JP7421356B2 - temperature detection circuit - Google Patents

Description

The present invention relates to a temperature detection circuit.

Semiconductor integrated circuits are equipped with temperature detection circuits for overheat protection and overheat notification such as thermal shutdown. FIG. 1 is a circuit diagram showing an example of a conventional temperature detection circuit. Temperature detection circuit 900 includes a temperature dependent voltage source 910, a reference voltage source 920, and a comparator 930. Temperature-dependent voltage source 910 includes a diode (or bipolar transistor) including a PN junction, and a current source that supplies a constant current to the PN junction. The forward voltage Vf(T) of a diode biased with a constant current exhibits a negative temperature coefficient. Temperature-dependent voltage source 910 utilizes this property to generate voltage Vf(T) with a negative temperature coefficient. Reference voltage source 920 is a bandgap reference circuit and generates a temperature independent reference voltage V _REF . Comparator 930 compares negative temperature coefficient voltage Vf with reference voltage V _REF and outputs a signal TEMP_DET indicating the comparison result.

FIG. 2 is a diagram illustrating the operation of the temperature detection circuit of FIG. 1. The upper row shows the temperature dependence of the negative temperature characteristic voltage Vf and the reference voltage V _REF , and the lower row shows the relationship between the temperature T and the temperature detection signal TEMP_DET. In a region where the temperature is low, Vf>V _REF , and as the temperature rises, Vf decreases, and at a certain threshold temperature _TTH , the magnitude relationship between the voltages Vf and V _REF is reversed, and the comparator 930 Output changes. According to this temperature detection circuit 900, it is possible to detect that the temperature of a semiconductor device in which it is integrated exceeds (or falls below) a certain threshold value.

Japanese Patent Application Publication No. 2000-241252

The threshold value _TTH of the temperature detection circuit is affected by process variations, power supply voltage variations, and matching variations. Process variations and power supply voltage variations are collectively referred to as PV variations. Furthermore, matching variations are mismatches between paired elements, and refer to variations that deteriorate the relative accuracy between paired elements (transistors or resistors).

Fluctuations in threshold temperature due to PV variations can be canceled, but fluctuations in threshold temperature due to matching variations cannot be canceled, so the final stability of the threshold temperature is dominated by the effect of matching variations. become a target. When the present inventors studied the temperature detection circuit 900 of FIG. 1 using a simulator, they came to recognize the problem that the threshold temperature fluctuates greatly due to matching variations.

The present invention has been made in view of the above problems, and one exemplary object of one aspect of the present invention is to provide a temperature detection circuit in which variations and fluctuations in threshold temperature are suppressed.

One aspect of the present invention relates to a temperature detection circuit. The temperature detection circuit has a first voltage having a positive temperature characteristic based on the difference between forward voltages of two PN junctions having different current densities, and a second voltage having a negative temperature characteristic based on the forward voltage of the PN junction. , and a comparator that compares the first voltage and the second voltage.

Note that arbitrary combinations of the above constituent elements and expressions of the present invention converted between methods, devices, etc. are also effective as aspects of the present invention. Furthermore, the description in this section (Means for Solving the Problems) does not describe all essential features of the present invention, and therefore, subcombinations of the described features may also constitute the present invention. .

According to an aspect of the present invention, variations and fluctuations in the threshold temperature of the temperature detection circuit can be suppressed.

FIG. 2 is a circuit diagram showing an example of a conventional temperature detection circuit. FIG. 2 is a diagram illustrating the operation of the temperature detection circuit of FIG. 1. FIG. FIG. 2 is a block diagram of a temperature detection circuit according to an embodiment. 4 is a diagram illustrating the operation of the temperature detection circuit of FIG. 3. FIG. 5(a) is a diagram showing the influence of offset on the temperature detection circuit of FIG. 1, and FIG. 5(b) is a diagram showing the influence of offset on the temperature detection circuit of FIG. 3. 1 is a block diagram of a temperature detection circuit according to Example 1. FIG. FIG. 2 is a block diagram of a temperature detection circuit according to a second embodiment. FIG. 2 is a circuit diagram showing a configuration example of a comparator. 3 is a circuit diagram of a temperature detection circuit according to Example 3. FIG. FIGS. 10A and 10B are diagrams (simulation results) showing the operation of the temperature detection circuit. FIG. 3 is a diagram showing an input offset voltage V _OFS introduced into a comparator.

