Temperature sensor and vehicle

Abstract

This temperature sensor comprises a single diode, a first adjustment circuit, and a second adjustment circuit. A current flowing into the single diode is adjusted to N / M times a reference current by the first adjustment circuit and the second adjustment circuit. The first adjustment circuit is configured to handle, among the N / M times the reference current, 1 / M times the reference current. The second adjustment circuit is configured to handle, among the N / M times the reference current, N times the reference current. M and N are each greater than 1.

Description

Temperature sensor and vehicle

[0001] The invention disclosed in this specification relates to a temperature sensor and a vehicle using the same.

[0002] 2. Description of the Related Art Conventionally, a temperature sensor that utilizes the temperature characteristics of the forward voltage of a diode is known (see, for example, Patent Document 1).

[0003] JP 2018-087824 A (paragraph 0041)

[0004] A temperature sensor that utilizes the temperature characteristics of the forward voltage of a diode can improve the output accuracy of the temperature sensor by repairing the forward voltage of the diode.

[0005] However, in order to repair the forward voltage of the diode, it is desirable to minimize the increase in the circuit area of ​​the temperature sensor.

[0006] The temperature sensor disclosed herein includes a single diode, a first adjustment circuit, and a second adjustment circuit. The current flowing through the single diode is adjusted to N / M times a reference current by the first and second adjustment circuits. The first adjustment circuit is configured to provide 1 / M times the reference current out of the N / M times the reference current. The second adjustment circuit is configured to provide N times the reference current out of the N / M times the reference current, where M and N are each greater than 1.

[0007] The vehicle disclosed in this specification has a temperature sensor having the above-described configuration.

[0008] According to the invention disclosed in this specification, it is possible to improve the output accuracy of the temperature sensor while suppressing an increase in the circuit area of ​​the temperature sensor.

[0009] FIG. 1 is a diagram showing a comparative example of a temperature sensor. FIG. 2 is a diagram showing characteristics of repair variation. FIG. 3 is a diagram showing M and N patterns. FIG. 4 is a diagram showing a first embodiment of a temperature sensor. FIG. 5 is a diagram showing a second embodiment of a temperature sensor. FIG. 6 is a diagram showing a third embodiment of a temperature sensor. FIG. 7 is an external view of a vehicle.

[0010] In this specification, a MOS (Metal Oxide Semiconductor) field effect transistor refers to a field effect transistor whose gate structure is composed of at least three layers: a layer made of a conductor or a semiconductor such as polysilicon with a low resistance value, an insulating layer, and a P-type, N-type, or intrinsic semiconductor layer. In other words, the gate structure of a MOS field effect transistor is not limited to a three-layer structure of a metal, an oxide, and a semiconductor.

[0011] In this specification, a constant voltage means a voltage that is constant under ideal conditions, but in reality it is a voltage that may fluctuate slightly due to temperature changes and the like.

[0012] In this specification, a constant current means a current that is constant under ideal conditions, but in reality it is a current that may fluctuate slightly due to temperature changes and the like.

[0013] 1 is a diagram showing a comparative example of a temperature sensor (i.e., a general configuration to be compared with the embodiments described later). The temperature sensor 10 of this comparative example includes a constant current source IS1, P-channel MOS field effect transistors Q1 and Q2_1 to Q2_n, switches SW1_1 to SW1_n and SW2_1 to SW2_m, and diodes D1_1 to D1_m.

[0014] A power supply voltage Vcc is applied to the sources of the P-channel MOS field effect transistors Q1 and Q2_1 to Q2_n.

[0015] The gates of the P-channel MOS field effect transistors Q1 and Q2_1 to Q2_n are connected to the drain of the P-channel MOS field effect transistor Q1 and a first terminal of a constant current source IS1. A second terminal of the constant current source IS1 is connected to a constant potential terminal. The constant current source IS1 outputs a constant current Io.

[0016] The drain of the P-channel MOS field effect transistor Q2_i is connected to the first terminal of the switch SW1_i, where i is a natural number between 1 and n. The second terminals of the switches SW1_1 to SW1_n are connected to the first terminals of the switches SW2_1 to SW2_m, respectively.

[0017] A second terminal of the switch SW2_j is connected to the anode of the diode D1_j, where j is a natural number equal to or greater than 1 and equal to or less than m. The cathodes of the diodes D1_1 to D1_m are connected to a constant potential terminal.

[0018] A constant voltage lower than the power supply voltage Vcc is applied to the constant potential end, which may be, for example, a ground voltage.

