JP2003075477A - Voltage detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a voltage detector circuit capable of immediately measuring a detection voltage by adding a simple circuit upon input of a specified test signal, thereby greatly reducing the required time for measuring the detection voltage. SOLUTION: When a test signal St at high level is inputted to a test signal input terminal 13 at a test mode, an input switching circuit 5 inputs an output signal from an operational amplifier 4 to an input end IN of a voltage divider circuit 3, instead of an input voltage Vi inputted from an input terminal 13, to measure an output voltage Vo from the operational amplifier 4 so that fuses HU1-HU9 of the divider circuit 3 are selectively blown off according to the measurement result.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to simplification of the manufacturing process of a voltage detecting IC used in a mobile phone or the like, and more specifically, shortening the time of measuring and adjusting the detection voltage of the voltage detecting IC. The present invention relates to a voltage detection circuit capable of achieving the above.

[0002]

2. Description of the Related Art In recent battery-powered electronic devices, in order to realize long-term use, the circuit is operated up to the minimum voltage necessary for normal operation. It was necessary to detect the battery voltage with high accuracy.
Therefore, in the voltage detection circuit that detects the battery voltage, the resistance value of the voltage adjustment resistor is adjusted by laser trimming or the like in order to improve the accuracy of the detection voltage, and the desired detection voltage accuracy is obtained.

FIG. 9 is a circuit diagram showing an example of a conventional voltage detection circuit. In FIG. 9, the input voltage Vi applied to the input terminal 110 is divided by the resistors R101 and R102 and input to the inverting input terminal of the operational amplifier 103. A predetermined reference voltage Vr is applied from the reference voltage generating circuit unit 104 to the non-inverting input terminal of the operational amplifier 103.

The operational amplifier 103 compares the divided voltage Vd obtained by dividing the input voltage Vi with the reference voltage Vr,
When the divided voltage Vd is higher than the reference voltage Vr, the output end is at a low level, and when the divided voltage Vd is lower than the reference voltage Vr, the output end is high (High).
h) Level. For example, in a device driven by a battery such as a mobile phone, the voltage of the battery is applied as the input voltage Vi, and in this case, the high-level signal output from the operational amplifier 103 becomes a reset signal for the CPU and the like.

[0005]

In such a voltage detecting circuit, only a high level or low level output signal can be obtained as a binary digital signal level from the output terminal of the voltage detecting circuit. Therefore, during manufacturing,
Resistor R10 for increasing the detection accuracy of the voltage detection circuit
1 and / or R102 is adjusted by gradually changing the input voltage Vi of the voltage detection circuit so that the output voltage of the voltage detection circuit changes from high level to low level.
Or, measuring the input voltage Vi when the opposite change occurs,
From the measurement result, a resistor R1 is formed by laser trimming or the like.
The resistance value in 01 and / or R102 was adjusted. However, since such measurement requires a lot of time, it has been a factor of increasing the cost of the voltage detection circuit.

On the other hand, Japanese Unexamined Patent Publication No. 10-111196 discloses a technique for improving the detection accuracy of the voltage detection circuit without adjusting the resistance using trimming.
The publication requires the provision of a highly accurate constant voltage circuit for generating the reference voltage. But I
The reference voltage causes the largest variation in the C manufacturing process, and the above publication does not disclose any means for improving the accuracy of the reference voltage.

The present invention has been made in order to solve the above problems, and by adding a simple circuit, the detection voltage can be measured immediately when a predetermined test signal is input. An object of the present invention is to obtain a voltage detection circuit that can significantly reduce the measurement time required to measure the detection voltage.

[0008]

A voltage detection circuit according to the present invention compares a voltage input from an input terminal with a predetermined reference voltage, outputs a signal according to the comparison result, and outputs the input voltage. In a voltage detection circuit for detecting that the voltage has reached a corresponding predetermined voltage, a reference voltage generation circuit section for generating and outputting the predetermined reference voltage, and a voltage dividing circuit section for dividing and outputting the input voltage. And an operational amplifier that compares the reference voltage from the reference voltage generating circuit unit with the divided voltage from the voltage dividing circuit unit and outputs a voltage according to the comparison result, and a predetermined externally input voltage. An input switching circuit unit that outputs either the voltage input to the input terminal or the output voltage of the operational amplifier as the input voltage of the voltage dividing circuit unit according to the test signal of 1. Is the input voltage of the voltage divider. As, during normal operation, the outputs the input voltage from the input terminal, in the test mode in which a predetermined test signal is inputted from the outside, and outputs an output voltage of the operational amplifier.

Further, the voltage detection circuit according to the present invention compares the voltage input from the input terminal with a predetermined reference voltage, outputs a signal according to the comparison result, and outputs a signal corresponding to the input voltage. In the voltage detection circuit for detecting that the predetermined voltage has been reached, a reference voltage generation circuit section that generates and outputs the predetermined reference voltage, a voltage division circuit section that divides and outputs the input voltage, and the reference Voltage comparison between the reference voltage from the voltage generation circuit section and the divided voltage from the voltage division circuit section,
Depending on the operational amplifier that outputs a voltage according to the comparison result and a predetermined test signal input from the outside, either the divided voltage from the voltage dividing circuit unit or the output voltage of the operational amplifier is operated. An input switching circuit section for outputting to a predetermined input terminal of the amplifier, wherein the input switching circuit section supplies the divided voltage from the voltage dividing circuit section to the predetermined input terminal of the operational amplifier during normal operation. In the test mode in which a predetermined test signal is output from the outside, the output voltage of the operational amplifier is output.

Specifically, the voltage dividing circuit section is composed of a plurality of resistors connected in series, and generates a divided voltage obtained by dividing the input voltage according to the ratio of the resistance values of the resistors. The divided voltage may be adjusted by adjusting the ratio of the resistance values by trimming based on the measurement value obtained by measuring the output voltage of the operational amplifier in the test mode.

In this case, the voltage dividing circuit section includes two voltage dividing resistors formed to have a predetermined ratio of the resistance values, and a plurality of adjusting resistors connected in series between the voltage dividing resistors. A resistor for resistance, each adjustment fuse connected in parallel corresponding to each adjustment resistor, and the voltage at the connection between the one voltage dividing resistor and the adjustment resistor as a divided voltage
It is composed of an output selection fuse and a second output selection fuse which outputs the voltage at the connection between the other voltage dividing resistor and the adjustment resistor as a divided voltage. While selectively cutting,
Either the first output selecting fuse or the second output selecting fuse is selected and cut.

On the other hand, the voltage detection circuit according to the present invention compares each voltage input from the plurality of input terminals with a predetermined reference voltage, outputs signals corresponding to the comparison result, and outputs each of the input signals. In a voltage detection circuit that detects that a voltage has reached a corresponding predetermined voltage, a reference voltage generation circuit unit that generates and outputs the predetermined reference voltage, and divides the voltage input from the corresponding input terminal. And outputs a voltage corresponding to the comparison result by performing a voltage comparison between each divided voltage circuit unit that outputs the divided voltage and the divided voltage from the divided voltage circuit unit corresponding to the reference voltage from the reference voltage generation circuit unit. According to each operational amplifier and a predetermined test signal input from the outside, each voltage dividing circuit corresponding to either each voltage input to each input terminal or each output voltage of each operational amplifier. Input voltage And an input switching circuit section for respectively outputting the input voltage, and the input switching circuit section outputs the input voltage from each corresponding input terminal during normal operation as an input voltage of each voltage dividing circuit section. In the test mode in which a predetermined test signal is input from, the output voltage of each corresponding operational amplifier is output.

Further, the voltage detection circuit according to the present invention compares each voltage input from the plurality of input terminals with a predetermined reference voltage, outputs signals corresponding to the comparison result, and outputs each signal. In a voltage detection circuit that detects that a voltage has reached a corresponding predetermined voltage, a reference voltage generation circuit unit that generates and outputs the predetermined reference voltage, and divides the voltage input from the corresponding input terminal. And outputs a voltage corresponding to the comparison result by performing a voltage comparison between each divided voltage circuit unit that outputs the divided voltage and the divided voltage from the divided voltage circuit unit corresponding to the reference voltage from the reference voltage generation circuit unit. According to each operational amplifier and a predetermined test signal input from the outside, each operation corresponding to each of the divided voltage from each of the voltage dividing circuit units or each output voltage of each of the operational amplifiers. Predetermined input of amplifier And an input switching circuit section for outputting the divided voltage from each corresponding voltage dividing circuit section to a predetermined input terminal of each operational amplifier during normal operation. In a test mode in which a predetermined test signal is output from the outside, the output voltage of each corresponding operational amplifier is output.

