JPH09264796A - Temperature detection circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To freely set a temp. coefficient by using a specific formula by reversing the control signal formed by a control signal forming circuit to add the same to the detection signal formed by a temp. detection circuit to obtain a temp. detection signal. SOLUTION: An NPN transistor Q26 is constituted so that the emitter thereof is connected to the contact (a) of a constant current source 35 and a resistor R22 and the base thereof is connected to the connection point of the collector of a transistor Q24 and the emitter of an NPN transistor Q27 and controls the current supplied to resistors R22, R23, R24 from the constent current source 35 when the band gap Zener voltage ΔVBE generated in a resistor 23 lowers. The change (Vs31 / T) of the output detection voltacje to the temp. of a temp. detection circuit 31 can be made larger than the change of the output detection voltage to the temp. of a conventional temp. detection circuit 1, and the change of the output detection and the change of the detection voltage to the temp. of the circuit 31 can be freely set on the basis of the ratio of the resistors R21, R23 as shown by the formula.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temperature detecting circuit, and more particularly to a temperature detecting circuit that detects temperature by utilizing a variation of a base-emitter voltage of a transistor with temperature.

[0002]

2. Description of the Related Art TCXO (Temperature Compensated cr
The oscillation circuit such as ystal Oscilator) detects the ambient temperature and corrects the oscillation frequency based on the detected temperature.
Therefore, it is necessary to detect the ambient temperature with high sensitivity and accuracy in a semiconductor chip equipped with an oscillation circuit.

As a method for detecting the temperature, a diode-connected transistor for temperature detection is formed on a semiconductor chip on which an oscillation circuit is formed, and the base-emitter voltage V _{BE of the} temperature detection transistor is set to the ambient temperature. The temperature was detected by utilizing the fact that it fluctuates according to the temperature.

FIG. 5 is a circuit diagram showing an example of a conventional temperature detecting circuit. A conventional temperature detection circuit 1 is connected to a constant current source 2 that generates a constant current from a power supply voltage V _CC and a diode connection,
The constant current I ₁ generated by the constant current source 2 is composed of a temperature detecting transistor Q ₁ flowing in the forward direction.

[0005] The constant current source 2 has one end connected to the power source voltage V _CC, to generate a constant current I ₁ from the power supply voltage V _CC. The other end of the constant current source 2 is connected to a temperature detecting transistor Q _1, which supplies a constant current I ₁ to the temperature detecting transistor Q _1. The temperature detecting transistor Q ₁ is composed of an NPN transistor, and is so-called diode-connected with its base and collector connected to each other. The collector and base serving as an anode are connected to the other end of the constant current source 2, and the emitter is grounded. Has been done. In the temperature detecting transistor Q ₁ , the base-emitter voltage V _BE1 drops when the ambient temperature rises, and the base-emitter voltage V _BE1 rises when the ambient temperature falls.

The output terminal T _OUT is connected to the connection point between the constant current source 2 and the temperature detecting transistor Q ₁ and outputs the base-emitter voltage V _BE1 of the temperature detecting transistor Q ₁ . In FIG. 5, the output detection voltage V _S1 output from the output terminal T _OUT is V _S1 = V _BE1 (1) where V _BE1 is the temperature detecting NPN transistor Q ₁
Is the base-emitter voltage.

The base-emitter voltage V _BE1 of the temperature detecting NPN transistor Q ₁ is V _BE1 = V _g0 (1-T / T ₀ ) + V _BE0 (T / T ₀ ) = V _S (2) (V _g0; bandgap voltage, T; temperature, T _0; the reference temperature, V _BE0; base at the reference temperature - emitter voltage) is represented by.

Here, the output detection voltage V _S1 is differentiated by the temperature T to obtain the change in the detection voltage with respect to the temperature (∂V _S1 / ∂T). ∂V _S1 / ∂T =-(V _g0 / T ₀ ) + (V _BE0 / T ₀ ) ... (3)

That is, the change in the detected voltage with respect to the temperature is determined by the equation (3). In addition, the above temperature detection circuit 1
However, since the base-emitter voltage V _BE of one temperature detecting transistor is used as the output detection signal, the change in the output detection signal with respect to the temperature change is small. Therefore, in some cases, a plurality of temperature detection transistors are connected in series and the base-emitter voltage V _BE of the plurality of temperature detection transistors is superimposed to increase the change in the output detection signal with respect to the temperature change.

FIG. 6 shows another example of the conventional temperature detecting circuit.
A road configuration diagram is shown. The temperature detection circuit 10 includes a constant current source 11,
And a plurality of temperature detecting transistors Q ₁₁~ Q_NMore
Is done. One end of the constant current source 11 has a power supply voltage V_CCConnect to
The power supply voltage V_CCTo constant current I ₁₁Generate Constant current
The other end of the source 11 has a temperature detecting transistor Q₁₁~ Q_NTo
Connected, temperature detection transistor Q₁₁~ Q_NConstant current
I₁₁Supply.

