JP4543582B2 - Circuit device and adjustment data setting method for circuit device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention includes a reference voltage generation circuit that generates a reference voltage based on a power supply voltage, a constant voltage generation circuit that generates a constant voltage by amplifying the reference voltage, and a constant voltage generation circuit based on turning on or off of the power supply. A circuit device configured to include a reset circuit that outputs a reset signal according to a level change, and a setting for setting adjustment data for adjusting a constant voltage level and a reset-on output threshold for the circuit device Regarding the method.
[0002]
[Prior art]
Conventionally, a constant voltage generation circuit configured as part of an LSI, for example, supplying power for operating the LSI generates a constant voltage Vcc by amplifying the reference voltage output from the reference voltage generation circuit with an appropriate amplification factor. It is configured to let you. However, since the LSI has manufacturing variations, the reference voltage itself is not necessarily constant. For this reason, after the LSI is manufactured, a trimming operation for adjusting the voltage Vcc generated by the constant voltage generation circuit to be a predetermined voltage is required.
[0003]
3 to 5 show one configuration example of such a circuit device. The circuit device 1 is a part of a semiconductor sensor 2 (for example, a G sensor) formed as an LSI. The reference voltage generation circuit 3 is configured as, for example, a band gap regulator, and generates a reference voltage VBGR of 1.25 V as a standard when a power supply voltage of 2 V or more is supplied from the outside. The reference voltage VBGR is supplied to the constant voltage generation circuit 4 and the power-on reset circuit 5.
[0004]
FIG. 4 shows a detailed configuration of the reference voltage generation circuit 3. The reference voltage generation circuit 3 is configured around two diode-connected transistors 6 and 7 (indicated by a diode symbol) and an operational amplifier 8. A series circuit of the resistor 9 and the transistor 6 and a series circuit of the resistors 10 and 11 and the transistor 7 are connected between the output terminal of the operational amplifier 8 and the ground. The common connection point of the resistor 9 and the transistor 6 is connected to the non-inverting input terminal of the operational amplifier 8, and the common connection point of the resistors 10 and 11 is connected to the inverting input terminal of the operational amplifier 8. Note that there are cases where a plurality of resistors 11 and transistors 7 are connected in series and in parallel for adjusting temperature characteristics and transistor characteristics, that is, for trimming.
[0005]
The reset circuit 5 compares the reference voltage VBGR with the constant voltage Vcc generated by the constant voltage generation circuit 4, and when the constant voltage Vcc changes to a predetermined level based on turning on or off of the power to the semiconductor sensor 2. This is a circuit for outputting a reset signal (power-on reset voltage VPOR) for turning on / off the reset. The reset signal is supplied to reset a logic circuit or the like (not shown) that processes the A / D converted sensor signal in the semiconductor sensor 2.
[0006]
As shown in FIG. 5, the constant voltage generation circuit 4 is configured as a non-inverting amplifier, and includes a decoder 12, a selector 13, a series resistance circuit 14, an operational amplifier 15, and the like. In the series resistance circuit 14, nine resistors 14a to 14i are connected in series between the output terminal of the operational amplifier 15 and the ground, and each connection point other than both ends is connected via a selector 13 configured as a switch array. It is connected to the inverting input terminal of the operational amplifier 15. A reference voltage VBGR generated by the reference voltage generation circuit 3 is applied to the non-inverting input terminal of the operational amplifier 15. The decoder 12 decodes 3-bit adjustment data supplied from an EPROM 16 to be described later and outputs the data to the selector 13. The selector 13 selects one of the eight switches 13a to 13h according to the decoded signal. Is to be closed selectively.
[0007]
If the reference voltage VBGR is 1.25 V, which is a standard value, the constant voltage generating circuit 4 amplifies the voltage by about four times to generate a constant voltage Vcc of about 5 V. The voltage amplification factor can be adjusted by changing the resistance value of the feedback resistor by switching the switch of the selector 13.
[0008]
The EPROM 16 is composed of 3-bit EPROM memory cells, and the output of the sense amplifier is directly connected to the decoder 12 of the constant voltage generation circuit 4 via a parallel data bus. The data written in the memory cell continues to be output to the constant voltage generation circuit 4 while the EPROM 16 is powered on.
[0009]
When trimming the constant voltage Vcc in the above configuration, the operator measures the value of the reference voltage VBGR using a voltmeter or the like, and sets the amplification factor corresponding to the voltage in the constant voltage generation circuit 4. The adjustment data is written in the EPROM 16. Then, if power is supplied from the outside in order to operate the semiconductor sensor 2, the adjustment data written in the ERPOM 16 is output to the constant voltage generation circuit 4, so that the constant voltage generation circuit 4 amplifies in accordance with the adjustment data. A constant voltage Vcc is generated at a rate.
