JP4753531B2 - Temperature detection circuit in semiconductor integrated circuit - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a temperature detection circuit applied to a temperature detection circuit, a thermometer, and the like.
[0002]
[Prior art]
When a large current flows through the semiconductor integrated circuit or when the ambient temperature rises and the semiconductor integrated circuit becomes high temperature, the semiconductor integrated circuit is destroyed. In order to prevent this destruction, it is necessary to detect the temperature and slow down the operation speed of the semiconductor integrated circuit or stop the operation itself when the temperature becomes high. A circuit with such a function compares the output of a PTAT voltage generation circuit that generates a PTAT (poportional-to-absolute-Temperature) voltage proportional to absolute temperature and a reference voltage generation circuit that generates a reference voltage. It consists of a comparison circuit for processing.
[0003]
The reference voltage is adjusted in advance to the PTAT voltage at the temperature T at which the semiconductor integrated circuit is to be controlled. When the temperature rises and the PTAT voltage from the PTAT voltage generation circuit exceeds the reference voltage, the comparison circuit Activate signals that control the operation of the circuit.
[0004]
If the accuracy of the PTAT voltage and reference voltage is poor, the control signal becomes active even if the semiconductor integrated circuit is within the operating temperature range, and the operation of the semiconductor integrated circuit is controlled. In spite of exceeding, the control signal does not become active and the semiconductor circuit is destroyed. Therefore, in this type of temperature protection circuit, the accuracy of both the PTAT voltage and the reference voltage is important.
[0005]
Conventionally, the temperature range in which the PTAT voltage can be accurately extracted is narrow, the temperature coefficient of the PTAT voltage cannot be freely set, and it is not easy to create a reference voltage having no temperature coefficient.
[0006]
Therefore, as a solution to the above-mentioned problem, Japanese Patent Application Laid-Open No. 2001-284464 (Patent Document 1) applies a “voltage generation circuit using a field effect transistor and a reference voltage source circuit”, which applies “the principle of work function difference of gates” Is known (Patent Document 1).
[0007]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 2001-284464 "Voltage generation circuit and reference voltage source circuit using field effect transistor" (Claim 1, FIG. 6)
[0008]
[Problems to be solved by the invention]
However, although the thing of patent document 1 came to be able to operate stably at high temperature, there existed a subject that it did not operate | move by a low voltage.
[0009]
An object of the present invention is to obtain a temperature detection circuit capable of high-temperature operation and capable of high-precision and low-voltage operation.
[0010]
[Means for Solving the Problems]
The temperature detection circuit according to the first aspect of the present invention does not have a temperature coefficient and a first voltage source circuit that outputs a voltage having a positive or negative temperature coefficient. A first and a second each proportional to the voltage generated Reference voltage Respectively A second voltage source circuit for outputting, and a subtracting circuit for subtracting a reference voltage having no temperature coefficient from the second voltage source circuit from an output voltage having a positive or negative temperature coefficient from the first voltage source circuit And the output voltage from the subtraction circuit and The first It comprises a comparison circuit that compares reference voltages.
[0011]
The second voltage source circuit includes a circuit that generates a voltage having a positive or negative temperature coefficient, and an amplifier circuit that has an input offset voltage having a temperature coefficient opposite to the temperature coefficient of the voltage. Alternatively, a voltage having a negative temperature coefficient is input to the amplifier circuit, and the output of the amplifier circuit is used as a reference voltage.
[0012]
The temperature detection circuit according to the second aspect of the present invention includes a first voltage source circuit that outputs a voltage having a positive or negative temperature coefficient, and a first voltage source circuit that has a positive or negative temperature coefficient generated therein, Adds the voltage from the voltage source circuit and has no temperature coefficient A first and a second each proportional to the voltage generated Reference voltage Respectively A second voltage source circuit for outputting, and an output voltage having a temperature coefficient from the first voltage source circuit. Second Reference voltage Decrease Subtracting circuit to calculate, output voltage from the subtracting circuit and the First It comprises a comparison circuit that compares the reference voltage.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
A “temperature detection circuit” that applies the “principle of work function of gate” disclosed in Patent Document 1 has been proposed (Japanese Patent Application 2002-81448). As shown in FIG. 19, this temperature detection circuit has a PTAT voltage Vptat having a positive temperature coefficient from the first voltage source circuit, and Tvptat (= (R1 + R2 + R3) converted by resistors R1, R2, and R5. / R3 * Vptat).
[0014]
A voltage Vpn (not shown) having a negative temperature coefficient generated by the second voltage source circuit and Vptat ′ (= (R2 + R3) / R3 * Vptat) obtained by converting Vptat at a predetermined ratio. A reference voltage Vref having no temperature coefficient generated by addition is generated, and Tvref (= R6 / (R5 + R6) * Vref) obtained by converting this Vref by resistors R5 and R6 is generated.
[0015]
As shown in FIG. 20, the comparison circuit detects whether or not the temperature T has been reached by comparing a voltage Tvptat having a positive temperature coefficient with a reference voltage Tvref having no temperature coefficient. Since the principle of the work function difference of the gate is applied to the first and second voltage source circuits that generate the voltage having the positive temperature coefficient and the voltage having the negative temperature coefficient, the voltage having the positive or negative temperature coefficient is applied. It can be accurately generated up to the operating limit temperature of the semiconductor. Further, since the temperature coefficient can be adjusted by simple resistance division, it is possible to obtain a voltage according to the purpose, such as a high-accuracy version with a large temperature coefficient or a low voltage version with a small temperature coefficient. Further, since the reference voltage is generated by adding the voltage having the positive temperature coefficient and the voltage having the negative temperature coefficient, the reference voltage can be generated with high accuracy up to the semiconductor operation limit temperature.
[0016]
As an application of FIG. 19, a circuit for detecting a plurality of temperatures is conceivable. An example is shown in FIG. FIG. 21 shows a circuit for detecting two types of temperatures. Tvref1 and Tvref2 are generated by the second voltage source circuit, and Tvref1, Tvref2 and Tvptat from the first voltage source circuit are compared by the first comparison circuit and the second comparison circuit, respectively. As shown in FIG. 22, the operation of this circuit detects the temperature T1 at Tvef1 and the temperature T2 at Tvref2. For example, if the operation speed of the semiconductor integrated circuit is slowed down at the temperature T1 and the operation of the semiconductor integrated circuit is stopped at the temperature T2, more accurate control is possible.
[0017]
However, in the temperature detection circuit of FIG. 19, if the temperature coefficient of Tvptat is increased from Tvptat1 to Tvptat2 in order to obtain a high-accuracy version as shown in FIG. There were drawbacks. Also in the circuit of FIG. 21, when the temperature coefficient of Tvptat is increased from Tvptat1 to Tvptat2 in order to obtain a high-accuracy version, the problem remains that the operating voltage increases and low voltage operation cannot be performed.
[0018]
(Embodiment 1)
FIG. 1 is a schematic block diagram showing Embodiment 1 of the present invention. As shown in FIG. 1, a first voltage source circuit that generates Svptat, which is a PTAT voltage having a positive or negative temperature coefficient in proportion to an absolute temperature, a first reference voltage Vref having no temperature coefficient, and a first voltage A second voltage source circuit for generating a second reference voltage Tvref and a third reference voltage Svref, an output Svptat from the first voltage source circuit and a third reference voltage Svref are differentially amplified, and the result is Tvptat And a comparison circuit that compares the Tvptat with the second reference voltage Tvref and outputs the comparison result Tout. As the second voltage source circuit, a voltage source circuit applying the principle of the work function difference of the gate disclosed in Patent Document 1 described above is employed.
[0019]
FIG. 2 shows a circuit diagram of Example 1 based on Embodiment 1, and this circuit is constructed on an n-type substrate. The first voltage source circuit is composed of an NPN transistor Tr1. By connecting the base of this Tr1 to the collector and connecting the emitter to the GND power source, Svptat is output from the collector. This NPN transistor can be formed by using a p-well in an n-type substrate as a base and using n-type diffusion in the p-well as an emitter and a collector.
[0020]
The second voltage source circuit includes a first reference voltage source circuit and a second reference voltage source circuit. The first reference voltage source circuit includes n-type channel field effect transistors (hereinafter simply referred to as n-type transistors) M1, M2, and M3 and resistors R2 and R3. The n-type transistors M1 and M2 have the same substrate and channel-doped impurity concentration, are formed in the p-well of the n-type substrate, and the substrate potential of each transistor is equal to the source potential. The n-type transistor M1 has a high-concentration n-type gate, the n-type transistor M2 has a low-concentration n-type gate, and the ratio S = W / L of the channel width W and the channel length L is equal to each other.
