Voltage detection device, and test device and test method for a voltage detection device.

Abstract

The resistance value of the trimming resistor can be accurately determined without requiring additional terminals for monitoring within the circuit. [Solution] The voltage divider resistor 11 is connected between the reference voltage source E11 and the detection terminal P1 and has an intermediate terminal N1 that generates an intermediate voltage Vn1 between the reference voltage Vref and the input voltage Va. The switch circuit 13 connects one of the detection terminal P1 and the intermediate terminal N1 to the input terminal X of the comparator 16. The voltage divider resistor 12 is connected between the reference voltage source E11 and the detection terminal P2 and has an intermediate terminal N2 that generates an intermediate voltage Vn2 between the reference voltage Vref and the input voltage Vb, and includes a trimming resistor Rm with a variable resistance value. The switch circuit 14 connects one of the detection terminal P2 and the intermediate terminal N2 to the input terminal Y of the comparator 16.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a voltage detection device, and a test apparatus and test method for a voltage detection device. BACKGROUND ART

[0002] A voltage detection device is used to detect voltage or current in a circuit. Generally, a voltage detection device includes a voltage dividing resistor and a comparator, and compares a voltage at a certain node in a circuit with a threshold voltage or a voltage at another node in the circuit.

[0003] The voltage detection device may have manufacturing variations such as deviation of the resistance value or resistance ratio of a voltage dividing resistor from a design value, offset voltage of a comparator, and the like. To reduce errors in detected voltage caused by such variations, for example, trimming resistors are used.

[0004] For example, Patent Document 1 discloses a trimming method for a voltage dividing circuit. PRIOR ART DOCUMENT PATENT DOCUMENT

[0005] Patent Document 1 Japanese Patent No. 4740771 SUMMARY OF THE INVENTION Problem to be Solved by the Invention

[0006] Voltage detection devices are tested during or after manufacturing to determine the resistance value of trimming resistors. These devices are tested, for example, by monitoring the behavior of the output signal when a known voltage is input. In this case, the output signal may contain errors relative to the design value due to the influence of multiple factors, such as deviations from the design value of the voltage divider resistor's resistance value or resistance ratio, and the comparator's offset voltage. Since the contribution of each factor is unknown, accurately determining the resistance value of the trimming resistor based on the error-laden output signal is difficult. Therefore, there is a need to determine the resistance value of the trimming resistor more accurately than before.

[0007] To accurately determine the resistance value of a trimming resistor, one might consider monitoring the behavior of individual circuit elements in a voltage detection device. However, if the voltage detection device is configured as an integrated circuit, additional terminals would need to be added to the device in order to monitor the behavior of individual circuit elements. In this case, the number of terminals that are not necessary for the normal operation of the voltage detection device increases, hindering miniaturization of the voltage detection device. Therefore, there is a need to determine the resistance value of the trimming resistor more accurately than conventional methods without requiring additional terminals for monitoring within the circuit.

[0008] The object of this disclosure is to provide a voltage detection device equipped with a trimming resistor that enables more accurate determination of the resistance value of the trimming resistor than conventional methods, without requiring additional terminals for monitoring within the circuit. The object of this disclosure is also to provide a test apparatus and test method for such a voltage detection device. [Means for solving the problem]

[0009] A voltage detection device according to one aspect of this disclosure is: A first detection terminal to which a first input voltage is applied, A second detection terminal to which a second input voltage is applied, A reference voltage source that generates a predetermined reference voltage, A comparison circuit having first and second input terminals and outputting a signal indicating which of the two voltages applied to the first and second input terminals is larger, A first voltage divider resistor is connected between the reference voltage source and the first detection terminal and has a first intermediate terminal that generates a first intermediate voltage between the reference voltage and the first input voltage, A first switch circuit that connects one of the first detection terminal and the first intermediate terminal to the first input terminal, A second voltage divider resistor connected between the reference voltage source and the second detection terminal, having a second intermediate terminal that generates a second intermediate voltage between the reference voltage and the second input voltage, the second voltage divider resistor includes a trimming resistor having a variable resistance value, The system includes a second switch circuit that connects one of the second detection terminal and the second intermediate terminal to the second input terminal. [Effects of the Invention]

[0010] According to one aspect of the present disclosure, a voltage detection device makes it possible to determine the resistance value of a trimming resistor more accurately than conventional methods without requiring additional terminals for monitoring within the circuit. [Brief explanation of the drawing]

[0011] [Figure 1] This figure shows the configuration of the voltage detection device 10 and the test device 20 according to the first embodiment. [Figure 2] This figure shows an example of the trimming resistor Rm shown in Figure 1. [Figure 3] This diagram shows the connection of switch circuits 13 and 14 when the voltage detection device 10 in Figure 1 is operating in normal mode. [Figure 4] This figure shows the connection of switch circuits 13 and 14 when the voltage detection device 10 in Figure 1 is operating in resistance ratio mode. [Figure 5] This diagram shows the connection of switch circuits 13 and 14 when the voltage detection device 10 in Figure 1 is operating in offset mode. [Figure 6]It is a flowchart showing test processing executed by the controller 21 in FIG. 1. [Figure 7] It is a diagram showing configurations of a voltage detection device 10A and a test device 20 according to a second embodiment. [Figure 8] It is a flowchart showing test processing executed by the controller 21 in FIG. 7. [Figure 9] It is a diagram showing configurations of a voltage detection device 10B and a test device 20 according to a third embodiment. [Figure 10] It is a diagram showing configurations of a voltage detection device 10C and a test device 20 according to a fourth embodiment. [Figure 11] It is a diagram showing a configuration of a voltage detection device 10D according to a fifth embodiment. MODE FOR CARRYING OUT THE INVENTION

[0012] Hereinafter, embodiments and modifications according to the present disclosure will be described with reference to the drawings. The same or similar components are denoted by the same reference numerals.

[0013] [First Embodiment] [Configuration of First Embodiment] FIG. 1 is a diagram showing configurations of a voltage detection device 10 and a test device 20 according to the first embodiment. The voltage detection device 10 compares two input voltages Va and Vb, and outputs a high-level signal Sout when a potential difference of one input voltage with respect to the other input voltage exceeds a predetermined threshold value, and outputs a low-level signal Sout otherwise. Further, the voltage detection device 10 includes a trimming resistor Rm having an adjustable resistance value. The test device 20 determines and sets the resistance value of the trimming resistor Rm so that the voltage detection device 10 can detect a desired target potential difference, that is, so that the signal Sout transitions between a high level and a low level when the two input voltages Va and Vb have the desired target potential difference.

