JPH11265220A - Temperature adjustment method by transistor and temperature adjustment circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify the constitution as much as possible, to accurately measure a temperature, and to make adjustable the temperature without the problem of a heat coupling by utilizing heat generation by the collector loss of a transis tor as a heat source. SOLUTION: When switching signals P oscillated by an oscillator 5 are at a high level, a switch Sw is connected to the side of a contact Sa and a temperature measurement state is attained. A power supply voltage Vcc is supplied through a resistor R1 to the base Tb of the transistor T, a forward direction current Ia flows and a base voltage Vbe is obtained. The voltage Vbe is inputted to an OP amplifier 3 and compared with the set value Vs of a variable resistor Rv and the analog value 3o of a compared result is outputted to a storage device 4. The storage device 4 samples and holds the analog value 3o from the OP amplifier 3 at the time of the fall of the switching signals P of the oscillator 5 and sends it to a control circuit 2 as a temperature feedback signal 4o. The control circuit 2 decides a control current Ib required for heating based on the value 4o and outputs it.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a temperature control method and a temperature control circuit using transistors.

[0002]

2. Description of the Related Art For example, when stability against temperature drift due to heat is required for an integrated circuit constituting a measuring circuit of a gas analyzer, the integrated circuit may be heated to a predetermined temperature in advance. FIG. 4 is a diagram showing a temperature control circuit 10 conventionally used, in which a heater 11 is used as a heating unit and a thermistor 12 is used as a temperature sensor. By heating the heater 11 while monitoring the thermistor 12, the measurement circuit can be adjusted to a desired temperature,
By stabilizing this temperature, the measured value of the analyzer can be stabilized.

[0003] Various types of heat generating parts have been proposed, such as a hot-wire heater and an infrared heater. FIG. 5 is a diagram showing a heating device (temperature control circuit) 10 disclosed in Japanese Patent Application Laid-Open No. 9-260036 which uses heat generated by the collector loss of the transistor 11 as a heat source.
Is suitable for easily heating a place having a small heat capacity. Reference numeral 12 denotes a thermistor provided near the transistor 11.

[0004]

However, in any of these conventional temperature control circuits 10, the temperature control portion 13 is provided.
In addition, it is necessary to attach at least two parts of the heat generating portion 11 and the temperature sensor 12, and the structure is inevitably complicated. In addition, the heat generating unit 13 is a temperature sensor 11
Physically separated from each other, a problem such as a variation in thermal coupling between the two may occur.

The present invention has been made in consideration of the above-mentioned matters, and simplifies the structure as much as possible, performs accurate temperature measurement, and enables temperature adjustment without a problem of thermal coupling. It is an object to provide a temperature control method and a temperature control circuit using transistors.

[0006]

In order to achieve the above object, a temperature control method using a transistor according to a first aspect of the present invention utilizes heat generated by a collector loss of a transistor as a heat source and performs temperature feedback control of the transistor on the same transistor base. -It is characterized by monitoring by the voltage between the emitters.

Therefore, according to the temperature control method using transistors of the present invention, since the heat source and the heat sensor are formed by one transistor, the configuration can be simplified as much as possible. Further, there is no problem due to thermal coupling between the heat generating portion and the thermal sensor, and accurate temperature control can always be performed without being affected by the surrounding environment.

In addition, a current is supplied to the base of the transistor, the base voltage at this time is compared with a set value of a base voltage corresponding to a set temperature, and a temperature measurement state for storing a comparison result is stored. Based on the result, control is performed so as to alternately switch the temperature adjustment state in which the control current for flowing the collector current such that the transistor approaches the set temperature to the base in a short cycle. When the temperature of the transistor is adjusted to the set temperature, the temperature can be accurately controlled by monitoring the voltage between the base and the emitter of the transistor, and the calorific value can be easily adjusted by comparing with the set value. The setting temperature can be changed very easily by changing the set value of the voltage to be compared with the base voltage.

Further, by controlling the switching so that the temperature measurement state is sufficiently shorter than the temperature adjustment state, the transistor is heated during the temperature measurement state in which current is supplied to the base of the transistor. Can be suppressed as much as possible. When the storage of the comparison result and the output of the control voltage are performed by digital control of the on / off operation, there is an advantage that the configuration can be simplified.