[0021]
The n-type transistors M1 and M2, which differ only in the impurity concentration of the gate, are connected in series, the n-type transistor M1 serves as a constant current source with the gate connected to the source, and the n-type transistor M2 includes the n-type transistor M3 and the resistor R2. And a gate potential is applied by a source follower circuit comprising a resistor R3. Vptat is output from the connection point between the gate of the n-type transistor M2 and the resistors R2 and R3, and Vptat ′ is output from the connection point between the source of the n-type transistor M3 and the resistor R2.
[0022]
The second reference voltage source circuit includes p-type transistors M4, M5, and M8, n-type transistors M6 and M7, and resistors R4, R5, and R6. The n-type transistors M6 and M7 have the same substrate and channel-doped impurity concentration, are formed in the p-well of the n-type substrate, and the substrate potential of each transistor is equal to the source potential. The n-type transistor M6 has a high-concentration n-type gate, the n-type transistor M7 has a high-concentration p-type gate, and the ratio S = W / L of the channel width W and the channel length L is equal to each other.
[0023]
The n-type transistors M6 and M7 differing only in the gate conductivity type are input transistors of the differential amplifier, and the p-type transistors M4 and M5 constitute a current mirror circuit. The output Vptat ′ from the first reference voltage source circuit is input to the gate of the n-type transistor M6, and the drain of the p-type transistor M8, that is, the output of this differential amplifier, is input to the gate of the n-type transistor M7. A certain first reference voltage Vref is input. The first reference voltage Vref is divided by the resistors R4, R5, and R6, the second reference voltage Tvref from the connection point of the resistors R4 and R5, and the third reference from the connection point of the resistors R5 and R6. The voltage Svref is output.
[0024]
Note that the transistor M2 having an n-type transistor having a low-concentration n-type gate and the transistor 7 having an n-type transistor having a high-concentration p-type gate are peculiar as elements. Surrounded by a square. The same applies to the following drawings.
[0025]
The subtracting circuit includes operational amplifiers OP1 and OP2 and resistors R7, R8, R9, and R10. The output Svref ′ of the operational amplifier OP1 is input to the inverting input terminal of the operational amplifier OP1, and the third reference voltage Svref is input to the non-inverting input terminal. The output Svref ′ of the operational amplifier OP1 is input to the inverting input terminal of the operational amplifier OP2 through the resistor R7, and further, the output Tvptat of the operational amplifier OP1 is input through the resistor R8. The output Svptat from the first voltage source circuit is input to the non-inverting input terminal of the operational amplifier OP2 via the resistor R9, and is further connected to the GND power supply via the resistor R10.
[0026]
The fourth comparison circuit is composed of an operational amplifier OP3. The second reference voltage Tvref is input to the inverting input terminal of the operational amplifier OP3, and the output Tvptat from the subtraction circuit is input to the non-inverting input terminal. The output of the operational amplifier OP3 becomes Tout.
[0027]
Next, the operation of the circuit of FIG. 2 will be described using the output characteristic diagram of FIG. First, since the first voltage source circuit uses diode connection of an NPN transistor, Svptat, which is a PTAT voltage having a negative temperature coefficient, is output as shown in FIG.
[0028]
Next, the second voltage source circuit will be described. First, in the first reference voltage source circuit, an n-type transistor M1 having a gate connected to a source is used as a constant current source, and n-type transistors M1 and M2 are connected in series. Since the same current flows in these n-type transistors M1 and M2 having the same conductivity type and different gates only in impurity concentration, as described in Patent Document 1, the source-gate voltage of the n-type transistor M1 is The potential difference from the source-gate voltage of the n-type transistor M2 becomes a PTAT voltage having a positive temperature coefficient.
[0029]
Here, since the gate of the n-type transistor M1 is connected to the source, there is no potential difference between the source and the gate, and the source-gate voltage of the n-type transistor M2 eventually becomes the PTAT voltage. When this voltage is Vptat, Vptat ′, which is the output of the first reference voltage source circuit, is
Vptat '= (R2 + R3) / R3 * Vptat (1)
It becomes. Vptat is converted by the ratio shown in equation (1) to generate Vptat ′. Since Vptat originally has a positive temperature coefficient, Vptat ′ also has a positive temperature coefficient. The resistance names R2, R3, etc. indicate the resistance values in the equations.
[0030]
Next, in the second reference voltage source circuit, p-type transistors M4 and M5 constitute a current mirror circuit, and n-type transistors M6 and M7 having different conductivity type gates are used as input transistors of the differential amplifier. Therefore, the same current flows through the n-type transistors M6 and M7. Since a feedback loop is formed between the differential amplifier and the p-type transistor M8, as described in Patent Document 1, the source-gate voltage of the n-type transistor M6 and the n-type transistor M7 Between the source-gate voltage, there is an input offset of Vpn having a negative temperature coefficient.
[0031]
Therefore, when Vptat ′ is applied from the first voltage source circuit to the gate of the n-type transistor M6, a voltage obtained by adding Vpnat to Vptat ′ is generated between the source and gate of the n-type transistor M7. This voltage is obtained by adding Vptat ′ obtained by converting Vptat having a positive temperature coefficient by a predetermined ratio and Vpn having a negative temperature coefficient, so that a first reference voltage Vref having no temperature characteristic is obtained. The second reference voltage Tvref and the third reference voltage Svref, which are output voltages of the second voltage source circuit, are obtained by dividing the first reference voltage Vref by the resistors R4, R5, and R6. Respectively,
Vref = (R2 + R3) / R3 * Vptat + Vpn = Vptat ′ + Vpn (2)
Tvref = (R5 + R6) / (R4 + R5 + R6) * Vref (3)
Svref = R6 / (R4 + R5 + R6) * Vref (4)
It becomes.
[0032]
FIG. 3B shows the temperature characteristics of these voltages. Vptat ′ having a positive temperature coefficient from the first reference voltage source circuit and Vpn having a negative temperature coefficient from the second reference voltage source circuit are added to generate Vref which is the first reference voltage. ing. This Vref is converted by the ratio shown in equations (3) and (4) to generate the second reference voltage Tvref and the third reference voltage Svref. Since Vref originally has no temperature coefficient, neither Tvref nor Svref has a temperature coefficient.
[0033]
Next, the subtracting circuit includes operational amplifiers OP1 and OP2 and resistors R7, R8, R9, and R10. First, since the operational amplifier OP1 is used as a voltage follower, a voltage having the same potential as that of the third reference power supply Svref that is an input to the non-inverting input terminal can be obtained as an output Svref ′. In the operational amplifier OP1, a current path is formed between the output Tvptat of the operational amplifier OP2 and the third reference voltage Svref through the resistors R8, R7, and R6, and each reference voltage output from the second voltage source circuit varies. It is provided to prevent this from happening.
[0034]
Next, the operational amplifier OP2 is used as a differential amplifier. Therefore, the output Tvptat of the operational amplifier OP2 is, as is well known, by setting R7 = R9 and R8 = R10,
Tvptat = (R8 / R7) * (Svptat−Svref ′) (5)
It becomes. FIG. 3C shows the temperature characteristics of these voltages. When the temperature is lower than T1, Tvptat is equal to (5) because Svptat> Svref. When the temperature is higher than T1, Tvptat becomes 0 V because Svptat <Svref. Therefore, even if the ratio of R8 / R7 is increased and the temperature coefficient of Tvptat is increased in order to obtain a highly accurate temperature detection circuit, the voltage of Tvptat is equal to Svref ′, that is, the third reference voltage Svref. Therefore, it is possible to operate at a lower voltage than the circuit of the prior application.
[0035]
Finally, the fourth comparison circuit is composed of an operational amplifier OP3. This operational amplifier is used as a comparator. Therefore, as shown in FIG. 3D, when the temperature is lower than T, Tvref <Tvptat, so that the potential of the non-inverting input terminal is higher than that of the inverting input terminal, so that the output Tout of the comparator is High. When the temperature becomes higher than T, since Tvref> Tvptat, the potential of the inverting input terminal is higher than that of the non-inverting input terminal, so that the output Tout of the comparator becomes Low.
[0036]
By using Tout as a control signal for the semiconductor integrated circuit, the operation of the semiconductor integrated circuit can be controlled at a predetermined temperature T even at a low operating voltage. The first reference voltage Vref can also be output to the outside as an output signal of the circuit.
