JP4824655B2 - Voltage sensor module - Google Patents

Description

  The present invention relates to a battery voltage monitoring device that detects a battery voltage in a power supply device configured by connecting a plurality of secondary batteries in series, and more particularly to a battery voltage monitoring device that detects an abnormal voltage related to voltage measurement.

  Conventionally, electric vehicles and hybrid vehicles have been known as vehicles that take the environment into consideration. In electric vehicles and hybrid vehicles, a motor is used as a drive source for driving the vehicle. A rechargeable secondary battery is connected to the motor, and a DC voltage obtained from the secondary battery is converted into an alternating current to drive the motor. Since this secondary battery requires a high voltage, it is usually configured as an assembled battery in which a plurality of battery cells are connected in series.

  A plurality of voltage sensors are used for voltage detection of each battery cell of the assembled battery. This voltage sensor is organized into a suitable number of modules. When there are a large number of battery cells connected in series, such as in an electric vehicle, a plurality of voltage sensor modules are also prepared and connected in series. Patent Documents 1, 2, and 3 disclose devices for monitoring the voltage of such an assembled battery. Hereinafter, an apparatus for monitoring a voltage of an assembled battery by forming a module having the plurality of voltage sensors by one semiconductor device (IC) and connecting a plurality of the semiconductor devices will be described.

  FIG. 10 shows a voltage monitoring device for monitoring the output voltage of a conventional assembled battery. The assembled battery is composed of a plurality of battery cells connected in series and a plurality of battery terminals, and the output of each battery cell is connected to the corresponding battery terminal. FIG. 10 shows an example in which 80 battery cells having an electromotive voltage of 3.6 V are connected in series.

  The voltage monitoring device includes a voltage sensor module (IC), an input terminal, and an output terminal. The input terminal is connected to the battery terminal of the assembled battery and the module input terminal of the voltage sensor module, receives the voltage output from each battery cell, and supplies it to the voltage sensor module. The output terminal is connected to the module output terminal of the voltage sensor module, and outputs the monitoring result of the voltage sensor module to the outside of the voltage monitoring device. In FIG. 10, the voltage monitoring device includes 20 voltage sensor modules that can monitor the output voltages of four battery cells, thereby monitoring the output voltages of all 80 battery cells included in the assembled battery. To be able to.

  FIG. 11 shows a conventional voltage sensor module that monitors the output voltages of four battery cells. The voltage sensor module has two types of comparators (overvoltage detection comparator and low voltage detection comparator) and a reference voltage generation circuit. The reference voltage output from the reference voltage generation circuit and the output voltage of the battery cell The undervoltage detection and the overvoltage detection of the output voltage of each battery cell are performed by comparing the voltage generated based on the voltage. In addition, in order to perform low voltage detection and overvoltage detection of one battery cell, one reference voltage generation circuit, one low voltage detection comparator, and one overvoltage detection comparator are required.

  The reference voltage generation circuit is connected between the module input terminals connected to both ends (positive electrode side and negative electrode side) of one battery cell via the battery terminal of the assembled battery and the input terminal of the voltage monitoring device. A reference voltage is generated based on the voltage applied between the terminals. In addition, three resistors are connected in series between the module input terminals in parallel with the reference voltage generation circuit, and two types of voltages are generated by resistance voltage division.

  Here, paying attention to the battery cell A in FIG. 11, the connection relationship between the reference voltage generation circuit (Vref), the low voltage detection comparator and the overvoltage detection comparator and the operation (undervoltage detection, overvoltage detection) are described in detail. Explained.

  The positive electrode side of the battery cell A is electrically connected to the module input terminal N3 of the voltage sensor module via the external terminal N1 of the assembled battery and the input terminal N2 of the voltage monitoring device. On the other hand, the negative electrode side of the battery cell A is electrically connected to the module input terminal N6 of the voltage sensor module via the external terminal N4 of the assembled battery and the input terminal N5 of the voltage monitoring device. In addition, three resistors connected in series are connected in parallel with VrefA between the module input terminals N3 and N6. As shown in FIG. 11, the connection points of the resistors connected in series are point A and point B, and the voltage across the module input terminals applied between N3 and N6 is divided by resistance (resistance division at point A> point B). Resistance partial pressure).