[0010]
[Problems to be solved by the invention]
By the way, conventionally, in the semiconductor sensor 2 and the microcomputer having such a configuration, the reset-on output threshold value is generally not trimmed in the reset circuit 5. However, for example, depending on the specifications of the semiconductor sensor 2, there may be a case where there is a request to always reset at 5V with respect to a constant voltage Vcc of 5V (for example, operating characteristics as a semiconductor sensor). To guarantee).
[0011]
In this case, assuming that the reset circuit 5 is trimmed to adjust the reset threshold by adopting the same configuration as the constant voltage generation circuit 4 described above, EPROMs are added by the number of bits of the adjustment data. Therefore, an extra circuit area is required. Moreover, since a trimming process is required separately, a problem that the number of work steps increases is expected.
[0012]
The present invention has been made in view of the above circumstances, and an object of the present invention is to adjust the reset threshold value of the reset circuit without requiring additional circuit area and trimming separately. And a setting method for setting adjustment data for adjusting a constant voltage level and a reset-on output threshold value in the circuit device.
[0013]
[Means for Solving the Problems]
According to the circuit device of claim 1, the adjustment data stored in the non-volatile memory is commonly output from the adjustment data output unit to the constant voltage generation circuit and the reset circuit, and the constant voltage generation circuit and the reset circuit are reset. Each circuit is configured such that the amplification factor and the reset-on output threshold can be adjusted based on the adjustment data.
[0014]
That is, in order to output a constant voltage when the reference voltage is higher than the standard level, it is necessary to make the amplification factor of the constant voltage generation circuit smaller than the standard. Further, since the reset circuit outputs a reset signal by comparing the constant voltage with a reference voltage, the reset circuit is reset at the same change level of the constant voltage when the reference voltage is higher than the standard level. Therefore, it is necessary to increase the output threshold value. When the reference voltage is lower than the standard level, the opposite can be said for the magnitude relationship.
[0015]
Therefore, for example, the adjustment data stored in the memory of the adjustment data output unit is such that the data value becomes smaller as the reference voltage generated by the reference voltage generation circuit is lower than the standard level, and the reference voltage is higher than the standard level. In addition to setting the data value to be large, the constant voltage generating circuit is configured so that the amplification factor increases as the adjustment data increases, and the reset-on output threshold value decreases as the adjustment data increases. Configure as follows. Of course, the relationship between the magnitude of the data value of the adjustment data and the level of the amplification factor and the reset-on output threshold value may be reversed.
[0016]
With this configuration, even when the reference voltage fluctuates due to variations in the manufacturing process, etc., the constant voltage generated from the constant voltage generation circuit and the output from the reset circuit by the common adjustment data output from the adjustment data output unit It is possible to simultaneously adjust the threshold value of the reset signal to be appropriate. Further, when the reset circuit needs to be adjusted, an adjustment data output unit is not required, so that the circuit device can be configured in a small size and at a low cost. Further, since it is not necessary to add a trimming process separately, the adjustment can be easily performed.
[0017]
According to the circuit device of claim 2, the reset circuit can also set the reset-off output threshold value simultaneously with the adjustment data output from the adjustment data output unit. For example, based on the adjustment data, the reference voltage If the voltage is lower than the standard level, the reset-off output threshold will be lower, and if the reference voltage is higher than the standard level, the reset-off output threshold will be higher. If you need to do it, you can respond.
[0018]
According to the adjustment data setting method of the circuit device according to claim 3, comprising a reference voltage generation circuit, a constant voltage generation circuit, and an adjustment data output unit configured to output adjustment data in common to these, The constant voltage generation circuit is configured to set a voltage amplification factor based on the adjustment data, and the reset circuit is configured to set a reset-on output threshold based on the adjustment data. When setting adjustment data, the level of the reference voltage generated by the reference voltage generation circuit is measured, and the higher the reference voltage is, the lower the amplification factor and the higher the reset-on output threshold. Set the data value as follows.
[0019]
In this case, for example, the adjustment data is set so that the data value decreases as the reference voltage is lower than the standard level, and the data value increases as the reference voltage is higher than the standard level. The generation circuit and the reset circuit may be configured such that the amplification factor and the reset-on output threshold value are adjusted as described above according to the magnitude relationship between the data values. Of course, the relationship between the magnitude of the data value of the adjustment data and the level of the amplification factor and the reset-on output threshold value may be reversed.