The temperature detecting transistors Q _{11 to} Q _N are N
It is composed of a PN transistor and is so-called diode-connected, in which the base and collector are connected, and they are connected in series. The anode side of the series circuit composed of the temperature detecting transistor Q ₁₁ to Q _N is connected to the other end of the constant current source 11, the emitter side is grounded.

Transistor Q for temperature detection₁₁~ Q_NIs constant
Constant current I supplied from current source 11 ₁₁By base-d
Inter-mitter voltage V_BE11~ V_BENIs generated. Base-D
Inter-mitter voltage V_BE11~ V_BENThe ambient temperature rises
And then, when the ambient temperature drops, it rises.

The output terminal T _OUT is connected to the connection point between the constant current source 11 and the temperature detecting transistor Q _11, and the base-emitter voltage V of the temperature detecting transistors Q _{11 to} Q _N.
Outputs an output detection signal with _{BE11 to} V _BEN superimposed. At this time, the output detection signal is the temperature detection transistor Q ₁₁ ...
Since the base-emitter voltage V _{BE11 to} V _BEN of Q _N is applied as a superposed voltage, the temperature- _dependent base-emitter voltage V _{BE11 of} the temperature detecting transistors Q _{11 to} Q _N is _given.
It is possible to obtain a signal on which the fluctuation of V _BEN is superimposed, and to obtain a signal that greatly changes according to the fluctuation of the temperature.

In FIG. 6, the output detection voltage V _S11 output from the output terminal T _OUT is the temperature detection transistor Q.
_{Assuming that} the base-emitter voltages V _{BE11 to} V _{BEN of 11 to} Q _N are the same, V _S11 = NV _BE11 (4).

Here, V _BE11 is the voltage between the base and emitter of each of the temperature detecting NPN transistors Q _{11 to} Q _N , N
Is the number of temperature detecting NPN transistors Q _{11 to} Q _N. The base-emitter voltage V _{BE 11} of each of the temperature detecting NPN transistors Q _{11 to} Q _N is V _BE11 = V _g0 (1-T / T ₀ ) + V _BE0 (T / T ₀ ) ... (5) ( V _g0 : bandgap voltage, T: temperature, T ₀ : reference temperature, V _BE0 : base-emitter voltage at the reference temperature).

Substituting equation (5) into equation (4), V _S11 = N {V _g0 (1-T / T ₀ ) + V _BE0 (T / T ₀ )} (6) where the output When the detected voltage V _S1 is differentiated by the temperature T to obtain the detected voltage change (∂V _S11 / ∂T) with respect to the temperature, ∂V _S11 / ∂T = −N {(V _g0 / T ₀ ) − (V _BE0 / T ₀ )} (7)

That is, the change in the detected voltage with respect to temperature is determined by the equation (7). Further, as a method of obtaining a signal that greatly changes in accordance with a change in temperature, a configuration in which an amplifier circuit is provided at the output of the circuit of FIG. 6 can be considered. FIG. 7 shows a circuit configuration diagram of another example of the conventional temperature detection circuit. In the figure, the same components as those in the figure are designated by the same reference numerals, and the description thereof will be omitted.

The temperature detection circuit 21 comprises an amplifier circuit 22 connected between a connection point between the constant current source 2 and the temperature detection transistor Q ₁ and the output terminal T _OUT . The amplifier circuit 22 includes an operational amplifier 22a and feedback resistors R ₁ and R ₂ . The output of the operational amplifier 22a is a feedback resistor R ₁ ,
The voltage is divided by R ₂ and supplied to the inverting input terminal, and the constant current source 2 and the temperature detecting transistor Q ₁ are connected to the non-inverting input terminal.
The connection point with is connected to form a non-inverting amplifier circuit.

The base-emitter voltage V _BE of the temperature detecting transistor Q ₁ is amplified by the amplifier circuit 22 and output from the output terminal T _OUT . In FIG. 7, the output terminal T
_The output detection voltage V _S21 output from _OUT is V _S21 = KV _BE1 (8) where V _BE1 is the base-emitter voltage of the temperature detecting NPN transistor Q ₁ , and K is the amplification of the amplifier circuit 22. It is degree.

The base-emitter voltage V _BE1 of the temperature detecting NPN transistor Q ₁ is V _BE1 = V _g0 (1-T / T ₀ ) + V _BE0 (T / T ₀ ) ... (9) (V _g0 Bandgap voltage, T; temperature, T ₀ ; reference temperature, V _BE0 ; base-emitter voltage at reference temperature). Therefore, the detection voltage V _S21 is V _S21 = KV _BE1 = K {V _g0 (1-T / T ₀ ) + V _BE0 (T / T ₀ )} (10).