(Summary of embodiment)
One embodiment disclosed herein relates to a temperature detection circuit. The temperature detection circuit has a first voltage having a positive temperature characteristic based on the difference between forward voltages of two PN junctions having different current densities, and a second voltage having a negative temperature characteristic based on the forward voltage of the PN junction. , and a comparator that compares the first voltage and the second voltage.

According to this configuration, it is possible to reduce the fluctuation range of the threshold temperature when the relative potentials of the first voltage and the second voltage vary.

The comparator may be configured such that its input offset voltage varies in response to the second voltage. Thereby, variations and fluctuations in threshold temperature can be further suppressed.

The comparator may include a differential pair, a tail current source that supplies a tail current to the differential pair, and a current mirror circuit connected as a load to the differential pair. An offset current corresponding to the second voltage may be input to the current mirror circuit. Thereby, variations in threshold temperature caused by variations in the size of the PN junction can be reduced.

The voltage generation circuit includes a first bipolar transistor whose base and collector are connected, a second bipolar transistor whose base and collector are connected and which is larger in size than the first bipolar transistor, and a resistor connected to the collector of the second bipolar transistor. and a current mirror circuit that returns the current flowing through the second bipolar transistor and supplies it to the first bipolar transistor. The first voltage may be proportional to the current flowing through the second bipolar transistor.

The second voltage may be responsive to a base-emitter voltage of the first bipolar transistor.

The voltage generation circuit may include a PTAT (Proportional To Absolute Temperature) current source having a pair of bipolar transistors of different sizes. The first voltage may be proportional to a Proportional To Absolute Temperature (PTAT) current generated by the PTAT current source, and the second voltage may be responsive to a voltage drop across one of the pair of bipolar transistors of the PTAT current source.

The voltage generation circuit may further include a first I/V conversion circuit that converts the PTAT current into a first voltage, and a constant multiplier circuit that multiplies the voltage drop of one of the pair of bipolar transistors by a constant.

The first I/V conversion circuit may include a resistor provided on the path of the PTAT current. Thereby, the voltage drop across the resistance can be taken out as the first voltage.

The resistance value of the resistor may change between two values depending on the output of the comparator. This allows the comparator to have hysteresis.

The constant multiplier circuit includes a V/I conversion circuit that converts the voltage drop of one of the pair of bipolar transistors into a current signal, and a second I/V conversion circuit that converts the output current of the V/I conversion circuit into a second voltage. , may also be included.

The comparator may include a differential pair, a tail current source that supplies a tail current to the differential pair, and a current mirror circuit connected as a load to the differential pair. The tail current corresponds to a current signal generated by the V/I conversion circuit, and the current mirror circuit may be supplied with an offset current generated by the V/I conversion circuit. This allows an input offset voltage that is independent of temperature and dependent on process variations to be introduced into the comparator.

The comparator further includes a repair circuit that supplies the current mirror circuit with a correction current obtained by multiplying the current signal generated by the V/I conversion circuit by a variable coefficient, and the variable coefficient may be trimmable.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on preferred embodiments with reference to the drawings. Identical or equivalent components, members, and processes shown in each drawing are designated by the same reference numerals, and redundant explanations will be omitted as appropriate. Further, the embodiments are illustrative rather than limiting the invention, and all features and combinations thereof described in the embodiments are not necessarily essential to the invention.

In this specification, "a state in which member A is connected to member B" refers to a case where member A and member B are physically directly connected, or where member A and member B are electrically connected. This also includes cases where it is indirectly connected via other members that do not affect the state or inhibit the function.
Similarly, "a state in which member C is provided between member A and member B" refers to the case where member A and member C or member B and member C are directly connected, as well as when member C is electrically connected. This also includes cases where the connection is made indirectly through other members that do not affect the connection state or inhibit the function.

