JP2009231374A - Integrated circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the number of terminals from increasing in an integrated circuit including a temperature detecting element while adding a function of outputting temperature information detected by the temperature detecting element. <P>SOLUTION: The integrated circuit includes a first series circuit having a first resistor and the temperature detecting element connected in series, a second series circuit having the first resistor and a transistor connected in series, a detection circuit for generating a control signal to stop operation of a driving circuit at a connection of the second series circuit by turning ON the transistor when it detects that the driving circuit for driving a target to be driven is under such conditions that it should be stopped, and a terminal connected in common with the connection of the first series circuit and the connection of the second series circuit. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to integrated circuits.

In Patent Document 1, an inverter device including an overheat detection circuit and an overcurrent detection circuit is disclosed.
When a control signal for operating the inverter device is output from the microcomputer, the inverter device starts driving the motor to be driven. During operation of the inverter device, when the overheat detection circuit detects an overheat state of the inverter device, or when the overcurrent detection circuit detects an overcurrent state of the inverter device, the inverter device is used to prompt the stop of the operation of the inverter device. An abnormal signal is output to the microcomputer. When the microcomputer receives the abnormal signal, the microcomputer stops outputting the control signal for operating the inverter device, and the inverter device stops its operation.
In this way, by stopping the operation of the inverter device, it is possible to prevent damage to devices inside the inverter device due to overheating or overcurrent.
JP 2000-224861 A

  The overheat detection circuit has a function of detecting a state in which the temperature detected by a temperature detection element such as a thermistor is equal to or higher than a predetermined temperature. However, in the configuration of the inverter device, the microcomputer receives only information on whether or not the temperature detected by the temperature detection element in the overheat detection circuit is equal to or higher than a predetermined temperature, and thus the temperature detected by the temperature detection element. It cannot respond to the demand for more efficient control using information.

  In addition, for integrated circuits including drive circuits such as inverter circuits that drive motors to be driven, single in-line packages suitable for miniaturization and cost reduction are used. -Since there are not many terminals in the package, it may be difficult to provide a dedicated terminal for outputting temperature information detected by the temperature detection element.

  For this reason, in an integrated circuit including a temperature detection element, it is desired that one terminal also has a function of outputting temperature information detected by the temperature detection element.

  The main present invention that solves the above-described problems includes a first series circuit in which a first resistor and a temperature detection element are connected in series, and a second series circuit in which the first resistor and a transistor are connected in series. In order to stop the operation of the drive circuit at the connection point of the second series circuit by turning on the transistor when it is detected that the drive circuit that drives the drive target is to be stopped. An integrated circuit comprising: a detection circuit for generating a control signal; and a terminal commonly connected to a connection point of the first series circuit and a connection point of the second series circuit.

  Other features of the present invention will become apparent from the accompanying drawings and the description of this specification.

  ADVANTAGE OF THE INVENTION According to this invention, the increase in the number of terminals can be prevented, adding the function which outputs the temperature information which the temperature detection element detected to the integrated circuit provided with the temperature detection element.

  At least the following matters will become apparent from the description of this specification and the accompanying drawings.

<First Embodiment>
Hereinafter, a configuration of an integrated circuit including a temperature detecting element according to an embodiment of the present invention will be described with reference to FIG. Note that the driving target in the present embodiment is, for example, a three-phase motor.

  The integrated circuit 1a for driving the motor 3 to be driven is controlled by the microcomputer 2, and the switching elements 11 to 16, the switching control circuit 4, the detection circuit 5, the protection circuit 7, the transistor 23, the temperature detection circuit 6a, And terminals 41 to 48. The terminals 42 and 43 are connected to the main circuit power supply VCC and its ground, the terminals 47 and 48 are connected to the power supply VDD applied to the control circuit 4 and the like, and its ground, and the terminals 44 to 46 are connected. The motor 3 is connected.

  In the present embodiment, the switching elements 11 to 16 are configured by IGBTs (Insulated Gate Bipolar Transistors). The collectors of the switching elements 11 to 13 constituting the upper arm are connected to the main circuit power supply VCC via the terminal 42, and the emitters of the switching elements 14 to 16 constituting the lower arm are resistances externally connected to the terminal 43 24 is grounded. Further, switching elements 11 and 14, switching elements 12 and 15, and switching elements 13 and 16 are connected in series, and each connection point is connected to terminals U, V of motor 3 via terminals 44, 45, and 46, respectively. It is connected to a drive coil (not shown) for each of the phase and the W phase.