[0037]
FIG. 4 shows a circuit diagram of Example 2 based on the first embodiment. This embodiment is an embodiment in the block diagram of FIG. 1, and this circuit is constructed on an n-type substrate. Vptat is generated as a PTAT voltage having a positive temperature coefficient from the first voltage source circuit, and the principle of the work function difference of the gate disclosed in Patent Document 1 is applied to the first and second voltage source circuits. The voltage source circuit is adopted.
[0038]
The first voltage source circuit is composed of n-type transistors M11, M12, M13 and resistors R12, R13. The n-type transistors M11 and M12 have the same substrate and channel-doped impurity concentrations, are formed in the p-well of the n-type substrate, and the substrate potential of each transistor is equal to the source potential. The n-type transistor M11 has a high-concentration n-type gate, the n-type transistor M12 has a low-concentration n-type gate, and the ratio S = W / L of the channel width W and the channel length L is equal to each other.
[0039]
The n-type transistors M11 and M12 differing only in the impurity concentration of the gate are connected in series, the n-type transistor M11 is a constant current source with the gate connected to the source, and the n-type transistor M12 is connected to the n-type transistor M13 and a resistor. A gate potential is applied by a source follower circuit composed of R12 and R13. Vptat is output from the connection point between the gate of the n-type transistor M12 and the resistors R12 and R13, and Svptat is output from the connection point between the source of the n-type transistor M13 and the resistor R12.
[0040]
The second voltage source circuit includes a first reference voltage source circuit and a second reference voltage source circuit. The first reference voltage source circuit includes n-type transistors M1, M2, and M3 and resistors R2 and R3. The n-type transistors M1 and M2 have the same substrate and channel-doped impurity concentration, are formed in the p-well of the n-type substrate, and the substrate potential of each transistor is equal to the source potential. The n-type transistor M1 has a high-concentration n-type gate, the n-type transistor M2 has a high-concentration p-type gate, and the ratio S = W / L of the channel width W and the channel length L is equal to each other.
[0041]
The n-type transistors M1 and M2 having different gate conductivity types are connected in series, the n-type transistor M1 connects the gate and the source to become a constant current source, and the n-type transistor M2 has a resistance different from that of the n-type transistor M3. A gate potential is applied by a source follower circuit composed of R2 and R3. Vpn having a negative temperature coefficient is output from the connection point between the gate of the n-type transistor M2 and the source of the n-type transistor M3, and Vpn ′ is output from the connection point between the resistors R2 and R3.
[0042]
The transistor M2 in FIG. 4 is an n-type transistor having a high-concentration p-type gate, while the transistor M2 in FIG. 2 is an n-type transistor having a low-concentration n-type gate. However, in order to make the correspondence in both figures easier to understand, the same reference names are given. The same applies to the transistor M7.
[0043]
The second reference voltage source circuit includes p-type transistors M4, M5, and M8, n-type transistors M6 and M7, and resistors R4, R5, and R6. The n-type transistors M6 and M7 have the same substrate and channel-doped impurity concentration, are formed in the p-well of the n-type substrate, and the substrate potential of each transistor is equal to the source potential. The n-type transistor M6 has a high-concentration n-type gate, the n-type transistor M7 has a low-concentration n-type gate, and the ratio S = W / L of the channel width W and the channel length L is equal to each other.
[0044]
The n-type transistors M6 and M7 differing only in the impurity concentration of the gate are input transistors of the differential amplifier, and the p-type transistors M4 and M5 constitute a current mirror circuit. The output Vpn ′ from the first reference voltage source circuit is input to the gate of the n-type transistor M6, and the drain of the p-type transistor M8, that is, the output of this differential amplifier, is input to the gate of the n-type transistor M7. A certain first reference voltage Vref is input. The first reference voltage Vref is divided by the resistors R4, R5, and R6, the second reference voltage Tvref from the connection point between the resistors R4 and R5, and the third reference voltage Svref from the connection point between the resistors R5 and R6. Is output.
[0045]
The subtracting circuit includes operational amplifiers OP1 and OP2 and resistors R7, R8, R9, and R10. The output Svref ′ of the operational amplifier OP1 is input to the inverting input terminal of the operational amplifier OP1, and the third reference voltage Svref is input to the non-inverting input terminal. The output Svref ′ of the operational amplifier OP1 is input to the inverting input terminal of the operational amplifier OP2 through the resistor R7, and the output Tvptat of the operational amplifier OP2 is input through the resistor R8. The output Svptat from the first voltage source circuit is input to the non-inverting input terminal of the operational amplifier OP2 via the resistor R9, and is further connected to the GND power supply via the resistor R10.
[0046]
The comparison circuit is composed of an operational amplifier OP3. The second reference voltage Tvref is input to the inverting input terminal of the operational amplifier OP3, and the output Tvptat from the third subtraction circuit is input to the non-inverting input terminal. The output of the operational amplifier OP3 becomes Tout.
[0047]
Next, the operation of FIG. 4 will be described with reference to the output characteristic diagram of FIG. First, in the first voltage source circuit, an n-type transistor M11 having a gate connected to a source is used as a constant current source, and n-type transistors M11 and M12 are connected in series. Since the same current flows in these n-type transistors M11 and M12 having the same conductivity type but different gates in impurity concentration, as described in Patent Document 1, the source-gate potential of the n-type transistor M11 is The potential difference from the source-gate voltage of the n-type transistor M12 becomes a PTAT voltage having a positive temperature coefficient.
[0048]
Since the n-type transistor M11 has the gate connected to the source, there is no potential difference between the source and gate, and the source-gate voltage of the n-type transistor M12 eventually becomes the PTAT voltage. If this voltage is Vptat, Svptat, which is the output of the first voltage source circuit, is
Svptat = (R12 + R13) / R13 * Vptat (6)
It becomes. The temperature characteristics of these voltages are shown in FIG. Vptat is converted by the ratio shown in equation (6) to generate Svptat. Since Vptat originally has a positive temperature coefficient, Svptat also has a positive temperature coefficient. This Svptat does not need to have a temperature coefficient as large as Tvptat2 shown in FIG.
[0049]
Next, the second voltage source circuit will be described. First, in the first reference voltage source circuit, an n-type transistor M1 having a gate connected to a source is used as a constant current source, and n-type transistors M1 and M2 are connected in series. Since the same current flows through the n-type transistors M1 and M2 having different gate conductivity types, as described in JP-A-2001-284464, the source-gate potential of the n-type transistor M1 and the n-type transistor M2 The potential difference from the source-gate voltage becomes a PTAT voltage having a negative temperature coefficient. Since the n-type transistor M1 has the gate connected to the source, there is no potential difference between the source and the gate, and the source-gate voltage of the n-type transistor M2 eventually becomes the PTAT voltage.
[0050]
When this PTAT voltage is Vpn, Vpn ′ which is the output of the first reference voltage source circuit is Vpn ′ = R3 / (R2 + R3) * Vpn (7)
It becomes. Vpn is converted by the ratio shown in Equation (7) to generate Vpn ′. Since Vpn has a negative temperature coefficient, Vpn ′ also has a negative temperature coefficient.
[0051]
Next, in the second reference voltage source circuit, p-type transistors M4 and M5 constitute a current mirror circuit, and n-type transistors M6 and M7 having gates with different impurity concentrations are used as input transistors of the differential amplifier. Therefore, the same current flows through the n-type transistors M6 and M7. Further, since a feedback loop is formed between the differential amplifier and the p-type transistor M8, as described in Japanese Patent Laid-Open No. 2001-284464, the source-gate voltage of the n-type transistor M6 and n An input offset of Vptat having a positive temperature coefficient is present between the source-gate voltage of the type transistor M7.
[0052]
Therefore, when Vpn ′ is applied from the first reference voltage source circuit to the gate of the n-type transistor M6, a voltage obtained by adding Vptat to Vpn ′ is generated between the source and gate of the n-type transistor M7. This voltage is the first reference voltage Vref having no temperature characteristics because Vpn ′ obtained by converting Vpn having a negative temperature coefficient by a predetermined ratio and Vptat having a positive temperature coefficient are added. Further, the second reference voltage Tvref and the third reference voltage Svref, which are output voltages of the second voltage source circuit, are obtained by dividing the first reference voltage Vref by the resistors R4, R5, and R6. Respectively,
Vref = R3 / (R2 + R3) * Vpn + Vptat = Vpn ′ + Vptat (8)
Tvref = (R5 + R6) / (R4 + R5 + R6) * Vref (3)
Svref = R6 / (R4 + R5 + R6) * Vref (4)
It becomes.
