JP6446974B2 - Temperature detection circuit and semiconductor device - Google Patents

Description

  The present invention relates to a temperature detection circuit and a semiconductor device.

  2. Description of the Related Art Conventionally, a temperature detection circuit that uses a comparator with a hysteresis circuit to determine whether a voltage that changes according to temperature has reached a predetermined threshold voltage is known (see, for example, Patent Document 1).

JP 2005-122753 A

FIG. 1 is a configuration diagram illustrating an example of a temperature detection circuit 130 that determines whether or not the detection voltage Vbb that changes according to temperature has reached a predetermined threshold voltage Vaa by a comparator 170 with a hysteresis circuit 160. The threshold voltage Vaa is generated by dividing a constant reference voltage Vz generated by the reference voltage circuit 110 with a resistor. Detection voltage Vbb is a voltage detected by the temperature detecting element 180, the base of the bipolar transistor Q11 - which is the sum of the voltage _{V BE12} of the emitter - base voltage _{V BE11} and bipolar transistor Q12 of the emitter. Voltage _{V BE11, V BE12,} respectively, since the changes with a negative temperature characteristic (-2 mV / ° C.), the detection voltage Vbb having a negative temperature characteristic.

  However, if a comparator with a hysteresis circuit is used to determine the magnitude relationship between a voltage having temperature characteristics and a predetermined threshold voltage, the circuit scale becomes large because the number of elements constituting the comparator and the circuit that generates the threshold voltage is large. Easy and power consumption increases.

  Accordingly, it is an object of the present invention to provide a temperature detection circuit and a semiconductor device that can reduce the circuit scale and reduce power consumption even when hysteresis is given to temperature determination.

One idea is that
A reference voltage circuit that is supplied with a power supply voltage and generates and outputs a reference voltage;
A temperature characteristic imparting circuit for generating a temperature characteristic voltage obtained by imparting a temperature characteristic to the reference voltage;
A bias circuit for generating a bias voltage of the transistor based on the temperature characteristic voltage;
An input unit to which the bias voltage is input, and an output unit that outputs a result of determining that the temperature corresponding to the temperature characteristic voltage has reached a predetermined temperature based on the forward voltage between the base and the emitter of the transistor A determination circuit having:
A hysteresis circuit that is connected between the input unit and the output unit, and that applies hysteresis to the determination of the determination circuit;
The temperature characteristic voltage, the base of the transistor - have a temperature characteristic of the forward voltage and the reverse polarity of the emitter,
The temperature characteristic providing circuit is:
The reference voltage is input to a base, the power supply voltage is supplied to a collector, and a first NPN transistor that outputs the temperature characteristic voltage from an emitter is included,
The bias circuit divides the temperature characteristic voltage and inputs it to the input unit,
The determination circuit includes:
The input section is connected to the base, the emitter is grounded, the collector is connected to the emitter of the first NPN transistor via a resistor, and the second NPN transistor is turned off at room temperature;
Determining that a temperature corresponding to the temperature characteristic voltage has reached the predetermined temperature based on a forward voltage between a base and an emitter of the second NPN transistor;
The hysteresis circuit is:
A third NPN transistor having a collector connected to the base, an emitter grounded, and a collector connected to the emitter of the first NPN transistor via a second resistor;
A third resistor connecting the collector of the third NPN transistor and the base of the second NPN transistor;
The third NPN transistor is provided with a temperature detection circuit including a plurality of transistor elements connected in parallel .

  According to one aspect, even when hysteresis is applied to temperature determination, the circuit scale can be reduced and power consumption can be reduced.

It is a block diagram which shows an example of a temperature detection circuit. It is a block diagram which shows one Embodiment of a semiconductor device. It is a figure which shows an example of an overheat protection characteristic. It is a block diagram which shows an example of a temperature detection circuit. It is a block diagram which shows an example of a temperature detection circuit. It is a block diagram which shows an example of a temperature detection circuit. It is a block diagram which shows an example of a temperature detection circuit.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 2 is a configuration diagram illustrating an example of the regulator 100 which is an embodiment of the semiconductor device. The regulator 100 is, for example, an integrated circuit that generates a constant output voltage Vout based on the input voltage Vin. The regulator 100 includes a ground terminal 1, a power input terminal 2, and a power output terminal 3.

