transistor, a second transistor, a light-emitting diode, a first driving voltage resistor, a second driving voltage resistor, a third driving voltage resistor, a first current limiting resistor, and a second current limiting resistor, the emitter of the second transistor is respectively connected to the Vd terminal of the driving voltage module, the first driving voltage resistor and the first end of the second driving voltage resistor are connected, the second end of the first driving voltage resistor is respectively connected to the base of the second transistor and the first end of the third driving voltage resistor, the second end of the second driving voltage resistor is connected in series with the light-emitting diode and then respectively connected to the second end of the third driving voltage resistor and the collector of the first transistor, the base of the first transistor is connected in series with the first current limiting resistor and then respectively connected to the control signal terminal and the first end of the second current limiting resistor, and the emitter of the first transistor and the second end of the second current limiting resistor are grounded.

[0015] Preferably, in the present invention, the first transistor is an NPN transistor, and the second transistor is a PNP transistor.

[0016] Preferably, the Vgs voltage stabilizing protection circuit includes a first voltage stabilizing diode, a second voltage stabilizing diode, a third diode, a fourth diode, a first voltage dividing resistor, a second voltage dividing resistor, a first voltage limiting resistor, a second voltage limiting resistor, a first current limiting resistor, and a second current limiting resistor. The first end of the first current limiting resistor is connected to the gate of the first transistor, the second end of the first current limiting resistor is respectively connected to the cathode of the first voltage stabilizing diode and the first end of the first voltage dividing resistor, the second end of the first voltage dividing resistor is respectively connected to the cathode of the third diode and the first end of the first voltage limiting resistor, and the first voltage limiting resistor is connected to the cathode of the third diode and the first end of the first voltage limiting resistor. The second end of the transistor is respectively connected to the anode of the first voltage-stabilizing diode and the source of the first field-effect transistor, the anode of the third diode is respectively connected to the collector of the second transistor and the anode of the fourth diode, the cathode of the fourth diode is respectively connected to the first end of the second voltage-dividing resistor and the first end of the second voltage-limiting resistor, the second end of the second voltage-limiting resistor is respectively connected to the anode of the second voltage-stabilizing diode and the source of the second field-effect transistor, the second end of the second voltage-dividing resistor is respectively connected to the first end of the second current-limiting resistor and the cathode of the second voltage-stabilizing diode, and the second end of the second current-limiting resistor is connected to the gate of the second field-effect transistor.

[0017] Preferably, in the present invention, the resistance values ​​Rd1 and Rd2 of the first voltage-dividing resistor and the second voltage-dividing resistor are:

[0018] Rd1=η1×(Vd-Vz) / Izt;

[0019] Rd2=η1×(Vd-Vz) / Izt;

[0020] Where Izt is the nominal current of the first Zener diode and the second Zener diode, and η1 is the margin coefficient.

[0021] Preferably, in the present invention, the resistance values ​​Rq1 and Rq2 of the first voltage limiting resistor and the second voltage limiting resistor are:

[0022] Rq1==Vgs(th) / (η2×Ir / 2);

[0023] Rq2==Vgs(th) / (η2×Ir / 2);

[0024] Where Ir is the leakage current of the second transistor, Vgs(th) is the gate-to-source turn-on voltage of the first field effect transistor or the second field effect transistor, and η2 is the margin coefficient.

[0025] Preferably, in the present invention, the third diode is used to block the battery voltage from being conducted to the gate of the second field effect transistor; and the fourth diode is used to block the energy output bus voltage from being conducted to the gate of the first field effect transistor.

[0026] Compared with the prior art, the driving voltage module in the present invention is a boost circuit, which can ensure that the driving voltage Vd can drive the field effect transistor switch circuit of each level of batteries, including the highest string; the field effect transistor switch array includes a pair of field effect transistors between the positive and negative poles of each battery and the energy output bus, which solves the problem that the source voltage platform of the field effect transistor changes due to the series connection of batteries and cannot be uniformly driven using the same driving voltage, and can greatly reduce the cost of the driving circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The present invention provides a structural schematic diagram of a cascade battery pack bus output drive circuit. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0029] The embodiment of the present invention provides a cascade battery pack bus output drive circuit, such as Figure 1 As shown, it includes multiple batteries B, a driving voltage module 1, a field effect transistor switching circuit, a field effect transistor driving circuit and an energy output bus 4;

[0030] The positive and negative electrodes of the plurality of batteries B connected in series are connected to the positive and negative electrodes of the driving voltage module 1;

[0031] The positive electrode or negative electrode of each battery B is connected in series with a field effect transistor switch circuit and then connected to the energy output bus 4;

[0032] Each of the field effect transistor drive circuits is connected in parallel to the gate of the field effect transistor switch circuit and is connected to the positive electrode or negative electrode of each battery B and the energy output bus 4 respectively.

