JP2008294850A - Function generator - Google Patents

Abstract

Provided is a function generation circuit which can be operated at a low voltage and can achieve power saving.
A function generation circuit according to the present invention is roughly divided into four blocks, and includes a low temperature sensor 156, a reference voltage circuit 161, a comparator block 126, and an adder 131. Here, the reference voltage (output voltage of the reference voltage circuit 161) of the plurality of comparators 111, 112, and 113 is constant, and the circuit has a difference in the zero-order component of the voltage of the diode 155 that varies with temperature. Thus, the operation range of the comparators 111, 112, and 113 can be made effective. Therefore, a sufficient operating temperature range can be obtained even with a low power supply voltage.
[Selection] Figure 1

Description

  The present invention relates to a function generation circuit that includes a temperature sensor that outputs a voltage corresponding to an ambient temperature and is suitable for temperature compensation of a crystal oscillation frequency. In particular, a temperature-compensated crystal oscillator that uses this function generation circuit has a low voltage. The present invention relates to a function generation circuit that enables operation.

  In recent years, electronic devices are required to be smaller and lighter, and more reliable and accurate. In such a background, many electronic devices use a crystal resonator for generating a clock signal.

  The oscillation frequency of a crystal oscillation circuit using a crystal resonator is required to be highly stable especially with respect to changes in ambient temperature. Among such quartz crystal resonators, the thickness sliding resonator is the most widely used.

  It is known that the oscillation frequency of a crystal oscillation circuit using a thickness-sliding oscillator shows a large change according to the change of the ambient temperature Ta without temperature compensation. For example, the ratio of the oscillation frequency Fa (ambient temperature Ta) to the reference frequency Fr (reference temperature Tr) shows a fluctuation of several tens of ppm in the range of the ambient temperature Ta from −30 ° C. to + 80 ° C. Further, the reference frequency Fr also varies.

  Such fluctuations and variations in the oscillation frequency become a serious problem in high-precision electronic equipment. Therefore, a crystal oscillation circuit with a more stable oscillation frequency is desired. For example, the variation in the frequency ratio Fa / Fr is required to be within 2.5 ppm, and the variation in the reference frequency Fr is required to be within 0.3 ppm.

  Therefore, temperature compensation of the crystal oscillation frequency is usually performed in high-precision electronic equipment. For example, a variable capacitance diode (varicap diode) is connected in series to a crystal resonator, and a compensation voltage corresponding to the ambient temperature Ta is applied to the variable capacitance diode.

  FIG. 8 shows an example of the configuration of a conventional function generation circuit. 8 includes a temperature sensor 212, comparators 213, 214, and 215, and a reference voltage circuit 211. The temperature sensor 212 includes a current source 141 connected to a power source. The end is connected to the anode of the diode group 142 and the positive input terminal of each comparator 213, 214, 215, and the cathode of the diode group 142 is connected to GND, so that the temperature at the input of the comparators 213, 214, 215 A voltage depending on is applied.

  In the reference voltage circuit 211, four variable resistors R1 to R4 are connected in series, and the midpoints VA, VB, and VC are connected to the negative input terminals of the comparators 213, 214, and 215, respectively. Each comparator 213, 214, 215 outputs a current proportional to the voltage difference between the two input sections, and outputs currents IA, IB, IC depending on temperature.

  The current source 240 is connected to the collector base of the NPN transistor 220 and the bases of the NPN transistors 224, 221, 222, and the emitters of the NPN transistors 224, 221, 222 are connected to GND.

  The collectors of the NPN transistors 224, 221, and 222 are connected to the collector and base of the PNP transistor 212 and the collectors of the PNP transistors 217 and 219, respectively. Further, the collectors of the PNP transistors 219, 223, and 217, which are current output units, are commonly connected to the midpoints of the plurality of feedback resistors R5 and R6 connected to the adder 231.

  The adder 231 has one operational amplifier 216, a plurality of feedback resistors R5 and R6 connected between its negative input terminal and output terminal, and a positive input terminal connected to a reference voltage. The currents IA, IB, and IC are temperature-dependent currents. The voltage is converted by the feedback resistors R5 and R6 described above, and a temperature-dependent voltage is output from the adder 231.