  The switching control circuit 4 is connected to the bases of the switching elements 11 to 16 and outputs a signal for appropriately switching the switching elements 11 to 16 so that the motor 3 rotates.

  The detection circuit 5 includes, for example, comparators 25 and 26 and an OR operation circuit 27. In the comparator 25, the reference voltage Vref1 is applied to the inverting input, and the non-inverting input is connected to the connection point between the switching elements 14 to 16 and the resistor 24. The reference voltage Vref1 is a value serving as a reference for determining that the current flowing through the switching elements 11 to 16 is an overcurrent. When the voltage at the connection point between the switching elements 14 to 16 and the resistor 24 is equal to or higher than the reference voltage Vref1, the output of the comparator 25 becomes high level. The comparator 26 is connected to the power supply VDD, to which the reference voltage Vref <b> 2 is applied to the non-inverting input and the inverting input is applied to the switching control circuit 4. The reference voltage Vref2 is a value serving as a reference for determining that the voltage of the power supply VDD applied to the switching control circuit 4 is insufficient for normally controlling the switching elements 11 to 16. When the voltage of the power supply VDD applied to the switching control circuit 4 is equal to or lower than the reference voltage Vref2, the output of the comparator 26 becomes high level. The outputs of the comparators 25 and 26 are input to the logical sum operation circuit 27, and the output of the logical sum operation circuit 27 is input to the protection circuit 7.

  The protection circuit 7 immediately shuts off the output signal from the switching control circuit 4 for switching control of the switching elements 11 to 16 when the output of the logical sum operation circuit 27 of the detection circuit 5 is at a high level. A function for protecting 11 to 16 from breakage is included. Further, the protection circuit 7 outputs a high level when the output of the logical sum operation circuit 27 of the detection circuit 5 is at a high level, and the protection circuit 7 when the output of the logical sum operation circuit 27 of the detection circuit 5 is at a low level. Is configured such that the output is at a low level.

  In the present embodiment, the transistor 23 is an N-channel MOSFET (Metal-Oxide Semiconductor Field-Effect Transistor). The output of the protection circuit 7 is input to the gate of the transistor 23. The drain of the transistor 23 is connected to the terminal 41 via the signal line 31, and the source is grounded.

  The temperature detection circuit 6a is configured by a circuit in which, for example, a resistor 21 and a thermistor 22 that is a temperature detection element are connected in series. In the present embodiment, the thermistor 22 has an NTC (Negative Temperature Coefficient: negative temperature coefficient) characteristic that the resistance value Rth decreases with increasing temperature inside the integrated circuit 1a as shown in FIG. 3, for example. It is a thermistor. The side of the resistor 21 that is not connected to the thermistor 22 is connected to the power supply VDD, and the side of the thermistor 22 that is not connected to the resistor 21 is grounded. The connection point between the resistor 21 and the thermistor 22 is connected to the terminal 41 through the signal line 32.

  The terminal 41 is connected in common to the drain of the transistor 23 and the connection point of the resistor 21 and the thermistor 22 as well as to the switching control circuit 4 through the signal line 33.

Next, the operation of the integrated circuit 1a will be described.
When a high level control signal for operating the switching control circuit 4 is output from the microcomputer 2 via the terminal 41 and the signal line 33, the switching control circuit 4 controls the switching of the switching elements 11 to 16. And the motor 3 is driven.

  During the operation of the switching control circuit 4, when the current flowing through the switching elements 11 to 16 increases and the current flowing through the resistor 24 increases, the voltage at the connection point between the switching elements 14 to 16 and the resistor 24 increases. When the voltage becomes equal to or higher than the reference voltage Vref1 and the current flowing through the switching elements 11 to 16 is in an overcurrent state, the output of the comparator 25 becomes high level and the output of the OR operation circuit 27 becomes high level. Then, the output of the protection circuit 7 becomes high level, and the transistor 23 is turned on. Further, during the operation of the switching control circuit 4, the voltage of the power supply VDD applied to the switching control circuit 4 is reduced to be equal to or lower than the reference voltage Vref2, and is insufficient to normally control the switching elements 11 to 16. That is, when the switching control circuit 4 becomes in a state where the power supply voltage is insufficient, the output of the comparator 26 becomes high level, the output of the logical sum operation circuit 27 becomes high level, the output of the protection circuit 7 becomes high level, Then, the transistor 23 is turned on. When the transistor 23 is turned on, the drain output of the transistor 23 indicates that the current flowing through the switching elements 11 to 16 is an overcurrent or that the switching control circuit 4 is in an abnormal state because the power supply voltage is insufficient. Become low level. Hereinafter, the low level output of the drain of the transistor 23 is referred to as an abnormality detection signal. The abnormality detection signal also functions as a low level control signal of the switching control circuit 4 via the signal lines 31 and 33. When the switching control circuit 4 receives the low level control signal, the switching control circuit 4 stops the switching control for the switching elements 11 to 16, and the switching control circuit 4 causes the device in the integrated circuit 1a to malfunction due to an overcurrent or a malfunction due to a power supply voltage shortage. Prevent damage.