  The inverting input terminal of the low voltage detection comparator A is connected to the point A, and the non-inverting input terminal is connected to VrefA. On the other hand, the inverting input terminal of the overvoltage detection comparator A is connected to VrefA, and the non-inverting input terminal is connected to point B. The outputs of the low voltage detection comparator A and the overvoltage detection comparator A are connected to module output terminals N7 and N8 of the voltage sensor module, respectively.

  When the reference voltage and the resistance output by VrefA can take a voltage range in which the output voltage of the battery cell A can be allowed, the low voltage detection comparator A and the overvoltage detection comparator A indicate “L” indicating a normal state. It is set to a value that outputs the level. Therefore, when the output voltage of the battery cell A becomes lower than the allowable range (the output voltage decreases to an abnormal value), the resistance partial pressure at point A also decreases to an abnormal value accordingly, and the low voltage detection amount Comparator A compares the abnormally low resistance voltage at point A with the reference voltage and outputs an “H” level as a signal indicating that an abnormality has occurred on the low voltage side. Conversely, when the output voltage of the battery cell A becomes an overvoltage side from the allowable range (the output voltage rises to an abnormal value), the resistance partial pressure at point B also rises to an abnormal value accordingly, and is used for overvoltage detection. The comparator A compares the resistance voltage at the point B that is abnormally high with the reference voltage, and outputs an “H” level as a signal that indicates an abnormality on the overvoltage side. In this way, the conventional voltage monitoring device detects an abnormality when the output voltage of the battery cell becomes a low voltage or an overvoltage.

  In the voltage monitoring device described above, when a voltage drop of a predetermined level or more occurs in the output voltage of the battery cell, the reference voltage generation circuit that generates the reference voltage based on the battery cell in which the voltage drop occurs is an appropriate reference voltage. It becomes impossible to make. If an appropriate reference voltage cannot be generated, normal operation of the low voltage detection system using the low voltage detection comparator cannot be expected.

  FIG. 12 shows the potential at point A, the output of VrefA, and the output of low voltage detection comparator A with respect to the change in the output voltage of battery cell A. When the output voltage of the battery cell A is equal to or higher than V1, the potential at the point A is larger than the output voltage of VrefA. In this case, the output of the low voltage detection comparator A is an 'L' level output, and it is detected that the battery cell A is outputting a voltage in the normal range (not low voltage). The

  When the output voltage of the battery cell A becomes V1 or less, the output voltage of the battery cell A becomes an abnormal voltage on the low voltage side. Further, when the output voltage of the battery cell A becomes V2, it becomes impossible to generate a threshold voltage (reference voltage) for detecting a low voltage as the reference voltage, and as the output voltage of the battery cell A decreases, the output voltage of VrefA gradually increases. It will drop to. While the output voltage of VrefA is higher than the potential at the point A (V3 to V1), the output of the low voltage detection comparator is at the “H” level, so the output voltage of the battery cell A is low. It can be detected normally. However, when the output voltage of the battery cell A becomes V3 or less, the output voltage of VrefA further decreases and falls below the potential at point A. In this case, although the output voltage of the battery cell A is an abnormal voltage, the output of the low voltage comparator A becomes the “L” level, and the battery cell A outputs a voltage in a normal range. Will be detected.

Therefore, the present applicant has described a voltage monitoring device using two low-voltage detection comparators in Japanese Patent Application No. 2007-129542. In the voltage monitoring apparatus described in Japanese Patent Application No. 2007-125942, a first reference voltage Vref1 generated with reference to the voltage of one battery cell and a second reference voltage Vref2 generated with reference to a plurality of battery cells are used. Used. Then, the first reference voltage and the resistance voltage dividing input are compared by the first low voltage detection comparator, and the low voltage abnormality of one battery cell is detected with high accuracy. Even if the second low voltage detection comparator compares the input of the second reference voltage and the resistance voltage and a malfunction occurs in the first low voltage detection comparator, the second low voltage detection comparator When the detection comparator detects the low voltage normally and outputs “H”, the abnormality can be detected accurately.
Japanese Patent Laid-Open No. 9-159701 JP 2003-092840 A JP 2006-275928 A