[0014] [Configuration of Voltage Detection Device] The voltage detection device 10 includes a reference voltage source E11, voltage dividing resistors 11 and 12, switch circuits 13 and 14, a drive circuit 15, a comparator 16, and a logic circuit 17. The voltage detection device 10 also has terminals P1 to P5.

[0015] An input voltage Va is applied to the terminal P1. An input voltage Vb is applied to the terminal P2. The terminals P1 and P2 are also referred to as "detection terminals".

[0016] The reference voltage source E11 generates a predetermined reference voltage Vref. One end of the reference voltage source E11 may be grounded via the terminal P3.

[0017] The voltage dividing resistor 11 is connected between the reference voltage source E11 and the detection terminal P1. The voltage dividing resistor 11 includes resistors R1 and R2 connected in series to each other via an intermediate terminal N1, and has a resistance ratio of R2 / (R1+R2). The resistor R1 is connected between the reference voltage source E11 and the intermediate terminal N1, and the resistor R2 is connected between the detection terminal P1 and the intermediate terminal N1. At the intermediate terminal N1, an intermediate voltage Vn1=(R2 / (R1+R2))×(Vref-Va)+Va between the reference voltage Vref and the input voltage Va is generated.

[0018] The voltage dividing resistor 12 is connected between the reference voltage source E11 and the detection terminal P2. The voltage dividing resistor 12 includes resistors R3, Rm and R4 connected in series to each other via an intermediate terminal N2, and has a resistance ratio of R4 / (R3+Rm+R4). The resistors R3 and Rm are connected between the reference voltage source E11 and the intermediate terminal N2, and the resistor R4 is connected between the detection terminal P2 and the intermediate terminal N2. At the intermediate terminal N2, an intermediate voltage Vn2=(R4 / (R3+Rm+R4))×(Vref-Vb)+Vb between the reference voltage Vref and the input voltage Vb is generated. The resistor Rm is a trimming resistor having a variable resistance value. In an initial state, Rm=0.

[0019] Figure 2 shows an embodiment of the trimming resistor Rm shown in Figure 1. The trimming resistor Rm comprises, for example, resistors Rm1 to RmN and fuses Fm1 to FmN. The resistors Rm1 to RmN are connected in series with each other, and each of the fuses Fm1 to FmN is connected in parallel with a corresponding resistor. The fuses Fm1 to FmN may be cut off, for example, by a laser beam 31 generated by a laser trimming device 30. The resistance value of the trimming resistor Rm is adjusted by selectively cutting the fuses Fm1 to FmN according to the resistance value to be set. In the initial state, each fuse Fm1 to FmN is conducting, and the resistance value of the trimming resistor Rm is zero.

[0020] Referring to Figure 1, the switch circuit 13 connects either the detection terminal P1 or the intermediate terminal N1 to the input terminal X of the comparator 16. The switch circuit 13 includes switch elements SW1 and SW2. Switch elements SW1 and SW2 are controlled so that only one of them is turned on and the other is turned off. When the switch circuit 13 has the detection terminal P1 connected to the input terminal X, a voltage Vx = Va is applied to the input terminal X. When the switch circuit 13 has the intermediate terminal N1 connected to the input terminal X, a voltage Vx = Vn1 = (R2 / (R1 + R2)) × (Vref - Va) + Va is applied to the input terminal X.

[0021] Switch circuit 14 connects either the detection terminal P2 or the intermediate terminal N2 to the input terminal Y of comparator 16. Switch circuit 14 includes switch elements SW3 and SW4. Switch elements SW3 and SW4 are controlled so that only one of them is turned on and the other is turned off. When switch circuit 14 has the detection terminal P2 connected to input terminal Y, a voltage Vy = Vb is applied to input terminal Y. When switch circuit 14 has the intermediate terminal N2 connected to input terminal Y, a voltage Vy = Vn2 = (R4 / (R3 + Rm + R4)) × (Vref - Vb) + Vb is applied to input terminal Y.

[0022] The drive circuit 15 is connected to the test device 20 via terminal P4 and controls the connection of the switch circuits 13 and 14 under the control of the test device 20. The drive circuit 15 controls the switch circuits 13 and 14 independently of each other. The voltage detection device 10 has three modes indicating the connection of the switch circuits 13 and 14: normal mode, resistance ratio mode, and offset mode. The drive circuit 15 controls the connection of the switch circuits 13 and 14 according to a control signal from the test device 20 that specifies one of the three modes.

[0023] Figure 3 shows the connections of switch circuits 13 and 14 when the voltage detection device 10 in Figure 1 is operating in normal mode. In normal mode, switch circuit 13 connects its intermediate terminal N1 to input terminal X, and switch circuit 14 connects its intermediate terminal N2 to input terminal Y. At this time, switch element SW1 is turned on, switch element SW2 is turned off, switch element SW3 is turned on, and switch element SW4 is turned off.

[0024] Figure 4 shows the connections of switch circuits 13 and 14 when the voltage detection device 10 in Figure 1 is operating in resistance ratio mode. In resistance ratio mode, switch circuit 13 connects its intermediate terminal N1 to input terminal X, and switch circuit 14 connects its detection terminal P2 to input terminal Y. At this time, switch element SW1 is turned on, switch element SW2 is turned off, switch element SW3 is turned off, and switch element SW4 is turned on.

[0025] Figure 5 shows the connections of switch circuits 13 and 14 when the voltage detection device 10 in Figure 1 is operating in offset mode. In offset mode, switch circuit 13 connects detection terminal P1 to input terminal X, and switch circuit 14 connects detection terminal P2 to input terminal Y. At this time, switch element SW1 is turned off, switch element SW2 is turned on, switch element SW3 is turned off, and switch element SW4 is turned on.

[0026] Referring to Figure 1, the comparator 16 has two input terminals X and Y, and amplifies the difference between the two voltages applied to input terminals X and Y, respectively, and outputs it. The comparator 16 is also called an error amplifier, differential amplifier, or operational amplifier. One of the input terminals X and Y is a non-inverting input terminal (+ terminal), and the other is an inverting input terminal (- terminal). The output voltage Vcmp of the comparator 16 is expressed as Vcmp = (Vx - Vy) × β when input terminal X is a non-inverting input terminal, and as Vcmp = (Vy - Vx) × β when input terminal Y is a non-inverting input terminal, where β is a constant.