When the temperature coefficient (∂V _S21 / ∂T) is obtained by differentiating the output detection voltage V _S1 with the temperature T, ∂V _S21 / ∂T = -K {(V _g0 / T ₀ ). − (V _BE0 / T ₀ )} (11)

That is, the voltage detection change with respect to temperature is determined by the equation (11).

[0023]

However, the conventional FIG.
Since the temperature detection circuit shown in FIG. 7 uses the temperature characteristic of the forward voltage of the diode formed by the temperature detection transistor as it is, the temperature coefficient is fixed and the temperature coefficient cannot be changed. there were.

The present invention has been made in view of the above points, and an object of the present invention is to provide a temperature detection circuit in which the temperature coefficient can be freely set.

[0025]

According to a first aspect of the present invention, there is provided a temperature detection circuit having a predetermined temperature characteristic and having a temperature detection signal generation circuit for generating a temperature detection signal according to the temperature. A control signal generation circuit that has a temperature characteristic having an inclination opposite to that of the generation circuit and that generates a control signal according to temperature; and a temperature detection signal generation circuit that inverts the control signal generated by the control signal generation circuit. And a detection signal control circuit that adds the temperature detection signal generated in Step 1.

According to the first aspect, the temperature characteristics of the temperature detection circuit and the control signal generation circuit have characteristics of opposite inclinations, and the control signal generated by the control signal generation circuit is inverted and generated by the temperature detection circuit. The temperature coefficient can be freely set by adding it to the detected signal to obtain a temperature detected signal.

According to a second aspect of the present invention, in the detection signal control circuit, the control signal generated by the control signal generation circuit is connected to the base, the collector is connected to the output terminal for outputting the temperature detection signal, and the emitter is connected to the output terminal. It is characterized by comprising a control transistor having a constant potential.

According to the second aspect of the present invention, the temperature detection signal can be controlled by superimposing a signal obtained by inverting the bandgap Zener voltage detected by the bandgap Zener detection means by the control transistor on the temperature detection signal. The change in the detected voltage with respect to the temperature can be increased as compared with the case where the base-emitter voltage of (3) is directly used as the temperature detection signal.

According to a third aspect of the present invention, there is provided a feedback amplifier which feeds back the output detection signal and amplifies the base-emitter voltage of the detection transistor, and the signal control circuit controls the feedback amplifier according to the bandgap Zener voltage. It is characterized in that it is configured to control the gain.

According to the present invention, the output detection signal is output via the feedback amplifier, and the feedback of the feedback amplifier is fed back via the signal control circuit according to the band cap zener voltage detected by the band gap zener detection circuit. By controlling the amount, the temperature-detection signal is controlled according to the bandgap Zener voltage in addition to the change in the base-emitter voltage of the detection transistor due to temperature, so the base-emitter voltage of the detection transistor remains unchanged. The change in the temperature detection voltage with respect to the temperature can be increased as compared with the case of using the temperature detection signal.

[0031]

FIG. 1 is a circuit diagram of a first embodiment of the present invention. The temperature detection circuit 31 of this embodiment is a TCX.
This is a temperature detection circuit for correcting fluctuations in the oscillation frequency of an oscillation circuit such as O (Temperature Compensated Cryst-al Oscilator) due to temperature. The temperature detection circuit 31 corresponds to an NPN transistor Q ₂₁ , which corresponds to the temperature detection signal generation circuit in the claims, a constant current source 32 which supplies a constant current I ₂₁ to the NPN transistor Q _21, and a signal control circuit in the claims. The signal control circuit 33, which corresponds to the control signal generation circuit in the claims, includes a bandgap zener voltage detection circuit 34 that detects the bandgap zener voltage and controls the signal control circuit 33, and an output resistor R ₂₁ .

The NPN transistor Q ₂₁ for temperature detection is
It has a negative temperature characteristic, the base and collector are connected,
It constitutes a diode. NPN transistor Q
_{In 21} , the base and collector correspond to the anode of the diode, and the emitter corresponds to the cathode of the diode.

The anode of the diode formed by the NPN transistor Q ₂₁ is connected to one end of the constant current source 32, and the cathode is grounded. The power supply voltage V _CC is applied to the other end of the constant current source 32. The constant current source 32 generates a constant current I ₂₁ from the power supply voltage V _CC , and the NPN transistor Q
_A current is supplied to the diode constituted by _{21 in the} forward direction.

A forward voltage V _F is generated in the diode formed by the NPN transistor Q ₂₁ . The forward voltage V _F of the diode corresponds to the base-emitter voltage V _BE21 of the NPN transistor Q ₂₁ . The connection point between the base and collector of the NPN transistor Q ₂₁ , which constitutes the anode of the diode, and the constant current source 32 is connected to the output terminal T _OUT via the output resistor R _21, and the base-emitter voltage V of the NPN transistor Q _21. A voltage corresponding to _BE21 is output from the output terminal T _OUT .