  In the above application, it becomes possible to reliably detect the low voltage abnormality. On the other hand, in the first low-voltage detection comparator and the second low-voltage detection comparator, a threshold value for detecting a low voltage may vary due to variations in manufacturing. Due to this variation, if the threshold voltage of the first low voltage detection comparator detects a low voltage is lower than the threshold value of the second low voltage detection comparator, the first low voltage detection is inherently performed. In some cases, the low voltage state that should be performed by the comparator for use cannot be detected, and this chip has been discarded as a defective chip, for example, by inspection in the shipping process. That is, the above application has a problem that the production efficiency cannot be improved.

  A voltage sensor module according to an embodiment of the present invention is a voltage sensor module that monitors the voltages of a plurality of battery cells, and receives a voltage applied to both ends of battery cells to be monitored included in the plurality of battery cells. The second terminal, the third and fourth terminals receiving the voltage applied to both ends of the plurality of battery cells, and the first and second terminals, and the first and second terminals based on the voltage applied to both ends of the battery cell to be monitored. A first reference voltage generation circuit that generates one reference voltage, and a second reference voltage generation circuit that is connected to the third and fourth terminals and generates a second reference voltage based on voltages applied to both ends of the plurality of battery cells. A reference voltage generation circuit; a first comparison circuit that compares a first reference voltage and a first voltage generated based on a voltage applied between the first and second terminals; Based on the voltage between terminals A second voltage generated and a second comparator circuit for comparing the second reference voltage, and a trimming circuit for setting said first voltage. With this configuration, even if the output of one battery cell becomes a predetermined level or less, a stable reference voltage can be generated if the other battery cells do not become the predetermined level or less. It is also possible to prevent the threshold values of the first comparison circuit and the second comparison circuit from being inverted.

  It is possible to prevent the threshold values of the first comparison circuit and the second comparison circuit from being inverted and improve the production efficiency.

Embodiment 1
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram illustrating a voltage monitoring apparatus according to Embodiment 1 of the present invention. In the voltage monitoring apparatus of FIG. 1, low voltage detection is performed using a first reference voltage Vref1 generated with reference to the voltage of one battery cell and a second reference voltage Vref2 generated with reference to a plurality of battery cells. I do.

  The voltage monitoring device 1 has a plurality of voltage sensor modules 10. Here, the voltage sensor module is an element having one or a plurality of voltage sensors as one module. In the present embodiment, one module is constituted by one semiconductor device (IC). In order to simplify the drawing, only one module is shown in FIG. Hereinafter, a case where one voltage sensor module (IC) detects the voltages of four battery cells will be described as an example. In addition, the battery cell said here does not necessarily indicate one battery. When a plurality of batteries are connected between adjacent terminals of the voltage sensor module, the plurality of batteries are referred to as battery cells.

  As shown in FIG. 1, in this embodiment, four battery cells C1 to C4 to be monitored by the voltage sensor module 10 (hereinafter also referred to as IC) are connected in series. The positive electrode of each battery cell is connected to the module input terminals V <b> 1 to V <b> 4 of the voltage sensor module 10 via the external terminal of the assembled battery 2 and the input terminal of the voltage monitoring device 1. Here, the voltage sensor module 10 sets the potential on the positive electrode side of the battery cell C1 as the first power supply potential (upper power supply potential), and sets the potential on the negative electrode side of the battery cell C4 as the second power supply potential (lower power supply potential). ) Is working as. Therefore, the positive electrode of the battery cell C1 is also connected to the first power supply terminal VCC. The negative electrode of the battery cell C4 is connected to the second power supply terminal VSS of the IC10.