Specifically, each of the voltage dividing circuit sections is composed of a plurality of resistors connected in series, and the divided voltage obtained by dividing the input voltage according to the ratio of the resistance values of the resistors is used. The divided voltage is adjusted by adjusting the ratio of the resistance values by trimming on the basis of the measured value obtained by measuring the output voltage of the corresponding operational amplifier in the test mode. You may

Further, in the test mode, there is provided a switching circuit section for outputting any one of the output voltages from the operational amplifiers to the outside according to a selection signal inputted from the outside.

Further, the voltage detection circuit according to the present invention compares each voltage input from the plurality of input terminals with a predetermined reference voltage, outputs a signal corresponding to the comparison result, and outputs each signal. In a voltage detection circuit that detects that a voltage has reached a corresponding predetermined voltage, a reference voltage generation circuit unit that generates and outputs the predetermined reference voltage, and divides the voltage input from the corresponding input terminal. And outputs a voltage corresponding to the comparison result by performing a voltage comparison between each divided voltage circuit unit that outputs the divided voltage and the divided voltage from the divided voltage circuit unit corresponding to the reference voltage from the reference voltage generation circuit unit. Either of the input voltage from the corresponding input terminal or the output voltage of the corresponding operational amplifier with respect to a predetermined one of the voltage dividing circuit units depending on each operational amplifier and a predetermined test signal input from the outside. Or input voltage The input switching circuit unit outputs the input voltage from the corresponding input terminal during normal operation as an input voltage of the predetermined voltage dividing circuit unit, and the input switching circuit unit outputs the predetermined voltage from the outside. In the test mode in which the test signal is input, the output voltage of the corresponding operational amplifier is output.

Further, the voltage detection circuit according to the present invention compares each voltage input from the plurality of input terminals with a predetermined reference voltage, outputs a signal corresponding to the comparison result, and outputs each signal. In a voltage detection circuit that detects that a voltage has reached a corresponding predetermined voltage, a reference voltage generation circuit unit that generates and outputs the predetermined reference voltage, and divides the voltage input from the corresponding input terminal. And outputs a voltage corresponding to the comparison result by performing a voltage comparison between each divided voltage circuit unit that outputs the divided voltage and the divided voltage from the divided voltage circuit unit corresponding to the reference voltage from the reference voltage generation circuit unit. In accordance with each operational amplifier and a predetermined test signal input from the outside, the divided voltage from the corresponding voltage dividing circuit section or the divided voltage of the operational amplifier is applied to one input terminal of the predetermined one operational amplifier. Either of output voltage And an input switching circuit section for outputting, wherein the input switching circuit section outputs a divided voltage from the corresponding voltage dividing circuit section to a predetermined input terminal of the one operational amplifier during normal operation. In the test mode in which a predetermined test signal is input from the outside, the output voltage of the operational amplifier is output.

Specifically, each of the voltage dividing circuit sections is composed of a plurality of resistors connected in series, and the divided voltage obtained by dividing the input voltage is divided according to the ratio of the resistance values of the resistors. The divided voltage is adjusted by adjusting the ratio of the resistance values by trimming based on the measured value obtained by measuring the output voltage of the predetermined one operational amplifier in the test mode. It may be performed.

In this case, each of the voltage dividing circuit units has two voltage dividing resistors formed to have a predetermined resistance value ratio, and a plurality of voltage dividing resistors connected in series between the voltage dividing resistors. The adjustment resistors, the adjustment fuses connected in parallel corresponding to the adjustment resistors, and the voltage at the connection between the one voltage dividing resistor and the adjustment resistor are output as a divided voltage. A first output selecting fuse and a second output selecting fuse that outputs the voltage at the connection between the other voltage dividing resistor and the adjusting resistor as a divided voltage, and each adjustment is made by trimming. The fuse is selectively cut, and either the first output selection fuse or the second output selection fuse is selected and cut.

On the other hand, the reference voltage generating circuit section is composed of a constant voltage generating section for generating and outputting a predetermined constant voltage, and a plurality of resistors connected in series. According to the measured value obtained by measuring the output voltage of the operational amplifier in the test mode to generate and output a reference voltage obtained by dividing the constant voltage from the constant voltage generating section, the resistance value by trimming It may be configured with a voltage adjusting unit that adjusts the ratio of the above and adjusts the reference voltage.

In this case, the voltage adjusting unit includes two voltage dividing resistors formed to have a predetermined ratio of the resistance values, and a plurality of adjusting resistors connected in series between the voltage dividing resistors. Output for outputting as reference voltage the voltage at the connection between the adjustment resistor, the adjustment fuses connected in parallel corresponding to the adjustment resistor, and the one voltage dividing resistor and the adjustment resistor. A fuse for selection and a second output selection fuse for outputting the voltage of the connection portion of the other voltage dividing resistor and the adjustment resistor as a reference voltage, and each trimming fuse selectively selects each adjustment fuse by the trimming. At the same time, the first output selecting fuse or the second output selecting fuse is selected and cut.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described in detail based on the embodiments shown in the drawings. First embodiment. FIG. 1 is a circuit diagram showing an example of a voltage detection circuit according to the first embodiment of the present invention. Figure 1
2, the voltage detection circuit 1 includes a reference voltage generation circuit section 2 that generates and outputs a predetermined reference voltage Vr, and a voltage division circuit section 3 that divides the input voltage to generate and output a divided voltage Vd. , And an operational amplifier 4 for comparing the reference voltage Vr with the divided voltage Vd and outputting a binary signal corresponding to the comparison result to the output terminal 11. Furthermore, the voltage detection circuit 1
Is an input switching circuit unit 5 that switches a signal input to the voltage dividing circuit unit 3 according to a test signal input from the outside.
Is equipped with.

The reference voltage generating circuit section 2 outputs the generated predetermined reference voltage Vr to the non-inverting input terminal of the operational amplifier 4. Further, the voltage dividing circuit unit 3 divides the voltage input to the input terminal IN by a predetermined ratio to generate a divided voltage Vd, and outputs the divided voltage Vd from the output terminal OUT to the inverting input terminal of the operational amplifier 4. The input switching circuit unit 5 receives the low-level test signal St during the normal operation and outputs the high-level test signal St during the test mode.
The h) level test signals St are input respectively. The input switching circuit unit 5 receives the voltage Vi input from the input terminal 12 when the input test signal St is at the low level.
Is output to the input terminal IN of the voltage dividing circuit section 3, and when the input test signal St is at a high level, the signal output from the output terminal of the operational amplifier 4 is input to the input terminal IN of the voltage dividing circuit section 3. input.

The voltage dividing circuit section 3 includes adjusting resistors R1 to R7,
It is composed of resistors R8 and R9 and fuses HU1 to HU9. The resistors R8 and R9 are resistors for voltage division, and the fuses HU1 to HU7 are adjustment fuses and the fuse H.
U8 is a first output selecting fuse, and fuse HU9 is a second output selecting fuse. In the voltage dividing circuit unit 3, a series circuit of a resistor R8, adjusting resistors R1 to R7, and a resistor R9 is connected between the input terminal IN and the ground, and the adjusting resistors R1 to R7 correspond to the series circuits. The fuses HU1 to HU7 are connected in parallel.

Further, a series circuit of fuses HU8 and HU9 is connected in parallel with the series circuit of the adjusting resistors R1 to R7, and the connecting portion between the fuses HU8 and HU9 is the output terminal OUT.
And is connected to the inverting input terminal of the operational amplifier 4.
In the initial state before adjustment of the detection voltage at the time of manufacturing, the adjustment resistors R1 to R7 are short-circuited by the corresponding fuses HU1 to HU7, respectively, so that the voltage dividing circuit unit 3 is connected to the input terminal IN. Input the voltage to the resistor R8
And R9 to generate a divided voltage Vd.