[0053]
FIG. 5B shows the temperature characteristics of these voltages. Vpnat having a negative temperature coefficient from the first reference voltage source circuit and Vptat having a positive temperature coefficient from the second voltage source circuit are added to generate Vref which is the first reference voltage. . This Vref is converted by the ratio shown in the equations (3) and (4) to generate the second reference voltage Tvref and the third reference voltage Svref. Since Vref originally has no temperature coefficient, neither Tvref nor Svref has a temperature coefficient.
[0054]
Next, the subtraction circuit includes operational amplifiers OP1 and OP2 and resistors R7, R8, R9, and R10. First, since the operational amplifier OP1 is used as a voltage follower, a voltage having the same potential as that of the third reference power supply Svref that is an input to the non-inverting input terminal can be obtained as an output Svref ′. The operational amplifier OP1 has a current path between the output Tvptat of the operational amplifier OP2 and the third reference voltage Svref through the resistor R8, the resistor R7, and the resistor R6, and each reference voltage output from the second voltage source circuit varies. It is provided to prevent this from happening.
[0055]
Next, the operational amplifier OP2 is used as a differential amplifier. Therefore, the output Tvptat of the operational amplifier OP2 is, as is well known, by setting R7 = R9 and R8 = R10, Tvptat becomes
Tvptat = (R8 / R7) * (Svptat−Svref ′) (5)
It becomes. FIG. 5C shows the temperature characteristics of these voltages. When the temperature is lower than T1, Tvptat is 0V because Svptat <Svref, but when the temperature is higher than T1, Svptat> Svref, so the potential of equation (5) is output. At this time, the ratio of the temperature coefficient of Tvptat to Vptat is calculated from the equations (6) and (5):
Tvptat temperature coefficient ratio = (R12 + R13) / R13 * R8 / R7 (9)
It becomes.
[0056]
In order to make the value of equation (9) the same as (R1 + R2 + R5) / R5 which is the temperature coefficient ratio of Tvptat in the prior application circuit shown in FIG. 19, resistors R12, R13 and resistors R7, R8 It can be easily obtained by adjusting the resistance ratio. For example, when the temperature coefficient ratio of Tvptat generated by the first voltage source circuit in the circuit of FIG. 19 is 50, in this circuit, the temperature coefficient ratio generated by the first voltage source circuit (= (R12 + R13) / R13). ) Is set to “10” and the temperature coefficient ratio (= R8 / R7) generated by the third subtracting circuit is set to 5, the temperature coefficient ratio of Tvptat is “50”, which is the same as that of the prior application circuit. It is done. Therefore, it is not necessary to generate Tvptat having a large temperature coefficient ratio only by the first voltage source circuit as in the circuit of the prior application.
[0057]
Finally, the comparison circuit is composed of an operational amplifier OP3. This operational amplifier is used as a comparator. Therefore, as shown in FIG. 5D, when the temperature is lower than T, Tvref> Tvptat, so that the potential of the inverting input terminal is higher than that of the non-inverting input terminal, so the output Tout of the comparator is Low. When the temperature becomes higher than T, since Tvref <Tvptat, the potential at the non-inverting input terminal is higher than that at the inverting input terminal, so that the output Tout of the comparator becomes High. If this Tout is used as a control signal for the semiconductor integrated circuit, the operation of the semiconductor integrated circuit can be controlled at a predetermined temperature T.
[0058]
In the first and second embodiments, as the first voltage source for outputting the PTAT voltage, a voltage source circuit applying the principle of the diode connection of the NPN transistor and the work function difference of the gate is used. It goes without saying that the circuit is not limited to these circuits as long as the PTAT voltage can be generated. Similarly, as the second voltage source for outputting the reference voltage, a reference voltage circuit applying the principle of the work function difference of the gate is used. However, a band gap reference circuit or the like is used as the second voltage source circuit. Also good.
[0059]
(Embodiment 2)
FIG. 6 is a schematic block diagram showing Embodiment 2 of the present invention. As shown in FIG. 6, a PTAT voltage (not shown) having a positive temperature coefficient in proportion to the absolute temperature is generated, and this PTAT voltage is a voltage having a positive temperature coefficient obtained by a resistance dividing circuit. And a first voltage source circuit for generating Svptat and a voltage having a negative temperature coefficient in proportion to the absolute temperature, and a value obtained by converting Vptat by a predetermined ratio to the voltage having the negative temperature coefficient. By adding, a second voltage source circuit that generates a first reference voltage Vref, a second reference voltage Tvref, and a third reference voltage Svref that do not have a temperature coefficient, and an output from the first voltage source circuit A subtracting circuit that differentially amplifies Svptat and the third reference voltage Svref and outputs the result as Tvptat, and a comparison circuit that compares Tvptat and the second reference voltage Tvref and outputs the comparison result Tout. ing.
[0060]
When the first voltage source circuit outputs a voltage having a negative temperature coefficient, the voltage generated inside the second voltage source circuit has a positive temperature coefficient. For these first and second voltage source circuits, voltage source circuits applying the principle of the work function difference of the gate described in Patent Document 1 are adopted.
[0061]
FIG. 7 shows a circuit diagram of Example 1 based on the second embodiment, and this circuit is constructed on an n-type substrate. The first voltage source circuit includes n-type transistors M1, M2, and M3 and resistors R1, R2, and R3. The n-type transistors M1 and M2 have the same substrate and channel-doped impurity concentration, are formed in the p-well of the n-type substrate, and the substrate potential of each transistor is equal to the source potential. The n-type transistor M1 has a high-concentration n-type gate, the n-type transistor M2 has a low-concentration n-type gate, and the ratio S = W / L of the channel width W and the channel length L is equal to each other.
[0062]
The n-type transistors M1 and M2 differing only in the impurity concentration of the gate are connected in series, the n-type transistor M1 serves as a constant current source with the gate connected to the source, and the n-type transistor M2 includes the n-type transistor M3 and the resistor R1. A gate potential is applied by a source follower circuit including R2, R3. Vptat is output from the connection point between the gate of the n-type transistor M2 and the resistors R2 and R3, Vptat 'is output from the connection point between the resistors R1 and R2, and Svptat is output from the connection point between the source of the transistor M3 and the resistor R1.
[0063]
The second voltage source circuit includes p-type transistors M4, M5, and M8, n-type transistors M6 and M7, and resistors R4, R5, and R6. The n-type transistors M6 and M7 have the same substrate and channel-doped impurity concentration, are formed in the p-well of the n-type substrate, and the substrate potential of each transistor is equal to the source potential. The n-type transistor M6 has a high-concentration n-type gate, the n-type transistor M7 has a high-concentration p-type gate, and the ratio S = W / L of the channel width W and the channel length L is equal to each other.
[0064]
The n-type transistors M6 and M7 differing only in the gate conductivity type are input transistors of the differential amplifier, and the p-type transistors M4 and M5 constitute a current mirror circuit. The output Vptat 'from the first voltage source circuit is input to the gate of the n-type transistor M6, and the drain of the p-type transistor M8, that is, the output of this differential amplifier, is input to the gate of the n-type transistor M7. The first reference voltage Vref is input. The first reference voltage Vref is divided by the resistors R4, R5, and R6, the second reference voltage Tvref from the connection point between the resistors R4 and R5, and the third reference voltage Svref from the connection point between the resistors R5 and R6. Is output.
[0065]
The subtracting circuit includes operational amplifiers OP1 and OP2 and resistors R7, R8, R9, and R10. The output Svref ′ of the operational amplifier OP1 is input to the inverting input terminal of the operational amplifier OP1, and the second reference voltage Svref is input to the non-inverting input terminal. Further, the output Svref ′ of the operational amplifier OP1 is input to the inverting input terminal of the operational amplifier OP2 through the resistor R7, and the output Tvptat of the operational amplifier OP2 is input through the resistor R8. The output Svptat from the first voltage source circuit is input to the non-inverting input terminal of the operational amplifier OP2 via the resistor R9, and is further connected to the GND power supply via the resistor R10.
[0066]
The comparison circuit is composed of an operational amplifier OP3. The second reference voltage Tvref is input to the inverting input terminal of the operational amplifier OP3, and the output Tvptat from the subtraction circuit is input to the non-inverting input terminal. The output of the operational amplifier OP3 becomes Tout.