[0033] like Figure 1 As shown, the field effect transistor switch circuit includes a first field effect transistor Q1 and a second field effect transistor Q2. The parameters of this group of field effect transistors are the same. The drain of the first field effect transistor Q1 is connected to the drain of the second field effect transistor Q2, the source of the first field effect transistor Q1 is connected to the positive electrode or the negative electrode of the battery B, and the gate of the first field effect transistor Q1 and the gate of the second field effect transistor Q2 are connected in series with the field effect transistor drive circuit.

[0034] like Figure 1 As shown, the driving voltage module 1 includes a boost circuit, whose input voltage is the sum of the voltages of multiple batteries B: ∑Vi, and outputs a fixed driving voltage: Vd, which is:

[0035] Vd=Max(∑Vi)+Vgs;

[0036] Where Max(∑Vi) is the sum of the charge cut-off voltages of all batteries B, Vgs is the optimal gate drive voltage of the first field effect transistor Q1 and the second field effect transistor Q2, and the on-resistance is as small as possible.

[0037] like Figure 1 As shown, the field effect transistor driving circuit includes a driving voltage switching circuit 2 and a Vgs voltage stabilizing protection circuit 3 . The driving voltage switching circuit 2 and the Vgs voltage stabilizing protection circuit 3 are connected in series and then connected to the control signal terminal 5 .

[0038] like Figure 1As shown, the driving voltage switch circuit 2 includes a first transistor P1, a second transistor P2, a light-emitting diode LED1, a first driving voltage resistor Rv1, a second driving voltage resistor Rv2, a third driving voltage resistor Rv3, a first current limiting resistor Rs1 and a second current limiting resistor Rs2, the emitter of the second transistor P2 is respectively connected to the Vd terminal of the driving voltage module 1, the first end of the first driving voltage resistor Rv1 and the first end of the second driving voltage resistor Rv2 are connected, and the second end of the first driving voltage resistor Rv1 is connected to the Vd terminal of the driving voltage module 1. They are respectively connected to the base of the second transistor P2 and the first end of the third driving voltage resistor Rv3, the second end of the second driving voltage resistor Rv2 is connected in series with the light-emitting diode LED1, and then respectively connected to the second end of the third driving voltage resistor Rv3 and the collector of the first transistor P1, the base of the first transistor P1 is connected in series with the first current-limiting resistor Rs1, and then respectively connected to the control signal terminal 5 and the first end of the second current-limiting resistor Rs2, and the emitter of the first transistor P1 and the second end of the second current-limiting resistor Rs2 are grounded GND.

[0039] like Figure 1 As shown, the first transistor P1 is an NPN transistor, and the second transistor P2 is a PNP transistor.

[0040] The control signals of each group of field effect transistor drive circuits can use non-isolated signals of the same level, such as 3.3V, or isolated signals.

[0041] like Figure 1As shown, the Vgs voltage stabilizing protection circuit 3 includes a first voltage stabilizing diode D1, a second voltage stabilizing diode D2, a third diode D3, a fourth diode D4, a first voltage dividing resistor Rd1, a second voltage dividing resistor Rd2, a first voltage limiting resistor Rq1, a second voltage limiting resistor Rq2, a first current limiting resistor Rs1 and a second current limiting resistor Rs2, a first end of the first current limiting resistor Rs1 is connected to the gate of the first transistor P1, a second end of the first current limiting resistor Rs1 is respectively connected to the cathode of the first voltage stabilizing diode D1 and the first end of the first voltage dividing resistor Rd1, a second end of the first voltage dividing resistor Rd1 is respectively connected to the cathode of the third diode D3 and the first end of the first voltage limiting resistor Rq1, and the first voltage limiting resistor Rs1 is respectively connected to the cathode of the third diode D3 and the first end of the first voltage limiting resistor Rq1. The second end of the resistor Rq1 is respectively connected to the anode of the first voltage-regulating diode D1 and the source of the first field-effect transistor Q1, the anode of the third diode D3 is respectively connected to the collector of the second transistor P2 and the anode of the fourth diode D4, the cathode of the fourth diode D4 is respectively connected to the first end of the second voltage-dividing resistor Rd2 and the first end of the second voltage-limiting resistor Rq2, the second end of the second voltage-limiting resistor Rq2 is respectively connected to the anode of the second voltage-regulating diode D2 and the source of the second field-effect transistor Q2, the second end of the second voltage-dividing resistor Rd2 is respectively connected to the first end of the second current-limiting resistor Rs2 and the cathode of the second voltage-regulating diode D2, and the second end of the second current-limiting resistor Rs2 is connected to the gate of the second field-effect transistor Q2.

