JPH082587Y2 - Temperature detection circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a temperature detection circuit for digitally outputting temperature information.

[Conventional technology]

FIG. 2 is a schematic configuration diagram of the temperature detecting circuit of the first conventional example. The resistance value of the thermistor 202, which is a kind of resistor, changes according to a certain rule with respect to temperature change. The thermistor 202 is supplied with a constant current by the constant current circuit 201, and a change in the resistance value of the thermistor 202 is converted into a change in the voltage across the thermistor 202. Both ends of the thermistor 202 are analog-digital converters (hereinafter referred to as A / D
It is connected to the input of 203). The A / D converter 203 outputs the temperature information as a digital value proportional to the input voltage.

Further, as a second conventional example, there is a temperature detection circuit described in Japanese Patent Laid-Open No. 63-101722. Although the second conventional example is not shown, its configuration will be described below. The other end of the first resistor connected to the power supply voltage line is connected to one end of the thermistor, the other end of the thermistor is connected to the emitter of the first transistor, and the second resistor is connected in parallel to the thermistor. ing. The base and collector of the first transistor are connected to each other, and the intersection is grounded via the third resistor,
The intersection of the base and collector of the first transistor is connected to the base of the second transistor. The emitter of the second transistor is connected to the power supply voltage line via the fourth resistor, and the collector of the second transistor is connected to the series circuit of the fifth resistor and the first capacitor such that the capacitor side is grounded. ing. The intersection of the fifth resistor and the first capacitor is connected to the sixth resistor, the other end of the sixth resistor is grounded via the seventh resistor, and the intersection of the sixth resistor and the seventh resistor is It is connected to the base of the third transistor. The emitter of the third transistor is grounded, the collector of the third transistor is connected to the power supply voltage line through the eighth resistor, and the collector is connected to the cathode of the first diode. The anode is connected to the intersection of the collector of the second transistor and the fifth resistor. An analog LPF and a set / reset pulse generator are connected to the intersection of the collector of the third transistor and the eighth resistance, and a clock is input from the clock generator to the set / reset pulse generator and set.・ Set output from reset pulse generator ・
A reset pulse is input to the counter, a clock is input to the counter from the clock generator, and digital data is output from the counter.

[Problems to be solved by the invention]

However, the temperature detecting circuits of the first conventional example and the second conventional example use thermistors as the temperature detecting elements.
Therefore, since the thermistor and other peripheral elements are made of different materials, it is impossible to provide them on the same semiconductor substrate, and at least two elements or more are required to configure the temperature detection circuit. However, there is a problem that the occupied area and volume increase.

The temperature detecting circuit of the second conventional example still has the first resistor, the thermistor, the second resistor, the first transistor, the third resistor, the fourth resistor, the second transistor, the fifth resistor, and the fifth resistor. It is an application of the current amplification means using the capacitor of 1.
The first transistor operates as a diode in which the emitter is the anode and the base and the collector are the cathodes by connecting the base and the collector. Therefore, when the power supply voltage line fluctuates, the amount of current flowing through the diode also fluctuates, and the amount of current flowing through the base of the second transistor also fluctuates, causing a problem that temperature information cannot be measured accurately.

[Purpose of device]

The object of the present invention is to solve such a problem, and by providing the temperature detecting element and other peripheral elements on the same semiconductor substrate, the occupied area and volume are reduced, and even if the power supply voltage line fluctuates, the temperature information remains unchanged. An object of the present invention is to provide a temperature detection circuit that accurately converts into digital data and outputs it without being affected by fluctuations in the power supply voltage line.

[Means for solving the problem]

The temperature detection circuit of the present invention comprises a plurality of current mirror circuits connected in series, a resistor having a temperature coefficient connected to the source terminal of the high potential side or low potential side current mirror circuit, and a plurality of current connected in series. A driver circuit to which an arbitrary output terminal of the mirror circuit is connected, an oscillation circuit in which the output terminal of the driver circuit is connected to a power supply terminal, and the oscillation frequency changes according to a change in the voltage of the output terminal of the driver circuit, and the oscillation circuit The counter has a counter for counting the oscillation output of and the pulse generating circuit for controlling the counting operation of the counter, and obtains the temperature information as a digital value which is the output of the counter.