The output terminal T_OUTOutput detection signal to
A signal control circuit 33 for controlling is connected. Faith
The signal control circuit 33 includes an NPN transistor Q._{twenty two}Made up of
It is. NPN transistor constituting the signal control circuit 33
Q_{twenty two}Is the output terminal T _OUTConnected to. Output end
Child T_OUTIs the frequency of the oscillator circuit such as TCXO.
It is connected to the frequency control terminal for controlling. The connection destination
However, it is not limited to the oscillation circuit.

The NPN transistor Q ₂₂ has a base connected to the bandgap Zener voltage detection circuit 34, an emitter grounded, and a collector connected to the output terminal T _OUT . The NPN transistor Q ₂₂ draws a current from the output terminal T _OUT according to the bandgap Zener voltage detected by the bandgap Zener voltage detection circuit 34, and controls the output detection voltage V _S31 .

Bandgap Zener voltage detection circuit 34
Is a constant current source 35 and a resistor R_{twenty two}, R_{twenty three}, R_{twenty four}, PNP Tiger
Transistor Q_{twenty four}, Q_{twenty five}, Q₂₆, NPN transistor Q_{twenty three},
Q₂₇, Q₂₈, Q₂₉It is composed of The constant current source 35 is
Power supply voltage V at the end_CCIs applied and the power supply voltage V_CCFrom constant current
I _{twenty two}Generate Resistance R_{twenty two}, R_{twenty three}, R_{twenty four}Is a constant current source 3
The other end of 5 and the NPN transistor Q_{twenty three}Between the collector of
The constant current I generated by the constant current source 35 connected in series_{twenty two}
Some current I_{twenty three}Is supplied to generate a voltage.

The NPN transistor Q ₂₃ has its base and collector connected together, its emitter grounded, and the NPN transistor Q _{23 of the} bandgap Zener voltage detection circuit 34.
A positive temperature characteristic is imparted to the collector current of. PNP
Transistors Q ₂₄ , Q ₂₅ , Q ₂₆ , NPN transistor Q
_27, Q _28, Q ₂₉ constitute a differential amplifier circuit to detect a voltage generated in the resistor R _23, the collector and base of the resistor R _22, R _23, NPN through R ₂₄ transistors Q ₂₃ Control the current supplied to.

The PNP transistor Q ₂₄ has an emitter connected to the other end of the constant current source 35, a base connected to the base and collector of the PNP transistor Q ₂₅ , and a collector N.
It is connected to the collector of the PN transistor Q ₂₇ . P
The NP transistor Q ₂₅ has an emitter connected to the other end of the constant current source 35, and a base and a collector connected to the base of the PNP transistor Q ₂₄ and the collector of the NPN transistor Q ₂₈ .

PNP transistor Q_{twenty four}, Q_{twenty five}Is current
It constitutes a mirror circuit, and NPN transistor Q₂₇,
Q₂₈Supply a constant current to the collector of. NPN Transis
TA Q₂₇, Q₂₈For the bandgap Zener voltage detection
It is a transistor. NPN transistor Q₂₇This
The PNP transistor Q _{twenty four}Connected to the collector of
Base is resistance R_{twenty two}And resistance R_{twenty three}Is connected to the connection point b with
NPN transistor Q whose emitter constitutes a constant current source₂₉
Connected to the collector.

The collector of the NPN transistor Q ₂₈ is P
It is connected to the base and collector of the NP transistor Q _25, the base is connected to the connection point c between the resistor R ₂₃ and the resistor R _24, and the emitter is connected to the collector of the NPN transistor Q ₂₉ forming a constant current source. There is.

The collector of the NPN transistor Q ₂₉ is N
It is connected to the emitters of the PN transistors Q ₂₇ and Q ₂₈ , the base is connected to the base and collector of the NPN transistor Q ₂₃ , the emitter is grounded, and the connection point d between the resistor R ₂₄ and the base and collector of the NPN transistor Q ₂₃ is connected. A current is drawn from the emitters of the NPN transistors Q ₂₇ and Q ₂₈ according to the voltage.

The emitter of the PNP transistor Q ₂₆ is connected to the connection point a between the constant current source 35 and the resistor R ₂₂ ,
The base is connected to the connection point between the collector of the PNP transistor Q _{24 and} the emitter of the NPN transistor Q ₂₇ , and the collector is grounded. From the constant current source 35 according to the bandgap Zener voltage ΔV _BE generated in the resistor R _23. The current supplied to the resistors R ₂₂ , R ₂₃ and R ₂₄ is controlled.

When the band gap Zener voltage ΔV _BE generated in the resistor R ₂₃ rises, the constant current source 35 causes the resistor R ₂₂ ,
When the current supplied to R ₂₃ and R ₂₄ is reduced and the bandgap Zener voltage ΔV _BE generated in the resistor R ₂₃ decreases, the current supplied from the constant current source 35 to the resistors R ₂₂ , R ₂₃ and R ₂₄ increases. To control.