[0042] like Figure 1 As shown, the resistance values ​​Rd1 and Rd2 of the first voltage-dividing resistor Rd1 and the second voltage-dividing resistor Rd2 are:

[0043] Rd1=η1×(Vd-Vz) / Izt;

[0044] Rd2=η1×(Vd-Vz) / Izt;

[0045] Where Izt is the nominal current of the first Zener diode D1 and the second Zener diode D2, and η1 is the margin coefficient.

[0046] like Figure 1 As shown, the resistance values ​​Rq1 and Rq2 of the first voltage limiting resistor Rq1 and the second voltage limiting resistor Rq2 are:

[0047] Rq1==Vgs(th) / (η2×Ir);

[0048] Rq2==Vgs(th) / (η2×Ir);

[0049] Wherein, Ir is the leakage current of the second transistor P2, Vgs(th) is the gate-to-source turn-on voltage of the first field effect transistor Q1 or the second field effect transistor Q2, and η2 is the margin coefficient.

[0050] like Figure 1 As shown, the third diode D3 is used to block the voltage of the battery B from being conducted to the gate of the second field effect transistor Q2; the fourth diode D4 is used to block the voltage of the energy output bus 4 from being conducted to the gate of the first field effect transistor Q1.

[0051] The working principle of the present invention is as follows:

[0052] The present invention generates a total driving voltage (Vd = Max(∑Vi) + Vgs) from the total voltage of the series-connected batteries through a boost circuit. When the field-effect transistor (FET) switching circuit (i.e., the first and second FETs) of the i-th string of batteries in the cascaded battery string needs to be driven to open, forming an electrical energy channel from the electrode to the energy bus, a high-level control signal connects the base of the first transistor, turning on the collector and emitter of the first transistor, and the emitter and collector of the second transistor, respectively. Vd is applied to the anodes of the third and fourth diodes. The voltage stabilization of the first and second zener diodes limits the actual turn-on voltage of the first and second FETs to no more than Vz. The first and second voltage-dividing resistors connected in series share the excess voltage, |Vd - Vi - Vz|, where Vi is the total voltage of the series-connected i-th string of batteries.

[0053] In summary, the driving voltage module in the present invention is a boost circuit, which can ensure that the driving voltage Vd can drive the field effect transistor switch circuit of each level of batteries, including the highest string; the field effect transistor switch array includes a pair of field effect transistors between the positive and negative poles of each battery and the energy output bus, which solves the problem that the source voltage platform of the field effect transistor changes due to the series connection of batteries and cannot be uniformly driven using the same driving voltage, and can greatly reduce the cost of the driving circuit.

[0054] The same or similar numbers in the drawings of this embodiment correspond to the same or similar parts; in the description of the present invention, it should be understood that the terms "upper", "lower", "left", "right", "inner", "outer", etc. indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the terms describing the position relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting this patent. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0055] It should be noted that, in this document, the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, article, or device comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, article, or device comprising the element.

[0056] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention.