[0020]
By setting the adjustment data in this way, even when the reference voltage fluctuates due to variations in the manufacturing process, the reference voltage generated from the constant voltage generation circuit is generated by the common adjustment data output from the adjustment data output unit. It is possible to properly adjust the reset signal output from the reset circuit, and even if the reset circuit needs to be adjusted, the adjustment data output unit is not required and the trimming process can be performed. Since there is no need to add, adjustment can be easily performed.
[0021]
According to the adjustment data setting method of the circuit device according to claim 4, the reset circuit can simultaneously set the reset-off output threshold value by the adjustment data output from the adjustment data output unit, and based on the adjustment data, As the reference voltage is lower than the standard level, the reset-off output threshold is lower, and as the reference voltage is higher than the standard level, the reset-off output threshold is higher. Therefore, the voltage level for releasing the reset is also adjusted. If you need to do it, you can respond.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment in which the present invention is applied to a circuit device configured as a part of a semiconductor sensor will be described below with reference to FIGS. The same parts as those in FIGS. 3 to 5 are denoted by the same reference numerals and description thereof is omitted, and only different parts will be described below. In FIG. 1, a circuit device 22 configured as a part of the semiconductor sensor 21 is obtained by replacing the power-on reset circuit 5 shown in FIG. 3 with a power-on reset circuit 23. The reset circuit 23 is provided with adjustment data output from an EPROM (adjustment data output unit) 24 instead of the EPROM 16 in common with the constant voltage generation circuit 4.
[0023]
FIG. 2 shows a detailed electrical configuration of the reset circuit 23. The reset circuit 23 includes a comparator 24, a series resistance circuit 25, two sets of selectors 26A and 26B, a decoder 27, and the like. Similar to the decoder 12 included in the constant voltage generation circuit 4, the decoder 27 outputs a decode signal obtained by decoding the 3-bit adjustment data to the selectors 26A and 26B.
[0024]
The series resistance circuit 25 is configured by connecting twelve resistors 25a to 25l in series between the constant voltage Vcc and the ground. The selectors 26A and 26B are each provided with eight switches, and the selectors 26A and 26B are for setting threshold values for reset off and on, respectively. One end of each of the eight switches 26Aa to 26Ah of the selector 26A is connected to each of eight common connection points between the resistors 25a to 25i of the series resistor circuit 25, and one end of each of the eight switches 26Bd to 26Bk of the selector 26B is Are connected to eight common connection points between the resistors 25d to 25l.
[0025]
The other end of the selector 26A that is commonly connected to the switches 26Aa to 26Ah is connected to the non-inverting input terminal of the comparator 24 via the switch 28A, and the other end of the switches 26Bd to 26Bk of the selector 26B. Is connected to the non-inverting input terminal via a switch 28B. A reference voltage VBGR is applied to the inverting input terminal of the comparator 24.
[0026]
The decoder 27 outputs eight decode signals to the selectors 26A and 26B, and these signals are given to the switches 26Aa and 26Bd to the switches to 26Ah and 26Bk, respectively. That is, the threshold value on the reset-off side is determined by selecting eight of the twelve common connection points of the series resistor circuit 25 on the constant voltage Vcc side. The value is determined by selecting eight of the twelve common connection points on the ground side.
[0027]
On / off of the two switches 28A and 28B connected to the non-inverting input terminal of the comparator 24 is switched by a signal output by the Schmitt trigger buffer 29 upon receiving the constant voltage Vcc. That is, the output signal of the buffer 29 is directly given to the switch 28A, and the output signal inverted by the inverter gate 30 is given to the switch 28B. Therefore, the switch 28A is switched from OFF to ON when the constant voltage Vcc rises, and the switch 28B is switched from OFF to ON at the fall.
[0028]
In the above configuration, when the reference voltage VBGR output from the reference voltage generation circuit 3 is the standard value of 1.25 V, the data value of the 3-bit adjustment data (0 to 7) is set to, for example, “3”. . When the data value “3” is given, the constant voltage generation circuit 4 sets the voltage amplification factor to “4” according to the decode signal output from the decoder 12 and outputs the constant voltage Vcc at about 5V. It is like that.
[0029]
As an example, it is assumed that the resistance value of the resistor 14a of the series resistor circuit 14 is 10.25 kΩ, the resistance value of 14i is 3 kΩ, and the resistance values of 14b to 14h are 0.25 kΩ each.