FIG. 3 is a block diagram of the temperature detection circuit 100 according to the embodiment. The temperature detection circuit 100 is integrated into a semiconductor chip and determines whether the temperature of the semiconductor chip is higher or lower than a predetermined threshold. The temperature detection circuit 100 mainly includes a voltage generation circuit 110 and a comparator 130. The voltage generation circuit 110 generates a first voltage _V1 having a positive temperature characteristic based on the difference ΔVf between the forward voltages of two PN junctions having different current densities, and a negative temperature characteristic based on the forward voltage Vf of the PN junction. A second voltage V ₂ is generated. The first voltage _V1 is a so-called PTAT (Proportional To Absolute Temperature) voltage.

The comparator 130 compares the first voltage V ₁ and the second voltage V ₂ and outputs a temperature detection signal TEMP_DET indicating the comparison result. Comparator 130 may have hysteresis.

The above is the basic configuration of the temperature detection circuit 100. Next, its operation will be explained. FIG. 4 is a diagram illustrating the operation of the temperature detection circuit 100 of FIG. 3. The upper part of FIG. 4 shows the temperature dependence of the first voltage _V1 and the second voltage _V2 , and the lower part shows the relationship between the temperature T and the temperature detection signal TEMP_DET.

In the state of V ₁ <V ₂ , the temperature detection signal TEMP_DET, which is the output of the comparator 130, takes the first level (low in this example), and in the state of V ₁ >V ₂ , the temperature detection signal TEMP_DET takes the second level (low in this example). In this example, select high).

Here, the first voltage V ₁ becomes larger as the temperature T rises, and the second voltage V ₂ becomes smaller as the temperature T rises. Since the two voltages V ₁ and V ₂ intersect at a certain threshold temperature T _TH , the temperature detection signal TEMP_DET indicates the magnitude relationship between the temperature T and the threshold value T _TH . As will be described later, when the comparator 130 has an input offset voltage V _OFS , the output of the comparator 130 changes when the potential difference between V ₁ and V ₂ becomes equal to the input offset voltage V _OFS . becomes.

The above is the operation of the temperature detection circuit 100. Next, we will explain its advantages.

For simplicity, it is assumed that at least one of the two voltages input to the comparator is offset upward or downward due to PV variation or matching variation. For ease of understanding, it is assumed here that in the temperature detection circuit 900 of FIG. 1 and the temperature detection circuit 100 of FIG. 3, the voltages Vf and _V2 having negative temperature coefficients are offset to the high potential side by V _SHIFT . do. 5(a) is a diagram showing the influence of offset on the temperature detection circuit 900 of FIG. 1, and FIG. 5(b) is a diagram showing the influence of offset on the temperature detection circuit 100 of FIG. 3.

In the temperature detection circuit 900 of FIG. 1, when the voltage Vf having a negative temperature coefficient α (<0) shifts upward by V _SHIFT as indicated by Vf', the threshold temperature T _TH becomes ΔT _TH =V _SHIFT /|α|, becomes higher.

On the other hand, in the temperature detection circuit 100 of FIG. 3, when the voltage V ₂ having a negative temperature coefficient α (<0) shifts upward by V _SHIFT as shown by V ₂ ', the threshold temperature T _TH changes. , ΔT _TH =V _SHIFT /(|α|+β), becomes higher. β is the positive temperature coefficient (V/degree) of the second voltage _V2 .

Therefore, it can be said that the temperature detection circuit 100 of FIG. 3 is less susceptible to voltage offset than the temperature detection circuit 900 of FIG. 1. This is the first advantage of temperature detection circuit 100.

Next, a second advantage of the temperature detection circuit 100 will be explained. The effects of PV variations and matching variations in the temperature detection circuit 900 of FIG. 1 and the temperature detection circuit 100 of FIG. 3 will be described. Regarding the conventional temperature detection circuit 900 shown in FIG. 1 and the temperature detection circuit 100 shown in FIG. 3, the magnitude of PV variation and matching variation was verified using a circuit simulator.

In the conventional circuit, the fluctuation width ΔT TH of the threshold temperature T _TH due to PV _{variation is 14.69 degrees, and the fluctuation range ΔT TH of} the threshold temperature T _TH due to matching variation is 9.37 degrees, and the overall , a fluctuation of 24.06 degrees is expected.