  As described above, the conventional function generation circuit needs a circuit that detects temperature variation and converts it into current or voltage, and has a temperature sensor 212 and comparators (primary function generation circuits) 213, 214, and 215. The terminal voltage Vd of the sensor 212 varies linearly depending on the temperature, and output currents IA, IB, and IC of the comparators (linear function generation circuits) 213, 214, and 215 are output depending on the temperature.

FIG. 9 shows the temperature characteristics of the diode in the conventional function generation circuit. When the input dynamic ranges of the comparators 213, 214, and 215 are V _{INL to} V _INH , the temperatures corresponding to the reference voltages VA, VB, and VC are Trl2, Tr, and Trh2.

  FIG. 10 shows the temperature characteristic of the output current of the comparator in the conventional function generation circuit. The output current IA of the comparator 213 has a negative temperature characteristic in the operating voltage range VHA to VLA, and the output current IB of the comparator 214 has a positive temperature characteristic in the operating voltage range VHB to VLB. The current IC has a negative temperature characteristic in the operating voltage range VHC to VLC.

FIG. 11 shows the temperature characteristics of a conventional function generation circuit. Tr is the reference temperature, TL2 indicates the low temperature operating limit, and TH2 indicates the high temperature operating limit. In the conventional function generating circuit, the reference potentials VA, VB and VC of the comparators 213, 214 and 215 are different, the operating temperature range is ΔT2 (= TH2−TL2), and the usable voltage range is ΔV2 (= ΔV1−ΔV3−ΔV4)
It becomes.

FIG. 12 shows a reference voltage adjusting circuit 601 in a conventional function generating circuit. A conventional adjustment circuit 601 is used by changing the resistance ratio of the resistors R1 and R2. That is, the detection voltage Vd is supplied from the temperature sensor 621 to the positive input terminal of the comparator 611, and the reference voltage VA from the middle point of the resistors R1 and R2 of the adjustment circuit 601 is supplied to the negative input terminal of the comparator 611 (for example, patent) Reference 1).
Patent No. 3160299 specification

  Thus, in order to compensate the temperature of the crystal oscillator, a function generation circuit suitable for temperature compensation of the crystal oscillation frequency is used. This function generation circuit generates a control voltage in response to temperature fluctuations. This function generation circuit is required to operate at a low voltage, and it is required to guarantee the operation when the power supply voltage is 1.8 V or less.

  However, the conventional circuit cannot cope with this. In order to cope with this, it is indispensable to widen the operating range of the function generation circuit constituting the temperature compensation circuit.

  Further, as shown in FIG. 8, since the temperature sensor 212 is used for a plurality of comparator circuits 213, 214, and 215 having different temperature compensation ranges, a plurality of reference potentials are required, and an optimum operating range for all temperature compensation circuits. Cannot be set, the power supply voltage of each temperature compensation circuit cannot be lowered.

  The present invention has been made in view of the above-described conventional circumstances, and an object of the present invention is to provide a function generation circuit that can operate at a low voltage and can achieve power saving.

  A function generation circuit according to the present invention is a function generation circuit that generates a function of an operating voltage range depending on an ambient temperature, and is configured to generate a plurality of offset detection voltages in proportion to a difference between the ambient temperature and a reference temperature. A temperature sensor circuit to generate, a reference voltage circuit to generate a reference voltage, a plurality of detections having a predetermined input dynamic range, comparing the plurality of detection voltages with the reference voltage, and corresponding to each operating temperature range A plurality of comparator circuits for generating a current; and an adder for adding the plurality of detection currents supplied from the plurality of comparator circuits to generate a function of the operating voltage range.

  According to the above configuration, the temperature sensor circuit generates a plurality of offset detection voltages that are proportional to the difference between the ambient temperature and the reference temperature. It can be used effectively, and a sufficient operating temperature range can be obtained even with a low power supply voltage. Accordingly, the temperature compensated crystal oscillator can be operated at a low voltage, and power saving of a portable device typified by a cellular phone can be achieved.

  In the function generation circuit according to the present invention, the temperature sensor circuit includes a diode that generates a forward voltage, and a plurality of series-connected resistors that are connected in parallel to the diode and output the plurality of detection voltages. .

  According to the above configuration, a plurality of offset detection voltages that are proportional to the difference between the ambient temperature and the reference temperature are supplied to the comparator circuit from a plurality of resistors connected in series. The conventional temperature range can be secured even if the power supply voltage is lowered.

  In the function generation circuit according to the present invention, the plurality of resistors include a variable resistor that adjusts the detection voltage.