The input switching circuit section 5 is composed of transmission gates TM1 and TM2 and inverters IV1 and IV2, and the transmission gates TM1 and TM2 are connected in series between the input terminal 12 and the output terminal of the operational amplifier 4. Transmission gate TM
The connecting portion between 1 and TM2 is the input terminal IN of the voltage dividing circuit portion 3,
That is, it is connected to the resistor R8. Here, the transmission gate is a PMOS transistor and an NMOS.
In the transmission gate, the gate of the PMOS transistor will be referred to as an inverting control input terminal and the NMO will be described below.
The gate of the S transistor is called a non-inverting control input terminal.

The test signal St inputted from the test signal input terminal 13 is inputted to the non-inverting control input terminal of the transmission gate TM1 and the inverting control input terminal of the transmission gate TM2 via the inverter IV1 and further to the inverter IV2. Are input to the inverting control input terminal of the transmission gate TM1 and the non-inverting control input terminal of the transmission gate TM2.

In such a configuration, the voltage detection circuit 1
Is a circuit that detects that the input voltage Vi has reached the predetermined voltage V1 by outputting a high level signal from the output terminal 11 when the input voltage Vi reaches the predetermined voltage V1. In the voltage detection circuit 1, the accuracy of detecting that the input voltage Vi has reached the predetermined voltage V1 is determined by the resistance R8,
It is affected by variations in resistance values of R9, variations in reference voltage Vr, and offset of the operational amplifier 4. Therefore, it is necessary to adjust the detection voltage for the voltage detection circuit 1 at the time of manufacturing.

Next, a measuring operation of the detection voltage for the voltage detection circuit 1 and a method of adjusting the detection voltage, which are performed at the time of manufacturing, will be described. The test signal St from the outside becomes high level, and the operation in the test mode for measuring the variation in the detection voltage of the voltage detection circuit 1 is started. Since the test signal St is at the high level, the transmission gate TM1 is turned off and turned off, and the transmission gate TM2 is turned on and turned on.

Therefore, the output signal from the operational amplifier 4 is input to the input terminal IN of the voltage dividing circuit section 3, and the voltage dividing circuit section 3 inverts the signal obtained by dividing the output signal of the operational amplifier 4. Output to the input terminal. By doing so, from the output terminal of the operational amplifier 4, variations in the reference voltage Vr input from the reference voltage generating circuit unit 2, variations in the resistance values of the resistors R8 and R9, and the offset of the operational amplifier 4 are eliminated. The included output voltage is output to the output terminal 11. In such a state, the voltage Vo output from the operational amplifier 4 to the output terminal 11 is expressed by the following equation (1). Vo = Vr (1 + R8 / R9) (1) In the equation (1), R8 represents the resistance value of the resistor R8, and R9 represents the resistance value of the resistor R9.

In the test mode, the voltage measuring device is connected to the output terminal 11, and the voltage Vo output from the output terminal 11 is measured when the test signal St is at the high level. How much the measured output voltage Vo is different from the desired detection voltage is obtained, and the fuse HU of the voltage dividing circuit unit 3 is changed so that the detection voltage of the voltage detection circuit 1 changes by the difference.
1 to HU9 are selected and cut. The cutting is performed by trimming using a semiconductor laser or the like. In addition,
The trimming is performed by the voltage Vo output from the output terminal 11.
May be performed while measuring and calculating
It is also possible to record the measured value of the voltage Vo output from the device and then perform another calculation.

The resistance values of the adjusting resistors R1 to R7 of the voltage dividing circuit section 3 are formed to have a ratio of, for example, 1: 2: 4: 8: 16: 32: 64. To increase the divided voltage Vd, the fuse HU9 is cut off, and then the fuse HU1 is cut off.
~ By selectively disconnecting HU7, a desired adjustment resistor is connected between the resistors R8 and R9, and the resistance value of the resistor R8 and the resistance value obtained by adding the resistance values of the resistor R9 and the adjustment resistor are added. The divided voltage Vd corresponding to the ratio of is generated and output.

To lower the divided voltage Vd, the fuse HU8 is cut, and then the fuses HU1 to HU7 are selectively cut to connect a desired adjustment resistor between the resistors R8 and R9. The divided voltage Vd is generated and output according to the ratio of the resistance value obtained by adding the resistance values of the resistor R8 and the adjustment resistor to the resistance value of the resistor R9. In this way, the detection voltage of the voltage detection circuit 1 can be adjusted.

Next, a normal operation of detecting the input voltage Vi by setting the test signal St to the low level will be described. Since the test signal St is at low level,
The transmission gate TM1 is turned on and brought into conduction, and the transmission gate TM2 is turned off and turned off. Therefore, the input terminal I of the voltage dividing circuit unit 3 is
The input voltage Vi input from the input terminal 12 is input to N, and the voltage dividing circuit unit 3 outputs the divided voltage Vd obtained by dividing the input voltage Vi to the inverting input terminal of the operational amplifier 4.

The operational amplifier 4 receives the input divided voltage Vd.
And a reference voltage Vr are compared, and when the divided voltage Vd is larger than the reference voltage Vr, a low level output signal is output, and when the divided voltage Vd is small, a high level output signal is output terminal 11. Respectively output. Therefore, the divided voltage Vd and the reference voltage Vr are set such that the operational amplifier 4 outputs a high level signal when the input voltage Vi becomes equal to or lower than the predetermined voltage V1.
That is, the voltage detection circuit 1 detects whether or not the input voltage Vi has dropped to the predetermined voltage V1 or less, and then the input voltage V1
When it is detected that i has fallen below a predetermined voltage V1, a high level signal indicating the detection is output from the output terminal 11.

Here, a case where voltage detection is performed for each of a plurality of input voltages will be described with reference to FIG.
In addition, in FIG. 2, in order to make the description easy to understand, a case where voltage detection of two input voltages is performed is shown as an example. Further, in FIG. 2, the same components as those in FIG. 1 are denoted by the same reference numerals, and the description thereof will be omitted here. In FIG.
The difference from FIG. 1 is that a voltage detection circuit 1a that detects a voltage different from that of the voltage detection circuit 1 is provided and that either one of the voltage detection circuit 1 or 1a is output according to a selection signal Ss from the outside. This is because the switching circuit unit 41 that outputs a voltage is provided. That is, the voltage detection circuits 1 and 1a and the switching circuit unit 41 form a voltage detection circuit that detects the voltage of two input voltages.

The voltage detection circuit 1a divides the voltage Via input to the input terminal 12a to generate and output the divided voltage Vda, the reference voltage Vr, and the divided voltage V.
An operational amplifier 4a that compares the voltage of da and outputs a binary signal corresponding to the comparison result, and an input that switches the signal input to the voltage dividing circuit unit 3a according to the test signal St input from the outside. And a switching circuit section 5a.

The voltage dividing circuit section 3a divides the voltage input to the input terminal INa by a predetermined ratio to generate a divided voltage Vda, which is output from the output terminal OUTa to the inverting input terminal of the operational amplifier 4a. The input switching circuit section 5a outputs the voltage Via input from the input terminal 12a to the input terminal INa of the voltage dividing circuit section 3a when the input test signal St is at the low level, and the input test signal is input. When St is at a high level, the output signal of the operational amplifier 4a is output to the input terminal INa of the voltage dividing circuit unit 3a.

The voltage dividing circuit section 3a includes adjusting resistors R1a to R1.
7a, resistors R8a and R9a, and fuses HU1a to HU
9a. In the voltage dividing circuit section 3a, the resistors R8a and R9a correspond to the resistors R8 and R9, the adjustment resistors R1a to R7a correspond to the adjustment resistors R1 to R7, and the fuses HU1a to HU9a correspond to the fuses HU1 to HU9. Since the same operation is performed, the description thereof will be omitted. The resistors R8a and R9a are resistors for voltage division, and the fuses HU1a to HU7a are adjustment fuses.
The fuse HU8a serves as a first output selecting fuse, and the fuse HU9a serves as a second output selecting fuse.