On the other hand, when a simulation is performed using the same device parameters for the temperature detection circuit 100 in FIG. 4, the variation width ΔT _TH of the threshold temperature T _TH due to PV variation is 18.52 degrees, which is due to matching variation. The fluctuation width ΔT _TH of the threshold temperature T _TH was found to be 2.06 degrees. Therefore, the overall fluctuation range ΔT _TH is 20.58 degrees, which can be suppressed compared to the conventional technology.

As described above, the component of the shift amount V _SHIFT caused by PV variations can be reduced to some extent by adding an offset circuit. On the other hand, a component of the shift amount V _SHIFT that is caused by matching variations cannot be canceled. The temperature detection circuit 100 in FIG. 3 has a smaller effect of matching variations than the temperature detection circuit 900 in FIG. In this case, the variation width ΔT _TH of the threshold temperature T _TH that remains can be reduced.

The present invention extends to various devices and methods that can be understood as the block diagram and circuit diagram of FIG. 3 or derived from the above description, and is not limited to a specific configuration. Hereinafter, more specific configuration examples and examples will be described, not to narrow the scope of the present invention, but to help understand and clarify the essence and operation of the invention.

(Example 1)
FIG. 6 is a block diagram of the temperature detection circuit 100A according to the first embodiment. The voltage generation circuit 110A includes a PTAT current source 112, an I/V conversion circuit 114, and a constant multiplier circuit 116. PTAT current source 112 generates a PTAT current I _PTAT . PTAT current source 112 includes two diodes D1, D2, a resistor R1, and a current mirror circuit CM1. The diodes D1 and D2 may be bipolar transistors whose bases and collectors are connected.

For example, the second diode D2 has a size n times (for example, eight times) the size of the first diode D1, and the resistor R1 is connected in series with the second diode D2. The current mirror circuit CM1 is biased so that the potentials Vx and Vy of the two nodes X and Y are equal, and at this time, the currents I _D1 and I D2 flowing through the two diodes D1 and _D2 are equal. Since the two diodes D1 and D2 have different sizes, when the same current flows through them, the current density of the first diode D1 is n times that of the second diode D2. At this time, the differential voltage ΔVf between the forward voltages Vf ₁ and Vf ₂ of the two diodes D1 and D2 is
ΔVf=Vf ₁ -Vf ₂ =V _T ln(n)
becomes.

Differentiating the differential voltage ΔVf with respect to temperature, we get
dΔVf/dT=(k/q)ln(n)
get. Since k is Boltzmann's constant and q is an elementary charge, both of which are constants including n, ΔVf is a voltage proportional to absolute temperature T.

A differential voltage ΔVf is generated across the resistor R1. Therefore, the current flowing through the resistor R1, in other words, the current I _D2 flowing through the second diode D2 is:
I _D2 =ΔVf/R1
Therefore, the current is proportional to absolute temperature (PTAT). The current mirror circuit CM1 copies the current ID2 flowing through the second diode _D2 and outputs it as a PTAT current _IPTAT (source in this example). Note that the PTAT current source 112 may be configured with the top and bottom reversed, and in this case, the PTAT current _IPTAT is sunk.

The I/V conversion circuit 114 converts the PTAT current _IPTAT output from the current mirror circuit CM1 into a first voltage _V1 that is a voltage signal. When the conversion gain of the I/V conversion circuit 114 is g, V ₁ =g×I _PTAT , and the first voltage V ₁ is a voltage proportional to absolute temperature (PTAT).

Further, the voltage generation circuit 110A outputs a second voltage V ₂ corresponding to the forward voltage Vf ₂ of one of the two diodes D1 and D2 (D1 in this example). For example, the constant multiplier circuit 116 multiplies the forward voltage Vf ₁ of one of the two diodes D1 and D2 (D1 in this example) by a constant (k times) and outputs it as a second voltage V ₂ .
_V2 =k× _Vf1
The forward voltage Vf of a diode (PN junction) biased with a constant current has a negative temperature characteristic, and its temperature coefficient is -1.5 mV/°K at T = 300 K and Vf = 750 mV. It has been known. Therefore, the temperature coefficient α of the second voltage V ₂ is (k×−1.5) mV/°K. Note that the constant multiplier circuit 116 may be omitted, and in this case, k=1.