  The ground terminal 1 is a part connectable to the ground (GND), for example, an electrode connectable to the ground wiring. The power supply input terminal 2 is a part to which an input voltage Vin equal to the power supply voltage of the DC power supply 140 is input. Specific examples of the DC power supply 140 include a battery and a converter. The power output terminal 3 is a part from which the output voltage Vout is output. For example, the power output terminal 3 is an electrode that can be connected to a load to which the output voltage Vout is applied.

  The regulator 100 includes a temperature detection circuit 80 and a power supply circuit 20. The temperature detection circuit 80 is an example of a circuit that detects the ambient temperature (for example, the temperature of the regulator 100 or the power supply circuit 20) and outputs a signal corresponding to the detected temperature. For example, the reference voltage circuit 10 and the overheat A protection circuit 30.

  The reference voltage circuit 10 is an example of a reference voltage circuit that is supplied with a power supply voltage and generates and outputs a reference voltage. For example, the reference voltage circuit 10 generates a constant reference voltage Vz from an input voltage Vin. For example, the reference voltage Vz is a band gap voltage (≈1.2 V), and the reference voltage circuit 10 is a band gap reference circuit that generates a constant band gap voltage from the input voltage Vin. The temperature characteristic of the reference voltage Vz is substantially zero (≈0 mV / ° C.).

  The power supply circuit 20 is an example of a constant voltage circuit that outputs a constant voltage. For example, the power supply circuit 20 is a regulator circuit that generates an output voltage Vout adjusted to a constant voltage value based on the input voltage Vin.

  The overheat protection circuit 30 detects the ambient temperature (for example, the temperature of the regulator 100 or the power supply circuit 20), and outputs a signal corresponding to the detected temperature. The overheat protection circuit 30 determines, for example, whether or not the detected temperature has reached a predetermined temperature, and restricts the function of the power supply circuit 20 when it is determined that the detected temperature has risen above the predetermined shutdown temperature T1. It is a thermal shutdown circuit that outputs a shutdown signal Sd. On the other hand, when it is determined that the detected temperature is lower than the predetermined return temperature T2, the overheat protection circuit 30 releases the function restriction of the power supply circuit 20 by stopping the output of the shutdown signal Sd. The return temperature T2 is a temperature lower than the shutdown temperature T1.

  The power supply circuit 20 is an example of a protection target circuit that is protected based on a determination result of whether or not the detected temperature has reached a predetermined temperature. For example, the power supply circuit 20 stops outputting the output voltage Vout when the shutdown signal Sd is input. Thereby, it is possible to prevent the regulator 100 or the power supply circuit 20 from continuing to operate in an overheated state, and it is possible to protect the regulator 100 or the power supply circuit 20 from overheating. On the other hand, the power supply circuit 20 restarts the output of the output voltage Vout, for example, when the input of the shutdown signal Sd is stopped. Thereby, when the ambient temperature falls below the return temperature T2, the operation of the regulator 100 or the power supply circuit 20 can be returned.

  The overheat protection circuit 30 has overheat protection characteristics as shown in FIG. 3, for example. When it is determined that the detected temperature has risen above the predetermined shutdown temperature T1, the overheat protection circuit 30 switches the shutdown signal Sd from the inactive level to the active level. On the other hand, the overheat protection circuit 30 switches the shutdown signal Sd from the active level to the inactive level when it is determined that the detected temperature is lower than the predetermined return temperature T2. For example, the inactive level is a high level and the active level is a low level. As described above, the overheat protection circuit 30 has hysteresis in the magnitude determination between the detected temperature and the predetermined threshold temperature.

  FIG. 4 is a configuration diagram showing a temperature detection circuit 81 which is an example of the temperature detection circuit 80 of FIG. The temperature detection circuit 81 includes a reference voltage circuit 10 and an overheat protection circuit 31 that is an example of the overheat protection circuit 30 of FIG.