The input switching circuit section 5a is composed of transmission gates TM1a and TM2a. The transmission gates TM1a and TM2a are connected in series between the input terminal 12a and the output terminal of the operational amplifier 4a. TM1a and TM
The connecting portion of 2a is connected to the input terminal INa of the voltage dividing circuit portion 3a, that is, the resistor R8a. The test signal St input from the test signal input terminal 13 receives the inverter IV
1 is input to the non-inverting control input terminal of the transmission gate TM1a and the inverting control input terminal of the transmission gate TM2a through the inverter IV.
2 is input to the inverting control input terminal of the transmission gate TM1a and the non-inverting control input terminal of the transmission gate TM2a.

The output signals of the operational amplifiers 4 and 4a are output to the switching circuit section 41 and the control circuit 45 which is an external circuit, respectively. The switching circuit unit 41 is configured to operate the operational amplifier 4 in accordance with a selection signal Ss input from the outside in the test mode.
And 4a, the voltage input from one of the output terminals is selected and output from the adjustment output terminal 42.

Next, the voltage detection circuit 1a performed at the time of manufacturing
The operation of measuring the detected voltage and the method of adjusting the detected voltage in Step 1 will be described. The operation of measuring the detected voltage and the method of adjusting the detected voltage in the voltage detection circuit 1 are the same as those in the case of FIG. The test signal St from the outside becomes high level, and the operation in the test mode for measuring the detection voltage of the voltage detection circuits 1 and 1a starts. Since the test signal St is at the high level, the transmission gate TM1a is turned off to be in the cutoff state, and the transmission gate TM2 is
a is turned on and becomes conductive.

Therefore, the input terminal INa of the voltage dividing circuit section 3a is
An output signal from the operational amplifier 4a is input to the input terminal of the operational amplifier 4a. By doing so, the variation in the reference voltage Vr input from the reference voltage generation circuit unit 2 and the resistance R are output from the output terminal of the operational amplifier 4a.
8a, R9a resistance value variations, and operational amplifier 4
The output voltage including the offset of a is output to the switching circuit unit 41 and the control circuit 45, respectively.

In the test mode, the adjustment output terminal 42
Is connected to the voltage measuring device and measures the voltage output from the adjustment output terminal 42 when the test signal St is at high level. The switching circuit unit 41 is selected according to the selection signal Ss.
When the output signal of the operational amplifier 4a is output from the output terminal 42 for adjustment from the adjustment output terminal 42, it is determined how much the measured output voltage is different from the desired detection voltage. In the case of the voltage detection circuit 1 of FIG. Similarly, the fuse HU of the voltage dividing circuit unit 3a is changed so that the detection voltage of the voltage detection circuit 1a changes by the difference.
1a to HU9a are selected and cut.

Needless to say, according to the selection signal Ss,
When the output signal of the operational amplifier 4 is output from the switching circuit unit 41 via the adjustment output terminal 42, the fuse HU1 of the voltage dividing circuit unit 3 is processed in the same manner as in the voltage detection circuit 1 of FIG.
~ HU9 is selected and cut. In this way, the detection voltages of the voltage detection circuits 1 and 1a can be adjusted respectively.

Next, the normal operation for detecting the input voltage Via when the test signal St becomes low level will be described. Since the test signal St is at the low level, the transmission gate TM1a turns on and becomes conductive, and at the same time, the transmission gate TM2a.
Turns off and enters the cutoff state. Therefore, the voltage dividing circuit unit 3a
The input voltage Via input from the input terminal 12a is input to the input terminal INa of the input terminal INa, and the voltage dividing circuit unit 3a outputs the divided voltage Vda obtained by dividing the input voltage Via to the inverting input terminal of the operational amplifier 4a. .

The operational amplifier 4a receives the input divided voltage V
The voltage da is compared with the reference voltage Vr to obtain the reference voltage Vr.
On the other hand, when the divided voltage Vda is high, a low level output signal is output from the output terminal, and when the divided voltage Vda is low, a high level output signal is output from the output terminal. Therefore, the divided voltage Vda and the reference voltage Vr are set so that the operational amplifier 4a outputs a high-level signal when the input voltage Via becomes equal to or lower than the predetermined voltage V2.

In other words, the voltage detection circuit 1 uses the input voltage V
It is detected whether or not i has dropped to a predetermined voltage V1 or lower, and when it is detected that the input voltage Vi has dropped to a predetermined voltage V1 or lower, a high level signal indicating the detection is output to the control circuit 45. To do. Similarly, the voltage detection circuit 1a
Detects whether the input voltage Via has dropped to a predetermined voltage V2 or lower, and when detecting that the input voltage Via has dropped to a predetermined voltage V2 or lower, controls a high-level signal indicating the detection. Output to the circuit 45. Control circuit 4
5 performs a predetermined operation according to each input signal.

On the other hand, in FIG. 2, resistors R8a and R9a are provided.
In the case where the variations in resistance values and the offset of the operational amplifier 4a in FIG. 3 can be ignored, the transmission gates TM1a and TM2a and the switching circuit unit 41 in FIG. In the case of FIG. 3, in the test mode, the voltage output from the operational amplifier 4 to the adjustment output terminal 42 is measured, and the fuses HU1 to HU1 to H are measured by the method described above based on the measured voltage.
U9 is selectively cut.

At the same time, assuming that the measured voltage is output from the operational amplifier 4a, an operation is performed based on the measured voltage, and the fuses HU1a to HU9a of the voltage dividing circuit section 3a are selectively selected from the operation result. Disconnect. By doing so, the voltage measurement time in the test mode can be shortened. In addition, in FIG. 2 and FIG. 3, when three or more input voltages are detected, the voltage detection circuit 1a may be added according to an increase in the number of input voltages detected.

In the above description, the divided voltage of the voltage dividing circuit section is adjusted according to the output voltage Vo measured in the test mode, but the reference voltage generating circuit is adjusted according to the measured output voltage Vo. The reference voltage Vr of the unit 2 may be adjusted. In such a case, the voltage detection circuit 1 of FIG. 1 becomes as shown in FIG. 4, and here only the differences from the case of FIG. 1 will be described. 4, the difference from FIG. 1 is that the voltage dividing circuit unit 3 is formed of a series circuit of resistors R8 and R9, and the reference voltage generating circuit unit 2 has a predetermined constant voltage Vr1 larger than the reference voltage Vr. Is composed of a constant voltage generating section 51 for generating and outputting and a voltage adjusting section 52 for adjusting the constant voltage Vr1 to generate and outputting a predetermined reference voltage Vr.

The voltage adjusting section 52 includes adjusting resistors R1 to R.
7, resistors R53 and R54, and fuses HU1 to HU9. The resistors R53 and R54 are resistors for voltage division. In the voltage adjusting unit 52, the constant voltage generating unit 51
Resistor R53 and adjusting resistor R1 between the output terminal and the ground
To R7 and a resistor R54 are connected in series, and the adjusting resistors R1 to R7 respectively have corresponding fuses H.
U1 to HU7 are connected in parallel.

Further, a series circuit of fuses HU8 and HU9 is connected in parallel with the series circuit of the adjusting resistors R1 to R7, and the reference voltage Vr is supplied from the connecting portion of the fuses HU8 and HU9 to the non-inverting input terminal of the operational amplifier 4. Is output. In the initial state before adjustment of the detection voltage at the time of manufacturing, the adjustment resistors R1 to R7 have the corresponding fuse HU1.
Since each of them is short-circuited by HU7, the voltage adjusting unit 52 controls the constant voltage Vr output from the constant voltage generating unit 51.
1 is divided by resistors R53 and R54 to generate a reference voltage Vr.

When the test signal St is at high level, the voltage Vo output from the output terminal 11 is measured. How much the measured output voltage Vo is different from the desired detection voltage is obtained, and the fuses HU1 to H of the voltage adjusting unit 52 are changed so that the detection voltage of the voltage detection circuit 1 changes by the difference.
Select U9 and disconnect. In order to increase the reference voltage Vr, the fuse HU9 is cut, and then the fuses HU1 to HU are used.
By selectively disconnecting 7 the resistors R53 and R5
4, a desired adjusting resistor is connected, and the reference voltage Vr is generated and output according to the ratio of the resistance value of the resistor R53 and the resistance value obtained by adding the resistance values of the resistor R54 and the adjusting resistor. It

In order to lower the reference voltage Vr, the fuse HU8 is cut off, and then the fuses HU1 to HU7 are selectively cut off so that a desired adjusting resistor is connected between the resistors R53 and R54. A reference voltage Vr is generated and output according to the ratio of the resistance value obtained by adding the resistance values of R53 and the adjustment resistor to the resistance value of the resistor R54.
In this way, the detection voltage of the voltage detection circuit 1 can be adjusted.