[0027] The logic circuit 17 outputs a high-level signal Sout when the output voltage Vcmp of the comparator 16 is high, and a low-level signal Sout otherwise. Thus, the signal Sout indicates which of the two voltages applied to the input terminals X and Y of the comparator 16 is greater. The signal Sout is output via terminal P5.

[0028] Comparator 16 and logic circuit 17 are examples of comparator circuits.

[0029] The voltage detection device 10 may be configured as an integrated circuit.

[0030] [Test equipment configuration] The test apparatus 20 includes a reference voltage source E21, a variable voltage source E22, and a controller 21. The reference voltage source E21 generates a predetermined first test voltage and applies the first test voltage as an input voltage Va to the detection terminal P1. The variable voltage source E22 generates a variable second test voltage under the control of the controller 21 and applies the second test voltage as a voltage Vb to the detection terminal P2. The controller 21 determines and sets the resistance value of the trimming resistor Rm by executing a test process described later with reference to Figure 6. The controller 21 also includes a memory 21m for storing the measured voltage acquired during the execution of the test process.

[0031] The controller 21 sends a control signal to the drive circuit 15 via terminal P4, thereby setting the voltage detection device 10 to one of three modes: normal mode, resistance ratio mode, and offset mode.

[0032] In each of the three modes, the controller 21 monitors the signal Sout output from terminal P5 while sweeping the voltage Vb, that is, while gradually increasing or decreasing the voltage Vb from its initial value. In each of the three modes, the controller 21 obtains the voltage Vb as the measured voltage when the signal Sout transitions between a high level and a low level (i.e., from a low level to a high level or vice versa).

[0033] The controller 21 determines and sets the resistance value of the trimming resistor Rm based on the measured voltage. The controller 21 determines the resistance value of the trimming resistor Rm so that the signal Sout transitions between high and low levels when the input voltages Va and Vb have a predetermined target potential difference. The controller 21 sets the determined resistance value to the trimming resistor Rm using the laser trimming device 30.

[0034] [Operation of the first embodiment] Figure 6 is a flowchart showing the test process performed by the controller 21 in Figure 1.

[0035] The reference voltage source E21 applies a voltage Va to the detection terminal P1. Also, in the initial state before the test process begins, the resistance value of the trimming resistor Rm is zero.

[0036] In step S1, the controller 21 sends a control signal to the drive circuit 15 to set the voltage detection device 10 to normal mode. In normal mode, the drive circuit 15 controls the switch circuit 13 to connect intermediate terminal N1 to input terminal X and the switch circuit 14 to connect intermediate terminal N2 to input terminal Y.

[0037] In step S2, the controller 21 monitors the signal Sout while sweeping the voltage Vb.

[0038] In step S3, the controller 21 stores the voltage Vb when the signal Sout transitions between high and low levels as the measured voltage V1 in memory 21m. The measured voltage V1 satisfies the following equation.

[0039] R2 / (R1+R2)×(Vref-Va)+Va+Vos=R4 / (R3+R4)×(Vref-V1)+V1 Formula (1)

[0040] Here, Vos represents the offset voltage of comparator 16.

[0041] In step S4, the controller 21 sets the voltage detection device 10 to resistance ratio mode. In resistance ratio mode, the drive circuit 15 controls the switch circuit 13 to connect the intermediate terminal N1 to the input terminal X, and controls the switch circuit 14 to connect the detection terminal P2 to the input terminal Y.

[0042] In step S5, the controller 21 monitors the signal Sout while sweeping the voltage Vb.

[0043] In step S6, the controller 21 stores the voltage Vb when the signal Sout transitions between high and low levels as the measured voltage V2 in memory 21m. The measured voltage V2 satisfies the following equation.

[0044] R2 / (R1+R2)×(Vref-Va)+Va+Vos=V2 Formula (2)

[0045] In step S7, the controller 21 sets the voltage detection device 10 to offset mode. In offset mode, the drive circuit 15 controls the switch circuit 13 to connect detection terminal P1 to input terminal X, and controls the switch circuit 14 to connect detection terminal P2 to input terminal Y.

[0046] In step S8, the controller 21 monitors the signal Sout while sweeping the voltage Vb.

[0047] In step S9, the controller 21 stores the voltage Vb when the signal Sout transitions between high and low levels as the measured voltage V3 in memory 21m. The measured voltage V3 satisfies the following equation.

[0048] Vos=V3 Equation (3)

[0049] The measured voltages V1 to V3 may be acquired in any other order. In other words, steps S1 to S3, steps S4 to S6, and steps S7 to S9 may be performed in any order.

[0050] In step S10, the controller 21 determines the resistance value of the trimming resistor Rm based on the measured voltages V1 to V3. The voltage Vb when the voltages Va and Vb have a desired target potential difference is expressed as Vb = Vt. When the trimming resistor Rm is adjusted so that the voltage detection device 10 detects the target potential difference, the resistance value of the trimming resistor Rm (expressed by the sign Rm) satisfies the following equation.

[0051] R2 / (R1+R2)×(Vref-Va)+Va+Vos=R4 / (R3+Rm+R4)×(Vref-Vt)+Vt Equation (4)

[0052] This yields the system of equations (1) through (4).

[0053] R2 / (R1+R2)×(Vref-Va)+Va+Vos=R4 / (R3+R4)×(Vref-V1)+V1 Formula (1) R2 / (R1+R2)×(Vref-Va)+Va+Vos=V2 Formula (2) Vos=V3 Equation (3) R2 / (R1+R2)×(Vref-Va)+Va+Vos=R4 / (R3+Rm+R4)×(Vref-Vt)+Vt Equation (4)

[0054] In equations (1) to (4), the resistance ratios R2 / (R1+R2) and R4 / (R3+R4) are unknown because they may deviate from their design values, and the resistance ratio R4 / (R3+Rm+R4) is also unknown. Furthermore, the offset voltage Vos is also unknown. On the other hand, the voltages Vref, Va, and Vt are known. Therefore, the controller 21 solves equations (1) to (4) based on the measured voltages V1, V2, and V3 to calculate the resistance ratio R4 / (R3+Rm+R4). The controller 21 determines the resistance value of the trimming resistor Rm so that the voltage divider resistor 12 has a resistance ratio of R4 / (R3+Rm+R4).