  The overheat protection circuit 31 includes a temperature characteristic providing circuit 40. The temperature characteristic applying circuit 40 generates a temperature characteristic voltage Va obtained by adding a temperature characteristic to the reference voltage Vz. The temperature characteristic applying circuit 40 includes, for example, a transistor Q1.

  The transistor Q1 is an example of an NPN-type first bipolar transistor having a base to which the reference voltage Vz is input, a collector to which the input voltage Vin is supplied, and an emitter connected in series to the bias circuit 41.

The overheat protection circuit 31 includes a bias circuit 41. The bias circuit 41 inputs a bias voltage Vb generated by dividing the emitter voltage of the transistor Q1 (voltage between the emitter of the transistor Q1 and the ground) to the input unit 51. The emitter voltage of the transistor Q1 is a temperature characteristic voltage Va output from the emitter of the transistor Q1, and is a difference (Vz−V _BE1 ) obtained by subtracting the voltage V _BE1 from the reference voltage Vz. That is, Va = Vz− _VBE1 . The voltage V _BE1 is a voltage between the base and emitter of the transistor Q1.

  The bias circuit 41 has, for example, a series circuit in which a resistor R1 and a resistor R2 are connected in series, and divides the emitter voltage of the transistor Q1 by the resistors R1 and R2. One end of the resistor R1 is connected to the emitter of the transistor Q1, the other end of the resistor R1 is connected to one end of the resistor R2, and the other end of the resistor R2 is grounded. The input unit 51 is connected to the other end of the resistor R1 and one end of the resistor R2.

  The overheat protection circuit 31 includes a determination circuit 50. The determination circuit 50 determines whether or not the temperature corresponding to the temperature characteristic voltage Va has reached a predetermined temperature based on the forward voltage Vf2 between the base and the emitter of the transistor Q2. The determination circuit 50 includes an input unit 51 and an output unit 52. The input unit 51 is an input point to which the bias voltage Vb is input. The output unit 52 outputs a determination level representing a result of determining whether or not the temperature corresponding to the temperature characteristic voltage Va has reached a predetermined temperature based on the forward voltage Vf2 between the base and the emitter of the transistor Q2. Is a point. In addition, the determination circuit 50 includes a transistor Q2 and a resistor R4 that pulls up the collector of the transistor Q2 to the emitter of the transistor Q1.

  The transistor Q2 is an example of an NPN-type second bipolar transistor having a base to which the input unit 51 is connected, a collector to which the output unit 52 is connected, and an emitter that is grounded to the ground. The collector of the transistor Q2 is pulled up to the emitter of the transistor Q1 by a resistor R4 having one end connected to the output unit 52.

For example, the determination circuit 50 determines whether or not the temperature corresponding to the bias voltage Vb has reached a predetermined temperature based on the magnitude relationship between the bias voltage Vb and the forward voltage Vf2. In the illustrated case, the base-emitter voltage V _BE2 of the transistor Q2 matches the forward voltage Vf2.

  For example, in the determination circuit 50, when the bias voltage Vb increases and reaches the forward voltage Vf2 between the base and the emitter of the transistor Q2, the temperature corresponding to the temperature characteristic voltage Va increases and reaches the shutdown temperature T1. Since the determination can be made, the transistor Q2 is switched from OFF to ON. The determination circuit 50 outputs a low-level determination signal from the output unit 52 indicating that it has been determined that the temperature corresponding to the temperature characteristic voltage Va has risen to reach the shutdown temperature T1 by turning on the transistor Q2.

  On the other hand, in the determination circuit 50, when the bias voltage Vb decreases and reaches the forward voltage Vf2 between the base and the emitter of the transistor Q2, the temperature corresponding to the temperature characteristic voltage Va decreases and reaches the return temperature T2. Since the determination can be made, the transistor Q2 is switched from on to off. The determination circuit 50 outputs from the output unit 52 a high-level determination signal indicating that it has been determined that the temperature corresponding to the temperature characteristic voltage Va has decreased to reach the return temperature T2 by turning off the transistor Q2.