[0067]
Next, the operation of the circuit of FIG. 7 will be described with reference to the temperature characteristic diagram of FIG. First, in the first voltage source circuit, an n-type transistor M1 having a gate connected to a source is used as a constant current source, and the n-type transistors M1 and M2 are connected in series. Since the same current flows in these n-type transistors M1 and M2 having the same conductivity type but different gates only in impurity concentration, as described in Patent Document 1, the source-gate potential of the n-type transistor M1 is The potential difference from the source-gate voltage of the n-type transistor M2 becomes a PTAT voltage having a positive temperature coefficient. Since the source and gate of the n-type transistor M1 are connected, there is no potential difference between the source and gate, and the source-gate voltage of the n-type transistor M2 eventually becomes the PTAT voltage. Assuming that this voltage is Vptat, Vptat 'and Svptat which are the outputs of the first voltage source circuit are
Vptat '= (R2 + R3) / R3 * Vptat (1)
Svptat = (R1 + R2 + R3) / R3 * Vptat (10)
It becomes.
[0068]
The temperature characteristics of these voltages are shown in FIG. Vptat is converted by the ratio shown in equations (1) and (10) to generate Vptat 'and Svptat. Since Vptat has a positive temperature coefficient, these also have a positive temperature coefficient. This Svptat does not need to have a temperature coefficient as large as Tvptat2 shown in FIG.
[0069]
Next, in the second voltage source circuit, p-type transistors M4 and M5 constitute a current mirror circuit, and n-type transistors M6 and M7 having different conductivity type gates are used as input transistors of the differential amplifier. Therefore, the same current flows through the n-type transistors M6 and M7. Since a feedback loop is formed between the differential amplifier and the p-type transistor M8, as described in Patent Document 1, the source-gate voltage of the n-type transistor M6 and the n-type transistor M7 It has an input offset of Vpn having a negative temperature coefficient between the source-gate voltage.
[0070]
Therefore, when Vptat ′ is applied from the first voltage source circuit to the gate of the n-type transistor M6, a voltage obtained by adding Vpnat to Vptat ′ is generated between the source and gate of the n-type transistor M7. This voltage is the first reference voltage Vref having no temperature characteristics because Vptat ′ obtained by converting Vptat having a positive temperature coefficient by a predetermined ratio and Vpn having a negative temperature coefficient are added. Further, the second reference voltage Tvref and the third reference voltage Svref, which are output voltages of the second voltage source circuit, are obtained by dividing the first reference voltage Vref by the resistors R4, R5, and R6. Respectively,
Vref = (R2 + R3) / R3 * Vptat + Vpn = Vptat ′ + Vpn (2)
Tvref = (R5 + R6) / (R4 + R5 + R6) * Vref (3)
Svref = R6 / (R4 + R5 + R6) * Vref (4)
become.
[0071]
FIG. 8B shows these temperature characteristics. Vptat having a positive temperature coefficient from the first voltage source circuit and Vpn having a negative temperature coefficient from the second voltage source circuit are added to generate Vref as the first reference voltage. This Vref is converted by the ratio shown in equations (3) and (4) to generate the second reference voltage Tvref and the third reference voltage Svref. Since Vref originally has no temperature coefficient, neither Tvref nor Svref has a temperature coefficient.
[0072]
Next, the subtraction circuit includes operational amplifiers OP1 and OP2 and resistors R7, R8, R9, and R10. First, since the operational amplifier OP1 is used as a voltage follower, a voltage having the same potential as that of the third reference power supply Svref that is an input to the non-inverting input terminal can be obtained as an output Svref ′. The operational amplifier OP1 has a current path between the output Tvptat of the operational amplifier OP2 and the third reference voltage Svref through the resistor R8, the resistor R7, and the resistor R6, and each reference voltage output from the second voltage source circuit varies. It is provided to prevent this from happening.
[0073]
Next, the operational amplifier OP2 is used as a differential amplifier. Therefore, as is well known, the output Tvptat of this operational amplifier OP1 is given by the following equation by setting R7 = R9 and R8 = R10.
Tvptat = (R8 / R7) * (Svptat−Svref ′) (5)
[0074]
FIG. 8C shows the temperature characteristics of these voltages. When the temperature is lower than T1, since Svptat <Svref, Tvptat is 0 V. However, when the temperature is higher than T1, since Svptat> Svref, the potential of the equation (5) is output. At this time, the ratio of the temperature coefficient of Tvptat to Vptat is expressed by the equations (10) and (5):
Tvptat temperature coefficient ratio = (R1 + R2 + R3) / R3 * R8 / R7 (11)
It becomes. In order to make the value of the equation (11) equal to (R1 + R2 + R5) / R5 which is the temperature coefficient ratio of Tvptat in the prior application circuit shown in FIG. 19, resistors R1 to R3 and resistors R7, R8 It can be easily obtained by adjusting the resistance ratio.
[0075]
For example, when the temperature coefficient ratio of Tvptat generated by the first voltage source circuit in the circuit of the prior application of FIG. 19 is “50”, in this circuit, the temperature coefficient ratio generated by the first voltage source circuit (= If (R1 + R2 + R3) / R3) is set to “10” and the temperature coefficient ratio (= R8 / R7) generated by the third subtracting circuit is set to “5”, the temperature coefficient ratio of Tvptat is A similar “50” is obtained. Therefore, it is not necessary to generate Tvptat having a large temperature coefficient ratio only by the first voltage source circuit as in the circuit of the prior application.
[0076]
Finally, the comparison circuit is composed of an operational amplifier OP3. This operational amplifier is used as a comparator. Therefore, as shown in FIG. 8D, when the temperature is lower than T, since Tvref> Tvptat, the potential of the inverting input terminal is higher than that of the non-inverting input terminal, so the output Tout of the comparator is Low. When the temperature becomes higher than T, since Tvref <Tvptat, the potential at the non-inverting input terminal is higher than that at the inverting input terminal, so that the output Tout of the comparator becomes High. If this Tout is used as a control signal for the semiconductor integrated circuit, the operation of the semiconductor integrated circuit can be controlled at a predetermined temperature T.
[0077]
FIG. 9 shows a circuit diagram of Example 2 based on Embodiment 2, and this circuit is constructed on an n-type substrate. The first voltage source circuit includes n-type transistors M1, M2, and M3 and resistors R1, R2, and R3. The n-type transistors M1 and M2 have the same substrate and channel-doped impurity concentration, are formed in the p-well of the n-type substrate, and the substrate potential of each transistor is equal to the source potential. The n-type transistor M1 has a high-concentration n-type gate, the n-type transistor M2 has a low-concentration n-type gate, and the ratio S = W / L of the channel width W and the channel length L is equal to each other.
[0078]
The n-type transistors M1 and M2 differing only in the impurity concentration of the gate are connected in series, the n-type transistor M1 serves as a constant current source with the gate connected to the source, and the n-type transistor M2 includes the n-type transistor M3 and the resistor R1. A gate potential is applied by a source follower circuit including R2, R3. Vptat is output from the connection point between the gate of the n-type transistor M2 and the resistors R1 and R2, Vptat 'is output from the connection point between the resistors R1 and R2, and Svptat is output from the connection point between the source of the transistor M3 and the resistor R1.
[0079]
The second voltage source circuit includes p-type transistors M4, M5, and M8, n-type transistors M6 and M7, and resistors R4, R5, and R6. The n-type transistors M6 and M7 have the same substrate and channel-doped impurity concentration, are formed in the p-well of the n-type substrate, and the substrate potential of each transistor is equal to the source potential. The n-type transistor M6 has a high-concentration n-type gate, the n-type transistor M7 has a high-concentration p-type gate, and the ratio S = W / L of the channel width W and the channel length L is equal to each other.
[0080]
The n-type transistors M6 and M7 differing only in the gate conductivity type are input transistors of the differential amplifier, and the p-type transistors M4 and M5 constitute a current mirror circuit. The output Vptat 'from the first voltage source circuit is input to the gate of the n-type transistor M6, and the drain of the p-type transistor M8, that is, the output of this differential amplifier, is input to the gate of the n-type transistor M7. The first reference voltage Vref is input. The first reference voltage Vref is divided by the resistors R4, R5, and R6, the second reference voltage Tvref from the connection point of the resistors R4 and R5, and the third reference voltage Svref from the connection point of the resistors R5 and R6. Are output respectively.