  Note that the resistor 21 of the temperature detection circuit 6a connected in series with the transistor 23 also serves as a pull-up resistor for the drain output of the transistor 23. Therefore, when the transistor 23 is on, the drain output of the transistor 23 is low. It is necessary to increase the resistance value R of the resistor 21 sufficiently so that the level is reached. In this case, while the transistor 23 is on, an abnormality detection signal is output to the terminal 41 regardless of the output of the temperature detection circuit 6a. While the transistor 23 is off, the drain output of the transistor 23 becomes high impedance, and the voltage value Vth at the connection point between the resistor 21 and the thermistor 22 is output from the temperature detection circuit 6a as a temperature detection signal.

  The temperature detection circuit 6a outputs the voltage value Vth at the connection point of the resistor 21 and the thermistor 22 as a temperature detection signal when the transistor 23 is off, that is, when no abnormality detection signal is output. As an example, when the resistance value R of the resistor 21 is 20 kΩ, the voltage value of the power supply VDD is 5 V, and the characteristics of the thermistor 22 are as shown in FIG. 3, the relationship between the temperature and the voltage value Vth is as shown by the solid line in FIG. The temperature detection signal that is the output of the temperature detection circuit 6a also functions as a control signal for the switching control circuit 4 via the signal lines 32 and 33. For example, if the threshold voltage value at which the switching control circuit 4 determines that the control signal is at a low level is 2.5 V, the control signal of the switching control circuit 4 becomes a low level at about 69 ° C. or higher, and the switching control circuit 4 Stops switching control for the switching elements 11 to 16, and prevents damage to devices inside the integrated circuit 1a due to heating above a predetermined temperature. The predetermined temperature is determined by the resistance value R of the resistor 21 and the characteristics of the thermistor 22.

  As described above, in the case of overcurrent, power supply voltage shortage, and overheating, the switching control circuit 4 does not depend on the microcomputer 2 to prevent the device inside the integrated circuit 1a from being damaged. Or switching control for 16 is stopped. However, for example, after the microcomputer 2 receives the temperature detection signal from the temperature detection circuit 6a via the signal line 32 and the terminal 41 and converts the temperature detection signal into a digital value by analog / digital conversion, the terminal 41 and the signal line It is also possible to provide a control signal corresponding to the digital value to the switching control circuit 4 via the control unit 33.

Second Embodiment
Hereinafter, with reference to FIG. 2, a configuration of an integrated circuit including a temperature detection element according to another embodiment of the present invention will be described.
The integrated circuit 1b has the same configuration as the integrated circuit 1a of the first embodiment except that the temperature detection circuit 6a of the first embodiment is a temperature detection circuit 6b. Further, in the temperature detection circuit 6b, the thermistor 22 is grounded via a resistor 28 instead of the thermistor 22 being directly grounded in the temperature detection circuit 6a of the first embodiment.

Next, the operation of the integrated circuit 1b will be described focusing on the operation of the temperature detection circuit 6b.
The temperature detection circuit 6b outputs the voltage value Vth at the connection point between the resistor 21 and the thermistor 22 as a temperature detection signal when the transistor 23 is off, that is, when no abnormality detection signal is output. As an example, if the resistance value R of the resistor 21 is 20 kΩ, the resistance value RL of the resistor 28 is 10 kΩ, the voltage value of the power supply VDD is 5 V, and the characteristics of the thermistor 22 are as shown in FIG. It becomes like the long broken line in FIG. As in the first embodiment, for example, when the threshold voltage value at which the switching control circuit 4 determines that the control signal is at a low level is 2.5 V, the control signal of the switching control circuit 4 is the same as in the first embodiment. The switching control circuit 4 stops the switching control for the switching elements 11 to 16 at a temperature higher than about 91 ° C., which is higher than the predetermined temperature, and prevents damage to devices inside the integrated circuit 1b due to heating at a predetermined temperature or higher. . As described above, since the resistor 21 also serves as a pull-up resistor for the drain output of the transistor 23, the resistance value R of the resistor 21 has a lower limit. In the first embodiment, the predetermined temperature is set. In this embodiment, the predetermined temperature can be arbitrarily set by the resistor 28 of the temperature detection circuit 6b.