When voltage detection is performed for each of a plurality of input voltages, the voltage detection circuit 1 shown in FIGS. 2 and 3 is configured as shown in FIG. 4 and the voltage detection circuit 1a shown in FIGS. The voltage dividing circuit section 3a is made a series circuit of resistors R8a and R9a, and the voltage input to the input terminal INa is set to R8a.
And R9a may be used to generate the divided voltage Vda.

As described above, the voltage detection circuit according to the first embodiment inputs the predetermined test signal St to the test signal input terminal 13 so as to detect the input voltage input from the input terminal in the test mode. Instead, the output signal of the operational amplifier is input to the input terminal of the corresponding voltage dividing circuit unit, the output voltage of the operational amplifier is measured, and each of the voltage dividing circuit unit or the reference voltage generating circuit unit is measured according to the measurement result. The fuse is selectively blown. From this, it is possible to measure the detection voltage in a short time, it is possible to significantly reduce the time required for the manufacturing process up to the trimming process for adjusting the detection voltage and the time required for the inspection process, The increase in cost can be reduced and the detection voltage can be adjusted with high accuracy.

Second Embodiment. In the IC manufacturing process, resistors made close to each other, such as a voltage dividing resistor, can make the ratio of the resistors extremely accurately. Therefore, the ratio of the resistors R8 and R9 forming the voltage dividing resistors of the voltage dividing circuit section can be obtained. Is built with precision. Therefore, each fuse of the voltage dividing circuit unit may be selectively trimmed so that a desired detection voltage can be obtained from the measured reference voltage. From the above, in the first embodiment, the input switching circuit unit responds to the test signal St input from the outside according to
Although the signal input to the voltage dividing circuit unit is switched, the input switching circuit unit switches the signal input to the inverting input terminal of the operational amplifier according to the test signal St input from the outside. This may be done, and this is the second embodiment of the present invention.

FIG. 5 is a circuit diagram showing an example of the voltage detection circuit according to the second embodiment of the present invention. Note that FIG.
The same parts as those in FIG. 1 are designated by the same reference numerals, the description thereof will be omitted here, and only the differences from FIG. 1 will be described. 5 is different from FIG. 1 in that the input switching circuit unit 5 is input to the inverting input terminal of the operational amplifier 4 by changing the connection of the transmission gates TM1 and TM2 of the input switching circuit unit 5 in FIG. This is because the signals are switched, and the input switching circuit unit 5 in FIG. 1 is changed to the input switching circuit unit 61, and accordingly, the voltage detection circuit 1 in FIG. 1 is changed to the voltage detection circuit 60. .

In FIG. 5, the voltage detecting circuit 60 includes a reference voltage generating circuit section 2, a voltage dividing circuit section 3, and an operational amplifier 4.
And an input switching circuit section 61 that switches a signal input to the inverting input terminal of the operational amplifier 4 according to a test signal St input from the outside. The input terminal IN of the voltage dividing circuit unit 3 is connected to the input terminal 12 and receives the input voltage Vi. The output terminal OUT of the voltage dividing circuit section 3 is connected to the inverting input terminal of the operational amplifier 4 via the input switching circuit section 61.

The input switching circuit section 61 receives the low-level test signal St in the normal operation and the high-level test signal St in the test mode. When the input test signal St is at the low level, the input switching circuit section 61 outputs the divided voltage V output from the voltage dividing circuit section 3.
d is output to the inverting input terminal of the operational amplifier 4, and when the input test signal St is at a high level, the signal output from the output terminal of the operational amplifier 4 is output to the inverting input terminal of the operational amplifier 4.

The input switching circuit section 61 includes transmission gates TM1 and TM2 and inverters IV1 and IV2.
And a transmission gate T between the output terminal OUT of the voltage dividing circuit section 3 and the output terminal of the operational amplifier 4.
M1 and TM2 are connected in series, and the connection portion of the transmission gates TM1 and TM2 is connected to the inverting input terminal of the operational amplifier 4. The test signal St input from the test signal input terminal 13 receives the inverter IV
1 through a non-inverting control input terminal of the transmission gate TM1 and an inverting control input terminal of the transmission gate TM2, and further via an inverter IV2 an inverting control input terminal of the transmission gate TM1 and a non-inverting control input terminal of the transmission gate TM2. Entered at each end.

In such a configuration, the voltage detection circuit 6
Reference numeral 0 is a circuit that detects that the input voltage Vi has reached the predetermined voltage V1 by outputting a high level signal from the output terminal 11 when the input voltage Vi reaches the predetermined voltage V1. As in the case of the voltage detection circuit 1 of FIG. 1, it is necessary to adjust the detection voltage of the voltage detection circuit 60 during manufacturing.

Next, the voltage detection circuit 60 performed at the time of manufacturing
The measurement operation of the detected voltage and the method of adjusting the detected voltage will be described. The test signal St from the outside becomes high level, and the operation in the test mode for measuring the variation in the detection voltage of the voltage detection circuit 60 starts. Since the test signal St is at the high level, the transmission gate TM1 is turned off and turned off, and the transmission gate TM2 is turned on and turned on.

Therefore, the output signal from the operational amplifier 4 is input to the inverting input terminal of the operational amplifier 4, and the operational amplifier 4 operates as a voltage follower circuit. By doing so, the reference voltage Vr input from the reference voltage generating circuit unit 2 is output from the output terminal of the operational amplifier 4.
An output voltage including the offset of the operational amplifier 4 is output to the output terminal 11. The difference between the output voltage Vo measured by the voltage measuring device connected to the output terminal 11 and the desired detection voltage is calculated, and the detection voltage of the voltage detection circuit 60 is changed by the difference, as shown in FIG. As in
The fuses HU1 to HU9 of the voltage dividing circuit unit 3 are selected and cut.

Next, the normal operation of detecting the input voltage Vi when the test signal St becomes low level will be described. Since the test signal St is at low level,
The transmission gate TM1 is turned on and brought into conduction, and the transmission gate TM2 is turned off and turned off. Therefore, the divided voltage Vd output from the voltage dividing circuit unit 3 is input to the inverting input terminal of the operational amplifier 4, and the operational amplifier 4 receives the reference voltage Vr and the divided voltage as in the case of FIG. A voltage comparison of Vd is performed, and a binary signal indicating the comparison result is output. That is, the voltage detection circuit 60 detects whether or not the input voltage Vi has dropped to the predetermined voltage V1 or lower, and when it detects that the input voltage Vi has dropped to the predetermined voltage V1 or lower, it indicates the detection. A high level signal is output from the output terminal 11.

Here, a case where voltage detection is performed for each of a plurality of input voltages will be described with reference to FIG.
Note that, also in FIG. 6, the case where the voltage detection of two input voltages is performed is illustrated as an example for easy understanding of the description. Further, in FIG. 6, the same components as those in FIG. 2 or 5 are denoted by the same reference numerals, and the description thereof will be omitted here.
6 is different from FIG. 5 in that a voltage detection circuit 60a for detecting a voltage different from that of the voltage detection circuit 60 is provided, and that the voltage detection circuit 6a is provided according to a selection signal Ss from the outside.
This is because the switching circuit unit 41 that outputs either the output voltage of 0 or 60a is provided. That is, the voltage detection circuits 60 and 60a and the switching circuit unit 41 form a voltage detection circuit that detects the voltage of two input voltages.

The voltage detection circuit 60a includes a voltage dividing circuit section 3a.
An operational amplifier 4a, and an input switching circuit section 61a for switching a signal input to the inverting input terminal of the operational amplifier 4a according to a test signal St input from the outside. The voltage dividing circuit unit 3a converts the generated divided voltage Vda into
It outputs from the output end OUTa to the inverting input end of the operational amplifier 4a via the input switching circuit section 61a. Input switching circuit section 6
1a outputs the divided voltage Vda output from the voltage dividing circuit unit 3a to the inverting input terminal of the operational amplifier 4a when the input test signal St is at a low level, and the input test signal St is At the high level, the output signal of the operational amplifier 4a is output to the inverting input terminal of the operational amplifier 4a.