  In the voltage monitoring device 1 configured as described above, the IC 10 measures the voltage output from each battery cell (C1 to C4). The IC 10 outputs an overvoltage detection signal and an undervoltage detection signal when the voltage of the battery cell becomes an overvoltage or a low voltage. The voltage monitoring device 1 monitors the voltage of the battery cell based on the overvoltage detection signal and the low voltage detection signal. The voltage monitoring apparatus 1 outputs a signal notifying that the voltage of the battery cell is abnormal from the output terminal of the voltage monitoring apparatus 1 connected to the output terminal of the IC 10. In FIG. 1, the output terminal of the IC 10 and the output terminal of the voltage monitoring device 1 are shown in a one-to-one correspondence, but it is not always necessary to output in a one-to-one correspondence. The configuration of the IC 10 used in the voltage monitoring device 1 will be described in detail below.

  As shown in FIG. 1, the IC 10 includes a voltage dividing resistor 11, an overvoltage detection comparator 12, a first low voltage detection comparator 13, a second low voltage detection comparator 14, and a first reference voltage generation. A circuit 15, a second reference voltage generation circuit 16, OR circuits 17, 18 and 19, and trimming circuits 20 and 21 are included. In this embodiment, since one voltage sensor module detects overvoltage and undervoltage of four battery cells, four voltage dividing resistors 11-1 to 11-4 and overvoltage detection comparators 12-1 to 12- 4, low voltage comparators 13-1 to 13-4, 14-1 to 14-4, reference voltage generation circuits 15-1 to 15-4, 16-1 to 16-4, OR circuit 17-1 to 17-4 and 1 and trimming circuits 20-1 to 20-4 and 211-1 to 21-4. In the present embodiment, the overvoltage detection comparator 12 and the first low voltage detection comparator 13 are used as the first comparison circuit, and the second low voltage detection comparator 14 is used as the second comparison circuit. Is used.

  The voltage dividing resistors 11-1 to 11-4 are configured by resistors connected in series between adjacent terminals of the IC 10. In the present embodiment, an overvoltage detection resistor string and a low voltage detection resistor string are provided in parallel. Trimming circuits 20-1 to 20-4 and 21-1 to 21-4 are inserted in the middle stage of each resistor row. The trimming circuits 20 and 21 are circuits for adjusting threshold values of the overvoltage detection comparator 12 and the first low voltage comparator 13 by adjusting a voltage value divided by the voltage dividing resistor. . Details of the trimming circuit will be described later.

  The overvoltage detection comparators 12-1 to 12-4 compare the voltage at the voltage dividing point set by the trimming circuit 20 with the first reference voltage Vref1. The overvoltage detection comparators 12-1 to 12-4 output an overvoltage detection signal when the voltage at the voltage dividing point becomes higher than the reference voltage Vref1.

  The first low-voltage detection comparators 13-1 to 13-4 compare the voltage at the voltage dividing point (first voltage) set by the trimming circuit 21 with the first reference voltage Vref <b> 1. The first low voltage detection comparators 13-1 to 13-4 output a low voltage detection signal when the voltage at the voltage dividing point becomes lower than the reference voltage Vref1.

  The second low voltage detection comparators 14-1 to 14-4 compare the voltage at the predetermined voltage dividing point (second voltage) in the resistor string with the second reference voltage Vref2. The second low voltage detection comparators 14-1 to 14-3 output a low voltage detection signal when the voltage at the voltage dividing point becomes higher than the reference voltage Vref2.

  The first reference voltage generation circuits 15-1 to 15-4 generate a first reference voltage Vref1 and supply it to each comparator. The first reference voltage generation circuits 15-1 to 15-4 are reference voltage generation circuits that generate the reference voltage Vref1 with reference to the output voltage of one battery cell to be monitored. For example, the first reference voltage generation circuit 15-1 generates the first reference voltage from the potential difference between V1 and V2 (the output voltage of the cell C1), where V1 is the first terminal and V2 is the second terminal. In the present embodiment, the first reference voltage generation circuits 15-1 to 15-4 are configured by a band gap reference (BGR) circuit.