A temperature control circuit using a transistor according to a second aspect of the present invention provides a temperature measurement state in which a constant current is supplied to a base of a transistor that uses heat generated by a collector loss as a heat source to measure a base voltage, and a temperature control in which a control current is supplied. A switch that switches the state, a comparator that compares the base voltage in the temperature measurement state with the set value of the base voltage corresponding to the set temperature, and a temperature that holds the comparison result when switching from the temperature measurement state to the temperature adjustment state. A storage device that enables a control current to be variably output to the base of the transistor based on the comparison result held in the adjustment state, and an oscillator that supplies a switching signal that alternately switches the state of the switch and the storage unit in a short cycle. It is characterized by having. In this case, since the temperature control circuit and the transistor are connected by a pair of signal lines, not only the configuration of the heat generating portion but also peripheral wiring can be simplified as much as possible.

When the switching signal is a pulse signal for sufficiently shortening the temperature measurement state as compared with the temperature adjustment state, the transistor supplied to the base when the switching signal is in the temperature measurement state causes the transistor to have a temperature. It can be prevented from rising. Further, when the comparison result is stored and the control voltage is output by the latch circuit, the circuit can be simplified as much as possible.

[0012]

FIG. 1 shows a first embodiment of a transistor temperature control circuit 1 according to the present invention. In FIG. 1, T is a transistor that utilizes heat generated by a collector loss as a heat source.
b, the emitter Te, and the collector Tc are each a switch S
w, ground G, and heating power supply Pw. Switch Sw has a contact Sa to connect the power supply Vcc via a resistor R _1, and a contact Sb to be connected to the control circuit 2 via the resistor R _2, the base of the transistor T by the switching of the switch Sw - emitter (Hereinafter referred to as base voltage) Vbe, and a temperature adjustment state in which the control circuit 2 supplies the control current Ib to the base Tb.

Rv is a transistor T corresponding to a set temperature.
Is a variable resistor for setting the reference value Vs of the base voltage Vbe. For example, a scale of the set temperature is formed by taking the variable resistor Rv. Reference numeral 3 denotes an OP amplifier that operates as a comparator (comparator) that compares the base voltage Vbe with a reference value Vs. 4 denotes an analog value 3o obtained during the temperature measurement state and holds the temperature during the temperature adjustment state. A storage unit 5 that outputs a feedback signal 4o is an oscillator that outputs a pulse signal P (switching signal) to the switch Sw and the storage unit 4.

The output of the storage unit 4 is input to the control circuit 2, and the control current Ib can be adjusted by the temperature feedback signal 4o held by the storage unit 4. That is, in the circuit of this example, the control circuit 2, the OP amplifier 3, and the storage device 4 form feedback control.

Next, the operation of the temperature control circuit 1 using the transistors of this embodiment will be described. When the switching signal P oscillated by the oscillator 5 is at a high level, the switch Sw
It is connected to the a side and enters a temperature measurement state. At this time, the base Tb of transistor T is a forward current flows Ia by the power supply voltage via a resistor R ₁ (constant voltage) Vcc is supplied. And the base T of the transistor T
A base voltage Vbe (to be used later as a temperature feedback signal) is obtained at b. This voltage Vbe is input to the OP amplifier 3, compared with the set value Vs of the variable resistor Rv, and outputs the comparison result analog value 3 o to the storage device 4.

The storage unit 4 samples and holds the analog value 3o from the OP amplifier 3 when the switching signal P of the oscillator 5 falls, and sends it to the control circuit 2 as a temperature feedback signal 4o. The control circuit 2 determines a control current Ib necessary for heating based on the value 4o and outputs it.

[0017] switching signal P of the oscillator 5 becomes a low level, the switch Sw is connected to the contact Sb side, the control current Ib from the control circuit 2 to the base Tb via the resistor R ₂ of the transistor T Is supplied and the control current I
When the collector current Ic according to b flows through the transistor T, the transistor T generates heat.

Now, for example, when the temperature of the transistor T is lower than the set value, the base voltage Vbe of the transistor T
Becomes higher than the set value Vs of the variable resistor Rv. At this time,
The output analog value 3o of the comparator 3 becomes a positive value, which is sent to the control circuit 2 as a temperature feedback signal 4o via the storage unit 4. The control circuit 2 receives a temperature feedback signal 4o, knows that the temperature of the transistor T is low, and outputs the number of the control current Ib by the base Tb of transistor T through a resistor R _2.

On the other hand, when the temperature of the transistor T is lower than the set value, the base voltage Vbe of the transistor T becomes lower than the set value Vs of the variable resistor Rv. 2 acts so as not to allow a current to flow through the base Tb of the transistor T. This control current I
The temperature is controlled by performing the operation of increasing / decreasing b in proportion to the difference between the temperature of the transistor T and the set value.