  According to the above configuration, the detection voltage can be adjusted by the variable resistor, and a desired temperature function can be generated.

  Further, in the function generation circuit according to the present invention, the temperature sensor circuit includes a plurality of diode groups that output the plurality of detection voltages from each anode, and each of the plurality of diode groups includes another diode group. The bonding area is different.

  According to the above configuration, each of the plurality of diode groups has a junction area different from that of the other diode groups, so that the zero-order component of the temperature characteristic of the voltage drop can be offset with respect to each of the plurality of diode groups. The input dynamic range of the comparator circuit can be used effectively.

  In the function generating circuit according to the present invention, each of the plurality of diode groups is configured by a transistor having an emitter size different from that of the other diode groups.

  According to the above configuration, each of the plurality of diode groups is composed of transistors having different emitter sizes. Therefore, the zero-order component of the temperature characteristic in the voltage drop of the emitter of each transistor can be offset, and the comparator circuit The input dynamic range can be used effectively.

  In the function generating circuit according to the present invention, each of the plurality of diode groups is constituted by two diodes connected in series.

  According to the above configuration, each of the plurality of diode groups includes two diodes connected in series, so that a plurality of detection voltages offset by a low voltage can be generated.

  In the function generating circuit according to the present invention, each of the plurality of diode groups has a different operating temperature range offset with respect to the input dynamic range of the comparator circuit.

  According to the above configuration, the reference voltage of the comparator circuit can be made common to different operating temperature ranges that are offset, and the operating range of the comparator circuit can be used effectively.

  In addition, the function generation circuit according to the present invention includes a first diode group that generates the reference voltage at a low temperature when the midpoint of the input dynamic range of the comparator is a reference voltage. It includes a second diode group that generates the reference voltage at room temperature and a third diode group that generates the reference voltage at high temperature.

  According to the above configuration, the midpoint of the input dynamic range of the comparator can be used as a common reference voltage for the low temperature, normal temperature, and high temperature ranges, and the operation range of the comparator circuit can be used effectively. .

  In the function generating circuit according to the present invention, the plurality of comparator circuits are supplied with a first detection voltage from the first diode group and have a first detection current having a negative characteristic in a first operating temperature range. And a second comparator circuit that outputs a second detection current having a positive characteristic in the second operating temperature range, supplied with a second detection voltage from the second diode group. And a third comparator circuit which is supplied with a third detection voltage from the third diode group and outputs a third detection current having a negative characteristic in the third operating temperature range.

  According to the above configuration, a plurality of comparator circuits having a common reference voltage can generate a detection current having a negative characteristic in the low temperature range, a positive characteristic in the normal temperature range, and a negative characteristic in the high temperature range. it can.

  Further, in the function generation circuit according to the present invention, the adder adds the first to third detection currents output from the first to third comparator circuits, and the first operation temperature range. A function voltage having a negative characteristic, having a positive characteristic in the second operating temperature range, and having a negative characteristic in the third operating temperature range is output.

  According to the above configuration, a plurality of comparator circuits having a common reference voltage can generate a function voltage having a negative characteristic in the low temperature range, a positive characteristic in the normal temperature range, and a negative characteristic in the high temperature range. it can.

  In the function generation circuit according to the present invention, the temperature sensor circuit includes a first adjustment circuit that is connected in parallel to each or any of the plurality of diode groups and adjusts the junction area.

  According to the above configuration, the temperature characteristic of the diode can be adjusted by providing the first adjustment circuit that adjusts the junction area of the diode.

  In the function generation circuit according to the present invention, the first adjustment circuit has a configuration in which an adjustment diode group equivalent to the diode group and a switch are connected in series.

  According to the above configuration, since the adjustment diode group equivalent to the diode group and the switch are connected in series, the temperature characteristics of the diode can be easily adjusted.

  In the function generation circuit according to the present invention, the reference voltage circuit includes a second adjustment circuit that adjusts the reference voltage.

  According to the above configuration, since the second adjustment circuit for adjusting the reference voltage is provided, the reference voltage of the reference voltage circuit can be adjusted with high accuracy.

  In the function generation circuit according to the present invention, the second adjustment circuit includes a variable resistor connected to a power supply potential and / or a ground potential.

  According to the above configuration, since the variable resistor connected to the power supply potential and / or the ground potential is included, the reference voltage of the reference voltage circuit can be easily adjusted.