[0055] In step S11, the controller 21 uses the laser trimming device 30 to set the determined resistance value to the trimming resistance Rm.

[0056] After setting the determined resistance value to the trimming resistor Rm, the controller 21 may test whether the voltage detection device 10 can detect the desired target potential difference. If a significant error exists, the controller 21 may re-run the test process and determine and set the resistance value of the trimming resistor Rm to reduce the error.

[0057] The controller 21 may determine the resistance value of the trimming resistor Rm using two of equations (1) to (3) and equation (4). In this case, the controller 21 sets the voltage detection device 10 to two of the normal mode, resistance ratio mode, and offset mode. In each of the two modes, the controller 21 obtains the voltage Vb as the voltage when the signal Sout transitions between high and low levels as the measured voltage. The controller 21 calculates the resistance ratio R4 / (R3+Rm+R4) using two of equations (1) to (3) and equation (4) corresponding to the two obtained measured voltages. The controller 21 determines the resistance value Rm of the trimming resistor Rm so that the voltage divider resistor 12 has a resistance ratio R4 / (R3+Rm+R4). This simplifies the process compared to setting the voltage detection device 10 to three modes.

[0058] As mentioned above, the voltage detection device 10 may be configured as an integrated circuit. In this case, the test device 10 may perform a test process on the voltage detection device 10 on the wafer, and the laser trimming device 30 may set a resistance value for the trimming resistor Rm of the voltage detection device 10 on the wafer.

[0059] [Effects of the first embodiment] According to the first embodiment, the test apparatus 20 sets the voltage detection device 10 to three modes, namely normal mode, resistance ratio mode, and offset mode, and acquires measurement voltages V1 to V3 in these modes. The test apparatus 20 can determine the resistance value of the trimming resistor Rm by solving equations (1) to (4) based on the measurement voltages V1 to V3. Equations (1) to (4) include the deviation of the resistance ratio of the voltage divider resistors 11 and 12 from the design value and the offset voltage of the comparator 16, so the test apparatus 20 can take these factors into consideration and determine the resistance value of the trimming resistor Rm more accurately than conventional methods.

[0060] According to the first embodiment, the test apparatus 20 may calculate the deviation of the resistance ratio of the voltage divider resistors 11 and 12 from the design value and the offset voltage of the comparator 16.

[0061] According to the first embodiment, the test apparatus 20 can determine the resistance value of the trimming resistor Rm without requiring additional terminals for monitoring the circuit of the voltage detection device 10 by setting the voltage detection device 10 to three modes and acquiring the measurement voltages V1 to V3. The test apparatus 20 does not need to directly measure the deviation of the resistance ratio of the voltage divider resistors 11 and 12 from the design value and the offset voltage of the comparator 16, and therefore does not need to provide additional terminals in the voltage detection device 10 for reading these parameters. This avoids increasing the size of the voltage detection device. Furthermore, since no additional terminals are required, the voltage detection device 10 can avoid being affected by noise through additional terminals.

[0062] Thus, according to the first embodiment, the test device 20 can determine the resistance value of the trimming resistor Rm more accurately than conventional methods without requiring additional terminals for monitoring the circuit.

[0063] Furthermore, according to the first embodiment, the test device 20 can determine the resistance value of the trimming resistor Rm with simpler processing and sufficient accuracy than when acquiring three measurement voltages, by setting the voltage detection device 10 to two of the three modes and acquiring two measurement voltages.

[0064] According to the first embodiment, the voltage detection device 10, by including switch circuits 13, 14 and a drive circuit 15, makes it possible to determine the resistance value of the trimming resistor Rm more accurately than conventional methods without requiring additional terminals for monitoring within the circuit.

[0065] According to the first embodiment, by setting the determined resistance value to the trimming resistor Rm, the voltage detection device 10 can accurately detect the desired target potential difference.

[0066] The voltage detection device 10 may be used, for example, to detect the voltage or current of a circuit, or to detect overcharging or over-discharging of a secondary battery.

[0067] [Second Embodiment] [Configuration of the second embodiment] Figure 7 shows the configuration of the voltage detection device 10A and the test device 20 according to the second embodiment. The voltage detection device 10A eliminates the voltage divider resistor 11 and the switch circuit 13 of Figure 1, and replaces the drive circuit 15 of Figure 1 with a drive circuit 15A. The drive circuit 15A controls only one switch circuit 14 under the control of the test device 20. The input terminal X of the comparator 16 is directly connected to the detection terminal P1. A voltage Vx = Va is applied to the input terminal X. In other respects, the voltage detection device 10A is configured the same as the voltage detection device 10.

[0068] The voltage detection device 10A has two modes for indicating the connection of the switch circuit 14: a normal mode and an offset mode. The drive circuit 15A controls the connection of the switch circuit 14 according to a control signal from the test device 20 that specifies one of the two modes. In the normal mode, the switch circuit 14 connects the intermediate terminal N2 to the input terminal Y. In the offset mode, the switch circuit 14 connects the detection terminal P2 to the input terminal Y.

[0069] The test apparatus 20 in Figure 7 is configured in the same way as the test apparatus 20 in Figure 1. The controller 21 determines and sets the resistance value of the trimming resistor Rm by performing the test process described later with reference to Figure 8.

[0070] The controller 21 sets the voltage detection device 10A to one of two modes: normal mode and offset mode.

[0071] In each of the two modes, the controller 21 monitors the signal Sout while sweeping the voltage Vb. In each of the two modes, the controller 21 obtains the voltage Vb as the measured voltage when the signal Sout transitions between high and low levels.

[0072] The controller 21 determines and sets the resistance value of the trimming resistor Rm based on the measured voltage. The controller 21 determines the resistance value of the trimming resistor Rm so that the signal Sout transitions between high and low levels when the potential difference between the input voltages Va and Vb equals a predetermined value. The controller 21 sets the determined resistance value to the trimming resistor Rm using the laser trimming device 30.

[0073] [Operation of the second embodiment] Figure 8 is a flowchart showing the test process performed by the controller 21 in Figure 7.