The input switching circuit section 61a is composed of transmission gates TM1a and TM2a, and the transmission gates TM1a and TM are provided between the output terminal OUTa of the voltage dividing circuit section 3a and the output terminal of the operational amplifier 4a.
2a are connected in series, and the connection portion of the transmission gates TM1a and TM2a is connected to the inverting input terminal of the operational amplifier 4a. The test signal St is transmitted to the transmission gate TM1 via the inverter IV1.
a non-inverting control input terminal and transmission gate T
It is input to the inverting control input terminal of M2a, and is further transmitted through the inverter IV2 to the transmission gate TM1.
a inversion control input terminal and transmission gate TM
It is input to the non-inverting control input terminal of 2a. The output signals of the operational amplifiers 4 and 4a are output to the switching circuit unit 41 and the control circuit 45, respectively.

Next, the voltage detection circuit 60 performed at the time of manufacturing
The measurement operation of the detection voltage and the adjustment method of the detection voltage in a will be described. The operation of measuring the detection voltage and the method of adjusting the detection voltage in the voltage detection circuit 60 are the same as in the case of FIG. The test signal St from the outside becomes high level, and the operation in the test mode for measuring the detection voltage of the voltage detection circuits 60 and 60a starts. Since the test signal St is at the high level, the transmission gate TM1a is turned off and turned off, and the transmission gate TM2a is turned on and turned on.

Therefore, the output signal from the operational amplifier 4a is input to the inverting input terminal of the operational amplifier 4a, and the operational amplifier 4a operates as a voltage follower circuit. By doing so, the reference voltage V input from the reference voltage generation circuit unit 2 is output from the output terminal of the operational amplifier 4a.
The output voltage including the variation of r and the offset of the operational amplifier 4a is output to the switching circuit unit 41 and the control circuit 45, respectively.

In the test mode, the adjustment output terminal 42
Is connected to the voltage measuring device, the voltage output from the adjustment output terminal 42 is measured when the test signal St is at a high level, and the voltage dividing circuit is operated in the same manner as in the first embodiment. The fuses HU1a to HU9a of the portion 3a are selected and cut. Needless to say, when the output signal of the operational amplifier 4 is output from the switching circuit unit 41 via the adjustment output terminal 42 in response to the selection signal Ss, the voltage dividing circuit is operated in the same manner as in the voltage detection circuit 60 of FIG. The fuses HU1 to HU9 of the part 3 are selected and cut. In this way
The detection voltages of the voltage detection circuits 60 and 60a can be adjusted respectively.

Next, the normal operation for detecting the input voltage Via when the test signal St becomes low level will be described. Since the test signal St is at the low level, the transmission gate TM1a turns on and becomes conductive, and at the same time, the transmission gate TM2a.
Turns off and enters the cutoff state. Therefore, the operational amplifier 4a
The divided voltage Vda output from the voltage dividing circuit unit 3a is input to the inverting input terminal of. The operational amplifier 4a receives the input divided voltage Vda and the reference voltage Vr as in the case of FIG.
, And a binary signal corresponding to the comparison result is output.

In this way, the voltage detection circuit 60 detects whether or not the input voltage Vi has dropped to the predetermined voltage V1 or lower, and when it detects that the input voltage Vi has dropped to the predetermined voltage V1 or lower, A high level signal indicating the detection is output to the control circuit 45. Similarly, the voltage detection circuit 60
a detects whether or not the input voltage Via has dropped below a predetermined voltage V2, and the input voltage Via is a predetermined voltage V2.
When it is detected that the voltage has dropped below, a high level signal indicating the detection is output to the control circuit 45.

On the other hand, in FIG. 6, when the offset of the operational amplifier 4a can be ignored, the transmission gates TM1a and TM2a and the switching circuit section 41 of FIG. In the case of FIG. 7, in the test mode, from the operational amplifier 4 to the adjustment output terminal 4
The voltage output to 2 is measured, and the fuses HU1 to HU9 are selectively blown by the method described above based on the measured voltage.

At the same time, assuming that the measured voltage is output from the operational amplifier 4a, an operation is performed based on the measured voltage, and the fuses HU1a to HU9a of the voltage dividing circuit section 3a are selectively selected from the operation result. Disconnect. By doing so, the voltage measurement time in the test mode can be shortened. In addition, in FIG. 6 and FIG. 7, when three or more input voltages are detected, the voltage detection circuit 60a may be added in accordance with the increase in the number of input voltages detected.

In the above description, the divided voltage of the voltage dividing circuit section is adjusted according to the output voltage Vo measured in the test mode. However, as in the case of the first embodiment, the divided voltage is adjusted. The reference voltage Vr of the reference voltage generation circuit unit 2 may be adjusted according to the measured output voltage Vo.
In this case, the voltage detection circuit 60 of FIG.
become that way. The reference voltage generating circuit section 2 and the voltage dividing circuit section 3 in the voltage detecting circuit 60 in FIG. 8 are the same as those in FIG. In addition, when voltage detection is performed for each of a plurality of input voltages, as shown in FIG.
The voltage detection circuit 60 of FIG. 8 is configured as shown in FIG. 8, and the voltage dividing circuit section 3a in the voltage detection circuit 60a of FIGS. 6 and 7 is formed as a series circuit of resistors R8a and R9a so that the voltage input to the input terminal INa is The divided voltage is V divided by R8a and R9a.
It suffices to generate da.

As described above, the voltage detection circuit according to the second embodiment inputs the predetermined test signal St to the test signal input terminal 13 so as to detect the input voltage input from the input terminal in the test mode. Instead, the output signal of the operational amplifier is input to the inverting input terminal of the operational amplifier, the output voltage of the operational amplifier is measured, and each fuse of the voltage dividing circuit unit or the reference voltage generating circuit unit is connected in accordance with the measurement result. It was made to selectively cut. From this, it is possible to measure the detection voltage in a short time, it is possible to significantly reduce the time required for the manufacturing process up to the trimming process for adjusting the detection voltage and the inspection process, The increase in cost can be reduced and the detection voltage can be adjusted with high accuracy.

In the first and second embodiments, the case where the divided voltage is adjusted by trimming and cutting the fuse in the voltage dividing circuit units 3 and 3a has been described as an example. , The voltage dividing voltage Vd is generated by the two voltage dividing resistors connected in series, and the resistors forming the two voltage dividing resistors are trimmed to adjust the respective resistance values. The voltage may be adjusted.

[0080]

As is apparent from the above description, according to the voltage detecting circuit of the present invention, as the input voltage of the voltage dividing circuit section, the input voltage from the input terminal is output during the normal operation, and the voltage is predetermined from the outside. The output voltage of the operational amplifier is output in the test mode in which the test signal is input. From this, the detection voltage of the voltage detection circuit can be measured by inputting a predetermined test signal.
The detection voltage can be measured in a short time, the time required for the inspection process can be significantly shortened, the manufacturing cost can be reduced, and the detection voltage itself can be measured. Accurate adjustment can be performed.

Further, the divided voltage from the voltage dividing circuit section is output to the predetermined input terminal of the operational amplifier during the normal operation, and the operation is performed in the test mode in which the predetermined test signal is input from the outside. The output voltage of the amplifier is output. From this, the reference voltage of the voltage detection circuit can be measured by inputting a predetermined test signal, so that the reference voltage can be measured in a short time, and the time required for the inspection process is greatly reduced. Therefore, the manufacturing cost can be reduced.

Specifically, in the voltage dividing circuit section, the ratio of the resistance value is adjusted by trimming based on the measured value obtained by measuring the output voltage of the operational amplifier in the test mode, and the divided voltage is Adjustments were made. Therefore, the time required for the manufacturing process up to the trimming process performed for adjusting the detection voltage and the time required for the inspection process can be significantly reduced, and the manufacturing cost can be reduced.

In this case, each trimming fuse of the voltage dividing circuit section is selectively cut by trimming, and either the first output selecting fuse or the second output selecting fuse of the voltage dividing circuit section is selected. I decided to disconnect.
Therefore, the detection voltage can be adjusted with high accuracy in a short time, and the manufacturing cost can be reduced.