(Example 2)
FIG. 7 is a block diagram of a temperature detection circuit 100B according to the second embodiment. The basic configuration of the voltage generation circuit 110B is similar to the voltage generation circuit 110A in FIG. 6. Constant multiplier circuit 116 includes a V/I conversion circuit 118 and an I/V conversion circuit 120. The V/I conversion circuit 118 converts the forward voltage Vf ₁ of the first diode D1 into a current signal _IA . The I/V conversion circuit 120 reconverts the current signal _IA into a voltage signal and outputs it as a second voltage _V2 . Further, the V/I conversion circuit 118 converts the forward voltage _Vf1 into a current signal _IB .

The comparator 130B is configured such that the input offset voltage V _OFS can be adjusted according to the offset current I _OFS supplied from the outside to the offset adjustment terminal OFS. A current I _B generated by the V/I conversion circuit 118 is supplied to the offset adjustment terminal _{OFS as an offset current I OFS} . This makes it possible to cancel fluctuations in the threshold temperature _TTH caused by process variations and power supply fluctuations.

FIG. 8 is a circuit diagram showing a configuration example of the comparator 130B. Comparator 130B includes a differential input stage 132, an output stage 134, and a repair circuit 136.

Differential input stage 132 includes an input differential pair 138, a tail current source 140, and a load 142. The tail current source 140 supplies the input differential pair 138 with a tail current I _TAIL proportional to the constant current I _C1 supplied to the current input terminal C1.

Load 142 is a cascode current mirror and is connected to input differential pair 138. The cascode current mirror is biased by a voltage V _BIAS supplied to the bias terminal BIAS. Further, an offset terminal OFS is drawn out from the load 142.

The output stage 134 converts the output of the differential input stage 132 into a high/low binary signal and outputs it from the output terminal COMPOUT.

The repair circuit 136 generates adjustable correction currents (also referred to as repair currents) I _COMP1 and I _COMP2 and supplies them to a cascode current mirror, which is a load 142 . Depending on the direction in which the offset voltage V _OFS is corrected, one of the correction currents I _COMP1 and I _COMP2 is selectively generated, and the amount of current is determined by the threshold temperature T _TH caused by process variations in the manufacturing and inspection process of semiconductor chips. is adjusted (trimmed) so that it is canceled.

The currents I _C1 , I _C2 and the offset current I _OFS may all be currents proportional to the second voltage V ₂ , and specifically, currents generated by the V/I conversion circuit 118 in FIG. 7 may be used. .

(Example 3)
FIG. 9 is a circuit diagram of a temperature detection circuit 100C according to the third embodiment. The PTAT current source 112 includes a first diode D1, a second diode D2, a resistor R1, transistors M11, M12, a first current mirror circuit CM11, and a second current mirror circuit CM12. The PTAT current source 112 has a configuration in which the PTAT current source 112 of FIG. 7 is upside down.

Current mirror circuits CM11 and CM12 return the PTAT current flowing through diodes D1 and D2 and supply it to I/V conversion circuit 114. In this embodiment, the I/V conversion circuit 114 includes a resistor R2 whose one end is grounded, and the voltage drop across the resistor R2 (R2×I _PTAT ) becomes the first voltage V ₁ . The first voltage _V1 is supplied to the non-inverting input terminal (+) of the comparator 130B.

The V/I conversion circuit 118 converts the voltage drop Vf ₁ of the first diode D1 into a current signal. The V/I conversion circuit 118 includes an operational amplifier OA3, transistors M31 to M33, and resistors R31 to R33.

In the operational amplifier OA3, feedback is applied so that the voltage at the non-inverting input terminal (+) and the voltage at the inverting input terminal (-) are equal (virtual grounding), so the voltage drop across the resistor R31 is due to the voltage across the first diode D1. The drop Vf becomes equal to ₁ . As a result, a current I _C of Vf ₁ /R31 flows through the resistor R31. This current I _C is proportional to the forward voltage Vf ₁ of the diode, and therefore has negative temperature characteristics.