[0074] The reference voltage source E21 applies a voltage Va to the detection terminal P1. Also, in the initial state before the test process begins, the resistance value of the trimming resistor Rm is zero.

[0075] In step S21, the controller 21 sends a control signal to the drive circuit 15A to set the voltage detection device 10A to normal mode. In normal mode, the drive circuit 15A controls the switch circuit 14 to connect the intermediate terminal N2 to the input terminal Y.

[0076] In step S22, the controller 21 monitors the signal Sout while sweeping the voltage Vb.

[0077] In step S23, the controller 21 stores the voltage Vb when the signal Sout transitions between high and low levels as the measured voltage V1a in memory 21m. The measured voltage V1a satisfies the following equation.

[0078] Va+Vos=R4 / (R3+R4)×(Vref-V1a)+V1a Formula (1a)

[0079] In step S24, the controller 21 sets the voltage detection device 10A to offset mode. In offset mode, the drive circuit 15A controls the switch circuit 14 to connect the detection terminal P2 to the input terminal Y.

[0080] In step S25, the controller 21 monitors the signal Sout while sweeping the voltage Vb.

[0081] In step S26, the controller 21 stores the voltage Vb when the signal Sout transitions between high and low levels as the measured voltage V3a in memory 21m. The measured voltage V3a satisfies the following equation.

[0082] Vos = V3a Equation (3a)

[0083] The measured voltages V1a and V3a may be obtained in a different order. In other words, steps S24 to S26 may be performed before steps S21 to S23.

[0084] In step S27, the controller 21 determines the resistance value of the trimming resistor Rm based on the measured voltages V1a and V3a. The voltage Vb when the voltages Va and Vb have a desired target potential difference is expressed as Vb = Vt. When the trimming resistor Rm is adjusted so that the voltage detection device 10A detects the target potential difference, the resistance value of the trimming resistor Rm (expressed by the sign Rm) satisfies the following equation.

[0085] Va+Vos=R4 / (R3+Rm+R4)×(Vref-Vt)+Vt Formula (4a)

[0086] This yields the simultaneous equations (1a), (3a), and (4a).

[0087] Va+Vos=R4 / (R3+R4)×(Vref-V1a)+V1a Formula (1a) Vos = V3a Equation (3a) Va+Vos=R4 / (R3+Rm+R4)×(Vref-Vt)+Vt Formula (4a)

[0088] The controller 21 solves equations (1a), (3a), and (4a) based on the measured voltages V1a and V3a to calculate the resistance ratio R4 / (R3+Rm+R4). The controller 21 determines the resistance value of the trimming resistor Rm so that the voltage divider resistor 12 has a resistance ratio of R4 / (R3+Rm+R4).

[0089] In step S28, the controller 21 uses the laser trimming device 30 to set the determined resistance value to the trimming resistance Rm.

[0090] [Effects of the second embodiment] According to the second embodiment, even when the input terminal X of the comparator 16 is directly connected to the detection terminal P1, the same effects as those described in relation to the first embodiment are obtained.

[0091] [Third Embodiment] Figure 9 shows the configuration of the voltage detection device 10B and the test device 20 according to the third embodiment. The voltage detection device 10B is equipped with a reference voltage source E11 and a voltage divider resistor 12 in different positions than in Figure 7. The reference voltage source E11 is connected between the detection terminal P1 and the input terminal X, and generates a predetermined reference voltage Vref which is added to the input voltage Va. A voltage Vaa = Va + Vref is applied to the input terminal X. The voltage divider resistor 12 is connected between the detection terminals P1 and P2 and has an intermediate terminal N2 which generates an intermediate voltage between the input voltages Va and Vb.

[0092] Since the input voltage Va and the reference voltage Vref have fixed values, the voltage detection device 10B operates in the same way as the voltage detection device 10A in Figure 7, even if the positions of the reference voltage source E11 and the voltage divider resistor 12 are different.

[0093] According to the third embodiment, even if the positions of the reference voltage source E11 and the voltage divider resistor 12 are different, the same effects as those described in relation to the first embodiment can be obtained.

[0094] [Fourth Embodiment] Figure 10 shows the configuration of the voltage detection device 10C and test device 20 according to the fourth embodiment. The voltage detection device 10C includes a resistor R5, a switch element SW5, and a logic circuit 17C instead of the comparator 16 and logic circuit 17 in Figure 7. In addition, terminal P1 in Figure 7 is removed, and only one input voltage Vb is supplied to terminal P2 of the voltage detection device 10C.

[0095] The resistor R5 and the switch element SW5 are connected in series with respect to the power supply and ground.

[0096] The switch element SW5 is, for example, an N-channel MOSFET. The switch circuit 14 connects one of its detection terminal P2 and intermediate terminal N2 to the control terminal (e.g., gate) of the switch element SW5. The switch element SW5 is turned on when the voltage applied to the control terminal exceeds a predetermined threshold voltage (e.g., gate threshold voltage), and turned off otherwise. When the voltage applied to the control terminal exceeds the threshold voltage, the node between the resistor R5 and the switch element SW5 becomes low level (e.g., ground voltage), and otherwise becomes high level (e.g., power supply voltage).

[0097] The switch element SW5 may be considered a comparator that compares the voltage applied to the control terminal with a threshold voltage.

[0098] The node between resistor R5 and switch element SW5 is connected to logic circuit 17C. Logic circuit 17C outputs a high-level signal Sout when the node between resistor R5 and switch element SW5 is low-level, and a high-level signal Sout otherwise. Thus, signal Sout indicates whether the voltage applied to the control terminal of switch element SW5 or the threshold voltage of switch element SW5 is greater.

[0099] The resistor R5, the switch element SW5, and the logic circuit 17C are examples of comparator circuits.

[0100] The controller 21 determines and sets the resistance value of the trimming resistor Rm by performing a process substantially similar to the test process described with reference to Figure 8. Here, the input terminal Y of the comparator 16 in Figure 7 is replaced by the control terminal of the switch element SW5 in Figure 10, and the voltage Va in Figure 7 is replaced by the threshold voltage of the switch element SW5 in Figure 10, but the content of the process is substantially the same as in the case of Figure 8.

[0101] According to the fourth embodiment, even if a resistor R5, a switch element SW5, and a logic circuit 17C are provided instead of the comparator 16 and logic circuit 17, the same effects as those described in relation to the first embodiment are obtained.