  The second reference voltage generation circuits 16-1 to 16-4 generate the second reference voltage Vref2 and supply the second reference voltage generation circuits 16-1 to 16-4 to the respective comparators. . The second reference voltage generation circuits 16-1 to 16-4 are reference voltage generation circuits that generate a reference voltage Vref2 with reference to output voltages of two or more battery cells. For example, the second reference voltage generation circuit 16-1 generates the second reference voltage from the potential V1 with the third terminal as V1 and the fourth terminal as VSS. In the present embodiment, the second reference voltage generation circuits 16-1 to 16-4 are configured by a circuit using a voltage drop using a current source and a resistor.

  The output of the trimming circuit 20-1 is connected to the non-inverting input terminal of the overvoltage detection comparator 12-1. The output of the trimming circuit 21-1 is connected to the inverting input terminal of the first low-voltage detection comparator 13-1. The voltage Vref1 output from the first reference voltage generation circuit 15-1 is input to the inverting input terminal of the overvoltage detection comparator 12-1 and the non-inverting input terminal of the first low voltage detection comparator 13-1. ing.

  Thereafter, similarly, the outputs of the trimming circuits 20-2 to 20-4 are connected to the non-inverting input terminals of the overvoltage detection comparators 12-2 to 12-4. The output of the trimming circuit 21-1 is connected to the inverting input terminals of the first low-voltage detection comparators 13-2 and 13-4. The voltages Vref1 output from the first reference voltage generation circuits 15-2 to 15-4 are the inverting input terminals of the overvoltage detection comparators 12-2 to 12-4 and the undervoltage detection comparators 13-2 to 13-. 4 is input to the non-inverting input terminal.

  In this embodiment, the upper second low voltage detection comparators 14-1 and 14-2 and the lower second low voltage detection comparators 14-3 and 14-4 Input is reversed.

  Since the upper second reference voltage generation circuits 16-1 and 16-2 generate the reference voltage Vref2 with reference to the upper potential, the outputs thereof are the second low voltage detection comparators 14-1 and 14. -2 inverting input terminal. Further, in the resistor string for detecting a low voltage, the voltage at the voltage dividing point corresponding to a voltage lower than the voltage generated by the trimming circuit 21-1 is the second low voltage detecting comparators 14-1, 14. -2 is input to the non-inverting input terminal.

  Since the lower second reference voltage generation circuits 16-3 and 16-4 generate the reference voltage Vref2 with reference to the lower potential, the output is the second low voltage detection comparator 14-3, 14-4 is connected to the non-inverting input terminal. Further, in the resistor string for detecting the low voltage, the voltage at the voltage dividing point corresponding to the voltage lower than the voltage generated by the trimming circuit 21-1 is the second low voltage detection comparator 14-3, 14. -4 input to the inverting input terminal.

  The outputs of the first low voltage detection comparators 13-1 to 13-4 and the second low voltage detection comparators 14-1 to 14-4 are connected to the OR gates 17-1 to 17-4, respectively. Has been. The OR gate outputs a low voltage detection signal when the first or second low voltage detection comparator detects a low voltage.

  The OR circuit 18 outputs an overvoltage detection signal as an output of each voltage sensor module when any of the overvoltage detection comparators 12-1 to 12-4 detects the overvoltage.

  The OR circuit 19 outputs a low voltage detection signal as an output of the voltage sensor module when any of the low voltage detection comparators 13-1 to 13-4 and 14-1 to 14-4 detects a low voltage. .

  The operation of the IC 10 configured as described above will be described with reference to FIGS. FIG. 2 is a diagram showing the voltage input to each comparator and the output of each comparator when the output voltage of the battery cells C1 and C2 drops. FIG. 3 is a diagram showing the voltages input to the comparators and the outputs of the comparators when the output voltages of the battery cells C3 and C4 are lowered.

The overvoltage detection comparators 12-1 to 12-4 output “H” level signals when the voltage at the voltage dividing point set by the trimming circuits 20-1 to 20-4 becomes higher than the reference voltage Vref 1. Output (refer to FIG. 2 and FIG. 3, points P and P ′). In this embodiment, an overvoltage detection signal is output when the cell voltage exceeds 4.2V.
The low voltage detection comparators 13-1 to 13-4 are signals of “H” level when the voltage at the voltage dividing point set by the trimming circuits 21-1 to 21-4 is lower than the reference voltage Vref1. Is output (see FIGS. 2 and 3, points Q and Q ′). In the present embodiment, a low voltage detection signal is output when the cell voltage falls below 2.5V.