  The overheat protection circuit 31 includes a hysteresis circuit 60 connected between the input unit 51 and the output unit 52. The hysteresis circuit 60 gives hysteresis to the determination of the determination circuit 50. The hysteresis circuit 60 includes, for example, a transistor Q3, a resistor R3, and a resistor R5.

  The transistor Q3 is a third NPN type transistor having a base connected to the collector of the transistor Q2 via the output unit 52, an emitter grounded to the ground, and a collector pulled up to the emitter of the transistor Q1 by the resistor R5. This is an example of a bipolar transistor.

  The resistor R3 is an example of a connection circuit that connects the collector of the transistor Q3 and the base of the transistor Q2. For example, one end of the resistor R3 is connected to a node to which the collector of the transistor Q3 and one end of the resistor R5 are connected, and the other end of the resistor R3 is connected to the input unit 51 connected to the base of the transistor Q2.

  The overheat protection circuit 31 includes a transistor Q4. The transistor Q4 is an example of an output circuit that outputs a shutdown signal Sd to the power supply circuit 20. For example, the transistor Q4 is an example of an NPN-type fourth bipolar transistor having a base to which the collector of the transistor Q3 is connected, an emitter grounded to the ground, and a collector that outputs a shutdown signal Sd. For example, the collector of the transistor Q4 is connected to the power supply circuit 20.

  Next, the hysteresis generated by the hysteresis circuit 60 will be described.

  In the period before shutdown due to temperature rise, the transistor Q2 is off, the transistor Q3 is on, and the transistor Q4 is off. That is, in the period from when the bias voltage Vb lower than the forward voltage Vf2 between the base and emitter of the transistor Q2 rises to reach the forward voltage Vf2, the level of the determination signal output from the output unit 52 and the shutdown signal Sd The level of is high. During this period, the resistor R2 and the resistor R3 are connected in parallel by turning on the transistor Q3.

したがって、シャットダウン前のバイアス電圧Ｖｂは、式１又は式２で表される。図示の場合、バイアス電圧Ｖｂは、トランジスタＱ２のベース−エミッタ間の電圧Ｖ_ＢＥ２に等しい。一方、トランジスタＱ１，Ｑ２のベース−エミッタ間の順方向電圧Ｖｆ１，Ｖｆ２は、周囲温度が高くなるほど低下する負の温度特性を有する。よって、トランジスタＱ１，Ｑ２のベース−エミッタ間の電圧Ｖ_ＢＥ１，Ｖ_ＢＥ２は、式３及び式４の関係が成立する。Ｖｆ１ａは、常温（Ｔａ＝２５℃）時のトランジスタＱ１のベース−エミッタ間の順方向電圧Ｖｆ１である。Ｖｆ２ａは、常温（Ｔａ＝２５℃）時のトランジスタＱ２のベース−エミッタ間の順方向電圧Ｖｆ２である。ｋは、バイポーラトランジスタのベース−エミッタ間の順方向電圧Ｖｆの負の温度特性を表す温度係数である（例えば、ｋ＝−２ｍＶ／℃）。Ｔは、絶対温度である。

Therefore, the bias voltage Vb before shutdown is expressed by Equation 1 or Equation 2. In the illustrated case, the bias voltage Vb is equal to the base-emitter voltage V _BE2 of the transistor Q2. On the other hand, the forward voltages Vf1 and Vf2 between the base and emitter of the transistors Q1 and Q2 have negative temperature characteristics that decrease as the ambient temperature increases. Therefore, the relations of the expressions 3 and 4 are established between the base-emitter voltages V _BE1 and V _BE2 of the transistors Q1 and Q2. Vf1a is a forward voltage Vf1 between the base and the emitter of the transistor Q1 at room temperature (Ta = 25 ° C.). Vf2a is a forward voltage Vf2 between the base and the emitter of the transistor Q2 at room temperature (Ta = 25 ° C.). k is a temperature coefficient representing the negative temperature characteristic of the forward voltage Vf between the base and the emitter of the bipolar transistor (for example, k = −2 mV / ° C.). T is the absolute temperature.