[0102] [Fifth Embodiment] Figure 11 shows the configuration of the voltage detection device 10D according to the fifth embodiment. The voltage detection device 10D includes a test device 20D integrated inside it. The test device 20D may set the resistance value of the trimming resistor Rm by, for example, switching off the fuses Fm1 to FmN of the trimming resistor Rm with current. According to the fifth embodiment, the test process can be completed inside the voltage detection device 10D.

[0103] The voltage detection devices 10A to 10C according to the second to fourth embodiments may also include a test device 20D integrated inside them.

[0104] [Other embodiments] Any part or all of the voltage divider resistors 11 and 12 may be trimming resistors. The trimming resistor may be connected between the reference voltage source E11 and the intermediate terminal N2, between the detection terminal P1 and the intermediate terminal N1, or between the reference voltage source E11 and the intermediate terminal N1.

[0105] The trimming resistor is not limited to the configuration shown in Figure 2, but may have any other configuration. The trimming resistor may include, for example, an antifuse, a fuse that is interrupted by current, a switch connected in parallel with the resistor, a variable resistor (such as a MOSFET) that responds to a temporary or continuous electrical input, a logic and transistor adjustment circuit, an eFUSE, an OTP (one-time programming) circuit, or an electrical trimming circuit.

[0106] A device for setting the trimming resistance, such as a laser trimming device, may be integrated into the test apparatus.

[0107] The test device 20 may sweep the voltage Va instead of the voltage Vb.

[0108] A bias voltage may be applied from outside terminal P3. Alternatively, the reference voltage source E11 may be located outside the voltage detection device, for example, inside the test device 20.

[0109] The measured voltage may be stored inside the voltage detection device instead of being stored inside the controller 21.

[0110] The test device 20 may, instead of obtaining the voltage Vb as the voltage when the signal Sout transitions between high and low levels, obtain the potential difference between voltages Va and Vb as the measured voltage.

[0111] Terminal P3 may be integrated with either detection terminal P1 or P2.

[0112] [Summary of Embodiments] A voltage detection device according to a first aspect of this disclosure is: A first detection terminal to which a first input voltage is applied, A second detection terminal to which a second input voltage is applied, A reference voltage source that generates a predetermined reference voltage, A comparison circuit having first and second input terminals and outputting a signal indicating which of the two voltages applied to the first and second input terminals is larger, A first voltage divider resistor is connected between the reference voltage source and the first detection terminal and has a first intermediate terminal that generates a first intermediate voltage between the reference voltage and the first input voltage, A first switch circuit that connects one of the first detection terminal and the first intermediate terminal to the first input terminal, A second voltage divider resistor connected between the reference voltage source and the second detection terminal, having a second intermediate terminal that generates a second intermediate voltage between the reference voltage and the second input voltage, the second voltage divider resistor includes a trimming resistor having a variable resistance value, The system includes a second switch circuit that connects one of the second detection terminal and the second intermediate terminal to the second input terminal.

[0113] The test apparatus relating to the second aspect of this disclosure is A test apparatus for a voltage detection device according to the first embodiment, A first voltage source that applies a predetermined first test voltage to the first detection terminal, A second voltage source that applies a variable second test voltage to the second detection terminal, The system includes a controller for determining and setting the resistance value of the trimming resistor, The aforementioned controller, The connection of the first and second switch circuits is set to one of several modes, In each of the above-mentioned modes, the signal output from the comparison circuit is monitored while sweeping the second test voltage. The resistance value of the trimming resistor is determined and set based on the signal output from the comparator circuit so that the signal output from the comparator circuit transitions when the first and second input voltages have a predetermined target potential difference.

[0114] According to the test apparatus of the third aspect of this disclosure, in the test apparatus of the second aspect, The aforementioned multiple modes are, A first mode in which the first intermediate terminal is connected to the first input terminal and the second intermediate terminal is connected to the second input terminal, A second mode in which the first intermediate terminal is connected to the first input terminal and the second detection terminal is connected to the second input terminal, This includes a third mode in which the first detection terminal is connected to the first input terminal and the second detection terminal is connected to the second input terminal, The aforementioned controller, In each of the first to third modes, the second test voltage at the time the signal output from the comparison circuit transitions is acquired as the measured voltage. The resistance value of the trimming resistor is determined based on the measured voltage.

[0115] According to the test apparatus of the fourth aspect of this disclosure, in the test apparatus of the third aspect, The controller calculates the resistance ratio R4 / (R3+Rm+R4) using the following equations (1) to (4): R2 / (R1+R2)×(Vref-Va)+Va+Vos=R4 / (R3+R4)×(Vref-V1)+V1 Formula (1) R2 / (R1+R2)×(Vref-Va)+Va+Vos=V2 Formula (2) Vos=V3 Equation (3) R2 / (R1+R2)×(Vref-Va)+Va+Vos=R4 / (R3+Rm+R4)×(Vref-Vt)+Vt Equation (4) Here, R2 / (R1+R2) represents the resistance ratio of the aforementioned first voltage divider resistors. R4 / (R3+R4) represents the resistance ratio of the second voltage divider resistors. Vref indicates the reference voltage, Va represents the first test voltage, Vos represents the offset voltage of the comparison circuit, V1 represents the measured voltage acquired in the first mode described above. V2 represents the measured voltage acquired in the second mode described above. V3 represents the measured voltage acquired in the third mode described above. Rm represents the resistance value of the trimming resistor. Vt represents the second test voltage when the first and second test voltages have the target potential difference, The controller determines the resistance value Rm of the trimming resistor such that the second voltage divider resistor has the resistance ratio R4 / (R3+Rm+R4).

[0116] According to the test apparatus of the fifth aspect of this disclosure, in the test apparatus of the second aspect, The aforementioned multiple modes are, A first mode in which the first intermediate terminal is connected to the first input terminal and the second intermediate terminal is connected to the second input terminal, A second mode in which the first intermediate terminal is connected to the first input terminal and the second detection terminal is connected to the second input terminal, This includes two modes: a first detection terminal connected to the first input terminal and a third mode in which the second detection terminal is connected to the second input terminal, The aforementioned controller, In each of the two modes, the second test voltage at the time the signal output from the comparison circuit transitions is acquired as the measured voltage. The resistance value of the trimming resistor is determined based on the measured voltage.