〔Example〕

Next, an embodiment of the present invention will be described with reference to the drawings. First
The drawing is an equivalent circuit diagram showing an embodiment of the temperature detecting circuit of the present invention. The temperature detection circuit according to the present invention shown in FIG. 1 includes a first current mirror circuit 104 and a second current mirror circuit 1
06, a first resistor 101 having a temperature coefficient, a second resistor 102 for current adjustment, an amplifier circuit 109, and a driver circuit 11
0, an oscillation circuit 111, a pulse generation circuit 112, an AND circuit 113, and a counter 114.

The first current mirror circuit 104 includes a first P-type MOS (Me
tal-Oxide-Silicon) transistor 103 and the second P-type MO
The gate terminal of the first P-type MOS transistor 103 is the second P-type MOS transistor 107.
Is connected to the gate terminal and the drain terminal of.

In addition, the second current mirror circuit 106 includes a first N-type MOS
It is composed of a transistor 105 and a second N-type MOS transistor 108, and the gate terminal and drain terminal of the first N-type MOS transistor 105 are connected to the gate terminal of the second N-type MOS transistor 108. .

The power supply terminal A, which is the power supply on the high potential side of the temperature detection circuit of the present invention, is connected to one terminal of the first resistor 101 having a temperature coefficient, and the other terminal of the first resistor 101 is connected to the second terminal. Resistance 1
02 one terminal and the second of the first current mirror circuit 104
Connected to the source terminal of the P-type MOS transistor 107 of
The other terminal of the resistor 102 is connected to the first current mirror circuit 1
It is connected to the source terminal of the first P-type MOS transistor 103 of 04.

The second P-type M that constitutes the first current mirror circuit 104
The drain terminal of the OS transistor 107 is connected to the second N-type MOS transistor 10 which constitutes the second current mirror circuit 106.
Connected to the drain terminal of 8, the first current mirror circuit 1
The drain terminal of the first P-type MOS transistor 103 constituting 04 is the first drain constituting the second current mirror circuit 106.
Of the N-type MOS transistor 105.

The source terminals of the first N-type MOS transistor 105 and the second N-type MOS transistor 108 of the second current mirror circuit 106 are connected to the power supply terminal B on the low potential side.

A typical example of the resistor 101 having a temperature coefficient is a diffusion resistor or a polysilicon resistor formed on a semiconductor substrate.

The second P-type M that constitutes the first current mirror circuit 104
A second N-type MOS transistor 108 forming a second current mirror circuit 106 and the drain terminal of the OS transistor 107.
The connection point with the drain terminal of is connected to the input terminal of the amplifier circuit 109, and the output of the amplifier circuit 109 is connected to the input terminal of the driver circuit 110.

The output of the driver circuit 110 is connected to the power supply terminal on the low potential side of the oscillator circuit 111, the output of the oscillator circuit 111 is connected to one input terminal of the AND circuit 113, and the other input terminal of the AND circuit 113 is pulse-generating. It is connected to the first pulse signal O1 output by the circuit 112.

Further, the output signal of the AND circuit 113 is connected to the input terminal of the counter 114, and the second pulse signal O2 output from the pulse generation circuit 112 is connected to the preset terminal of the counter 114.

Next, the operation of the temperature detecting circuit of the present invention will be described. First, when a voltage is applied to the power supply terminals A and B, the first N-type MOS transistor 1 in which the gate terminal and the drain terminal are connected
In 05, a drain current flows when the gate-source voltage exceeds the threshold voltage of the first N-type MOS transistor 105.

The second N-type MOS transistor 108 has the same threshold voltage because it is manufactured in the same process as the first N-type MOS transistor 105, and the gate terminal voltage of the first N-type MOS transistor 105 is the second N-type MOS transistor 105. Type MOS transistor 108 is also applied to the gate terminal thereof, and a drain current also flows through the second N-type MOS transistor 108.