The output detection voltage V _S31 is an NPN for temperature detection.
The base of transistor Q ₂₁ - emitter voltage and V _BE21, when the current drawn by the NPN transistor Q ₂₂ and I _{C2 2,} expressed by _{V S31 = V BE21 -R 21 ·} I C22 ··· (12).

At this time, the voltage generated in the resistor R ₂₃ is ΔV
_{Assuming BE} , the current I ₂₃ flowing through the resistor R ₂₃ is I ₂₃ = ΔV _BE / R ₂₃ (13)

The current I ₂₃ is supplied to the base of the NPN transistor Q ₂₂ . The NPN transistor Q ₂₂ draws the same current as the current I ₂₃ supplied to the collector of the NPN transistor Q _{23 from} the collector. Therefore, since I ₂₃ = I _C22 (14), I _C22 = I ₂₃ = ΔV _BE / R ₂₃ (15)

Therefore, by substituting the equation (15) into the equation (12), the output detection voltage V _S31 is expressed by V _S31 = V _BE21 − (R ₂₁ / R ₂₃ ) · ΔV _BE (16) It Also, the base of NPN transistor Q ₂₁
The emitter-to-emitter voltage V _BE1 is generally V _BE21 = V _g0 (1-T / T ₀ ) + V _BE0 (T / T ₀ ) ... (17) (V _g0 ; bandgap voltage, T; temperature, T ₀ ; Reference temperature, V _BE0 ; base-emitter voltage at the reference temperature).

Further, the NPN transistor Q₂₇, Q₂₈No
Source-emitter voltage is V_BE27, V _BE28, NPN Tran
Jista Q₂₇, Q₂₈The emitter area ratio of (n₂₇/ N₂₈) =
If m, the bandgap Zener voltage ΔV_BEIs ΔV_BE= V_BE27-V_BE28= (KT / q) ln (n₂₇/ N₂₈) = (KT / q) ln (m) ... (18)

By substituting the equations (17) and (18) into the equation (16), the output detection voltage V _S31 becomes V _S31 = V _g0 (1-T / T ₀ ) + V _BE0 (T / T ₀ )-( represented by the _{R 21 / R 23) · (} kT / q) ln (m) ··· (19).

Here, the equation (19) is differentiated by the temperature T to change the output detection voltage V _{S31 with} respect to the temperature T (∂V _S31 / ∂).
When T) is _calculated , ∂V _S31 / ∂T = − (V _g0 / T ₀ ) + (V _BE0 / T ₀ ) − (R ₂₁ / R ₂₃ ) · (kT / q) ln (m) = (V _BE0 / T ₀₎ - represented by _{{(V g0 / T 0)} + (R 21 / R 23) · (kT / q) ln (m)} ··· (20).

Here, from the change (∂V _S31 / ∂T) of the output detection voltage with respect to the temperature obtained by the expression (20), the expression (3) is obtained.
Change in the output detection voltage for a conventional temperature shown in (∂V _S1
Subtracting / ∂T), (∂V _S31 / ∂T)-(∂V _S1 / ∂T) = (V _BE0 / T ₀ )-{(V _g0 / T ₀ ) + (R ₂₁ / R ₂₃ ). · (kT / q) ln ( m)} - {(V g0 / T 0) + (V BE0 / T 0)} = (R 21 / R 23) · (kT / q) ln (m) ··· (21)

This is because the change in the output detection voltage with respect to the temperature of the temperature detection circuit 31 of this embodiment (∂V _S31 / ∂T) is the change of the output detection voltage with respect to the temperature of the conventional temperature detection circuit 1 (∂V _S1 / It is shown that it can be made larger than ∂T),
The change (∂V _S31 / ∂T) of the output detection voltage with respect to the temperature of the temperature detection circuit 31 of the present embodiment can be freely set by the ratio of the resistors R ₂₁ and R ₂₃ as shown in the equation (21). I understand.

FIG. 2 shows a characteristic diagram of the first embodiment of the present invention. FIG. 2 shows a characteristic diagram of the change (∂V _S31 / ∂T) in the output detection voltage with respect to temperature according to the ratio of the resistors R ₂₁ and R ₂₃ . As shown in FIG. 2, it can be seen that the temperature coefficient (∂V _{S3 1} / ∂T) can be varied by changing the ratio of the resistors R ₂₁ and R ₂₃ .

As described above, according to this embodiment, the change (∂V _S31 / ∂T) in the output detection voltage with respect to the temperature is (R ₂₁ / R ₂₃ )  (kT / q) ln (m ) And can be freely changed by changing the ratio of the resistors R ₂₁ and R ₂₃ . FIG. 3 shows a circuit configuration diagram of the second embodiment of the present invention. In the figure, the same components as those of FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.

In the temperature detecting circuit 41 of this embodiment, the temperature detecting transistor is biased through a resistor, the constant current source 32 is constituted by a current mirror circuit, and the signal control circuit 3 is used.
3 is configured to control the output detection voltage V _S41 by controlling the bias voltage of the temperature detecting transistor by controlling the input current of the current mirror circuit.