[0117] According to the test apparatus of the sixth aspect of this disclosure, in the test apparatus of the fifth aspect, The controller calculates the resistance ratio R4 / (R3+Rm+R4) using two of the following equations (1) to (3) corresponding to the two modes, and equation (4) below. R2 / (R1+R2)×(Vref-Va)+Va+Vos=R4 / (R3+R4)×(Vref-V1)+V1 Formula (1) R2 / (R1+R2)×(Vref-Va)+Va+Vos=V2 Formula (2) Vos=V3 Equation (3) R2 / (R1+R2)×(Vref-Va)+Va+Vos=R4 / (R3+Rm+R4)×(Vref-Vt)+Vt Equation (4) Here, R2 / (R1+R2) represents the resistance ratio of the aforementioned first voltage divider resistors. R4 / (R3+R4) represents the resistance ratio of the second voltage divider resistors. Vref indicates the reference voltage, Va represents the first test voltage, Vos represents the offset voltage of the comparison circuit, V1 represents the measured voltage acquired in the first mode described above. V2 represents the measured voltage acquired in the second mode described above. V3 represents the measured voltage acquired in the third mode described above. Rm represents the resistance value of the trimming resistor. Vt represents the second test voltage when the first and second test voltages have the target potential difference, The controller determines the resistance value Rm of the trimming resistor such that the second voltage divider resistor has the resistance ratio R4 / (R3+Rm+R4).

[0118] A voltage detection device according to the seventh aspect of this disclosure is: A first detection terminal to which a first input voltage is applied, A second detection terminal to which a second input voltage is applied, A reference voltage source that generates a predetermined reference voltage, A comparison circuit having first and second input terminals and outputting a signal indicating which of two voltages applied to the first and second input terminals is larger, wherein the first input terminal is connected to a comparison circuit connected to a first detection terminal, A voltage divider resistor having an intermediate terminal connected between the reference voltage source and the second detection terminal, which generates an intermediate voltage between the reference voltage and the second input voltage, the voltage divider resistor including a trimming resistor having a variable resistance value, The system includes a switch circuit that connects one of the second detection terminal and the intermediate terminal to the second input terminal.

[0119] According to the voltage detection device of the eighth aspect of this disclosure, A first detection terminal to which a first input voltage is applied, A second detection terminal to which a second input voltage is applied, A comparison circuit having first and second input terminals and outputting a signal indicating which of the two voltages applied to the first and second input terminals is larger, A reference voltage source connected between the first detection terminal and the first input terminal, which generates a predetermined reference voltage and adds it to the first input voltage, A voltage divider resistor having an intermediate terminal connected between the first and second detection terminals and generating an intermediate voltage between the first and second input voltages, the voltage divider resistor including a trimming resistor having a variable resistance value, The system includes a switch circuit that connects one of the second detection terminal and the intermediate terminal to the second input terminal.

[0120] A voltage detection device according to the ninth aspect of this disclosure is A detection terminal to which an input voltage is applied, A reference voltage source that generates a predetermined reference voltage, A comparison circuit having a control terminal and outputting a signal indicating which is greater, the voltage applied to the control terminal or a predetermined threshold voltage, A voltage divider resistor connected between the reference voltage source and the detection terminal, having an intermediate terminal that generates an intermediate voltage between the reference voltage and the input voltage, the voltage divider resistor includes a trimming resistor having a variable resistance value, The system includes a switch circuit that connects one of the detection terminal and the intermediate terminal to the control terminal.

[0121] According to the test method relating to the tenth aspect of this disclosure, A test method for a voltage detection device according to the first embodiment, Applying a predetermined first test voltage to the first detection terminal, A variable second test voltage is applied to the second detection terminal, The connection of the first and second switch circuits is set to one of several modes, In each of the above-mentioned modes, the signal output from the comparison circuit is monitored while sweeping the second test voltage, This includes determining and setting the resistance value of the trimming resistor based on the signal output from the comparator circuit, such that the signal output from the comparator circuit transitions when the first and second input voltages have a predetermined target potential difference. [Industrial applicability]

[0122] A voltage detection device according to an embodiment of the present disclosure may be used, for example, to detect the voltage or current of a circuit, or to detect overcharging or over-discharging of a secondary battery. [Explanation of Symbols]

[0123] 10, 10A~10D Voltage Detection Device 11,12 Voltage divider resistors 13,14 Switch Circuits 15 Drive Circuit 16 Comparator 17,17C Logic Circuit 20,20D Test Equipment 21 Controllers 21MB memory 30 Laser trimming device E11 Reference Voltage Source E21 Reference Voltage Source E22 Variable Voltage Source Fm1~FmN fuses R1~R5 Resistors Rm trimming resistor Rm1~RmN Resistance SW1~SW5 Switching elements

Claims

1. A first detection terminal to which a first input voltage is applied, A second detection terminal to which a second input voltage is applied, A reference voltage source that generates a predetermined reference voltage, A comparison circuit having first and second input terminals and outputting a signal indicating which of the two voltages applied to the first and second input terminals is larger, A first voltage divider resistor is connected between the reference voltage source and the first detection terminal and has a first intermediate terminal that generates a first intermediate voltage between the reference voltage and the first input voltage, A first switch circuit that connects one of the first detection terminal and the first intermediate terminal to the first input terminal, A second voltage divider resistor connected between the reference voltage source and the second detection terminal, having a second intermediate terminal that generates a second intermediate voltage between the reference voltage and the second input voltage, the second voltage divider resistor including a trimming resistor having a variable resistance value, The system includes a second switch circuit that connects one of the second detection terminal and the second intermediate terminal to the second input terminal. Voltage detection device.

2. A test apparatus for a voltage detection device according to claim 1, A first voltage source that applies a predetermined first test voltage to the first detection terminal, A second voltage source that applies a variable second test voltage to the second detection terminal, The system includes a controller for determining and setting the resistance value of the trimming resistor, The aforementioned controller, The connection of the first and second switch circuits is set to one of several modes, In each of the above-mentioned modes, the signal output from the comparison circuit is monitored while sweeping the second test voltage. The resistance value of the trimming resistor is determined and set based on the signal output from the comparison circuit so that the signal output from the comparison circuit transitions when the first and second input voltages have a predetermined target potential difference. Test equipment.