Further, as the input voltage of each voltage dividing circuit section, the input voltage from each corresponding input terminal is output during the normal operation, and each corresponding voltage is output in the test mode in which a predetermined test signal is input from the outside. The output voltage of each operational amplifier is output. From this, it is possible to measure each detection voltage in a short time because the detection voltage can be measured by inputting a predetermined test signal in the voltage detection circuit that detects a plurality of voltages. In addition, the time required for the inspection process can be significantly reduced, the manufacturing cost can be reduced, and each detection voltage itself can be measured, so that highly accurate adjustment can be performed.

In a normal operation mode, the divided voltage from each corresponding voltage dividing circuit section is output to a predetermined input terminal of each operational amplifier, and a predetermined test signal is input from the outside. At times, the output voltage of each corresponding operational amplifier is output. From this, in the voltage detection circuit for detecting a plurality of voltages, it is possible to measure the reference voltage including the offset of each operational amplifier by inputting a predetermined test signal,
The reference voltage including the offset of each operational amplifier can be measured in a short time respectively, the time required for the inspection process can be significantly shortened, and the manufacturing cost can be reduced.

Specifically, in each voltage divider circuit section, the ratio of the resistance values is adjusted by trimming based on the measured value obtained by measuring the output voltage of the corresponding operational amplifier in the test mode. The divided voltage is adjusted individually. As a result, the time required for the manufacturing process up to the trimming process performed for adjusting each detection voltage and the time required for the inspection process can be significantly reduced, and the manufacturing cost can be reduced.

Further, in the test mode, the switching circuit section for outputting any one of the output voltages from the operational amplifiers to the outside according to the selection signal input from the outside is provided. The measurement voltage can be easily measured.

Further, as the input voltage of the predetermined voltage dividing circuit section, the input voltage from the corresponding input terminal is output during the normal operation, and the corresponding operational amplifier is output during the test mode in which the predetermined test signal is input from the outside. The output voltage of is output. From this, in a voltage detection circuit that detects a plurality of voltages, the reference voltage can be measured by inputting a predetermined test signal, so that the reference voltage can be measured in a short time and the inspection process It is possible to further significantly reduce the time required for manufacturing, reduce the manufacturing cost, reduce the increase in the number of pins, and realize a highly accurate voltage detection circuit with a small number of pins.

In a test mode in which a divided voltage from a corresponding voltage dividing circuit section is output to a prescribed input terminal of one operational amplifier during normal operation, and a prescribed test signal is input from the outside. The output voltage of the operational amplifier is output. From this, in a voltage detection circuit that detects a plurality of voltages, the reference voltage can be measured by inputting a predetermined test signal, so that the reference voltage can be measured in a short time and the inspection process It is possible to further significantly reduce the time required for manufacturing, reduce the manufacturing cost, reduce the increase in the number of pins, and realize a highly accurate voltage detection circuit with a small number of pins.

Specifically, in each voltage dividing circuit section, the resistance value ratio is adjusted by trimming based on the measured value obtained by measuring the output voltage of one predetermined operational amplifier in the test mode. The divided voltage is adjusted accordingly. As a result, the time required for the manufacturing process up to the trimming process performed for adjusting each detection voltage and the time required for the inspection process can be significantly reduced, and the manufacturing cost can be reduced.

In these cases, trimming is performed to selectively cut each adjusting fuse of the voltage dividing circuit section, and
Either the first output selecting fuse or the second output selecting fuse of the voltage dividing circuit section is selected and cut. As a result, each detection voltage can be adjusted with high accuracy in a short time, and the manufacturing cost can be reduced.

On the other hand, the reference voltage generating circuit section generates a predetermined constant voltage and outputs it, and the constant voltage output from the constant voltage generating section divides the constant voltage to generate and output the reference voltage. Based on the measurement value obtained by measuring the output voltage of the operational amplifier in the test mode.
The reference voltage is adjusted by adjusting the resistance value ratio by trimming in the voltage adjusting unit. Therefore, the time required for the manufacturing process up to the trimming process performed for adjusting the detection voltage and the time required for the inspection process can be significantly reduced, and the manufacturing cost can be reduced.

In this case, each trimming fuse of the voltage regulator is selectively cut off by trimming, and either the first output selection fuse or the second output selection fuse of the voltage regulator is selected. I decided to disconnect.
Therefore, the detection voltage can be adjusted with high accuracy in a short time, and the manufacturing cost can be reduced.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an example of a voltage detection circuit according to a first embodiment of the present invention.

2 is a circuit diagram showing an example in which voltage detection is performed for a plurality of input voltages using the voltage detection circuit of FIG.

FIG. 3 is a circuit diagram showing another example in which voltage detection is performed on a plurality of input voltages using the voltage detection circuit of FIG.

FIG. 4 is a circuit diagram showing another example of the voltage detection circuit according to the first embodiment of the present invention.

FIG. 5 is a circuit diagram showing an example of a voltage detection circuit according to a second embodiment of the present invention.

FIG. 6 is a circuit diagram showing an example in which voltage detection is performed on a plurality of input voltages using the voltage detection circuit of FIG.

FIG. 7 is a circuit diagram showing another example of the case where voltage detection is performed for a plurality of input voltages using the voltage detection circuit of FIG.

FIG. 8 is a circuit diagram showing another example of the voltage detection circuit according to the second embodiment of the present invention.

FIG. 9 is a circuit diagram showing an example of a conventional voltage detection circuit.

[Explanation of symbols]

1,1a, 60,60a Voltage detection circuit 2 Reference voltage generation circuit 3,3a voltage dividing circuit 4,4a Operational amplifier 5, 5a, 61, 61a Input switching circuit unit 11 output terminals 12 input terminals 13 Test signal input terminal 41 Switching circuit section 42 Output terminal for adjustment 45 Control circuit 51 Constant voltage generator 52 Voltage regulator R1 to R7 adjustment resistor R8, R9, R53, R54 resistance HU1 to HU9 fuses

Claims (14)