When the switch 13e of the selector 13 is closed by the decode signal output corresponding to the data value “3” and the common connection point of the resistors 14e and 14f is connected to the inverting input terminal of the operational amplifier 15, the non-inverting amplifier The amplification factor is (1 + 11.25 / 3.75 = 4).
[0030]
Further, when the data value “3” is given, the reset circuit 23 outputs a reset-on (sets VPOR to a low level) in accordance with the decode signal output from the decoder 27, for example, a threshold voltage of 4.5V. And reset-off is output (VPOR is set to high level). For example, the threshold voltage is set to 4.75V. That is, the switches 26Ae and 26Bh of the selectors 26A and 26B are turned on by the decode signal, and the respective threshold values are set by the respective voltage dividing resistance ratios.
Other configurations are the same as those shown in FIGS.
[0031]
Next, the operation of this embodiment will be described. When trimming the circuit device 22, the operator measures the level of the reference voltage VBGR output from the reference voltage generation circuit 3 while the semiconductor sensor 21 is powered on. When the reference voltage VBGR is the standard value of 1.25 V, the data value of the 3-bit adjustment data is set to “3”, and the operator writes the data value “3” in the EPROM 24. That is, write data is applied to the data bus in a state where a necessary write voltage is applied to the EPROM 24. In this case, each voltage is determined as described above.
[0032]
When the reference voltage VBGR is lower than the standard value of 1.25 V, the data value of the adjustment data is determined to be “0 to 2” (for example, “2”) according to the value. The operator writes the 3-bit data in the EPROM 24. When the trimming operation is completed and the semiconductor sensor 21 is turned on again, the EPROM 24 outputs the adjustment data written to the 3-bit data bus via the sense amplifier. Then, in the constant voltage generation circuit 4, one switch 13f on the ground side in the selector 13 is closed instead. In this case, since the amplification factor of the non-inverting amplifier is larger than that of the data value “3”, the decrease of the reference voltage VBGR can be compensated by increasing the amplification factor, and a constant voltage Vcc of about 5 V is output. It becomes like this.
[0033]
At this time, in the reset circuit 23, the switches 26Af and 26Bi of the selectors 26A and 26B are closed instead. That is, as the reference voltage VBGR decreases, the divided potential to be compared needs to be decreased. As a result, the reset on and reset off output thresholds are set to approximately 4.5V and 4.75V.
[0034]
On the other hand, when the reference voltage VBGR exceeds the standard value of 1.25 V, the data value of the adjustment data is determined to be “4-7” according to the value (for example, “4”), The operator writes the 3-bit data in the EPROM 24. When the semiconductor sensor 21 is turned on again after the work is completed, in the constant voltage generation circuit 4, one switch 13 d on the power supply side is closed instead of the selector 13. In this case, since the amplification factor of the non-inverting amplifier is smaller than that of the data value “3”, the amplification factor is adjusted by decreasing the amplification factor with respect to the increase of the reference voltage VBGR.
[0035]
At this time, in the reset circuit 23, the switches 26Ad and 26Bg of the selectors 26A and 26B are closed instead. That is, as the reference voltage VBGR increases, the divided potential to be compared needs to be increased. The output threshold values for reset-on and reset-off are set to substantially expected values.
[0036]
As described above, according to the present embodiment, the common adjustment data stored in the EPROM 24 by the trimming operation is applied to the constant voltage generation circuit 4 and the reset circuit 5 of the circuit device 22 configured as a part of the semiconductor sensor 21. Output it. The adjustment data is set so that the data value decreases as the reference voltage VBRG is lower than the standard level, and the data value increases as the reference voltage VBRG is higher than the standard level. The voltage amplification factor is configured to increase with the magnitude of the data value, and the reset circuit 5 is configured to decrease the reset on / off output threshold value with the magnitude of the data value.
[0037]
Therefore, even when the reference voltage VBGR fluctuates due to variations in the manufacturing process, the constant voltage Vcc generated from the constant voltage generation circuit 4 and the reset output from the reset circuit 5 based on the common adjustment data output from the EPROM 24. It is possible to appropriately adjust the threshold value of the signal, and even if the reset circuit 5 needs to be adjusted, an extra EPROM 24 is not required, so that the circuit device 22 is configured in a small size and at a low cost. Can do. For example, in order to form the 3-bit EPROM 24 in the process of 0.8 μm, an area of about 200 μm × 300 μm is required, so that the chip area can be reduced accordingly. In addition, since there is no need to add a trimming process, the adjustment work can be easily performed.