When the setting of the temperature is changed, the set value Vs may be adjusted by adjusting the variable resistor Rv, and there is no need to make any circuit change. In addition, by displaying the temperature at the time of taking the variable resistor Rv as in this example, it is possible to further facilitate the temperature adjustment.

The switching signal P generated by the oscillator 5 has a duty cycle such that the high-level period T ₁ indicating the temperature measurement state is sufficiently shorter than the low-level period T ₂ indicating the temperature adjustment state. The ratio has been adjusted. That is, the power supply via a resistor R ₁ in the temperature detection period T ₁ V
The generation of heat by the base current Ia flowing from the cc to the transistor T is minimized.

In the above example, the temperature feedback control of the transistor T is performed by the base Tb of the same transistor T.
This is an example of a temperature control circuit using transistors performed by monitoring the voltage between the transistor Te and the emitter Te, and the circuit configuration is not limited. That is, in the above-described example, the storage circuit 4 is connected to the control circuit 2 so that the control circuit 2 calculates and outputs an appropriate control current Ib, but the present invention is not limited to this. is not. For example based T of the temperature feedback signal 4o output from the storage unit 4 via the resistor R ₂ transistor T
b.

Further, in the temperature control circuit 1 using transistors shown in the present embodiment, the feedback control is performed using the base voltage Vbe. However, the present invention is not limited to this, and the base Tb and the emitter Te can be formed by any method. It is possible to monitor the voltage between them.

In the above-described example, the power supply Vcc for the temperature control circuit 1 using transistors and the power supply Pw for heat generation are provided separately. However, it goes without saying that these may be taken from the same power supply line. .

FIG. 2 shows the structure of the temperature control circuit 1 using simplified transistors. In FIG. 2, the members denoted by the same reference numerals as those in FIG. 1 are the same or equivalent members. Omitted. In FIG. 2, reference numeral 6 denotes a latch circuit of a digital circuit, which is provided in place of the storage unit 4 and the control circuit 2 shown in FIG. 1. The data input unit 6d is an OP amplifier 3, and the clock input 6c is an oscillator 5. , data output is connected to the switch Sw through the resistor R _2.

Therefore, during the temperature measurement state T ₁ , the latch circuit 6 sets the set value (set temperature) Vs of the variable resistor Rv and the base voltage (heater temperature) of the transistor T.
The analog value 3o indicating the difference of Vbe is taken in, and the analog value 3o is determined by comparing a large value or a small value. Then, the latch circuit 6 stores the determination value at the falling edge of the switching signal P, during the subsequent temperature adjustment state T _2, controls the transistor T is turned on or off based on the determination value. Therefore, in this example, the configuration of the temperature control circuit 1 using transistors is simplified as compared with the configuration of FIG.

If the base voltage Vbe of the transistor T is higher than the set value Vs of the variable resistor Rv, OP
Since the output analog value 3o of the amplifier 3 becomes large, the latch circuit 6 latches the high level at the rise of the switching signal. Then the subsequent temperature adjustment state output 6q period in the latch circuit 6 of T _2, to heat the transistor T. If the temperature is above the elevated setting temperature in the next temperature measurement state T _1, decreases the base voltage Vbe of the transistor T,
Since the base voltage Vbe becomes lower than the set value Vs, OP
The output of the amplifier 3 also decreases, and the latch circuit 6 latches the low level. Then, the subsequent duration of the temperature adjustment state T _2, no current flows through the transistor T, it is possible to lower the temperature of the transistor T. Then, the temperature is controlled by repeating the on / off operation.

FIG. 3 shows an example in which the temperature control circuit 1 using transistors shown in FIG. 1 is applied. Transistor temperature control circuit according to one of the example 'is an integrated circuit including a plurality of temperature control circuit 1 according to the above-mentioned transistors, setting performing power input unit V, and G, the temperature settings of each transistor T ₁ through T _n a temperature input section S ₁ to S _n, the transistors T ₁ ~
Control signal output units B ₁ connected to the bases of T _n , respectively.
To _Bn . The operation of the circuit is the same as that shown in FIG. 1, and a description thereof will be omitted. Further, the configuration of the temperature control circuit 1 is not limited to the configuration shown in FIG. 1, and it goes without saying that the configuration shown in FIG.