[0081]
The subtracting circuit includes an operational amplifier OP2 and resistors R7, R8, R9, and R10. The third reference voltage Svref is input to the inverting input terminal of the operational amplifier OP2 through the resistor R7, and the output Tvptat of the OP2 is input through the resistor R8. The output Svptat from the first voltage source circuit is input to the non-inverting input terminal of the operational amplifier OP2 via the resistor R9, and is further connected to the GND power supply via the resistor R10.
[0082]
The comparison circuit is composed of an operational amplifier OP3. The second reference voltage Tvref is input to the inverting input terminal of the operational amplifier OP3, and the output Tvptat from the third subtraction circuit is input to the non-inverting input terminal. The output of the operational amplifier OP2 becomes Tout.
[0083]
Next, the operation of the circuit of FIG. 9 will be described. First, since the first voltage source circuit has the same configuration as that in FIG. 7, Vptat, which is a PTAT voltage having a positive temperature characteristic, is output between the source and gate of the n-type transistor M2. Further, Vptat ′ and Svptat are converted by resistors R1, R2 and R3, respectively, and are given by equations (1) and (10), respectively. As shown in FIG. 8 (a), these have a positive temperature coefficient.
[0084]
Next, since the second voltage source circuit has the same configuration as that shown in FIG. 7, it has a negative temperature coefficient between the source-gate voltage of the n-type transistor M6 and the source-gate voltage of the n-type transistor M7. Since Vptat ′ is applied from the first voltage source circuit to the gate of the n-type transistor M6 with an input offset of Vpn, the equation (2) is shown between the source and gate of the n-type transistor M7. Thus, the first reference voltage Vref obtained by adding Vpn to Vptat ′ is generated. In addition, the second reference voltage Tvref and the third reference voltage Svref are obtained by dividing the first reference voltage Vref by the resistors R4, R5, and R6, and these are expressed by the equations (3) and (4), respectively. It becomes the indicated voltage. FIG. 8B shows their temperature characteristics.
[0085]
Next, the subtracting circuit is composed of an operational amplifier OP1 and resistors R7, R8, R9, and R10. This operational amplifier is used as a differential amplifier. Therefore, the output Tvptat of OP1 is, as is well known, by setting R7 = R9 and R8 = R10.
Tvptat = (R8 / R7) * (Svptat−Svref) (5)
It becomes. FIG. 8C shows these temperature characteristics. When the temperature is lower than T1, since Svptat <Svref, Tvptat is 0V, but when the temperature is higher than T1, the voltage of equation (5) is output. At this time, the ratio of the temperature coefficient of Tvptat to Vptat is expressed by the equations (10) and (5):
Tvptat temperature coefficient ratio = (R1 + R2 + R3) / R3 * R8 / R7 (11)
It becomes. In order to make the value of the equation (11) equal to (R1 + R2 + R5) / R5 which is the temperature coefficient ratio of Tvptat in the prior application circuit shown in FIG. 19, resistors R1 to R3 and resistors R7, 8 It can be easily obtained by adjusting the resistance ratio.
[0086]
For example, when the temperature coefficient ratio of Tvptat generated by the first voltage source circuit in the circuit of the prior application of FIG. 19 is “50”, in this circuit, the temperature coefficient ratio generated by the first voltage source circuit (= If (R1 + R2 + R3) / R3) is set to “10” and the temperature coefficient ratio (= R8 / R5) generated by the third subtracting circuit is set to “5”, the same “50” is set as the temperature coefficient ratio of Tvptat. can get. Therefore, it is not necessary to generate Tvptat having a large temperature coefficient ratio only by the first voltage source circuit as in the circuit of the prior application.
[0087]
Also, unlike the embodiment of FIG. 7, a current path is created through resistors R8, R7, R6 between Tvptat and the third reference power source Svref, and each reference voltage output by the second voltage source circuit is Since the output cannot be performed accurately, the resistance values of these resistors R7 to R10 must be sufficiently larger than the resistor R6 of the second voltage source circuit in order to reduce the influence of the current path.
[0088]
Finally, the comparison circuit is composed of an operational amplifier OP3. This operational amplifier is used as a comparator. Therefore, as shown in FIG. 8D, when the temperature is lower than T, since Tvref> Tvptat, the potential of the inverting input terminal is higher than that of the non-inverting input terminal, so the output Tout of the comparator is Low. When the temperature becomes higher than T, since Tvref <Tvptat, the potential at the non-inverting input terminal is higher than that at the inverting input terminal, so that the output Tout of the comparator becomes High. If this Tout is used as a control signal for the semiconductor integrated circuit, the operation of the semiconductor integrated circuit can be controlled at a predetermined temperature T.
[0089]
FIG. 10 shows a comparison waveform of the circuit of each example according to the first and second embodiments and the circuit according to the prior application. As shown in FIG. 13, in order to construct a highly accurate temperature detection circuit with the circuit of the prior application, it is necessary to convert the temperature coefficient of Tvptat into a large value with the first voltage source circuit. Therefore, Tvptat becomes higher on the high temperature side, which greatly affects the operating voltage of the circuit.
[0090]
However, in the present invention, the first voltage source circuit does not convert it to a very large value and outputs it as Svptat, and this Svptat and the third reference voltage Svref are subtracted and amplified by the third subtraction circuit. Tvptat is generated. Therefore, when the temperature coefficient of Tvptat is positive, the output voltage shifts to the lower side while the Tvptat has the same temperature coefficient as indicated by an arrow, so that the operating voltage can be lowered. Even when the temperature coefficient of Tvptat is negative, the output voltage is similarly shifted to a lower side, so that the operating voltage can be lowered.
[0091]
(Embodiment 3)
FIG. 11 is a schematic block diagram showing Embodiment 3 of the present invention. In FIG. 11, the difference from FIG. 1, which is the first embodiment, is that two subtraction circuits and a comparison circuit are provided, and reference voltages Svref1 and Svref2 are respectively supplied from the second voltage source circuit. The comparison results Tout1 and Tout2 can be output at different temperatures.
[0092]
FIG. 12 shows a circuit diagram of Example 1 based on Embodiment 3, which is different from FIG. 2 of Example 1 based on Embodiment 1 in the first subtraction circuit and the first comparison circuit. (Corresponding to the subtraction circuit and comparison circuit in FIG. 2), a second subtraction circuit, and a second comparison circuit. Then, the resistor R5 in FIG. 2 is divided into R5a and R5b in FIG. 12, and the reference voltage Scerf1 is extracted from the connection point between the resistors R6 and R5b, and the reference voltage Scerf2 is extracted from the connection point between the resistors R5a and R5b. Are supplied to the operational amplifier OP1 of the first subtraction circuit and the operational amplifier OP11 of the second subtraction circuit.
[0093]
Next, the operation of the circuit of FIG. 12 will be described using the temperature characteristic diagram of FIG. First, since the first voltage source circuit uses a diode connection of an NPN transistor as in FIG. 2, as shown in FIG. 13A, Svptat that is a PTAT voltage having a negative temperature coefficient is output. .
[0094]
Next, also in the second voltage source circuit, similarly to the circuit of FIG. 2, when Vptat ′ is applied from the first voltage source circuit to the gate of the n-type transistor M6, the distance between the source and gate of the n-type transistor M7 is increased. Generates a voltage obtained by adding Vpn to Vptat ′. This voltage is the first reference voltage Vref having no temperature characteristics because Vptat ′ obtained by converting Vptat having a positive temperature coefficient by a predetermined ratio and Vpn having a negative temperature coefficient are added. Further, the reference voltage Tvref, which is the output voltage of the second voltage source circuit, and the third reference voltages Svref1 and Svref2 are obtained by dividing the first reference voltage Vref by the resistors R4, R5a, R5b, and R6. These are as follows.
[0095]
Vref = (R2 + R3) / R3 * Vptat + Vpn = Vptat ′ + Vpn (2)
Tvref = (R5 + R6) / (R4 + R5 + R6) * Vref (3)
Svref1 = R7 / (R4 + R5a + R5b + R6) * Vref (4)
Svref2 = (R5b + R6) / (R4 + R5a + R5b + R6) * Vref (5)
These signals are shown in FIG.
[0096]
Next, the operation of the first subtracting circuit is the same as that of FIG. 2 only by replacing the reference voltage Sverf in FIG. 2 with Svref1. Therefore, the output Tvptat1 of the operational amplifier OP2 is
Tvptat1 = (R9 / R8) * (Svptat−Svref1 ′) (6)
The temperature characteristics are shown in FIG.