  Further, the lower limit of the voltage value Vth as the temperature detection signal can be set by a combination of the resistance value R of the resistor 21 and the resistance value RL of the resistor 28. For example, a digital signal output from the drain of the transistor 23 in parallel with the microcomputer 2 using the input signal from the terminal 41 as a temperature detection signal that is an analog signal output from the temperature detection circuit 6b. When used also as a certain abnormality detection signal, the voltage value Vth as the temperature detection signal needs to fluctuate in a region equal to or higher than a threshold voltage value at which the microcomputer 2 determines that the input signal from the terminal 41 is at a low level. There is. As an example, if the resistance value R of the resistor 21 is 20 kΩ, the resistance value RL of the resistor 28 is 20 kΩ, the voltage value of the power supply VDD is 5 V, and the characteristics of the thermistor 22 are as shown in FIG. It looks like the short dashed line in FIG. In this case, for example, if the threshold voltage value at which the microcomputer 2 determines that the input signal from the terminal 41 is at a low level is 2.5 V, the voltage value Vth as the temperature detection signal is the threshold voltage regardless of the temperature. Since the value is 2.5 V or more, the microcomputer 2 can use the input signal as a temperature detection signal when the input signal from the terminal 41 is at a high level. When the signal is at a low level, the input signal can be used as an abnormality detection signal.

  In the present embodiment, the connection order of the thermistor 22 and the resistor 28 may be switched. Even in this case, the operation of the temperature detection circuit 6b does not change.

  As described above, in the integrated circuit 1a, the temperature detection circuit 6a outputs the voltage value Vth at the connection point of the series connection of the resistor 21 and the thermistor 22 as a temperature detection signal, and the detection circuit 5 drives the drive target. When the drive circuit is in a state to be stopped, by turning on the transistor 23, an abnormality detection signal for stopping the operation of the drive circuit is output to the connection point of the series connection of the resistor 21 and the transistor 23, and By connecting the connection point of the resistor 21 and the thermistor 22 and the connection point of the resistor 21 and the transistor 23 to the input terminal 41 of the drive circuit control signal and the common terminal 41, a function for outputting a temperature detection signal and an abnormality detection signal are provided. The function of outputting and the function of inputting the control signal of the driving circuit can be shared by one terminal.

  In the integrated circuit 1b, as shown in the temperature detection circuit 6b, the resistor 28 is further connected in series to the thermistor 22 to stop the operation of the drive circuit at a predetermined temperature or higher. Or the lower limit of the voltage value Vth as the temperature detection signal can be set.

  Further, as shown in the integrated circuit 1a, the side of the resistor 21 that is not connected to the thermistor 22 is connected to the power supply VDD, the side of the thermistor 22 that is not connected to the resistor 21 is grounded, and the terminal 41 of the transistor 23 is connected. A more general-purpose NTC thermistor and N-channel MOSFET can be used by grounding the source not connected to the.

  Also, as shown in the integrated circuit 1b, the side of the resistor 21 not connected to the thermistor 22 is connected to the power supply VDD, the side of the thermistor 22 not connected to the resistor 21 is grounded via the resistor 28, and By adopting a configuration in which the source not connected to the terminal 41 of the transistor 23 is grounded, a more general-purpose NTC thermistor and N-channel MOSFET can be used.

  Further, as shown in the integrated circuits 1a and 1b, when the voltage at the connection point between the switching elements 14 to 16 and the resistor 24 is equal to or higher than the reference voltage Vref1, the output of the comparator 25 is connected to a high level. Then, by inputting the output to the gate of the transistor 23 via the logical sum operation circuit 27 and the protection circuit 7, in the case of an overcurrent, an abnormality detection signal is output to the terminal 41 and the microcomputer 2 Regardless of the control, the switching control for the switching elements 11 to 16 of the switching control circuit 4 can be stopped.

  Further, as shown in the integrated circuits 1a and 1b, when the voltage of the power supply VDD applied to the switching control circuit 4 is equal to or lower than the reference voltage Vref2, connection is made so that the output of the comparator 26 becomes high level. Then, by inputting the output to the gate of the transistor 23 through the logical sum operation circuit 27 and the protection circuit 7, in the case of a power supply voltage shortage, the abnormality detection signal is output to the terminal 41 and the microcomputer 2 Regardless of the control, the switching control for the switching elements 11 to 16 of the switching control circuit 4 can be stopped.

