JP5050409B2 - Temperature detector - Google Patents

Description

  The present invention relates to a temperature detection device, and more particularly to a temperature detection device that is formed on a semiconductor substrate and outputs an output signal corresponding to an ambient temperature.

  In recent years, in the field of semiconductor integrated circuits, a lot of heat is generated as the circuit becomes highly integrated. For this reason, in order to protect the circuit from heat, a heating protection circuit is mounted that stops the operation of the circuit when the temperature reaches a predetermined temperature (see, for example, Patent Document 1).

  In such a semiconductor integrated circuit heating protection circuit, a band gap circuit using a bipolar transistor or a circuit using a diode is conventionally known as a temperature detection circuit for detecting the ambient temperature.

On the other hand, in recent years, semiconductor integrated circuits have been configured with MOS transistors that can reduce power consumption compared to bipolar transistors. In a semiconductor integrated circuit using MOS transistors, the temperature detection circuit also needs to be formed of MOS transistors in order to improve the process efficiency (see, for example, Patent Documents 2 and 3).
JP-A-7-13643 JP 2002-108465 A JP 2005-122753 A

  However, in a temperature detection circuit using a MOS transistor, the influence of manufacturing variations on temperature dependency is large, and it is necessary to adjust a temperature detection diode and a resistance element by laser trimming or the like. For this reason, it is necessary to mount an adjustment diode or a resistance element, and the area efficiency is deteriorated. In addition, adjustment work is required, and there is a problem that production efficiency is deteriorated.

  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 device that can reduce the influence of manufacturing variations on temperature dependency.

The present invention provides a constant current source (DTr1) that generates a constant current and a current generated by the constant current source (DTr1) in a temperature detection device that is formed on a semiconductor substrate and outputs an output signal corresponding to an ambient temperature. The first temperature detection element (D1) supplied and the applied voltage changes according to the ambient temperature, and the current corresponding to the current supplied from the constant current source (DTr1) to the first temperature detection element (D1) The first current mirror circuit (Tr2, Tr3) for output, the first resistor (R1) to which the current output from the first current mirror circuit (Tr2, Tr3) is supplied, and the first current mirror circuit A current is supplied from (Tr2, Tr3) through the first resistor (R1), and a second temperature detection element (D2) whose applied voltage changes according to the ambient temperature, and a first current mirror circuit (Tr2, Tr3) From) Current is supplied from the second current mirror circuit (Tr4, Tr5) and the second current mirror circuit (Tr4, Tr5) that generate a current corresponding to the current supplied to the second temperature detection element (D2). A second resistor (R2) that generates a voltage corresponding to the current generated by the second current mirror circuit (Tr4, Tr5), a voltage applied to the first temperature detection element (D1), and a second voltage according to the difference between the applied voltage of the resistor (R2) have a temperature detection circuit (111) for performing temperature detection, wherein the first temperature detecting element and the second temperature detecting element, and the same no pairs The first current mirror circuit and the second current mirror circuit are paired and made in the same process, and the first resistor and the second resistor are paired and the same It is made in the process, And wherein the door.

  The first temperature detection element (D1) and the second temperature detection element (D2), and the first resistance (R1) and the second resistance (R2) have equivalent temperature characteristics. To do.

  The first temperature detection element (D1) and the second temperature detection element (D2) are formed on an n-type well region (122) formed on the p-type substrate (121) and on the n-type well region (122). The p-type diffusion region (123) is formed, and the p-type diffusion region (123) serves as an anode and is connected to the first current mirror circuit (Tr2, Tr3) or the first resistor (R1), and n The mold well region (122) is grounded using the cathode as a cathode.

  The constant current source (DTr1) is composed of depletion type MOS field effect transistors, and the first current mirror circuit (Tr2, Tr3) and the second current mirror circuit (Tr4, Tr5) are composed of enhancement type MOS field effect transistors. It is configured.

  The temperature detection circuit (111) includes a comparator (COM1), and the comparator (COM1) operates an internal current source according to a constant current generated by the constant current source (DTr1).

  In addition, the said reference code is a reference to the last, and description of a claim is not limited by this.