  In the voltage monitoring apparatus shown in FIG. 1, a case where the cell voltage between V1 and V2 of the IC 10 is lowered to a voltage at which the BGR circuit cannot operate will be described. Here, the second reference voltage Vref2 is generated with reference to the potential of V1. That is, the potential is lower than the potential of V1 by the voltage drop of the resistor (see the comparator 14-input in FIG. 2).

  With this configuration, even if the voltage between V1 and V2 to be monitored decreases, the reference voltage Vref2 is generated from the potential of V1, so that the potential on the positive side of the cell C2 is at least the original. Can be entered. On the other hand, a voltage having a predetermined ratio to the cell voltage is input to the non-inverting input terminal of the low voltage detection comparator (refer to the comparator 14 + input in FIG. 2). Therefore, in the present embodiment, the second low voltage detection is performed when the voltage input to the non-inverting input terminal of the second low voltage detection comparator 14-1 exceeds the second reference voltage Vref2. The comparator 14-1 outputs an “H” level signal (see point R in FIG. 2). In this embodiment, a low voltage detection signal is output when the cell voltage falls below 2.1V. The second low voltage detection comparator 14-2 also outputs a low voltage detection signal in the same operation.

  On the other hand, when the voltage is between the V4 and VSS terminals of the IC 10, the second reference voltage Vref2 is a potential obtained by adding the voltage increase due to the resistance to the VSS terminal with reference to the potential of the VSS terminal. Therefore, when the voltage falls below the second reference voltage Vref2 input to the second low voltage detection comparator 14-4, the second low voltage detection comparator 14-1 outputs an "H" level signal. (See point R ′ in FIG. 2).

  With this configuration, even when the reference voltage Vref1 input to the first low voltage detection comparator is not normally generated (for example, the cell voltage is 1.8 V or less), the output of the low voltage detection signal is maintained. (See FIG. 2 and FIG. 3, point S, point S ′, output of OR circuit 17).

  Here, the trimming circuits 20 and 21 of the present embodiment will be described. As described above, the trimming circuits 20 and 21 according to the present embodiment set the voltage dividing points to be input to the overvoltage and undervoltage detection comparators 12 and 13, thereby more accurately detecting overvoltage and undervoltage. It is a circuit for performing. FIG. 4 shows this trimming circuit. As shown in FIG. 4, the trimming circuit of this embodiment includes a trimming value setting unit 201, a decoder 202, a switch unit 203, and a resistor string 204. The resistor string 204 shown in FIG. 4 corresponds to a part of the resistance between adjacent terminals of the IC 10 shown as 11-1 to 11-4 in FIG. The resistor array shown in FIG. 4 has a configuration in which seven resistors having a resistance value R are connected in series.

  The trimming value setting unit 201 includes a plurality of fuses F1 to F6 and a logic circuit such as an OR circuit and an AND circuit. In this embodiment, a logic value corresponding to “H” or “L” is input to the logic circuit by blowing one of the two fuses connected in series between the power supplies VCC and VSS. In the circuit shown in FIG. 4, fuses F1 and F2, F3 and F4, and F5 and F6 are connected in series. A node between the two fuses is connected to the OR circuit and the AND circuit.

  In the present embodiment, three sets of F1 and F2, F3 and F4, and F5 and F6 are connected in parallel, and a 3-bit logic signal is output from the AND circuit and OR circuit depending on how the fuses are blown. This logic circuit portion may be configured to output a necessary logic signal according to the method of fusing the fuse, and may be configured by any logic circuit.

  In the circuit shown in FIG. 4, a resistor R1 is connected between the fuse F1 and the power supply VCC, and a resistor R2 is connected between the fuse F2 and the power supply VSS. Similarly, the resistors R3 to R6 are connected between the fuse and the power supply VCC or VSS. This resistor is a resistor for setting a default value when the fuse is not blown, that is, when the threshold value of the first low-voltage detection comparator 13 is not adjusted. Assuming that the first bit is “H”, the second bit, and the third bit are “L” as default values, R1 << R2, R4 << R3, and R6 << R5 are set.