3. The aforementioned multiple modes are, A first mode in which the first intermediate terminal is connected to the first input terminal and the second intermediate terminal is connected to the second input terminal, A second mode is characterized by connecting the first intermediate terminal to the first input terminal and the second detection terminal to the second input terminal, This includes a third mode in which the first detection terminal is connected to the first input terminal and the second detection terminal is connected to the second input terminal, The aforementioned controller, In each of the first to third modes, the second test voltage at the time the signal output from the comparison circuit transitions is acquired as the measured voltage. The resistance value of the trimming resistor is determined based on the measured voltage. The test apparatus according to claim 2.

4. The controller calculates the resistance ratio R4 / (R3+Rm+R4) using the following equations (1) to (4): R2 / (R1+R2)×(Vref-Va)+Va+Vos=R4 / (R3+R4)×(Vref-V1)+V1 Formula (1) R2 / (R1+R2)×(Vref-Va)+Va+Vos=V2 Formula (2) Vos=V3 Formula (3) R2 / (R1+R2)×(Vref-Va)+Va+Vos=R4 / (R3+Rm+R4)×(Vref-Vt)+Vt Formula (4) Here, R2 / (R1+R2) represents the resistance ratio of the first voltage divider resistors. R4 / (R3+R4) represents the resistance ratio of the second voltage divider resistors. Vref indicates the aforementioned reference voltage. Va represents the first test voltage, Vos represents the offset voltage of the comparison circuit. V1 represents the measured voltage acquired in the first mode, V2 indicates the measurement voltage acquired in the second mode described above. V3 indicates the measured voltage acquired in the mode described in the third mode. Rm represents the resistance value of the trimming resistor, Vt represents the second test voltage when the first and second test voltages have the target potential difference, The controller determines the resistance value Rm of the trimming resistor such that the second voltage divider resistor has the resistance ratio R4 / (R3+Rm+R4). The test apparatus according to claim 3.

5. The aforementioned multiple modes are, A first mode in which the first intermediate terminal is connected to the first input terminal and the second intermediate terminal is connected to the second input terminal, A second mode is characterized by connecting the first intermediate terminal to the first input terminal and the second detection terminal to the second input terminal, This includes two modes: a first detection terminal connected to the first input terminal and a third mode in which the second detection terminal is connected to the second input terminal, The aforementioned controller, In each of the two modes, the second test voltage at the time the signal output from the comparison circuit transitions is acquired as the measured voltage. The resistance value of the trimming resistor is determined based on the measured voltage. The test apparatus according to claim 2.

6. The controller calculates the resistance ratio R4 / (R3+Rm+R4) using two of the following equations (1) to (3) corresponding to the two modes, and the following equation (4). R2 / (R1+R2)×(Vref-Va)+Va+Vos=R4 / (R3+R4)×(Vref-V1)+V1 Formula (1) R2 / (R1+R2)×(Vref-Va)+Va+Vos=V2 Formula (2) Vos=V3 Formula (3) R2 / (R1+R2)×(Vref-Va)+Va+Vos=R4 / (R3+Rm+R4)×(Vref-Vt)+Vt Formula (4) Here, R2 / (R1+R2) represents the resistance ratio of the first voltage divider resistors. R4 / (R3+R4) represents the resistance ratio of the second voltage divider resistors. Vref indicates the aforementioned reference voltage. Va represents the first test voltage, Vos represents the offset voltage of the comparison circuit. V1 represents the measured voltage acquired in the first mode, V2 indicates the measurement voltage acquired in the second mode described above. V3 indicates the measured voltage acquired in the mode described in the third mode. Rm represents the resistance value of the trimming resistor, Vt represents the second test voltage when the first and second test voltages have the target potential difference, The controller determines the resistance value Rm of the trimming resistor such that the second voltage divider resistor has the resistance ratio R4 / (R3+Rm+R4). The test apparatus according to claim 5.

7. A first detection terminal to which a first input voltage is applied, A second detection terminal to which a second input voltage is applied, A reference voltage source that generates a predetermined reference voltage, A comparison circuit having first and second input terminals and outputting a signal indicating which of two voltages applied to the first and second input terminals is larger, wherein the first input terminal is connected to a comparison circuit connected to a first detection terminal, A voltage divider resistor having an intermediate terminal connected between the reference voltage source and the second detection terminal, which generates an intermediate voltage between the reference voltage and the second input voltage, and which includes a trimming resistor having a variable resistance value, The system includes a switch circuit that connects one of the second detection terminal and the intermediate terminal to the second input terminal. Voltage detection device.

8. A first detection terminal to which a first input voltage is applied, A second detection terminal to which a second input voltage is applied, A comparison circuit having first and second input terminals and outputting a signal indicating which of the two voltages applied to the first and second input terminals is larger, A reference voltage source connected between the first detection terminal and the first input terminal, which generates a predetermined reference voltage and adds it to the first input voltage, A voltage divider resistor having an intermediate terminal connected between the first and second detection terminals and generating an intermediate voltage between the first and second input voltages, the voltage divider resistor including a trimming resistor having a variable resistance value, The system includes a switch circuit that connects one of the second detection terminal and the intermediate terminal to the second input terminal. Voltage detection device.

9. A detection terminal to which an input voltage is applied, A reference voltage source that generates a predetermined reference voltage, A comparison circuit having a control terminal and outputting a signal indicating which is greater, the voltage applied to the control terminal or a predetermined threshold voltage, A voltage divider resistor connected between the reference voltage source and the detection terminal, having an intermediate terminal that generates an intermediate voltage between the reference voltage and the input voltage, the voltage divider resistor includes a trimming resistor having a variable resistance value, The system includes a switch circuit that connects one of the detection terminal and the intermediate terminal to the control terminal. Voltage detection device.

10. A test method for a voltage detection device according to claim 1, Applying a predetermined first test voltage to the first detection terminal, A variable second test voltage is applied to the second detection terminal, The connection of the first and second switch circuits is set to one of several modes, In each of the above-mentioned modes, the signal output from the comparison circuit is monitored while sweeping the second test voltage, This includes determining and setting the resistance value of the trimming resistor based on the signal output from the comparator circuit, such that the signal output from the comparator circuit transitions when the first and second input voltages have a predetermined target potential difference. Testing method.

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