  According to the present invention, a pair can be constituted by the first temperature detection element and the second temperature detection element, the first resistance and the second resistance, and the first and second current mirror circuits. Since the influence of element variations on temperature dependence can be offset, accurate temperature detection can be performed.

  FIG. 1 is a circuit diagram showing an embodiment of the present invention.

  The temperature detection device 100 of the present embodiment is formed with other circuits on a p-type semiconductor substrate.

  Depletion type n channel MOS field effect transistor DTr1, enhancement type n channel MOS field effect transistors Tr2 and Tr3, enhancement type p channel MOS field effect transistors Tr4 and Tr5, diodes D1 and D2, resistors R1 and R2, and temperature detection circuit 111 Has been.

  The transistor DTr1 constitutes a constant current source, the power supply voltage VDD is applied to the drain, the source and the gate are short-circuited, and a constant current is output from the source. The constant current generated by the transistor DTr1 is supplied to the drain and gate of the transistor Tr2 and the gate of the transistor Tr3.

  The transistor Tr2 forms a first current mirror circuit together with the transistor Tr3. The drain of the transistor Tr2 is connected to its own gate, the source and gate of the transistor DTr1, and the gate of the transistor Tr3.

  The transistor Tr2 supplies a current corresponding to the constant current supplied from the source of the transistor DTr1 to the diode D1.

  The diode D1 constitutes a first temperature detection element, the anode is connected to the source of the transistor Tr2, and the cathode is grounded. The applied voltage of the diode D1 changes according to the ambient temperature.

  FIG. 2 shows a configuration diagram of the diode D1. FIG. 2 shows a cross-sectional view when the diode D1 is mounted on a semiconductor substrate.

  The diode D1 includes an n-type well region 122 formed on the p-type semiconductor substrate 121 and a p-type diffusion region 123 formed on the n-type well region 122.

  The diode D1 has a p-type diffusion region 123 as an anode, and is connected to the source of the transistor Tr2 constituting the first current mirror circuit. The diode D1 is grounded with the n-type well region 122 as a cathode. A connection point between the source of the transistor Tr2 and the anode of the diode D1 is connected to the temperature detection circuit 111.

  The transistor Tr3 has a drain connected to the drain and gate of the transistor Tr4, a source connected to one end of the resistor R1, and constitutes a first current mirror circuit together with the transistor Tr2. The transistor Tr3 draws a current corresponding to the drain current of the transistor Tr2 from the drain and supplies the current to the resistor R1 from the source.

  The resistor R1 is a first resistor, and one end is connected to the source of the transistor Tr3 and the other end is connected to the anode of the diode D2. The diode D2 constitutes a second temperature detection element, the anode is connected to one end of the resistor R1, and the cathode is grounded.

  The diode D2 has the same configuration as the diode D1 shown in FIG. At this time, the diode D2 is produced by the same process as the diode D1, and therefore has a temperature characteristic equivalent to that of the diode D1.

  In the transistor Tr4, the power supply voltage VDD is applied to the source, and the drain is connected to its own gate, the drain of the transistor Tr3, and the gate of the transistor Tr5, and forms a second current mirror circuit together with the transistor Tr5. Yes. The transistor Tr4 draws a current corresponding to the drain current of the transistor Tr3 from the power supply voltage VDD.

  In the transistor Tr5, the source voltage VDD is applied to the source, and one end of the resistor R2 is connected to the drain. The transistor Tr5 forms a second current mirror circuit together with the transistor Tr4. The transistor Tr5 outputs a current corresponding to the drain current of the transistor Tr4 from the drain and supplies it to one end of the resistor R2.

  The resistor R2 constitutes a second resistor, one end is connected to the drain of the transistor Tr5, and the other end is grounded. The resistor R2 generates a voltage corresponding to the current across the drain of the transistor Tr5. At this time, the resistor R2 is produced by the same process as the resistor R1, and therefore has a temperature characteristic equivalent to that of the resistor R1. The connection point between the drain of the transistor Tr5 and one end of the resistor R2 is connected to the temperature detection circuit 111.

  The temperature detection circuit 111 includes a comparator COM1 and a transistor Tr6.