[0029] By using the transistor temperature control circuit 1 'according to the above-described, it is possible to temperature control optionally the transistors T ₁ through T _n in each separate. Moreover,
Since each of the transistors T _{1 to} T _n and the temperature control circuit 1 ′ are only connected by a pair of wires, the configuration can be simplified as much as possible. Further, each transistor T ₁
Because through T _n is in each controlled so as to ensure the same temperature, the set temperature input section S ₁ to S _n as in this embodiment by the same voltage, as variations in temperature does not occur in each part numerous heat source comprising a transistor T ₁ through T _n respectively control, to eliminate the influence of the temperature drift of such analyzers, it allows it to very easily to be the entire foundation and uniform temperature.

[0030] In the present example, the voltage of the set temperature input section S ₁ to S _n in order to achieve uniform temperature is the same voltage, setting each voltage corresponding to an arbitrary temperature this It goes without saying that it is good. In addition to controlling a plurality of transistors, the temperature control circuit 1 using a single transistor may be integrated.

[0031]

As described above, according to the present invention,
By using the same transistor as the heater and sensor,
Not only is the configuration of the heat generating portion simple, but also there is no influence from variations in thermal coupling between the sensor portion and the heat generating portion. That is, the temperature of the heat generating portion can be kept constant without being affected by the mounting method of the sensor portion and the heat generating portion or the surrounding environment. A temperature measurement state for measuring a temperature by a base voltage of the transistor;
In the case where the temperature control state for supplying the control current to the base is controlled so as to be alternately switched in a short cycle, the voltage between the base and the emitter of the transistor can be accurately monitored by the base voltage, and the heat generation amount can be accurately determined. Can be adjusted. When the set temperature is changed, it can be performed very easily by changing the set value of the base voltage.

Further, when switching control is performed so that the temperature measurement state is sufficiently shorter than the temperature adjustment state, heating by the transistor during the temperature measurement state can be suppressed as much as possible. . When the storage of the comparison result and the output of the control voltage are performed by digital control of the on / off operation, there is an advantage that the configuration can be simplified.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a temperature control circuit using a transistor of the present invention.

FIG. 2 is a diagram showing a modification of the temperature control circuit using the transistor.

FIG. 3 is a diagram showing another modification using a temperature control circuit using the transistor.

FIG. 4 is a diagram showing an example of a conventional temperature control circuit using a heater.

FIG. 5 is a diagram showing an example of a conventional temperature control circuit using transistors.

[Explanation of symbols]

1: Temperature control circuit using transistors, 3: Comparator, 3o ...
Comparison result, 4 ... Storage device, 4o ... Hold comparison result, 5 ... Oscillator, 6 ... Latch circuit, Ib ... Control current, P
... Switching signal, Sw ... Switch, T ... Transistor, T
b: base, Te: emitter, T ₁ : temperature measurement state, T
₂ ... temperature adjustment state, Vbe ... base voltage, Vs ... set value of base voltage.

Claims (7)

[Claims] 1. A temperature control method using a transistor, wherein heat generated by a collector loss of a transistor is used as a heat source and temperature feedback control of the transistor is performed by monitoring a voltage between a base and an emitter of the same transistor. 2. A temperature measurement state in which a current is supplied to the base of the transistor, the base voltage at this time is compared with a set value of a base voltage corresponding to a set temperature, and a comparison result is stored, and the stored comparison is performed. Based on the results, the transistor temperature is controlled to the set temperature by controlling the temperature control state to supply the control current for flowing the collector current that approaches the set temperature to the base alternately in a short cycle. A temperature control method using a transistor according to claim 1. 3. The method according to claim 2, wherein the switching control is performed such that the temperature measurement state is sufficiently shorter than the temperature adjustment state. 4. The temperature control method according to claim 2, wherein the storing of the comparison result and the output of the control voltage are performed by digital control of an on / off operation. 5. A switch for switching between a temperature measurement state in which a constant current is supplied to a base of a transistor using a heat generated by a collector loss as a heat source to measure a base voltage and a temperature adjustment state in which a control current is supplied, and a temperature measurement state. And a comparator for comparing the base voltage at the set temperature with the set value of the base voltage corresponding to the set temperature, and holding the comparison result at the time of switching from the temperature measurement state to the temperature adjustment state to thereby hold the comparison result held in the temperature adjustment state. A memory for enabling the control current to be variably output to the base of the transistor, and an oscillator for supplying a switching signal for alternately switching the state of the switch and the memory in a short cycle. Tuning circuit. 6. The transistor temperature control circuit according to claim 5, wherein the switching signal is a pulse signal for making the temperature measurement state sufficiently shorter than the temperature adjustment state. 7. The transistor temperature control circuit according to claim 5, wherein the comparison result is stored and the control voltage is output by a latch circuit.