  The first embodiment and the second embodiment are for facilitating the understanding of the present invention, and are not intended to limit the present invention. The present invention can be changed and improved without departing from the gist thereof, and equivalents thereof are also included in the present invention.

  In the said embodiment, although the drive object was set to the motor 3 which is a three-phase motor, it is not limited to this. Even if it is a motor with other driving methods such as a single phase motor, or other driving target such as a heat source, light source, display module, etc., it is desired to provide a temperature detection element in the integrated circuit Is applicable.

  In the above embodiment, the switching elements 11 to 16, the switching control circuit 4, and the protection circuit 7 included in the drive circuit exist inside the integrated circuits 1 a and 1 b, but the drive circuit may exist outside the integrated circuit. .

  In the above embodiment, IGBTs are used as the switching elements 11 to 16, but other power semiconductor devices such as power MOSFETs may be used.

  In the above embodiment, the thermistor 22 is used as the temperature detecting element, the thermistor 22 is an NTC thermistor, the transistor 23 is an N-channel MOSFET, and the switching control circuit 4 receives the low-level control signal. Although the switching control is stopped, the present invention is not limited to this. For example, the thermistor 22 is a PTC (positive temperature coefficient) thermistor, the transistor 23 is a P-channel MOSFET, and the switching control circuit 4 stops switching control for the switching elements 11 to 16 when receiving a high level control signal. In addition, the temperature detection circuits 6a and 6b and the transistor 23 can be configured by exchanging connections to the power supply VDD or ground. Further, for example, a platinum resistance temperature detector can be used as the temperature detection element, and a bipolar transistor can be used as the transistor 23.

It is a circuit block diagram which shows the structure of the integrated circuit provided with the temperature detection element in 1st Embodiment of this invention. It is a circuit block diagram which shows the structure of the integrated circuit provided with the temperature detection element in 2nd Embodiment of this invention. It is a characteristic view which shows an example of the relationship between the temperature of a thermistor used for the integrated circuit provided with the temperature detection element of this invention, and resistance value. It is a characteristic view which shows an example of the relationship between the temperature of a thermistor used for the integrated circuit provided with the temperature detection element of this invention, and a voltage value.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1a, 1b Integrated circuit 2 Microcomputer 3 Motor 4 Switching control circuit 5 Detection circuit 6a, 6b Temperature detection circuit 7 Protection circuit 11, 12, 13, 14, 15, 16 Switching element 21, 24, 28 Resistance 22 Thermistor 23 Transistor 25 , 26 Comparator 27 OR circuit 31, 32, 33 Signal line 41, 42, 43, 44, 45, 46, 47, 48 Terminals

Claims (6)

A first series circuit in which a first resistor and a temperature detection element are connected in series;
A second series circuit in which the first resistor and the transistor are connected in series;
Control for stopping the operation of the drive circuit at the connection point of the second series circuit by turning on the transistor when it is detected that the drive circuit for driving the drive target is to be stopped A detection circuit for generating a signal;
A terminal commonly connected to a connection point of the first series circuit and a connection point of the second series circuit;
An integrated circuit comprising:   The first series circuit is a circuit in which the first resistor, the temperature detection element, and the second resistor are connected in series via the terminal. Integrated circuit. The temperature detecting element has a characteristic that the resistance value decreases with increasing temperature,
The side of the first resistor that is not connected to the temperature detection element is connected to a power source,
The side of the temperature detection element that is not connected to the first resistor is grounded,
2. The integrated circuit according to claim 1, wherein a side of the transistor not connected to the first resistor is grounded. The temperature detecting element has a characteristic that the resistance value decreases with increasing temperature,
The side of the first resistor that is not connected to the terminal is connected to a power source,
The side of the temperature detection element and the second resistor that is not connected to the terminal is grounded,
3. The integrated circuit according to claim 2, wherein a side of the transistor that is not connected to the terminal is grounded. The drive circuit includes a switching element for controlling the drive current of the motor as the drive target, and a switching control circuit for controlling the switching of the switching element,
The detection circuit generates a signal for stopping the operation of the switching control circuit as the control signal when it is detected that a current of a predetermined current value or more flows in the switching element. The integrated circuit according to claim 1. The drive circuit includes a switching element for controlling the drive current of the motor as the drive target, and a switching control circuit for controlling the switching of the switching element,
The detection circuit generates a signal for stopping the operation of the switching control circuit as the control signal when detecting that the power supply voltage applied to the switching control circuit is equal to or lower than a predetermined voltage value. The integrated circuit according to claim 1, wherein the integrated circuit is characterized in that:

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