The temperature characteristic of the reference voltage Vz is substantially zero (≈0 mV / ° C.), and the voltage V _BE1 (= forward voltage Vf1) between the base and the emitter of the transistor Q1 has a negative temperature characteristic. Va (= Vz−V _BE1 ) has a positive temperature characteristic. On the other hand, the base-emitter voltage V _BE2 (= forward voltage Vf2) of the transistor Q2 has a negative temperature characteristic. That is, the temperature characteristic voltage Va has a temperature characteristic opposite to that of the forward voltage Vf2.

  The absolute temperature T derived from the simultaneous equations of Equations 1, 2, 3, and 4 represents the shutdown temperature T1. In other words, in Equations 1 to 4, the shutdown temperature T1 can be set to an arbitrary temperature by adjusting constants such as the resistor R1 to an appropriate value.

  On the other hand, in the period before returning from the shutdown, the transistor Q2 is on, the transistor Q3 is off, and the transistor Q4 is on. That is, in the period from when the bias voltage Vb higher than the forward voltage Vf2 between the base and the emitter of the transistor Q2 decreases and reaches the forward voltage Vf2, the level of the determination signal output from the output unit 52 and the shutdown signal Sd The level of is low level.

したがって、シャットダウンから復帰する前のシャットダウン状態でのバイアス電圧Ｖｂ'は、式５又は式６で表される。ただし、式５において、抵抗Ｒ１の抵抗値は抵抗Ｒ５の抵抗値よりも十分に大きいとする。

Therefore, the bias voltage Vb ′ in the shutdown state before returning from the shutdown is expressed by Equation 5 or Equation 6. However, in Equation 5, it is assumed that the resistance value of the resistor R1 is sufficiently larger than the resistance value of the resistor R5.

  The absolute temperature T derived from the simultaneous equations of equations 3, 4, 5, and 6 represents the return temperature T2. In other words, in Equations 3, 4, 5, and 6, the return temperature T2 can be set to an arbitrary temperature by adjusting constants such as the resistor R1 to appropriate values.

  By setting the shutdown temperature T1 and the return temperature T2 in this way, an overheat protection characteristic having a hysteresis characteristic as shown in FIG. 3 is obtained. Further, according to the above-described embodiment, the comparator for comparing the magnitude relationship between the voltage having the temperature characteristic and the predetermined threshold voltage and the generation circuit for generating the threshold voltage are unnecessary, so that the circuit scale and power consumption of the temperature detection circuit are not required. Can be reduced.

Further, according to the above-described embodiment, at room temperature (Ta = 25 ° C.) lower than the return temperature T2,
Vz = 1.2V
Vf1 = Vf2 = Vf3 = Vf4 = 0.7V
Then,
Vz <Vf1 + Vf2 = Vf1 + Vf3 = Vf1 + Vf4
The relationship is established. Vf1, Vf2, Vf3, and Vf4 are forward voltages between the base and emitter of the transistors Q1, Q2, Q3, and Q4, respectively.

Vz <Vf1 + Vf2 = Vf1 + Vf3 = Vf1 + Vf4
If this relationship is established, the base currents flowing through the respective bases of the transistors Q2, Q3, and Q4 cannot be secured, so that the transistors Q2, Q3, and Q4 are all turned off.

  Therefore, the circuit current I flowing through the overheat protection circuit 31 via the transistor Q1 flows through the resistors R1 and R2 without flowing through the transistors Q2, Q3, and Q4, so that the current consumption of the overheat protection circuit 31 can be suppressed. That is, current consumption of the temperature detection circuit 81 and the regulator 100 can be suppressed in a normal room temperature environment where the regulator 100 is used.

なお、回路電流Ｉは、式７で表すことができる。ただし、抵抗Ｒ１の抵抗値は抵抗Ｒ５の抵抗値よりも十分に大きいとする。

The circuit current I can be expressed by Equation 7. However, it is assumed that the resistance value of the resistor R1 is sufficiently larger than the resistance value of the resistor R5.