The configuration of the comparator 130B is as shown in FIG. The current mirror circuit CM2 copies the current I _C and supplies bias currents I C1 and _{I C2} to the C1 terminal and C2 terminal of the comparator 130B, respectively. The bias currents I _C1 and I _C2 have negative temperature coefficients.

Similarly to FIG. 7, constant multiplier circuit 116 includes a V/I conversion circuit 118 and an I/V conversion circuit 120. In the V/I conversion circuit 118, the voltage drops across the resistors R32 and R33 also become equal to the forward voltage Vf ₁ of the first diode D1. The current I _A flowing through the resistor R32 and the transistor M32 becomes Vf ₁ /R32, and the current I _B flowing through the resistor R33 and the transistor M33 becomes Vf ₁ /R33.

Current _IA is supplied to I/V conversion circuit 120. The I/V conversion circuit 120 is a resistance circuit, and a voltage drop proportional to the current _IA occurs. The voltage drop of the I/V conversion circuit 120 becomes the second voltage _V2 , which is supplied to the inverting input terminal (-) of the comparator 130B.

In the third embodiment, the comparator 130B is a hysteresis comparator, and the resistance value of the I/V conversion circuit 120 is switched between two values according to the output of the comparator 130B. As a result, the gain of the I/V conversion circuit 120 changes.

I/V conversion circuit 120 includes, for example, resistors R41 and R42 and transistor M41, and ON/OFF of transistor M41 is controlled according to the output of comparator 130B. Note that in FIG. 9, an inverter 152, a low-pass filter 154, a Schmitt buffer 156, and an inverter 158 are connected after the comparator 130B, and the final temperature detection signal TEMP_DET is generated. In this case, turning on and off the transistor M41 may not be directly controlled by the output of the comparator 130B, but may be controlled according to the final temperature detection signal TEMP_DET.

The current I _B generated by the V/I conversion circuit 118 is supplied to the offset adjustment terminal OFS of the comparator 130B. The offset current I _OFS based on this current I _B is proportional to the forward voltage of the diode D1 and therefore has a negative temperature coefficient.

The above is the configuration of the temperature detection circuit 100C according to the third embodiment. Next, its operation will be explained. FIGS. 10A and 10B are diagrams (simulation results) showing the operation of the temperature detection circuit 100C. The temperature of the voltages V ₁₁ and V _{12 of the cathodes (actually, the emitter or collector of a bipolar transistor whose base and collector are connected) of the first diode D1 and the second diode D2 is shown in the upper part of FIG. 10} (a). Dependencies are shown. The lower part of FIG. 10A shows the forward voltage Vf ₁ of the first diode D1 and the voltage drop ΔVf of the resistor R1.

The output TEMP_DET of the temperature detection _{circuit 100C} is shown at the top of FIG. The currents (tail current I _TAIL , bias current I _C1 , offset current I _OFS ) are shown. In this example, the threshold temperature _TTH is set to 160°C.

FIG. 11 is a diagram showing the input offset voltage V _OFS introduced into the comparator 130. In the simulation, the temperature dependence of the offset voltage V _OFS was investigated when the size of the NPN transistor, which is the first diode D1, was changed in three ways (typ, small, large). The offset voltage V _OFS remains unchanged with respect to temperature variations, while varying depending on the size of the first diode D1. As shown in FIG. 5, when the size of the diode D ₁ (or D ₂ ) changes, the first voltage V ₁ and the second voltage V ₂ shift relatively, and the offset voltage V _OFS is determined by this shift amount V Since it changes following _SHIFT , variations in the threshold temperature _TTH can be suppressed.

As mentioned above, when the input offset voltage V _OFS of the comparator 130 is not optimized, the variation width ΔT _TH of the threshold temperature T _TH is 20.58 degrees, but under the same conditions, the temperature detection circuit of FIG. 9 When operating at 100C, the threshold temperature fluctuation width ΔT _TH can be reduced to 9.8 degrees, allowing more accurate temperature detection.

Although the present invention has been described using specific words and phrases based on the embodiments, the embodiments merely illustrate the principles and applications of the present invention, and the embodiments do not include the scope of the claims. Many modifications and changes in arrangement are possible without departing from the spirit of the present invention.