  The decoder 202 outputs a signal for selecting any one of the plurality of switch elements of the switch unit 203 according to the 3-bit signal output from the trimming value setting unit and turning it on. The number of bits of the input logic signal, the switch selected based on the logic signal, and the like can be changed as appropriate. The relationship of the outputs O1 to O8 with respect to the decoder inputs I1 to I3 in this embodiment is shown in FIG. Shown in

  The switch unit 203 is composed of a plurality of switch elements. The plurality of switch elements connect an arbitrary voltage dividing point of the resistor string to the output of the trimming circuit based on the output of the decoder 202.

  In the present embodiment, it is possible to adjust the threshold value of the first low-voltage detection comparator at the time of manufacture by blowing the fuse. In other words, by selecting a switch corresponding to an arbitrary voltage dividing point by blowing a fuse and inputting it to the low voltage detection comparator 13, the threshold value of the first low voltage detection comparator is adjusted to ensure In addition, it is possible to set a value larger than the threshold value of the second low-voltage detection comparator.

Embodiment 2
FIG. 6 is a diagram showing a trimming circuit according to the second embodiment of the present invention. Since the configuration and operation of the voltage monitoring device itself are the same as those described in the first embodiment, description thereof is omitted.

  In the present embodiment, the setting in the trimming circuit 21 of the low-voltage detection comparator 13 is different from that in the first embodiment. In the first embodiment, an example is shown in which all the resistances of the resistor strings in the trimming circuit 21 have R of the same value. However, in the present embodiment, among the seven resistors connected in series, four resistors on the upper voltage side of the cell have a resistance value 2R, and three resistors on the lower voltage side of the cell have a resistance value R.

  Here, it is assumed that the decoder 202 selects the switch connected to O5 shown in FIG. 6 in the default state when trimming is not performed as in the above-described embodiment. In this case, the value input to the first low voltage detection comparator 13 in the default state becomes smaller. That is, the inclination of “Comparator 13 -Input” shown in FIGS. 2 and 3 becomes a gentler direction. As a result, the threshold value of the first low-voltage detection comparator becomes higher. Here, by appropriately setting the values of R and 2R, the threshold value of the low voltage detection comparator before trimming is set to (2.1V + maximum threshold value variation of the second low voltage detection comparator 14). + Threshold maximum variation of first low-voltage detection comparator 13) (see FIG. 7). By setting the threshold value before trimming, it is possible to make the value larger than the threshold value of the second low-voltage detection comparator more reliably.

Embodiment 3
FIG. 8 is a diagram showing a trimming circuit according to the third embodiment of the present invention. Since the configuration and operation of the voltage monitoring device itself are the same as those described in the first embodiment, description thereof is omitted.

  In the present embodiment, the setting in the trimming circuit 21 of the low-voltage detection comparator 13 is different from those in the first and second embodiments. In the second embodiment, the threshold value of the first low-voltage detection comparator 13 before trimming is changed to the threshold of the second low-voltage detection comparator 14 by changing the resistance value of the resistor string in the trimming circuit 21. It is a large value considering the value variation. In this embodiment, it is assumed that the decoder 202 selects the switch O8 shown in FIG. 8 in the default state when trimming is not performed. That is, the resistance of the threshold setting unit 202 is set to satisfy R1 << R2, R3 << R4, and R5 << R6. In this case, this increases the threshold value of the first low-voltage detection comparator. Here, by appropriately setting the value of R, the threshold value of the first low-voltage detection comparator before trimming is set to (2.5V + maximum threshold value of the first low-voltage detection comparator 13). Variation) (see FIG. 9). By setting the threshold before trimming, it is only necessary to adjust the threshold of the first low-voltage detection comparator so that the threshold is lowered to 2.5V. For this reason, it is possible to make the value larger than the threshold value of the second low-voltage detection comparator more reliably.