  The transistor Q3 may be composed of a plurality of transistor elements connected in parallel. As a result, the forward voltage Vf3 between the base and the emitter of the transistor Q3 can be lowered, so that the transistor Q3 is turned off from the on-off state while the temperature rises from room temperature to the shutdown temperature T1, and the transistor Q4 is turned off. Can be reliably switched from on to off. That is, it is possible to prevent a malfunction in which the transistor Q4 is erroneously switched from OFF to ON before the transistor Q3 is switched from ON to OFF while the temperature is rising from the normal temperature to the shutdown temperature T1.

なお、式８は、バイポーラトランジスタのベース−エミッタ間の順方向電圧Ｖｆの一般式である。

Expression 8 is a general expression of the forward voltage Vf between the base and the emitter of the bipolar transistor.

V _T is a thermal voltage, ln is a natural logarithm, Ie is an emitter current, n is the number of transistor elements connected in parallel, and Is is a saturation current.

  FIG. 5 is a configuration diagram showing a temperature detection circuit 82 which is an example of the temperature detection circuit 80 of FIG. The temperature detection circuit 82 includes a reference voltage circuit 10 and an overheat protection circuit 32 that is an example of the overheat protection circuit 30 of FIG. A description of the same configurations and effects as those of the above-described embodiment will be omitted.

  In the overheat protection circuit 32 of FIG. 5, the resistors R4 and R5 of the overheat protection circuit 31 of FIG. 4 are replaced with constant current sources 71 and 72, respectively, which are examples of constant current circuits for supplying a constant current. The determination circuit 53 includes a transistor Q2 and a constant current source 71. The hysteresis circuit 61 includes a transistor Q3, a resistor R3, and a constant current source 72.

  Thus, the transistor Q2 may be biased by the constant current source 71, and the transistor Q3 may be biased by the constant current source 72. The collector of the transistor Q2 may be pulled up to the input voltage Vin through the constant current source 71, or may be pulled up to the emitter of the transistor Q1 through the constant current source 71. The collector of the transistor Q3 may be pulled up to the input voltage Vin through the constant current source 72, or may be pulled up to the emitter of the transistor Q1 through the constant current source 72.

  FIG. 6 is a configuration diagram showing a temperature detection circuit 83 which is an example of the temperature detection circuit 80 of FIG. The temperature detection circuit 83 includes the reference voltage circuit 10 and an overheat protection circuit 33 that is an example of the overheat protection circuit 30 of FIG. A description of the same configurations and effects as those of the above-described embodiment will be omitted.

  The temperature detection circuit 81 of FIG. 4 is an example of a circuit in which a transistor for generating hysteresis and a path for generating a shutdown signal are shared by the transistor Q3. On the other hand, the temperature detection circuit 83 in FIG. 6 is an example of a circuit in which the hysteresis generating transistor Q3 and the shutdown signal generating path are separated.

  The determination circuit 54 includes transistors Q2 and Q5 and resistors R4, R6 and R7. Resistor R7 is connected in series between the collector of transistor Q2 and the base of transistor Q5. The transistor Q5 has a base connected to the collector of the transistor Q2 through the resistor R7, an emitter grounded to the ground, and a collector connected to the emitter of the transistor Q1 through the resistor R6. This is an example of a bipolar transistor. The collector of transistor Q5 is connected to the base of transistor Q4.

  Transistor Q5 may be composed of a plurality of transistor elements connected in parallel. Arbitrary m transistor elements are connected in parallel, whereby the forward voltage Vf5 between the base and the emitter of the transistor Q5 can be lowered. Therefore, the transistor Q4 can be reliably switched from OFF to ON after the transistor Q5 is switched from ON to OFF while the temperature rises from room temperature to the shutdown temperature T1.

  Hysteresis circuit 62 includes resistors R3, R5, and R8, and transistor Q3. Resistor R8 is connected in series between the collector of transistor Q2 and the base of transistor Q3.

  FIG. 7 is a configuration diagram showing a temperature detection circuit 84 which is an example of the temperature detection circuit 80 of FIG. The temperature detection circuit 84 includes a reference voltage circuit 11 and an overheat protection circuit 31 that is an example of the overheat protection circuit 30 of FIG. A description of the same configurations and effects as those of the above-described embodiment will be omitted.