  In the function generation circuit according to the present invention, the temperature sensor circuit includes a plurality of temperature detection circuits that output the plurality of detection voltages, and each of the plurality of temperature detection circuits includes a diode that generates a forward voltage. And a plurality of resistors connected in series to the diode and outputting the detection voltage.

  According to the above configuration, a plurality of offset detection voltages that are proportional to the difference between the ambient temperature and the reference temperature are supplied to the comparator circuit from a plurality of resistors connected in series. The conventional temperature range can be secured even if the power supply voltage is lowered.

  In the function generation circuit according to the present invention, the plurality of resistors include a variable resistor that adjusts the detection voltage.

  According to the above configuration, the detection voltage can be adjusted by the variable resistor, and a desired temperature function can be generated.

  According to the function generating circuit of the present invention, the temperature sensor circuit generates a plurality of offset detection voltages that are proportional to the difference between the ambient temperature and the reference temperature. The operating range of the circuit can be used effectively, and a sufficient operating temperature range can be obtained even with a low power supply voltage.

(First embodiment)
FIG. 1 shows an example of a function generation circuit according to an embodiment of the present invention. This function generation circuit generates a function of an operating voltage range depending on the ambient temperature, and is composed of four blocks: a temperature sensor 156, a reference voltage circuit 161, a comparator 126, and an adder 131.

  The temperature sensor 156 generates a plurality of detection voltages offset in proportion to the difference between the ambient temperature and the reference temperature. The temperature sensor 156 connects the current source 141 to the collector and base of the PNP transistor 142, and the emitter thereof is connected to the voltage source through the resistor 150 to become the parent of the current mirror circuit, and the collector and base are connected to the PNP transistors 143 to 143. 146 is connected to the base. The emitters of the PNP transistors 143 to 146 are connected to a power source via resistors 151 to 154, respectively. The collector of the PNP transistor 143 is connected to the anode of the diode 155 and the resistor R1, and the cathode of the diode 155 is connected to GND. The other end of the resistor R1 is connected to the resistor R2 and the base of the PNP transistor 149. The other end of the resistor R2 is connected to the resistor R3 and the base of the PNP transistor 148. The other end of the resistor R3 is connected to the resistor R4 and the base of the PNP transistor 147. The other end of the resistor R4 is connected to GND. The emitters of the PNP transistors 147, 148, and 149 are connected to the collectors of the PNP transistors 144, 145, and 146, respectively, and the collectors of the PNP transistors 147, 148, and 149 are connected to the GND.

  The reference voltage circuit 161 generates a reference voltage, connects two resistors in series between the power supply and GND, and outputs the voltage at the midpoint as the reference voltage.

  The comparator block 126 includes three comparators 111, 112, and 113. Each of the comparators 111 to 113 has a predetermined input dynamic range, compares a plurality of detection voltages generated by the temperature sensor 156 with the reference voltage generated by the reference voltage circuit 161, and corresponds to each operating temperature range. The detection current to be generated is generated. The negative input terminals of the comparators 111 to 113 are connected to the midpoint of the reference voltage circuit 161, respectively. The positive input terminals of the comparators 111 to 113 are connected to the emitters of the PNP transistors 147, 148, and 149, respectively, and a voltage depending on the ambient temperature is applied. As a result, currents proportional to the voltage difference between the two input units are output from the respective comparators 111, 112, and 113, and currents IA, IB, and IC depending on the ambient temperature are output.

  The constant current source 140 included in the comparator block 126 is connected to the collector / base of the NPN transistor 120 and the bases of the NPN transistors 124, 121, 122, and the emitters of the NPN transistors 124, 121, 122 are connected to GND. The The collector of the NPN transistor 124 is connected to the collector and base of the PNP transistor 125, and the collectors of the NPN transistors 121 and 122 are connected to the collectors of the PNP transistors 117 and 119. Further, the collectors of the PNP transistors 119, 123, and 117, which are current output units, are connected in common to the middle points of the plurality of feedback resistors R5 and R6 connected to the adder 131.

  The adder 131 adds the currents IA, IB, and IC supplied from the comparators 111 to 113, and generates a function of the operating voltage range depending on the ambient temperature. The adder 131 includes one operational amplifier 117 and a plurality of feedback resistors R5 and R6 connected between its negative input terminal and output terminal. The positive input terminal of the operational amplifier 117 is connected to the reference voltage. . The adder 131 converts the currents IA, IB, and IC output from the comparators 111 to 113 by the feedback resistors R5 and R6, and outputs a voltage depending on the ambient temperature.