In the temperature detecting NPN transistor Q ₃₁ of this embodiment, the base is connected to the connection point of the resistors R ₃₁ and R ₃₂ connected in series, and the collector is connected to the resistor R ₃₃ .
The emitter is grounded. The resistor R ₃₃ has one end connected to the collector of the temperature detecting NPN transistor Q ₃₁ and the other end connected to the current mirror circuit 42. Resistor R ₃₁ and the resistor R ₃₂ are connected in series, the resistor R _31, R
One end of the series circuit composed of ₃₂ is connected to the connection point of the current mirror circuit 42 and the resistor R ₃₃ , the other end is grounded, and the connection point of the resistor R ₃₁ and the resistor R ₃₂ is the temperature detection NPN transistor Q ₃₁ . Connected to the base.

The current mirror circuit 42 comprises PNP transistors Q ₃₂ and Q ₃₃ . PNP transistor Q
_{In 32} , the power supply voltage V _CC is applied to the emitter, the collector is connected to the resistor R ₃₃ , and the base is the PNP transistor Q _33.
Connected to the base and collector of. The power supply voltage V _CC is applied to the emitter of the PNP transistor Q ₃₃ , and the collector and base are connected to the base of the PNP transistor Q ₃₂ and the signal control circuit 33. The current mirror circuit 42 supplies a current according to the current drawn from the PNP transistor Q ₃₃ to the resistor R ₃₃ .

In this embodiment, the output detection signal V _S41 output from the output terminal T _OUT is the base-emitter voltage of the temperature detecting NPN transistor Q ₃₁ which is V _BE31 , and the PNP transistor Q ₃₂ of the current mirror circuit 42. When the collector current is I _C32 , it can be expressed as V _S41 = V _BE31 {1+ (R ₃₁ / R ₃₂ )} − R ₃₃ I _C32 (22).

The collector current I _C32 of the PNP transistor Q ₃₂ of the current mirror circuit 42 is _generated by the signal control circuit 3 forming the current mirror circuit 42 and the current mirror circuit.
3 becomes a current equal to the output current I _{23 of the} bandgap Zener voltage detection circuit 34. Therefore, equation (18)
Is V _S41 = V _BE31 {1+ (R ₃₁ / R ₃₂ )} − R ₃₃ I ₂₃ (23).

Here, the output current I ₂₃ of the band gap zener voltage detection circuit 34 is I ₂₃ = ΔV _BE / since the band gap zener voltage ΔV _BE is generated in the resistor R ₂₃ of the band gap zener voltage detection circuit 34. R ₂₃ is a ... (24).

Substituting equation (22) into equation (24), it can be expressed as V _S41 = V _BE31 {1+ (R ₃₁ / R ₃₂ )}-(R ₃₃ / R ₂₃ ) ΔV _BE (25) .

The base-emitter voltage V _BE31 of the NPN transistor Q ₃₁ is V _BE31 = V _g0 (1-T / T ₀ ) + V _BE0 (T / T ₀ ) ... (26) as in the equation (17). And the bandgap Zener voltage ΔV _BE is
Since ΔV _BE = (kT / q) ln (m) (27) from the equation (18), when the equations (26) and (27) are substituted into the equation (25), the detection voltage V _S41 becomes V _S41 = {V _g0 (1-T / T ₀ ) + V _BE0 (T / T ₀ )}-{1+ (R ₃₁ / R ₃₂ )}-(R ₃₃ / R ₂₃ )-(kT / q) ln ( m) (28)

[0064] Equation (28) by differentiating at a temperature T a, when determining the change of the output detection voltage V _S41 with respect to the temperature _{T (V S41 / ∂T),} ∂V S41 / ∂T = {- (V g0 / T _{0) + (V BE0 / T} 0)} · {1+ (R 31 / R 32)} - (R 33 / R 23) · (kT / q) ln (m) = (V BE0 / T 0) · { _{1+ (R 31 / R 32)} - [(V g0 / T 0) · {1+ (R 31 / R 32)} + (R 33 / R 23) · (kT / q) ln (m)] = (V _{BE0 / T 0) - [(} V g0 / T 0) · {1+ (R 31 / R 32)} + (R 33 / R 23) · (kT / q) ln (m) - (V BE0 / T 0 ) (R ₃₁ / R ₃₂ )] ... (29).

Here, from the change in output detection voltage with respect to temperature (∂V _S41 / ∂T) obtained by the equation (29), the change in output detection voltage with respect to temperature (∂V _S1 / ∂T) shown in the equation (3).
By subtracting T), (∂V _S41 / ∂T)-(∂V _S1 / ∂T) = (V _BE0 / T ₀ )-[(V _g0 / T ₀ ) ・ {1+ (R ₃₁ / R ₃₂ )) _{} + (R 33 / R 23} ) · (kT / q) ln (m) - (V BE0 / T 0) (R 31 / R 32)] - {(V g0 / T 0) + (V BE0 / T _{0)} = (R 33 /} R 23) · (kT / q) ln (m) - (R 31 / R 32) {(V g0 / T 0) - (V BE0 / T 0)} ··· ( 30).