As described above, the gate-source voltage of the second N-type MOS transistor 108 that determines the drain current of the second N-type MOS transistor 108 is the first N-type MOS transistor 105.
Of the first N-type MOS transistor 105 and the second N-type MOS transistor 105 in the embodiment of the present invention.
The gate-source voltage of the transistor 108 is equal.

In addition, the drain current of the second N-type MOS transistor 108 is the second N-type MOS transistor 108 even if the drain-source voltage exceeding the saturation voltage is applied between the drain and the source of the second N-type MOS transistor 108. It is obvious that if the gate-source voltage of the MOS transistor 108 is constant, it becomes almost constant regardless of the drain-source voltage.

Therefore, the second N-type MOS transistor 108 acts as a constant current source for the second P-type MOS transistor 107 connected in series, and the P-type MOS transistor 107 is driven by a constant current.

Second P-type MOS transistor 1 under constant current drive condition
In 07, since the drain terminal and the gate terminal are connected, the drain-source voltage of the second P-type MOS transistor 107 becomes constant.

A similar relationship exists between the first N-type MOS transistor 105 and the first N-type MOS transistor 105.
Of the first P-type MOS transistor 103
When VDS is applied between the drain and the source of the n-type MOS transistor 103 exceeding the saturation voltage, the first n-type MOS transistor 103
The drain-source voltage of 105 is also constant.

The output voltage V1 of the first current mirror circuit 104 is
Of the voltage drop across the resistor 101 and the second P-type MOS transistor 10
It is equal to the sum of drain-source voltage of 7.

As described above, the current flowing through the first resistor 101 is constant, the voltage drop across the first resistor 101 is also constant, and the drain-source voltage of the second P-type MOS transistor 107 is also constant current driven. Since it is done, it will be constant.

Therefore, when the potential difference between the power supply terminal A and the power supply terminal B exceeds a certain value, the output voltage V1 of the first current mirror circuit 104 becomes constant regardless of the potential difference between the power supply terminal A and the power supply terminal B.

Similarly, the output voltage of the second current mirror circuit 106, which is the potential difference between the power supply terminal B and the drain terminal voltage of the first N-type MOS transistor 105, also has a constant potential difference between the power supply terminal A and the power supply terminal B. Beyond, the voltage becomes constant regardless of the potential difference between the power supply terminal A and the power supply terminal B.

From the above description, if the temperature is constant, the first resistor 10 can be used irrespective of the fluctuation of the voltage between the power supply terminal A and the power supply terminal B.
The voltage across the first and second resistors 102 and the drain-source voltage between the first N-type MOS transistor 105 and the second P-type MOS transistor 107 are constant, and the power supply terminal A and the power supply terminal B are connected. The fluctuation of the voltage between the first P-type MOS transistor 1
It appears in the drain-source voltage between 03 and the second N-type MOS transistor 108.

Therefore, the output voltage V1 of the first current mirror circuit 104 has a characteristic that it hardly depends on the fluctuation of the voltage between the power supply terminal A and the power supply terminal B, but only on the temperature. Here, assuming that the voltage drop in the first resistor 101 having a temperature coefficient is Vr and the drain-source voltage of the P-type MOS transistor 107 is Vds1, the first current mirror circuit.
The output voltage V1 of 104 is represented by V1 = VR + Vds1. In the above equation, assuming that the resistance value of the first resistor 101 is R and the current value flowing through the first resistor 101 is I, it is expressed by Vr = IR, so V1 = IR + Vds1 and the current value I is the first current mirror. The current flowing through the circuit 104 and the second current mirror circuit 106 is a constant current as is clear from the above description.

Therefore, since the resistance value R of the first resistor 101 has a temperature coefficient, the voltage drop Vr of the first resistor 101 has temperature dependency, and as a result, the output voltage V1 of the first current mirror circuit 104 is increased. Also has temperature dependency, and the output voltage V1 of the first current mirror circuit 104 can be used as temperature information.

At this time, the output voltage V1 of the first current mirror circuit 104
In order to increase N, by inserting N current mirror circuits having the same configuration as the first current mirror circuit 104 between the first current mirror circuit 104 and the second current mirror circuit 106, N × The voltage can be increased by the amount corresponding to VDS1.