  As described above, the temperature sensor 156 of the function generation circuit according to the present embodiment includes the diode 155 that generates the forward voltage, and the plurality of series-connected resistors R1 that are connected in parallel to the diode 155 and output a plurality of detection voltages. , R2, R3, and R4, a plurality of resistors R1, R2, R3, and R4 connected in series are proportional to the difference between the ambient temperature and the reference temperature, and a plurality of offset detection voltages are compared with the comparators 111, 112, 113 can be supplied, the operating range of the comparators 111, 112, 113 can be used effectively, and the conventional temperature range can be secured even if the power supply voltage is lowered.

(Second Embodiment)
FIG. 2 is an example of a function generation circuit according to the present invention. The function generation circuit includes a plurality of temperature sensors 325, 326, 327, comparators 322, 323, 324, a reference voltage circuit 321 and a current source 341 of a current mirror circuit.

  The constant current source 341 is connected to the collector base of the PNP transistor 342 and the bases of the transistors 343, 344, and 345, and the emitters of the transistors 343, 344, and 345 are connected to voltage sources via resistors 352, 353, and 354, respectively. Connected.

  Further, the collectors of the PNP transistors 343, 344, and 345 are connected to the anodes of the diode groups 330, 331, and 332, respectively, and are connected to the positive input portions of the comparators 322, 323, and 324, and a temperature-dependent voltage is applied. The Further, the cathodes of the respective diode groups 330, 331, and 332 are connected to GND. Negative input portions of the comparators 322, 323, and 324 are connected to the reference voltage circuit 321. As a result, currents proportional to the voltage difference between the two input units are output from the respective comparators 322, 323, and 324, and currents IA, IB, and IC that depend on temperature are output.

  The diode groups 330, 331, and 332 of the temperature sensors 325, 326, and 327 are N stages (two stages in the figure), respectively. When the junction area of the diode group 331 is used as a reference, the junction area of the diode group 330 is The junction area of the diode group 331 is m times, and the junction area of the diode group 332 is 1 / m times that of the diode group 331. These diode groups 330, 331, and 332 can also be configured by transistors. In this case, the emitter sizes of the diode group 330 and the diode group 332 are respectively set to m times and 1 /, based on the emitter size of the diode group 331. m times.

When the emitter size is doubled, the voltage drop is reduced by about 18 mV, and when the emitter size is doubled, the voltage drop is increased by about 18 mV. Therefore, the temperature sensor (TS _A ) 325 generates a detection voltage for low temperature, The temperature sensor (TS _B ) 326 generates a detection voltage for normal temperature, and the temperature sensor (TS _C ) 327 generates a detection voltage for high temperature.

  As described above, since the junction areas (emitter sizes) of the diode groups 330, 331, and 332 of the temperature sensors 325, 326, and 327 are different, the temperature characteristics of the voltage at the anode portion of each of the diode groups 330, 331, and 332 are as follows. As shown in FIG. 3, a difference occurs in the reference temperature.

FIG. 3 is a diagram showing the relationship between the temperature characteristics of the diode group, the input dynamic range, and the reference voltage, where the horizontal axis is temperature and the vertical axis is voltage. That is, if the input dynamic range of the comparators 322, 323, and 324 is V _{INL to} V _INH and the middle point is the V reference (optimum point), the temperatures corresponding to the V reference are Trl1 (for low temperature) and Tr (for room temperature). ), Trh1 (for high temperature).

  For this reason, the output current of each comparator 322, 323, 324 has a temperature characteristic as shown in FIG. 4, and the operating temperature characteristic of the output voltage of the adder 131 to which the outputs of the comparators 322, 323, 324 are connected is As shown in FIG. Here, Tr is a reference temperature, TL1 indicates a low temperature operating limit, and TH1 indicates a high temperature operating limit.

In the conventional function generation circuit (see FIG. 8), the reference potentials VA, VB, and VC (see FIG. 9) of the comparators 213, 214, and 215 are different, and the operation range is the same difference under the same power supply voltage. It will be disadvantageous. Therefore, each operating temperature range is always ΔT1 (= TH1−TL
1)> ΔT2 (= TH2-TL2: see FIG. 11). In addition, the usable voltage range must be Δ
V1> ΔV2 (= ΔV1−ΔV3−ΔV4). Therefore, the function generation circuit according to the present embodiment can ensure the conventional temperature range even when the power supply voltage is lowered.