This is the temperature of the temperature detection circuit 31 of this embodiment.
Change in output detection voltage (∂V _S41// T) is conventional
Output detection voltage (∂V_S1
/ ∂T), it can be made larger than
Of the output detection voltage with respect to the temperature of the temperature detection circuit 41 of
(∂V_S41/ ∂T) is the resistance R as shown in equation (30).
₃₁, R₃₂, R₃₃And R_{twenty three}The ratio can be set freely
You can see that

FIG. 4 shows a circuit configuration diagram of the third embodiment of the present invention. In the figure, the same components as those of FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted. Temperature detection circuit 51 of this embodiment
Is a constant current source 32 and a temperature detecting NPN transistor Q _21.
An amplifier circuit 52 is provided in place of the output resistor R ₂₁ between the connection point with and the output terminal T _OUT, and the feedback current of the amplifier circuit 5 is controlled by the signal control circuit 33 via the current mirror circuit 53. Become.

The amplifier circuit 52 comprises an operational amplifier 54 and a feedback resistor R ₄₁ . In the operational amplifier 54, the non-inverting input terminal is connected to the connection point between the constant current source 32 and the temperature detecting PNP transistor Q ₂₁ , the output is connected to the output terminal T _OUT , and the inverting input terminal is output via the feedback resistor R _41. It is connected to the terminal T _OUT . The operational amplifier 54 and the feedback resistor R _{41 form a} non-inverting amplifier circuit.

The current mirror circuit 53 is an operational amplifier 54.
It is connected to the inverting input terminal of. Current mirror circuit
53 is a PNP transistor Q₄₁And Q₄₂Consists of
You. PNP transistor Q₄₁Is the power supply voltage V
_CCIs applied, and the collector is the inverting input terminal of the operational amplifier 54.
PNP transistor Q connected to the child₄₂Base and
Connected to the lector. Also, the PNP transistor Q₄₂Is
Power supply voltage V to emitter _CCIs applied to the collector and base
The PNP transistor Q₄₁Base and signal control circuit
Connected to 33. The current mirror circuit 53 is a PNP
Transistor Q₄₂Current depending on the current drawn from
Anti-R₄₁Output from.

In this embodiment, the output detection signal V _S51 output from the output terminal T _OUT is the base-emitter voltage of the temperature detecting NPN transistor Q ₂₁ , which is V _BE21 , and the PNP transistor Q ₄₁ of the current mirror circuit 53. When the collector current is I _C41 and the amplification degree of the amplifier circuit 52 is 1, V _S51 = V _BE21 −R ₄₁ I _C41 (31)

The collector current I _C41 of the PNP transistor Q ₄₁ of the current mirror circuit 53 becomes equal to the output current I _{23 of the} bandgap Zener voltage detection circuit 34 by the current mirror circuit 53 and the signal control circuit 33. Therefore, the equation (31) becomes V _S51 = V _BE21 −R ₄₁ I ₂₃ (32).

Here, the output current I ₂₃ of the band gap zener voltage detection circuit 34 is I ₂₃ = ΔV _BE / since the band gap zener voltage ΔV _BE is generated in the resistor R ₂₅ of the band gap zener voltage detection circuit 34. R ₂₃ is a ... (33).

By substituting the equation (33) into the equation (32), it can be expressed as V _S51 = V _BE21 − (R ₄₁ / R ₂₃ ) · ΔV _BE (34). The base-emitter voltage V _BE21 of the NPN transistor Q ₂₁ can be expressed as V _BE21 = V _g0 (1-T / T ₀ ) + V _BE0 (T / T ₀ ) ... (35) as in the equation (17). , And the bandgap Zener voltage ΔV _BE is
Since ΔV _BE = (kT / q) ln (m) (36) from the equation (18), when the equations (35) and (36) are substituted into the equation (34), the detection voltage V _S51 becomes _{V S51 = {V g0 (1} -T / T 0) + V BE0 (T / T 0)} - a _{(R 41 / R 23) ·} (kT / q) ln (m) ··· (37).