  In the comparator COM1, the potential Va at the connection point between the source of the transistor Tr2 and the anode of the diode D1 is applied to the non-inverting input terminal, and the potential at the connection point between the drain of the transistor Tr5 and one end of the resistor R2 is applied to the inverting input terminal. Is applied. The comparator COM1 sets the output to a low level when the potential Va is lower than the potential Vb, and sets the output to a high level when the potential Va is higher than the potential Vb.

  The output of the comparator COM1 is supplied to the gate of the transistor Tr6. The transistor Tr6 is composed of an enhancement type p-channel MOS field effect transistor, the power supply voltage VDD is applied to the source, and the drain is connected to the gate of the output control transistor Tr7.

  The transistor Tr6 is turned off when the output of the comparator COM1 is at a high level, is turned on when the output of the comparator COM1 is at a low level, and the gate of the output control transistor Tr7 is set to a high level. The output control transistor Tr7 is composed of an enhancement type p-channel MOS field effect transistor, the power supply voltage VDD is applied to the source, and the drain is grounded through the resistor R3. The output control transistor Tr7 is turned on when the transistor Tr6 is off, and is turned off when the transistor Tr6 is on. A connection point between the drain of the transistor Tr6 and the output control transistor Tr7 is a temperature detection output terminal Tout.

  In the temperature detection output terminal Tout, the device temperature becomes higher than the predetermined temperature T0, the potential Va becomes lower than the potential Vb, and the output of the comparator COM1 becomes low level, whereby the transistor Tr6 is turned on and the output control transistor Tr7 is turned on. Turn off. The temperature detection output terminal Tout has the device temperature lower than the predetermined temperature T0, the potential Va is higher than the potential Vb, and the output of the comparator COM1 becomes high, whereby the transistor Tr6 is turned off, and the output control transistor Tr7 Turns on and plays a role as an output transistor.

  The output of the temperature detection output terminal Tout is supplied to a circuit on the same semiconductor substrate. The circuit to which the temperature detection output terminal Tout is connected is controlled so that, for example, when the temperature detection output terminal Tout becomes a high level, the substrate temperature decreases by reducing the power consumption of the circuit.

  FIG. 3 is an operation explanatory diagram of one embodiment of the present invention.

  The diode D1 has a negative temperature characteristic (approximately −2 mV / C °), and as a result, the potential Va exhibits a negative temperature characteristic that attenuates according to the temperature as shown in FIG. Similarly to the diode D1, the diode D2 has negative temperature characteristics, and the potential Vb is a potential corresponding to a current obtained by turning back the current flowing through the diode D2. At this time, since the current is limited by the resistor R1, as shown in FIG. 3, the slope is different from that of the potential Va and is gentle, and has a positive temperature characteristic that increases with temperature. For this reason, it is possible to detect the temperature based on the difference between the potential Va and the potential Vb.

  The characteristics of the potential Va and the characteristics of the potential Vb intersect at the temperature T0. In the temperature detection circuit 111 of the present embodiment, when the device temperature is higher than the temperature T0, the temperature detection output terminal Tout becomes high level, and the output control transistor Tr7 is turned off.

  At this time, the diodes D1 and D2, the resistors R1 and R2, the transistors Tr2 and Tr3; Tr4 and Tr5 are paired and created by the same process, so the variations cancel each other, and the potential Va and the potential Vb Can reduce the influence of manufacturing variations on temperature dependence.

  For example, when the potential Va varies as shown by a broken line as shown in FIG. 3, the potential Vb also varies as shown by a broken line, and when the potential Va varies as shown by a one-dot chain line as shown in FIG. Since the potential Vb also varies as indicated by the alternate long and short dash line, temperature detection can be performed at the same temperature T0 as the solid line detection temperature T0.

  According to the present embodiment, it is possible to reduce manufacturing variations with respect to temperature dependency. Further, the diodes D1 and D2 are structured as shown in FIG. 2, and the cathode is grounded as shown in FIG. 1, so that the parasitic transistor 124 shown in FIG. 2 can be prevented from operating.

  FIG. 4 is a circuit diagram showing a modification of the embodiment of the present invention. In the figure, the same components as in FIG.

  In this modification, the potential Vref at the connection point between the source and drain of the transistor DTr1, the drain and gate of the transistor Tr2, and the gate of the transistor Tr3 is used as a drive source of the current source of the comparator COM1.