100 Temperature detection circuit 110 Voltage generation circuit 112 PTAT current source D1 First diode D2 Second diode 114 I/V conversion circuit 116 Constant multiplier circuit 118 V/I conversion circuit 120 I/V conversion circuit CM1 Current mirror circuit 130 Comparator 132 Difference Dynamic input stage 134 Output stage 136 Repair circuit 138 Input differential pair 140 Tail current source 142 Load

Claims (11)

A voltage that generates a first voltage having a positive temperature characteristic based on the difference in forward voltage of two PN junctions having different current densities, and a second voltage having a negative temperature characteristic based on the forward voltage of the PN junction. a generation circuit;
a comparator that compares the first voltage and the second voltage;
Equipped with
The temperature detection circuit, wherein the comparator is configured such that its input offset voltage changes depending on the second voltage. The comparator is
differential pair;
a tail current source that supplies tail current to the differential pair;
a current mirror circuit connected to the differential pair as a load;
including;
2. The temperature detection circuit according to claim 1 , wherein an offset current corresponding to the second voltage is input to the current mirror circuit. A voltage that generates a first voltage having a positive temperature characteristic based on the difference in forward voltage of two PN junctions having different current densities, and a second voltage having a negative temperature characteristic based on the forward voltage of the PN junction. a generation circuit;
a comparator that compares the first voltage and the second voltage;
Equipped with
The comparator is
differential pair;
a tail current source that supplies tail current to the differential pair;
a current mirror circuit connected to the differential pair as a load;
including;
A temperature detection circuit characterized in that an offset current corresponding to the second voltage is input to the current mirror circuit. The voltage generation circuit includes a PTAT (Proportional To Absolute Temperature) current source having a pair of bipolar transistors of different sizes,
the first voltage is proportional to a PTAT current generated in the PTAT current source;
4. The temperature detection circuit according to claim 1, wherein the second voltage is responsive to a voltage drop of one of the pair of bipolar transistors of the PTAT current source. The voltage generation circuit is
a first I/V conversion circuit that converts the PTAT current to the first voltage;
a constant multiplier circuit that multiplies the voltage drop of the one of the pair of bipolar transistors by a constant;
The temperature detection circuit according to claim 4, further comprising: A voltage that generates a first voltage having a positive temperature characteristic based on the difference in forward voltage of two PN junctions having different current densities, and a second voltage having a negative temperature characteristic based on the forward voltage of the PN junction. a generation circuit;
a comparator that compares the first voltage and the second voltage;
Equipped with
The voltage generation circuit includes a PTAT (Proportional To Absolute Temperature) current source having a pair of bipolar transistors of different sizes,
the first voltage is proportional to a PTAT current generated in the PTAT current source;
the second voltage is responsive to a voltage drop of one of the pair of bipolar transistors of the PTAT current source;
The voltage generation circuit is
a first I/V conversion circuit that converts the PTAT current to the first voltage;
a constant multiplier circuit that multiplies the voltage drop of the one of the pair of bipolar transistors by a constant;
A temperature detection circuit further comprising: 7. The temperature detection circuit according to claim 5 , wherein the first I/V conversion circuit includes a resistor provided on a path of the PTAT current. 8. The temperature detection circuit according to claim 7 , wherein the resistance value of the resistor changes in two values depending on the output of the comparator. The constant multiplier circuit is
a V/I conversion circuit that converts the voltage drop of the one of the pair of bipolar transistors into a current signal;
a second I/V conversion circuit that converts the output current of the V/I conversion circuit into the second voltage;
The temperature detection circuit according to any one of claims 5 to 8 , characterized in that the temperature detection circuit includes: The comparator is
differential pair;
a tail current source that supplies tail current to the differential pair;
a current mirror circuit connected to the differential pair as a load;
including;
The tail current is responsive to the current signal generated by the V/I conversion circuit,
10. The temperature detection circuit according to claim 9 , wherein the current mirror circuit is supplied with an offset current generated by the V/I conversion circuit. The comparator further includes a repair circuit that supplies the current mirror circuit with a correction current obtained by multiplying the current signal generated by the V/I conversion circuit by a variable coefficient, and the variable coefficient is trimmable. The temperature detection circuit according to item 10 .

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