1 is a diagram illustrating a voltage monitoring apparatus according to a first embodiment of the present invention. It is a figure which shows the relationship of the electric potential at the time of overvoltage detection and low voltage detection. It is a figure which shows the relationship of the electric potential at the time of overvoltage detection and low voltage detection. 1 is a diagram showing a trimming circuit according to a first embodiment of the present invention. It is a figure which shows the relationship of the figure coincidence selected with the input logic signal of a decoder. It is a figure which shows the trimming circuit of Embodiment 2 of this invention. It is a figure which shows the relationship of the threshold value of the 1st, 2nd low voltage detection comparator. It is a figure which shows the trimming circuit of Embodiment 3 of this invention. It is a figure which shows the relationship of the threshold value of the 1st, 2nd low voltage detection comparator. It is a figure which shows the conventional voltage monitoring apparatus. It is a figure which shows the conventional voltage sensor module. It is a figure which shows the relationship between a reference voltage output and a battery cell voltage.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Voltage monitoring apparatus 2 Battery assembly 10 Voltage sensor module 11 Voltage dividing resistor 12, 12-1 to 12-4 Overvoltage detection comparator 13, 13-1 to 13-4 Low voltage detection comparator 14, 14-1 14-4 Low Voltage Detection Comparator 15, 15-1 to 15-4 Reference Voltage Generation Circuit 16, 16-1 to 16-4 Reference Voltage Generation Circuit 17, 18, 19 OR Circuit 20, 20-1 to 20- 4 Trimming circuits 21, 211-1 to 21-4 Trimming circuit 201 Trimming value setting unit 202 Decoder 203 Switch unit 204 Resistance row C1 to C4 Battery cells F1 to F6 Fuses R1 to R6 Resistance

Claims (8)

A voltage sensor module for monitoring the voltage of a plurality of battery cells,
First and second terminals for receiving a voltage applied to both ends of a battery cell to be monitored included in the plurality of battery cells;
Third and fourth terminals for receiving a voltage applied to both ends of the plurality of battery cells;
A first reference voltage generation circuit connected to the first and second terminals and generating a first reference voltage based on a voltage applied to both ends of the battery cell to be monitored;
A second reference voltage generation circuit which is connected to the third and fourth terminals and generates a second reference voltage based on voltages applied to both ends of the plurality of battery cells;
A first comparison circuit for comparing a first voltage generated based on a voltage applied between the first and second terminals and the first reference voltage;
A second comparison circuit for comparing a second voltage generated based on a voltage applied between the first and second terminals and the second reference voltage;
A voltage sensor module comprising a trimming circuit for setting the first voltage. The trimming circuit has the first voltage so that a threshold voltage at which the comparison result of the first comparison circuit transitions is larger than a threshold voltage at which the comparison result of the second comparison circuit transitions. The voltage sensor module according to claim 1, wherein:


The trimming circuit includes a plurality of resistors connected in series, and sets the first voltage by selecting an arbitrary node among a plurality of nodes between the plurality of resistors. Item 2. The voltage sensor module according to Item 1.
Le.   The trimming circuit includes a plurality of switch elements disposed between the plurality of nodes and the output terminal of the first voltage, and the first voltage is applied based on a conduction state of the plurality of switch elements. The voltage sensor module according to claim 3, wherein the voltage sensor module is set.   5. The voltage sensor module according to claim 4, wherein the trimming circuit includes a decoder that turns on an arbitrary switch among the plurality of switch elements based on an input logic signal. 6.   The trimming circuit includes a trimming value setting unit that determines a logic signal to be input to the decoder, and the logic signal is set based on a variation in voltage value at which a comparison result of the first comparison circuit transitions. The voltage sensor module according to claim 5.   The trimming circuit includes a trimming value setting unit that determines a logic signal to be input to the decoder, and the logic signal is set based on a variation in voltage value at which a comparison result of the second comparison circuit transitions. The voltage sensor module according to claim 5, wherein the voltage sensor module is a voltage sensor module. The voltage sensor module according to claim 5, wherein the logic signal is determined by a conduction state of a fuse connected to a power supply potential or a ground potential.

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