  The comparator COM1 is composed of transistors Tr11 to Tr19. The transistors Tr11 and Tr12 constitute a differential transistor, and currents corresponding to the potentials Va and Vb are drawn from the transistors Tr13 and Tr14. The transistors Tr13 and Tr14 constitute a current mirror circuit, and supplies a current corresponding to the current drawn from the transistor Tr12 to the transistor Tr11.

  The transistor Tr15 is a constant current source, and draws a constant current from the transistors Tr11 and Tr12. The potential Vref of the connection point between the source and drain of the transistor DTr1, the drain and gate of the transistor Tr2, and the gate of the transistor Tr3 is applied to the gate of the transistor Tr15, and the transistor Tr15 serving as a current source has the potential Vref. Driven by.

  The transistors Tr16 to Tr19 constitute an output stage circuit of the comparator COM1, and a connection point between the transistors Tr13 and Tr11 is supplied as a differential output. The transistors Tr16 and Tr17 constitute a source follower circuit, and the transistor Tr17 constitutes a constant current source and draws a constant current from the transistor Tr16. At this time, the potential Vref of the connection point between the source and drain of the transistor DTr1, the drain and gate of the transistor Tr2, and the gate of the transistor Tr3 is applied to the gate of the transistor Tr17. And driven by the potential Vref.

  The transistors Tr18 and Tr19 constitute an inverter, and the outputs of the transistors Tr16 and Tr17 are inverted and output as the output of the comparator COM1.

  According to this modification, it is not necessary to separately provide a circuit for generating a potential for driving the current source of the comparator COM1, so that the configuration can be simplified.

  In addition, this invention is not limited to the said Example, A various modified example can be considered, without deviating from the summary of this invention.

It is a circuit block diagram of one Example of this invention. It is a block diagram of the diode D1. It is operation | movement explanatory drawing of one Example of this invention. It is a circuit block diagram of the modification of one Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Temperature detection apparatus 111 Temperature detection circuit DTr1 Depletion type n channel MOS field effect transistor Tr2, Tr3 Enhancement type n channel MOS field effect transistor Tr4, Tr5 Enhancement type p channel MOS field effect transistor D1, D2 Diode, R1, R2 Resistance

Claims (5)

In a temperature detector that is formed on a semiconductor substrate and outputs an output signal according to the ambient temperature,
A constant current source for generating a constant current;
A first temperature detecting element to which a current generated by the constant current source is supplied and an applied voltage changes according to an ambient temperature;
A first current mirror circuit that outputs a current corresponding to a current supplied from the constant current source to the first temperature detection element;
A first resistor to which a current output from the first current mirror circuit is supplied;
A second temperature detecting element that is supplied with a current from the first current mirror circuit through the first resistor and whose applied voltage changes according to an ambient temperature;
A second current mirror circuit that outputs a current corresponding to a current supplied from the first current mirror circuit to the second temperature detection element;
A second resistor that is supplied with current from the second current mirror circuit and generates a voltage corresponding to the current supplied from the second current mirror circuit;
Have a temperature sensing circuit for performing temperature detection in accordance with the difference between the second applied voltage of the resistor and the applied voltage of the first temperature sensing element,
The first temperature detection element and the second temperature detection element are paired and made in the same process,
The first current mirror circuit and the second current mirror circuit are paired and made in the same process,
The temperature sensor according to claim 1, wherein the first resistor and the second resistor are paired and made by the same process . 2. The temperature detection according to claim 1, wherein the first temperature detection element and the second temperature detection element, and the first resistance and the second resistance have equivalent temperature characteristics. apparatus. The first temperature detection element and the second temperature detection element include an n-type well region formed on a p-type substrate,
A p-type diffusion region formed on the n-type well region,
2. The structure of claim 1, wherein the p-type diffusion region is an anode, is connected to the first current mirror circuit or the first resistor, and the n-type well region is a grounded cathode. Temperature sensing device. The constant current source is composed of a depletion type MOS field effect transistor,
2. The temperature sensing device according to claim 1, wherein the first current mirror circuit and the second current mirror circuit are composed of enhancement-type MOS field effect transistors. The temperature detection circuit is composed of a comparator,
The temperature detector according to claim 4, wherein the comparator operates an internal current source according to a constant current generated by the constant current source.

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