  As described above, according to the function generation circuit of this embodiment, the temperature sensors 325, 326, and 327 include the plurality of diode groups 330, 331, and 332 that output a plurality of detection voltages from the respective anodes, and the plurality of diode groups. Since each of 330, 331, and 332 has a different junction area from the other diode groups, it is possible to give an offset to the zero-order component of the temperature characteristic of the voltage drop with respect to each of the plurality of diode groups 330, 331, and 332 The input dynamic range of the comparators 322, 323, and 324 can be used effectively.

  FIG. 6 shows an example of a method for adjusting each temperature sensor 649. In the temperature sensor 649, it is necessary to adjust the voltage Vd at the reference temperature. At this time, as shown in this circuit format, a plurality of diodes are selected by a switch so as to adjust to an appropriate voltage Vd.

  That is, 2N adjustment circuits in which diodes and switches are connected in series are connected in parallel, and the switches are turned on in order, so that the diode emitter size is 1 ×, 2 ×, 2 (N−1) ×, and 2N times. The voltage Vd can be adjusted. If the reference voltage VA is adjusted by a variable resistor of the reference voltage 648, the temperature characteristic can be adjusted with higher accuracy.

  In the conventional function generation circuit, as shown in FIG. 12, only the one that changes the resistance ratio of the resistors R1 and R2 is used to adjust the reference voltage. However, one adjustment is necessary when using a plurality of comparators. Although it has been difficult to accurately adjust all the comparators in the circuit 601, it is possible to adjust accurately by using the adjusting circuit according to this embodiment. Therefore, when the same temperature range as that of the conventional function generation circuit is to be ensured, the power supply voltage can be lowered from that of the conventional function generation circuit, and the low voltage, which is the object of the present invention, can be realized.

(Third embodiment)
FIG. 7 shows an example of the configuration of the function generation circuit according to the present invention, in which the form of the temperature detection circuits 431, 432, and 433 is partially changed from the second embodiment shown in FIG. Without changing the size of each of the diodes 411, 412 and 413 of the temperature detection circuits 431, 432 and 433, the voltage Vda, Vdb and Vdc differ depending on the resistance ratio of R1 and R2, R3 and R4, and R5 and R6. Has occurred. Thereby, the operation range becomes the same as that shown in FIG.

  According to the function generation circuit of this embodiment, each of the temperature detection circuits 431, 432, and 433 is connected in parallel to the diodes 411, 412, and 413 that generate the forward voltage, and the diodes 411, 412, and 413, and detects them. Since a plurality of resistors R1, R2, R3, R4, R5, and R6 connected in series for outputting a voltage are provided, the ambient temperature and the plurality of resistors R1, R2, R3, R4, R5, and R6 connected in series are A plurality of offset detection voltages that are proportional to the difference from the reference temperature can be supplied to the comparators 441, 442, and 443, and the operation range of the comparators 441, 442, and 443 can be effectively used to reduce the power supply voltage. In addition, the conventional temperature range can be secured.

  As described above, the function generation circuit according to the present invention enables low-voltage operation, and thus can save power, and thus is useful for portable devices such as mobile phones.

The figure which shows an example of the function generator circuit which concerns on the 1st Embodiment of this invention The figure which shows an example of the function generator circuit which concerns on the 2nd Embodiment of this invention The figure which shows an example of the operating range of the temperature sensor circuit which concerns on the 2nd Embodiment of this invention The figure which shows an example of the temperature characteristic of the comparator output current using the temperature sensor circuit which concerns on the 2nd Embodiment of this invention. The figure which shows an example of the temperature characteristic of the function generator circuit which concerns on the 2nd Embodiment of this invention The figure which shows an example of the adjustment circuit of the temperature sensor which concerns on the 2nd Embodiment of this invention The figure which shows an example of the function generator circuit which concerns on the 3rd Embodiment of this invention The figure which shows an example of the conventional function generation circuit The figure which shows an example of the operation range of the conventional temperature sensor circuit The figure which shows an example of the temperature characteristic of the comparator output current using the conventional temperature sensor circuit The figure which shows an example of the temperature characteristic of the conventional function generation circuit The figure which shows an example of the adjustment circuit of the conventional temperature sensor