Claims

1. A cascade battery pack bus output drive circuit, characterized in that: It includes multiple batteries, a driving voltage module, a field effect transistor switching circuit, a field effect transistor driving circuit and an energy output bus; The positive and negative electrodes of the plurality of batteries connected in series are connected to the positive and negative electrodes of the driving voltage module; The positive electrode or negative electrode of each battery is connected in series with a field effect transistor switch circuit and then connected to the energy output bus; Each of the field effect transistor drive circuits is connected in series with the gate of the field effect transistor switch circuit and is respectively connected to the positive electrode or negative electrode of each battery and the energy output bus; The field effect transistor switch circuit includes a first field effect transistor and a second field effect transistor, the drain of the first field effect transistor is connected to the drain of the second field effect transistor, the source of the first field effect transistor is connected to the positive electrode or the negative electrode of the battery, and the gate of the first field effect transistor and the gate of the second field effect transistor are connected in series with the field effect transistor drive circuit; The field effect tube driving circuit includes a driving voltage switching circuit and a Vgs voltage stabilizing protection circuit, wherein the driving voltage switching circuit and the Vgs voltage stabilizing protection circuit are connected in series and then connected to the control signal terminal; The driving voltage switch circuit includes a second transistor, the emitter of which is connected to the Vd terminal of the driving voltage module; the Vd terminal is the output terminal of the driving voltage module; The Vgs voltage stabilizing protection circuit includes a first voltage stabilizing diode, a second voltage stabilizing diode, a third diode, a fourth diode, a first voltage dividing resistor, a second voltage dividing resistor, a first voltage limiting resistor, a second voltage limiting resistor, a first current limiting resistor and a second current limiting resistor, wherein the first end of the first current limiting resistor is connected to the gate of the first field effect transistor, the second end of the first current limiting resistor is respectively connected to the cathode of the first voltage stabilizing diode and the first end of the first voltage dividing resistor, the second end of the first voltage dividing resistor is respectively connected to the cathode of the third diode and the first end of the first voltage limiting resistor, and the first end of the first voltage limiting resistor is respectively connected to the cathode of the third diode and the first end of the first voltage limiting resistor. The two ends are respectively connected to the anode of the first voltage-stabilizing diode and the source of the first field-effect transistor, the anode of the third diode is respectively connected to the collector of the second transistor and the anode of the fourth diode, the cathode of the fourth diode is respectively connected to the first end of the second voltage-dividing resistor and the first end of the second voltage-limiting resistor, the second end of the second voltage-limiting resistor is respectively connected to the anode of the second voltage-stabilizing diode and the source of the second field-effect transistor, the second end of the second voltage-dividing resistor is respectively connected to the first end of the second current-limiting resistor and the cathode of the second voltage-stabilizing diode, and the second end of the second current-limiting resistor is connected to the gate of the second field-effect transistor; The resistance values ​​Rd1 and Rd2 of the first and second voltage-dividing resistors are: Rd1=η1×(Vd-Vz) / Izt; Rd2=η1×(Vd-Vz) / Izt; Where Izt is the nominal current of the first Zener diode and the second Zener diode, η1 is the margin factor, and Vd is the driving voltage; The resistance values ​​Rq1 and Rq2 of the first and second voltage limiting resistors are: Rq1=Vgs(th) / (η2×Ir); Rq2=Vgs(th) / (η2×Ir); Where Ir is the leakage current of the second transistor, Vgs(th) is the gate-to-source turn-on voltage of the first field effect transistor or the second field effect transistor, and η2 is the margin coefficient.

2. The cascade battery pack bus output drive circuit according to claim 1, characterized in that: The driving voltage module includes a boost circuit, whose input voltage is the sum of the voltages of multiple batteries: ∑Vi, and outputs a fixed driving voltage: Vd. The driving voltage is: Vd=Max(∑Vi)+Vgs; Where Max (∑Vi) is the sum of the charge cut-off voltages of the multiple batteries, and Vgs is the gate drive voltage of the first field effect transistor and the second field effect transistor.

3. The cascade battery pack bus output drive circuit according to claim 2, characterized in that: The driving voltage switching circuit also includes a first transistor, a light-emitting diode, a first driving voltage resistor, a second driving voltage resistor, a third driving voltage resistor, a first current limiting resistor and a second current limiting resistor. The emitter of the second transistor is also connected to the first ends of the first driving voltage resistor and the second driving voltage resistor. The second end of the first driving voltage resistor is respectively connected to the base of the second transistor and the first end of the third driving voltage resistor. The second end of the second driving voltage resistor is connected in series with the light-emitting diode and then connected to the second end of the third driving voltage resistor and the collector of the first transistor respectively. The base of the first transistor is connected in series with the first current limiting resistor and then connected to the control signal end and the first end of the second current limiting resistor respectively. The emitter of the first transistor and the second end of the second current limiting resistor are grounded.

4. The cascade battery pack bus output drive circuit according to claim 3, characterized in that: The first transistor is an NPN transistor, and the second transistor is a PNP transistor.

5. The cascade battery pack bus output drive circuit according to claim 4, characterized in that: The voltage stabilization values ​​Vz of the first and second voltage stabilizing diodes are matched according to the optimal Vgs values ​​of the first and second field effect transistors, where Vgs is the gate drive voltage of the first and second field effect transistors.

6. The cascade battery pack bus output drive circuit according to claim 5, characterized in that: The third diode is used to block the battery voltage from being conducted to the gate of the second field effect transistor, and the fourth diode is used to block the energy output bus voltage from being conducted to the gate of the first field effect transistor.

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