When the change (∂V _S51 / ∂T) of the output detection voltage V _{S51 with} respect to the temperature T is obtained by differentiating the expression (37) by the temperature T, ∂V _S51 / ∂T = {-(V _g0 / _{T 0) + (V BE0 /} T 0)} - (R 41 / R 23) · (kT / q) ln (m) = (V BE0 / T 0) - {(V g0 / T 0) + (R ₄₁ / R ₂₃ ) · (kT / q) ln (m)} (38)

Here, from the change (∂V _S51 / ∂T) of the output detection voltage with respect to the temperature obtained by the expression (38), the expression (1
Change in output detection voltage with respect to conventional temperature shown in 1) (∂
When V _S21 / ∂T) is subtracted, (∂V _S51 / ∂T)-(∂V _S21 / ∂T) = (V _BE0 / T ₀ )-{(V _g0 / T ₀ ) + (R ₄₁ / R _{23) · (kT / q)} ln (m)} - {(V BE0 / T 0) - (V g0 / T 0)} = (R 41 / R 23) · (kT / q) ln (m) ·・ It becomes (39).

This is because the output voltage (∂V _S51 / ∂T) with respect to the temperature of the temperature detection circuit 51 of the present embodiment changes with the temperature of the conventional temperature detection circuit 1 (∂V _S1 / ∂).
T), the output voltage (∂V _S51 / ∂) with respect to the temperature of the temperature detection circuit 51 of this embodiment.
It can be seen that T) can be freely set by the ratio of the resistors R ₄₁ and R ₂₃ as shown in the equation (39).

The bandgap Zener voltage detection circuit 34 of the first to third embodiments can provide a positive temperature characteristic for the signal supplied to the base of the NPN transistor Q ₂₂ .
The circuit format does not matter. It goes without saying that the same operation can be realized by reversing the polarities of the transistors of the first to third embodiments and reversing the polarities of the power supply voltages.

[0078]

As described above, according to claim 1 of the present invention, the temperature characteristics of the temperature detection circuit and the control signal generation circuit are set to have characteristics of opposite slopes, and the control signal generated by the control signal generation circuit is set. By inverting and adding to the detection signal generated by the temperature detection circuit to obtain a temperature detection signal, the temperature coefficient can be freely set.

According to the present invention, the signal for inverting the bandgap Zener voltage detected by the bandgap Zener detecting means by the controlling transistor can be superimposed on the temperature detecting signal to control the temperature detecting signal. Compared to the base-emitter voltage of (1) which is used as a temperature detection signal as it is, it has a feature that a change in detected voltage with respect to temperature can be increased.

According to the third aspect of the present invention, the output detection signal is output via the feedback amplifier, and is fed back via the signal control circuit according to the detected band cap zener voltage detected by the band gap zener detection circuit. By controlling the amount of feedback of the amplifier, in addition to the change in the base-emitter voltage of the detection transistor due to temperature, the temperature detection signal is controlled according to the bandgap Zener voltage. Has a feature that the temperature coefficient can be increased as compared with the case where is used as the temperature detection signal as it is.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram of a first embodiment of the present invention.

FIG. 2 is an operation explanatory diagram of the first embodiment of the present invention.

FIG. 3 is a circuit configuration diagram of a second embodiment of the present invention.

FIG. 4 is a circuit configuration diagram of a third embodiment of the present invention.

FIG. 5 is a circuit configuration diagram of an example of the related art.

FIG. 6 is a circuit configuration diagram of another conventional example.

FIG. 7 is a circuit configuration diagram of another example of the related art.

[Explanation of symbols]

31, 41, 51 Temperature detection circuit 32, 35 Constant current source 33 Signal control circuit 34 Bandgap Zener voltage detection circuit 42, 53 Current mirror circuit 52 Amplification circuit 54 Operational amplifier Q ₂₁ , Q ₃₁ Temperature detection NPN transistor R ₂₁ Output resistance Q ₂₂ , Q ₂₃ , Q ₂₇ , Q ₂₈ , Q ₂₉ , Q ₃₁ NPN transistor Q ₂₄ , Q ₂₅ , Q ₂₆ , Q ₃₂ , Q ₃₃ , Q ₄₁ , Q ₄₂ PNP transistor R ₂₄ , R ₂₅ , R ₂₆ , R ₃₁ , R ₃₂ , R ₃₃ , R ₄₁ resistance

Claims (3)

[Claims] 1. A temperature detection circuit having a predetermined temperature characteristic and having a temperature detection circuit for generating a temperature detection signal according to the temperature, wherein the temperature detection circuit has a temperature characteristic having an inclination opposite to that of the temperature detection circuit. Temperature detection, which includes a control signal generation circuit that generates a control signal in accordance with the temperature detection signal, and a detection signal control circuit that inverts the control signal generated by the control signal generation circuit and adds the control signal to the temperature detection signal. circuit. 2. In the detection signal control circuit, the control signal generated by the control signal generation circuit is connected to a base, a collector is connected to an output terminal that outputs the temperature detection signal, and an emitter is a constant potential. The temperature detecting circuit according to claim 1, wherein the temperature detecting circuit comprises a controlled transistor. 3. The control signal generation circuit has a feedback amplifier for amplifying a base-emitter voltage of the output transistor, and the signal control circuit has a feedback current of the feedback amplifier according to a bandgap Zener voltage. The temperature detection circuit according to claim 1, wherein