[0038]
Furthermore, according to the present embodiment, the reset circuit 5 can also adjust the reset-off output threshold value simultaneously with the adjustment data, so that it is possible to respond to a request for strictly adjusting the reset release voltage level. can do. Since the series resistance circuit 25 used for adjusting the reset-off output threshold value is shared with the one used on the reset-on side, an increase in circuit area can be suppressed as much as possible.
[0039]
The present invention is not limited to the embodiments described above and illustrated in the drawings, and the following modifications or expansions are possible.
The number of bits of the adjustment data is not limited to “3”, and may be set as appropriate according to individual design.
Further, the resistance value of each resistor may be appropriately changed according to the individual design.
It is also possible to reverse the setting of the adjustment data with respect to the measured reference voltage level, and reverse the settings relating to the magnitude of the amplification factor and the reset signal threshold corresponding to the adjustment data. That is, the data value increases as the reference voltage is lower than the standard level, and the data value decreases as the reference voltage is higher than the standard level. The gain increases as the adjustment data increases in the constant voltage generation circuit. The reset circuit may be configured to be lower, and the reset circuit may be configured such that the reset-on output threshold value increases as the adjustment data increases.
[0040]
The reset circuit may be configured to be able to adjust only the reset ON output threshold.
The nonvolatile memory constituting the adjustment data output unit is not limited to ERPM, but may be EEPROM, one-time PROM, or the like.
You may apply not only to a semiconductor sensor but to CPU, microcomputer, ECU for vehicles, IC for communication, etc. For a CPU that needs to be reset off after a time of several hundreds of milliseconds after the constant voltage Vcc is fixed at the rated value, such as a CPU, an appropriate delay circuit is added to the output side of the reset circuit. And respond.
[Brief description of the drawings]
FIG. 1 is a functional block diagram showing an electrical configuration in one embodiment when the present invention is applied to a semiconductor sensor; FIG. 2 is a diagram showing a detailed electrical configuration of a reset circuit; FIG. 4 is a diagram showing a detailed electrical configuration of the reference voltage generating circuit. FIG. 5 is a diagram showing a detailed electrical configuration of the constant voltage generating circuit.
Reference numeral 3 is a reference voltage generation circuit, 4 is a constant voltage generation circuit, 22 is a circuit device, 23 is a power-on reset circuit, and 24 is an EPROM (adjustment data output unit).

Claims (4)

By comparing the reference voltage and the constant voltage, a reference voltage generation circuit that generates a reference voltage based on a power supply voltage, a constant voltage generation circuit that generates a constant voltage by amplifying the reference voltage, In a circuit device configured to include a reset circuit that outputs a reset signal in response to a level change of the constant voltage based on power on or off,
An adjustment data output unit configured to output adjustment data stored in a nonvolatile memory in common to the constant voltage generation circuit and the reset circuit;
The adjustment data stored in the memory of the adjustment data output unit is set to a value corresponding to the reference voltage level generated by the reference voltage generation circuit,
The constant voltage generation circuit is configured to set an amplification factor based on the adjustment data,
The circuit device, wherein the reset circuit is configured to set a reset-on output threshold value based on the adjustment data. 2. The circuit device according to claim 1, wherein the reset circuit is configured such that a reset-off output threshold value is also set at the same time by adjustment data output from the adjustment data output unit. By comparing the reference voltage and the constant voltage, a reference voltage generation circuit that generates a reference voltage based on a power supply voltage, a constant voltage generation circuit that generates a constant voltage by amplifying the reference voltage, A reset circuit that outputs a reset signal in response to a change in the level of the constant voltage based on power on or off, and adjustment data stored in a nonvolatile memory for the constant voltage generation circuit and the reset circuit are shared. An adjustment data output unit configured to output to
The constant voltage generation circuit is configured to set an amplification factor based on the adjustment data, and the reset circuit is configured to set a reset-on output threshold value based on the adjustment data. A setting method for setting the adjustment data for a configured circuit device,
Measuring the level of the reference voltage generated by the reference voltage generating circuit;
The adjustment data is set so that the amplification factor increases as the reference voltage becomes lower than the standard level and the reset-on output threshold value becomes lower. The amplification factor decreases as the reference voltage becomes higher than the standard level. And adjusting data is set so that the reset-on output threshold value becomes higher. The reset circuit can simultaneously set a reset-off output threshold value based on the adjustment data output from the adjustment data output unit. Based on the adjustment data, as the reference voltage is lower than a standard level, the reset-off output threshold is set. 4. The adjustment data setting method for a circuit device according to claim 3, wherein the reset-off output threshold value increases as the output threshold value decreases and the reference voltage is higher than a standard level.

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