[0097]
When the temperature is lower than T1, Tvptat1 is equal to Equation (6) because Svptat> Svref1, and when the temperature is higher than T1, Svptat <Svref1 is 0V. Therefore, to obtain a highly accurate temperature detection circuit, even if the ratio of R9 / R8 is increased and the temperature coefficient of Tvptat1 is increased, the voltage of Tvptat1 is reduced by Svref1 ′, that is, by the reference voltage Svref1. Therefore, it is possible to operate at a lower voltage than that of the previous application.
[0098]
The same applies to the second subtraction circuit. The output Tvptat2 of the operational amplifier OP11 is
Tvptat2 = (R19 / R18) * (Svptat−Svref2 ′) (7)
FIG. 13 (d) shows the temperature characteristics. In this case as well, the voltage of Tvptat2 is lower by Svref2 ′, that is, by the reference voltage Svref2, and can operate at a lower voltage than that of the previous application.
[0099]
Finally, as shown in FIG. 13E, the first comparator circuit is Tvref <Tvptat1 when the temperature is lower than T1, so the output Tout1 of the comparator is High, and when the temperature is higher than T1, the output of the comparator Tout1 becomes Low. Further, in the second comparison circuit, Tvref <Tvptat2 when the temperature is lower than T2, the output Tout2 of the comparator OP13 is High, and Tvref> Tvptat2 when the temperature is higher than T2, and the output Tout2 of the comparator OP13 is Low. . If these Tout1 and Tout2 are used as control signals for the semiconductor integrated circuit, the operation of the semiconductor integrated circuit can be controlled at predetermined temperatures T1 and T2. In this embodiment, the circuit composed of the subtraction circuit and the comparison circuit is two systems, but more circuits can be provided.
[0100]
(Embodiment 4)
FIG. 14 is a schematic block diagram showing Embodiment 4 of the present invention. FIG. 14 differs from FIG. 6 which is the second embodiment in that two subtraction circuits and comparison circuits are provided, and reference voltages Svref1 and Svref2 are respectively supplied from the second voltage source circuit. The comparison results Tout1 and Tout2 can be output at different temperatures.
[0101]
FIG. 15 shows a circuit diagram of Example 1 based on the third embodiment. This circuit diagram is different from FIG. 7 of Example 1 based on the second embodiment in that the first subtracting circuit and the first comparing circuit are shown. (Corresponding to the subtraction circuit and comparison circuit in FIG. 7), a second subtraction circuit, and a second comparison circuit. Then, the resistor R5 in FIG. 2 is divided into R5a and R5b in FIG. 12, and the reference voltage Scerf1 is extracted from the connection point between the resistors R6 and R5b, and the reference voltage Scerf2 is extracted from the connection point between the resistors R5a and R5b. Are supplied to the operational amplifier OP1 of the first subtraction circuit and the operational amplifier OP11 of the second subtraction circuit.
[0102]
Next, the operation of the circuit of FIG. 15 will be described with reference to the temperature characteristic diagram of FIG. First, in the first voltage source circuit, similarly to the case of FIG. 7, the source-gate voltage of the n-type transistor M2 is a PTAT voltage having a positive temperature coefficient. The source circuit outputs Vptat 'and Svptat are
Vptat '= (R2 + R3) / R3 * Vptat (1)
Svptat = (R1 + R2 + R3) / R3 * Vptat (10)
It becomes.
[0103]
The temperature characteristics of these voltages are shown in FIG. Vptat is converted by the ratio shown in equations (1) and (10) to generate Vptat 'and Svptat. Since Vptat originally has a positive temperature coefficient, these also have a positive temperature coefficient. This Svptat does not need to have a temperature coefficient as large as Tvptat2 shown in FIG.
[0104]
Next, also in the second voltage source circuit, when Vptat ′ is applied from the first voltage source circuit to the gate of the n-type transistor M6, similarly to the circuit of FIG. Generates a voltage obtained by adding Vpn to Vptat ′. This voltage is the first reference voltage Vref having no temperature characteristics because Vptat ′ obtained by converting Vptat having a positive temperature coefficient by a predetermined ratio and Vpn having a negative temperature coefficient are added. The reference voltage Tvref, which is the output voltage of the second voltage source circuit, and the third and fourth reference voltages Svref1 and Svref2 are obtained by dividing the first reference voltage Vref by resistors R4, R5a, R5b, and R6. Therefore, these are as follows.
[0105]
Vref = (R2 + R3) / R3 * Vptat + Vpn = Vptat ′ + Vpn (2)
Tvref = (R5 + R6) / (R4 + R5 + R6) * Vref (3)
Svref1 = R7 / (R4 + R5a + R5b + R6) * Vref (4)
Svref2 = (R5b + R6) / (R4 + R5a + R5b + R6) * Vref (5)
These signals are shown in FIG.
[0106]
Next, the operation of the first subtracting circuit is the same as that of FIG. 7 only by replacing the reference voltage Sverf in FIG. 7 with Svref1. Therefore, the output Tvptat1 of the operational amplifier OP2 is
Tvptat1 = (R9 / R8) * (Svptat−Svref1 ′) (6)
FIG. 16C shows the temperature characteristics.
[0107]
When the temperature is lower than T1, since Svptat <Svref1, Tvptat is 0 V. However, when the temperature is higher than T1, since Svptat> Svref1, the potential of equation (6) is output. At this time, the ratio of the temperature coefficient of Tvptat1 to Vptat is expressed by the equations (8) and (6):
Temperature coefficient ratio of Tvptat1 = (R1 + R2 + R3) / R3 * R8 / R7 (9)
It becomes. In order to make the value of the equation (9) the same as (R1 + R2 + R5) / R5 which is the temperature coefficient ratio of Tvptat in the circuit shown in FIG. 19, the resistance ratio of the resistors R1 to R3 and the resistors R7 and R8 If it is adjusted, it can be easily obtained.
[0108]
For example, when the temperature coefficient ratio of Tvptat1 generated by the first voltage source circuit in the circuit of FIG. 19 is “50”, in this circuit, the temperature coefficient ratio generated by the first voltage source circuit (= (R1 + R2 + R3) / R3) is set to “10” and the temperature coefficient ratio (= R8 / R7) generated by the third subtracting circuit is set to “5”, the temperature coefficient ratio of Tvptat1 is set to “ 50 "is obtained. Therefore, it is not necessary to generate Tvptat having a large temperature coefficient ratio only by the first voltage source circuit as in the circuit of the prior application.
[0109]
The same applies to the second subtraction circuit. The output Tvptat2 of the operational amplifier OP11 is
Tvptat2 = (R19 / R18) * (Svptat−Svref2 ′) (7)
FIG. 13 (d) shows the temperature characteristics.
[0110]
When the temperature is lower than T2, since Svptat <Svref2, Tvptat2 is 0 V. However, when the temperature is higher than T1, since Svptat> Svref2, the potential of equation (7) is output. At this time, the ratio of the temperature coefficient of Tvptat2 to Vptat is expressed by the equations (8) and (7):
Tvptat2 temperature coefficient ratio = (R1 + R2 + R3) / R3 * R18 / R17 (15)
It becomes. In order to make the value of the equation (15) equal to (R1 + R2 + R5) / R5 which is the temperature coefficient ratio of Tvptat in the circuit shown in FIG. 19, the resistance ratio of the resistors R1 to R3 and the resistors R17 and R18 If it is adjusted, it can be easily obtained.
[0111]
For example, when the temperature coefficient ratio of Tvptat2 generated by the first voltage source circuit in the circuit of FIG. 19 is 50, in this circuit, the temperature coefficient ratio generated by the first voltage source circuit (= (R1 + R2 + R3) / R3 ) Is set to 10 and the temperature coefficient ratio (= R18 / R17) generated by the third subtracting circuit is set to “5”, the temperature coefficient ratio of Tvptat2 is “50”, which is the same as that of the prior application circuit. It is done. Therefore, it is not necessary to generate Tvptat having a large temperature coefficient ratio only by the first voltage source circuit as in the circuit of the prior application.