Explanation of symbols

111, 112, 113, 322, 323, 324, 441, 442, 443, 647 Comparator 117 Operational amplifier 126 Comparator block 131 Adder 140, 141, 341 Current source 142, 143, 144, 145, 146 PNP transistor 150, 151 152,153,154 Resistance 156,325,326,327,649 Temperature sensor 161,321,444,648 Reference voltage circuit 330,331,332 Diode group 411,412,413 Diode 431,432,433 Temperature detection circuit

Claims (16)

A function generation circuit for generating a function of an operating voltage range depending on an ambient temperature,
A temperature sensor circuit that generates a plurality of offset detection voltages proportional to a difference between the ambient temperature and a reference temperature;
A reference voltage circuit for generating a reference voltage;
A plurality of comparator circuits having a predetermined input dynamic range, comparing the plurality of detection voltages with the reference voltage, and generating a plurality of detection currents corresponding to each operating temperature range;
An adder for adding the plurality of detection currents supplied from the plurality of comparator circuits to generate a function of the operating voltage range;
A function generation circuit comprising: The function generation circuit according to claim 1,
The temperature sensor circuit includes a diode that generates a forward voltage;
A plurality of resistors connected in parallel to the diode and outputting the plurality of detection voltages;
A function generation circuit comprising: A function generation circuit according to claim 2,
The function generating circuit, wherein the plurality of resistors include a variable resistor for adjusting the detection voltage. The function generation circuit according to claim 1,
The temperature sensor circuit includes a plurality of diode groups that output the plurality of detection voltages from each anode,
Each of the plurality of diode groups has a junction area different from that of the other diode groups. A function generation circuit according to claim 4,
Each of the plurality of diode groups is a function generating circuit configured by transistors having emitter sizes different from those of other diode groups. A function generation circuit according to claim 4,
Each of the plurality of diode groups is a function generating circuit configured by two diodes connected in series. A function generation circuit according to claim 4,
Each of the plurality of diode groups has a different operating temperature range that is offset with respect to the input dynamic range of the comparator circuit. A function generation circuit according to claim 4,
When the midpoint of the input dynamic range of the comparator is used as a reference voltage,
The plurality of diode groups are:
A first diode group for generating the reference voltage at a low temperature;
A second diode group for generating the reference voltage at room temperature;
A third diode group for generating the reference voltage at a high temperature;
A function generation circuit that includes: A function generation circuit according to claim 8,
The plurality of comparator circuits include:
A first comparator circuit which is supplied with a first detection voltage from the first diode group and outputs a first detection current having a negative characteristic in a first operating temperature range;
A second comparator circuit which is supplied with a second detection voltage from the second diode group and outputs a second detection current having a positive characteristic in a second operating temperature range;
A third comparator circuit which is supplied with a third detection voltage from the third diode group and outputs a third detection current having a negative characteristic in a third operating temperature range;
A function generation circuit comprising: A function generating circuit according to claim 9, wherein
The adder adds the first to third detection currents output from the first to third comparator circuits, has a negative characteristic in the first operating temperature range, and performs the second operation. A function generating circuit which outputs a function voltage having a positive characteristic in a temperature range and having a negative characteristic in the third operating temperature range. A function generation circuit according to claim 4,
The temperature sensor circuit is a function generation circuit including a first adjustment circuit that is connected in parallel to each or any of the plurality of diode groups and adjusts the junction area. A function generation circuit according to claim 11, wherein
The first adjustment circuit is a function generation circuit having a configuration in which an adjustment diode group equivalent to the diode group and a switch are connected in series. A function generation circuit according to claim 4,
The reference voltage circuit includes a second adjustment circuit that adjusts the reference voltage. A function generation circuit according to claim 13,
The function adjustment circuit, wherein the second adjustment circuit includes a variable resistor connected to a power supply potential and / or a ground potential. The function generation circuit according to claim 1,
The temperature sensor circuit includes a plurality of temperature detection circuits that output the plurality of detection voltages,
Each of the plurality of temperature detection circuits includes:
A diode that generates a forward voltage; and
A plurality of resistors connected in parallel to the diode and outputting the detection voltage; and
A function generation circuit comprising: The function generation circuit according to claim 15, wherein
The function generating circuit, wherein the plurality of resistors include a variable resistor for adjusting the detection voltage.

Images