The output voltage V1 is input to the driver circuit 110 amplified by the amplifier circuit 109. If the output voltage V1 has a sufficient value, the amplifier circuit 110 may be omitted.

The output voltage V2 of the driver circuit 110 becomes a voltage proportional to the output voltage V1 and is connected to the power supply terminal of the oscillation circuit 111 whose oscillation frequency changes with the power supply voltage.

The oscillation circuit 111 outputs a transmission signal to the AND circuit 113, and a pulse generation circuit including a reference oscillator or a time constant circuit.
The 112 outputs the first pulse signal O1 having a period sufficiently longer than the output signal of the oscillation circuit 111 to the AND circuit 113.

Therefore, when the first pulse signal O1 is "1", the output signal of the AND circuit 113 outputs the oscillation signal of the oscillator circuit 111, and when the first pulse signal O1 is "0", the AND circuit 113 is output. The output signal of is 0.

Next, the generation circuit 112 outputs the second pulse signal O2 to output the counter 114 when the first pulse signal O1 is in the “0” state.
After presetting, the pulse signal O1 is set to "1" and the oscillation signal of the oscillation circuit 111 is output to the counter 114.

The counter 114 counts the oscillation signals of the oscillation circuit 111 via the AND circuit 113 and outputs the digital output O3.

As is clear from the above description, since the power supply voltage of the oscillation circuit 111 has temperature dependency, the cycle of the oscillation signal of the oscillation circuit 111 also changes with temperature, and as a result, the counter 114
The digital output O3 of changes with temperature.

An oscillator circuit whose oscillation frequency changes depending on the power supply voltage
Typical examples of the 111 include a ring oscillation circuit and an oscillation circuit including a varicap diode.

Further, when the oscillation frequency of the oscillation circuit 111 itself has a temperature coefficient, the detection sensitivity of the temperature detection circuit of the present invention is the sum of the temperature coefficient of the oscillation circuit and the temperature coefficient of the output voltage of the current mirror circuit described above. By adjusting the respective temperature coefficients, it becomes possible to widely adjust the detection sensitivity of the temperature detection circuit.

Although the output voltage of the current mirror circuit 104 is used as the power supply voltage of the oscillation circuit 111 in the above description, the first resistor 101 and the second resistor 102 are used as the second current mirror circuit 10.
The second current mirror circuit 106 is connected to the low potential side of 6.
The same effect can be obtained by using the output voltage of 1 as the power supply voltage of the oscillation circuit 111.

[Effect of device]

As described above, according to the present invention, by using at least two or more current mirror circuits and resistors having a temperature coefficient, it is possible to provide the temperature detecting element and other peripheral elements on the semiconductor substrate at the same position. Therefore, the occupied area and volume can be significantly reduced, and a temperature detection circuit having no voltage dependence can be provided, which can be applied to many fields.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a temperature detecting circuit of the present invention, and FIG. 2 is a schematic configuration diagram of a conventional temperature detecting circuit. 101 ... first resistance, 102 ... second resistance, 103 ... first
P-type MOS transistor, 104 ... First current mirror circuit, 105 ... First N-type MOS transistor, 106 ... Second current mirror circuit, 107 ... Second P-type MOS transistor, 108 ... … Second N-type MOS transistor, 109 ……
Amplifier circuit, 110 …… Driver circuit, 111 …… Oscillation circuit,
112 …… Pulse generation circuit, 113 …… AND circuit, 114 …… Counter.

Claims (1)

[Scope of utility model registration request] 1. A plurality of current mirror circuits connected in series, a resistor connected to the source terminal of a high-potential-side or low-potential-side current mirror circuit and having a temperature coefficient formed on a semiconductor substrate, and a plurality of series-connected resistors. A driver circuit for inputting an output voltage having a temperature dependency which is an output of the current mirror circuit connected to the driver circuit, and an output of the driver circuit is connected to a power supply terminal, and an oscillation frequency is changed by a change in a voltage of the output of the driver circuit. A temperature detection circuit comprising an oscillation circuit, a counter for counting the oscillation output of the oscillation circuit, and a pulse generation circuit for controlling the counting operation of the counter.