  The temperature detection circuit 84 includes a reference voltage circuit 11 that generates a reference voltage Vzz obtained by dividing the reference voltage Vz by resistors R9 and R10. A reference voltage Vzz is input to the base of the transistor Q1. According to the embodiment of FIG. 7, it is possible to generate the reference voltage Vzz having almost no temperature characteristics and having a voltage value lower than the reference voltage Vz.

  As described above, the temperature detection circuit and the semiconductor device have been described in the embodiment. However, the present invention is not limited to the embodiment. Various modifications and improvements such as combinations and substitutions with some or all of the other embodiments are possible within the scope of the present invention.

  For example, the semiconductor device is not limited to the regulator, and may be other embodiments such as a DC-DC converter, an AC-DC converter, a load driving device, and the like.

  For example, transistors Q3, Q4, and Q5 may be N-channel MOS transistors.

DESCRIPTION OF SYMBOLS 1 Ground terminal 2 Power supply input terminal 3 Power supply output terminal 10, 11 Reference voltage circuit 20 Power supply circuit 30, 31, 32, 33 Overheat protection circuit 40 Temperature characteristic provision circuit 41 Bias circuit 50, 53, 54 Judgment circuit 51 Input part 52 Output Units 60, 61, 62, 160 Hysteresis circuits 71, 72 Current sources 80, 81, 82, 83, 84, 130 Temperature detection circuit 100 Regulator 140 DC power supply 170 Comparator 180 Temperature detection element Q * Transistor (* is a number)

Claims (7)

A reference voltage circuit that is supplied with a power supply voltage and generates and outputs a reference voltage;
A temperature characteristic imparting circuit for generating a temperature characteristic voltage obtained by imparting a temperature characteristic to the reference voltage;
A bias circuit for generating a bias voltage of the transistor based on the temperature characteristic voltage;
An input unit to which the bias voltage is input, and an output unit that outputs a result of determining that the temperature corresponding to the temperature characteristic voltage has reached a predetermined temperature based on the forward voltage between the base and the emitter of the transistor A determination circuit having:
A hysteresis circuit that is connected between the input unit and the output unit, and that applies hysteresis to the determination of the determination circuit;
The temperature characteristic voltage, the base of the transistor - have a temperature characteristic of the forward voltage and the reverse polarity of the emitter,
The temperature characteristic providing circuit is:
The reference voltage is input to a base, the power supply voltage is supplied to a collector, and a first NPN transistor that outputs the temperature characteristic voltage from an emitter is included,
The bias circuit divides the temperature characteristic voltage and inputs it to the input unit,
The determination circuit includes:
The input section is connected to the base, the emitter is grounded, the collector is connected to the emitter of the first NPN transistor via a resistor, and the second NPN transistor is turned off at room temperature;
Determining that a temperature corresponding to the temperature characteristic voltage has reached the predetermined temperature based on a forward voltage between a base and an emitter of the second NPN transistor;
The hysteresis circuit is:
A third NPN transistor having a collector connected to the base, an emitter grounded, and a collector connected to the emitter of the first NPN transistor via a second resistor;
A third resistor connecting the collector of the third NPN transistor and the base of the second NPN transistor;
The third NPN transistor is a temperature detection circuit including a plurality of transistor elements connected in parallel . The temperature detection circuit according to claim 1, further comprising a fourth NPN transistor having a base connected to a collector of the third NPN transistor and an emitter grounded. The temperature detection circuit according to claim 1 or 2 , wherein the resistor connected to the collector of the second NPN transistor is a constant current circuit. The sum of the forward voltage between the base and emitter of the first NPN transistor and the forward voltage between the base and emitter of the second NPN transistor is higher than the reference voltage at room temperature or lower than the predetermined temperature. The temperature detection circuit according to any one of claims 1 to 3 , wherein the temperature detection circuit is also higher. It said reference voltage is a bandgap voltage, a temperature sensing circuit according to any one of claims 1 to 4. A temperature detection circuit according to any one of claims 1 to 5 ;
And a protection target circuit that is protected based on a determination result of the determination circuit. The semiconductor device according to claim 6 , wherein the protection target circuit is a constant voltage circuit that outputs a constant voltage.

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