[0112]
Finally, as shown in FIG. 16 (e), the first comparator circuit is Tvref <Tvptat1 when the temperature is lower than T1, so the output Tout1 of the comparator is High, and when the temperature is higher than T1, the output of the comparator Tout1 becomes Low. Further, in the second comparison circuit, Tvref <Tvptat2 when the temperature is lower than T2, the output Tout2 of the comparator OP13 is High, and Tvref> Tvptat2 when the temperature is higher than T2, and the output Tout2 of the comparator OP13 is Low. . If these Tout1 and Tout2 are used as control signals for the semiconductor integrated circuit, the operation of the semiconductor integrated circuit can be controlled at predetermined temperatures T1 and T2.
[0113]
FIG. 17 shows a comparison waveform between the third embodiment and the prior application circuit. As shown in FIG. 23, in order to construct a highly accurate temperature detection circuit with the circuit of the prior application, it is necessary to convert the temperature coefficient of Tvptat into a large value with the first voltage source circuit. Therefore, Tvptat becomes higher on the high temperature side, which greatly affects the operating voltage of the circuit. However, in the present invention, the output Svptat from the first voltage source circuit and the third reference voltages Svref1 and Svref2 are subtracted and amplified by the first and second subtraction circuits to generate Tvptat1 and Tvptat2. I am letting. Therefore, Tvptat1 and Tvptat2 can be lowered by the potential of Svref1 and Svref2, respectively, so that the output voltage shifts to the lower side while maintaining the same temperature coefficient as Tvptat of the earlier application circuit, so that the operating voltage is lowered. Can do.
[0114]
FIG. 18 shows a comparison waveform between the fourth embodiment and the prior application circuit. Similarly, in the case of the fourth embodiment, the first voltage source circuit outputs it as Svptat without converting it to a very large value, and this Svptat and the third reference voltages Svref1 and Svref2 are output as the first and second reference voltages. The subtracting circuit 2 subtracts and amplifies the signals to generate Tvptat1 and Tvptat2. Therefore, the output voltage is shifted to the lower side while the temperature coefficients of Tvptat1 and Tvptat2 have the same temperature coefficient as that of the circuit of the prior application, so that the operating voltage can be lowered.
[0115]
【The invention's effect】
As described above, according to the present invention, before the voltage having the temperature coefficient from the first voltage source circuit is compared with the reference voltage by the comparison circuit, the subtraction circuit outputs the voltage from the first voltage source circuit. Since the reference voltage is subtracted from the voltage, a temperature detection circuit capable of high-precision and low-voltage operation can be obtained. In addition, since each circuit uses a circuit that applies the principle of work function difference of the gate, the PTAT voltage and the reference voltage can be generated with high precision up to the operating limit of the semiconductor integrated circuit, enabling higher temperature operation. Thus, it is possible to obtain a temperature detection circuit capable of high-precision and low-voltage operation.
[0116]
In addition, by providing two systems including a subtraction circuit and a comparison circuit and supplying different reference voltages to the respective circuits, two different temperatures can be detected with high accuracy by low voltage operation.
[Brief description of the drawings]
FIG. 1 is a schematic block diagram showing a first embodiment of the present invention.
FIG. 2 is a circuit diagram showing Example 1 in Embodiment 1 of the present invention.
3 is a graph showing temperature characteristics of various signals in the circuit diagram of FIG.
FIG. 4 is a circuit diagram showing Example 2 in Embodiment 1 of the present invention.
5 is a graph showing temperature characteristics of various signals in the circuit diagram of FIG.
FIG. 6 is a schematic block diagram showing a second embodiment of the present invention.
FIG. 7 is a circuit diagram showing Example 1 in Embodiment 2 of the present invention.
8 is a graph showing temperature characteristics of various signals in the circuit diagram of FIG.
FIG. 9 is a circuit diagram showing Example 2 in Embodiment 2 of the present invention.
10 is a graph showing the operation of each circuit of FIGS. 2, 4, 7, and 9. FIG.
FIG. 11 is a schematic block diagram showing a third embodiment of the present invention.
FIG. 12 is a circuit diagram showing Example 1 in Embodiment 3 of the present invention.
13 is a graph showing temperature characteristics of various signals in the circuit diagram of FIG.
FIG. 14 is a schematic block diagram showing a fourth embodiment of the present invention.
FIG. 15 is a circuit diagram showing Example 1 in Embodiment 4 of the present invention;
16 is a graph showing temperature characteristics of various signals in the circuit diagram of FIG.
FIG. 17 is a graph showing the operation of the circuit of FIG.
18 is a graph showing the operation of the circuit of FIG.
FIG. 19 is a circuit diagram disclosed in the “temperature detection circuit” of the prior application;
20 is a graph showing the operation of the circuit of FIG.
FIG. 21 is a diagram showing another circuit conceivable from the circuit of FIG.
22 is a graph showing the operation of the circuit of FIG.
FIG. 23 is a graph showing the operation of the circuit of FIG.
[Explanation of symbols]
Tr1 transistor, M1-M8 MOS transistor, OP operational amplifier, R resistance

Claims (12)

A first voltage source circuit that outputs a voltage having a positive or negative temperature coefficient;
A second voltage source circuit which outputs a first and second respective reference voltage proportional to said voltage to generate a voltage having no temperature coefficient,
A subtracting circuit for subtracting the second reference voltage from an output voltage having a positive or negative temperature coefficient from the first voltage source circuit;
Temperature detection circuit in the semiconductor integrated circuit, characterized by that a comparator circuit for comparing the output voltage and the first reference voltage from the subtractor circuit. Said second voltage source circuit in which a voltage having a positive or negative temperature coefficient created internally, obtained by inputting to the amplifier circuit with input offset voltage temperature coefficient opposite temperature coefficient of the voltage The temperature detection circuit in the semiconductor integrated circuit according to claim 1. A first voltage source circuit that outputs a voltage having a positive or negative temperature coefficient;
A voltage having no temperature coefficient is generated by adding a voltage from the first voltage source circuit to a voltage having a positive or negative temperature coefficient generated internally, and each of the first and second references proportional to the voltage is generated. A second voltage source circuit for outputting each voltage;
A subtracting circuit for subtracting said second reference voltage from the output voltage having a positive or negative temperature coefficient from said first voltage source circuit,
Temperature detection circuit in the semiconductor integrated circuit, characterized by that a comparator circuit for comparing the output voltage and the first reference voltage from the subtractor circuit. Wherein with subtraction circuit and a plurality of systems of circuits composed of the comparator circuit, the temperature detection circuit in the semiconductor integrated circuit according to claim 1 for inputting a reference voltage of different values to each circuit. The temperature detection circuit in the semiconductor integrated circuit according to claim 1, wherein the first voltage source circuit includes a plurality of field effect transistors having gates of the same conductivity type and different impurity concentrations. It said first voltage source circuit includes a first field effect transistor of the high-concentration n-type gate, a second field effect transistor of the low-concentration n-type gate, for providing a gate voltage to the second field effect transistor 6. The temperature detection circuit in a semiconductor integrated circuit according to claim 5, comprising a source follower circuit comprising a third field effect transistor and at least one resistor. The temperature detection circuit in the semiconductor integrated circuit according to claim 1, wherein the second voltage source circuit is composed of a plurality of field effect transistors having different conductivity type gates. It said second voltage source circuit includes a first field effect transistor of the high-concentration n-type gate, a second field effect transistor of the high-concentration p-type gate, for providing a gate voltage to the second field effect transistor 8. The temperature detection circuit in a semiconductor integrated circuit according to claim 7, comprising a source follower circuit comprising a third field effect transistor and at least one resistor. 5. The semiconductor according to claim 1, wherein the subtracting circuit includes a differential amplifier including a first operational amplifier and first to fourth resistors, and a voltage follower including a second operational amplifier. A temperature detection circuit in an integrated circuit. The subtraction circuit is constituted by a first operational amplifier and the differential amplifier consisting of the first to fourth resistors, the source of the first to the resistance value of the fourth resistor, said second voltage supply circuit The temperature detection circuit in the semiconductor integrated circuit according to claim 1, wherein the temperature detection circuit is larger than a resistance value of a resistor constituting the follower circuit. The comparison circuit includes a first input transistor and the second field effect transistor the output of the field effect transistor and the subtraction circuit is inputted to the gate of the output is input to the gate of the source follower circuit of the second voltage source circuit 5. The temperature detection circuit in a semiconductor integrated circuit according to claim 1, wherein the temperature detection circuit comprises a differential amplification circuit and outputs a predetermined determination signal by comparing the magnitudes of the two input voltages. The temperature detection circuit in the semiconductor integrated circuit according to claim 1, wherein a reference voltage having no temperature coefficient generated by the second power supply circuit is externally output.

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