[Claims] 1. A voltage detector that compares a voltage input from an input terminal with a predetermined reference voltage, outputs a signal according to the comparison result, and detects that the input voltage has reached a predetermined voltage. In the circuit, a reference voltage generating circuit unit that generates and outputs the predetermined reference voltage, a voltage dividing circuit unit that divides and outputs the input voltage, a reference voltage from the reference voltage generating circuit unit, and the dividing voltage. A voltage input to the input terminal according to a predetermined test signal input from the outside and an operational amplifier that outputs a voltage according to the comparison result by performing a voltage comparison with the divided voltage from the voltage circuit unit. Or an input switching circuit unit that outputs one of the output voltages of the operational amplifier as an input voltage of the voltage dividing circuit unit, the input switching circuit unit, as an input voltage of the voltage dividing circuit unit,
A voltage detection circuit which outputs an input voltage from the input terminal during a normal operation and outputs an output voltage of the operational amplifier during a test mode in which a predetermined test signal is input from the outside. 2. A voltage detector that compares a voltage input from an input terminal with a predetermined reference voltage, outputs a signal according to the comparison result, and detects that the input voltage has reached a predetermined voltage. In the circuit, a reference voltage generating circuit unit that generates and outputs the predetermined reference voltage, a voltage dividing circuit unit that divides and outputs the input voltage, a reference voltage from the reference voltage generating circuit unit, and the dividing voltage. The voltage from the voltage dividing circuit is compared with the divided voltage from the voltage dividing circuit according to an operational amplifier that outputs a voltage according to the comparison result and a predetermined test signal input from the outside. An input switching circuit section for outputting either a piezo voltage or an output voltage of the operational amplifier to a predetermined input terminal of the operational amplifier, wherein the input switching circuit section is provided with respect to a predetermined input terminal of the operational amplifier. During normal operation, the voltage divider circuit Divided voltage outputs, in the test mode in which a predetermined test signal is inputted from the outside, the voltage detection circuit and outputs the output voltage of the operational amplifier. 3. The voltage dividing circuit section is composed of a plurality of resistors connected in series, and generates a divided voltage obtained by dividing the input voltage according to a ratio of resistance values of the respective resistors, in a test mode. 3. The divided voltage is adjusted by adjusting the ratio of the resistance values by trimming on the basis of a measured value obtained by measuring the output voltage of the operational amplifier. The voltage detection circuit described. 4. The voltage dividing circuit section includes two voltage dividing resistors formed to have a predetermined ratio of the resistance values, and a plurality of adjustment resistors connected in series between the voltage dividing resistors. A resistor for resistance, each adjustment fuse connected in parallel corresponding to each adjustment resistor, and a voltage at the connection between the one voltage dividing resistor and the adjustment resistor is output as a divided voltage. An output selection fuse and a second output selection fuse that outputs the voltage at the connection between the other voltage dividing resistor and the adjustment resistor as a divided voltage, and each trimming fuse is adjusted by the trimming. Selectively disconnecting the first output selection fuse or the second output
4. The voltage detection circuit according to claim 3, wherein one of the output selection fuses is selected and cut. 5. The respective voltages input from a plurality of input terminals are compared with a predetermined reference voltage, and signals corresponding to the comparison result are output respectively, so that each of the input voltages becomes a corresponding predetermined voltage. In the voltage detection circuit for detecting that, a reference voltage generation circuit unit that generates and outputs the predetermined reference voltage, and a voltage division circuit unit that divides and outputs the voltage input from the corresponding input terminal. , Each operational amplifier that performs voltage comparison between the reference voltage from the reference voltage generation circuit section and the corresponding divided voltage from the voltage division circuit section and outputs a voltage according to the comparison result, In accordance with a predetermined test signal, an input for outputting each of the respective voltages input to the respective input terminals or the respective output voltages of the respective operational amplifiers as the corresponding input voltage of the respective voltage dividing circuit section. Switching times The input switching circuit section outputs the input voltage from each of the corresponding input terminals during the normal operation as an input voltage of each voltage dividing circuit section, and a predetermined test signal is input from the outside. In the test mode, the voltage detection circuit outputs the output voltage of each corresponding operational amplifier. 6. The respective voltages input from a plurality of input terminals are compared with a predetermined reference voltage, and signals corresponding to the comparison result are respectively output so that each of the input voltages becomes a corresponding predetermined voltage. In the voltage detection circuit for detecting that, a reference voltage generation circuit unit that generates and outputs the predetermined reference voltage, and a voltage division circuit unit that divides and outputs the voltage input from the corresponding input terminal. , Each operational amplifier that performs voltage comparison between the reference voltage from the reference voltage generation circuit section and the corresponding divided voltage from the voltage division circuit section and outputs a voltage according to the comparison result, In response to a predetermined test signal, the divided voltage from each of the voltage dividing circuit units or the output voltage of each of the operational amplifiers is output to a corresponding predetermined input terminal of each of the operational amplifiers. Input switching circuit The input switching circuit section outputs a divided voltage from each corresponding voltage dividing circuit section to a predetermined input terminal of each operational amplifier during a normal operation, and outputs a predetermined voltage from the outside. A voltage detection circuit which outputs the output voltage of each corresponding operational amplifier in a test mode in which a test signal is input. 7. Each of the voltage dividing circuit units is composed of a plurality of resistors connected in series, and generates a divided voltage obtained by dividing the input voltage according to the ratio of resistance values of the resistors. In the test mode, the divided voltage is adjusted by adjusting the ratio of the resistance values by trimming based on the measured value obtained by measuring the output voltage of the corresponding operational amplifier. The voltage detection circuit according to claim 5 or 6. 8. A switching circuit unit for outputting any one of the output voltages from the respective operational amplifiers to the outside in response to a selection signal input from the outside in the test mode. The voltage detection circuit according to 5, 6, or 7. 9. The respective voltages input from a plurality of input terminals are compared with a predetermined reference voltage, and signals corresponding to the comparison result are respectively output so that each of the input voltages becomes a corresponding predetermined voltage. In the voltage detection circuit for detecting that, a reference voltage generation circuit unit that generates and outputs the predetermined reference voltage, and a voltage division circuit unit that divides and outputs the voltage input from the corresponding input terminal. , Each operational amplifier that performs voltage comparison between the reference voltage from the reference voltage generation circuit section and the corresponding divided voltage from the voltage division circuit section and outputs a voltage according to the comparison result, Input switching for outputting, as an input voltage, either one of the input voltage from the corresponding input terminal or the output voltage of the corresponding operational amplifier to one of the predetermined one of the voltage dividing circuit sections according to a predetermined test signal. Circuit part, A test mode in which the input switching circuit section outputs an input voltage from the corresponding input terminal during normal operation as an input voltage of the predetermined voltage dividing circuit section and a predetermined test signal is input from the outside. At times, the voltage detection circuit is characterized by outputting the output voltage of the corresponding operational amplifier. 10. The respective voltages input from a plurality of input terminals are compared with a predetermined reference voltage, and signals corresponding to the comparison results are respectively output so that each of the input voltages becomes a corresponding predetermined voltage. In the voltage detection circuit for detecting that, a reference voltage generation circuit unit that generates and outputs the predetermined reference voltage, and a voltage division circuit unit that divides and outputs the voltage input from the corresponding input terminal. , Each operational amplifier that performs voltage comparison between the reference voltage from the reference voltage generation circuit section and the corresponding divided voltage from the voltage division circuit section and outputs a voltage according to the comparison result, According to a predetermined test signal, one of the input terminals of one of the operational amplifiers,
An input switching circuit section that outputs either the divided voltage from the corresponding voltage dividing circuit section or the output voltage of the operational amplifier, wherein the input switching circuit section is a predetermined input terminal of the one operational amplifier. On the other hand, in the normal operation, the divided voltage from the corresponding voltage dividing circuit unit is output, and in the test mode in which a predetermined test signal is input from the outside, the output voltage of the operational amplifier is output. Voltage detection circuit. 11. Each of the voltage dividing circuit sections is composed of a plurality of resistors connected in series, and generates a divided voltage obtained by dividing the input voltage according to a ratio of resistance values of the resistors. The adjustment of the resistance value ratio by trimming based on the measured value obtained by measuring the output voltage of the predetermined one operational amplifier in the test mode to adjust the divided voltage, respectively. The voltage detection circuit according to claim 9 or 10, characterized in that. 12. Each of the voltage dividing circuit sections includes two voltage dividing resistors formed to have a predetermined ratio of the resistance values, and a plurality of series-connected resistors between the voltage dividing resistors. An adjusting resistor; each adjusting fuse connected in parallel corresponding to each adjusting resistor; and a voltage at the connection between the one voltage dividing resistor and the adjusting resistor is output as a divided voltage. A fuse for one output selection, and a fuse for second output selection that outputs the voltage of the connection portion of the other voltage dividing resistor and the adjusting resistor as a divided voltage, respectively, and each adjustment is performed by trimming. For selectively disconnecting the fuse for use in the first output selecting fuse or the second fuse
12. The voltage detection circuit according to claim 7, wherein one of the output selection fuses is selected and blown. 13. The reference voltage generating circuit section is composed of a constant voltage generating section for generating and outputting a predetermined constant voltage, and a plurality of resistors connected in series. According to the measured value obtained by measuring the output voltage of the operational amplifier in the test mode to generate and output a reference voltage obtained by dividing the constant voltage from the constant voltage generating section, the resistance value by trimming The voltage detection circuit according to claim 1, 2, 5, 6, 9 or 10, further comprising: a voltage adjustment unit that adjusts the ratio of the reference voltage to adjust the reference voltage. 14. The voltage adjusting unit includes two voltage dividing resistors formed so as to have a predetermined ratio of the resistance values, and a plurality of adjusting resistors connected in series between the voltage dividing resistors. A resistor, each adjustment fuse connected in parallel corresponding to each adjustment resistor, and a first output selection for outputting a voltage at a connection portion of the one voltage dividing resistor and the adjustment resistor as a reference voltage. Fuse, and a second output selecting fuse that outputs the voltage of the connection portion of the other voltage dividing resistor and the adjusting resistor as a reference voltage, and selectively adjusts each adjusting fuse by the trimming. And the fuse for selecting the first output or the second fuse
14. The voltage detection circuit according to claim 13, wherein one of the output selection fuses is selected and cut.