[0019] Generally, the forward voltage Vf of a diode is expressed by the forward current If of the diode, the reverse saturation current Is of the diode, and the thermal voltage Vt as shown in the following equation (1): Vf=Vt×Ln(If / Is) (1)

[0020] In the temperature sensor 10, N switches among SW1_1 to SW1_n are turned on, and M switches among SW2_1 to SW2_m are turned on. At this time, the output voltage of the temperature sensor 10, i.e., the forward voltage Vf_ref after repair, is expressed by the constant current Io, the reverse saturation current Is of the diode, M and N, and the thermal voltage Vt, as shown in the following equation (2): Vf_ref=Vt×Ln(Io×N / (M×Is)) (2)

[0021] By substituting the above equation (1) into the above equation (2) and modifying it, the forward voltage Vf_ref after repair can be expressed as follows: Vf_ref=Vf+Vt×Ln(N / M) Vf_ref=Vf+ΔVf

[0022] Even if there is variation in the forward voltage Vf of the diode, by adjusting M and N to adjust the repair fluctuation amount ΔVf, the forward voltage Vf_ref after repair can be made closer to the design value of the forward voltage Vf.

[0023] Fig. 2 is a diagram showing the characteristics of the repair variation amount ΔVf. Fig. 3 is a diagram showing patterns of M and N. When M = N = 12, if the forward voltage Vf_ref after repair is larger than the design value of the forward voltage Vf, reducing N can make the forward voltage Vf_ref after repair closer to the design value of the forward voltage Vf. On the other hand, when M = N = 12, if the forward voltage Vf_ref after repair is smaller than the design value of the forward voltage Vf, reducing M can make the forward voltage Vf_ref after repair closer to the design value of the forward voltage Vf.

[0024] By selecting patterns M and N such that the forward voltage Vf_ref after repair approaches the design value of the forward voltage Vf, the output accuracy of the temperature sensor 10 can be improved.

[0025] However, the temperature sensor 10 has a configuration including multiple diodes. The area of ​​each diode is larger than the area of ​​each field-effect transistor and larger than the circuit area of ​​each switch. Therefore, the temperature sensor 10 has a problem of large circuit area.

[0026] In view of the above considerations, a novel embodiment is proposed below that can improve the output accuracy of the temperature sensor while suppressing an increase in the circuit area of ​​the temperature sensor.

[0027] 4 is a diagram showing a temperature sensor 11 according to a first embodiment of the present invention. The temperature sensor 11 includes a first adjustment circuit 1A, a second adjustment circuit 2, and a single diode D1.

[0028] The current flowing through the single diode D1 is adjusted to N / M times the reference current by the first adjustment circuit 1A and the second adjustment circuit 2. M and N are both greater than 1. The reference current is the current that flows through the single diode D1 when one of switches SW1_1 to SW1_n (described later) is turned on and one of switches SW3_1 to SW3_m (described later) is turned on.

[0029] The first adjustment circuit 1A has a plurality of switches SW3_1 to SW3_m. More specifically, the first adjustment circuit 1A has P-channel MOS field effect transistors Q1 and Q2_1 to Q2_n, an N-channel MOS field effect transistor Q3, a constant voltage generation circuit 3, resistors R1_1 to R1_m, and switches SW3_1 to SW3_m. The P-channel MOS field effect transistors Q1 and Q2_1 to Q2_n are transistors of the same size.

[0030] A power supply voltage Vcc is applied to the sources of the P-channel MOS field effect transistors Q1 and Q2_1 to Q2_n.

[0031] The gates of the P-channel MOS field effect transistors Q1 and Q2_1 to Q2_n are connected to the drain of the P-channel MOS field effect transistor Q1 and the drain of the N-channel MOS field effect transistor Q3. The constant voltage Vconst output from the constant voltage generating circuit 3 is supplied to the gate of the N-channel MOS field effect transistor Q3.

[0032] The series circuit of the resistors R1_1 to R1_m is provided between the source of the N-channel MOS field effect transistor Q3 and the constant potential end.

[0033] A first terminal of the resistor R1_j is connected to a first terminal of the switch SW3_j, and a second terminal of the resistor R1_j is connected to a second terminal of the switch SW3_j, where j is a natural number between 1 and m.

[0034] The second adjustment circuit 2 has a plurality of switches SW1_1 to SW1_n. A first terminal of the switch SW1_i is connected to the drain of the P-channel MOS field effect transistor Q2_i, and a second terminal of the switch SW1_i is connected to the anode of a single diode D1, where i is a natural number between 1 and n. The anode of the single diode D1 is connected to a constant potential terminal.

[0035] A constant voltage lower than the power supply voltage Vcc is applied to the constant potential end, which may be, for example, a ground voltage.

[0036] Here, the temperature sensor 11 turns on N of the switches SW1_1 to SW1_n and turns on M of the switches SW3_1 to SW3_m. At this time, the anode voltage of the single diode D1, i.e., the forward voltage Vf_ref after repair, is expressed by the same formula as in the case of the temperature sensor 10.

[0037] The temperature sensor 11 can easily adjust N by controlling the switches SW1_1 to SW1_n, and can easily adjust M by controlling the switches SW3_1 to SW3_m. Therefore, the output accuracy of the temperature sensor 11 can be easily improved.

[0038] The temperature sensor 11 has a single diode D1, which can prevent an increase in the circuit area.

[0039] 5 is a diagram showing a temperature sensor 12 according to a second embodiment of the present invention. The temperature sensor 12 includes a first adjustment circuit 1B, a second adjustment circuit 2, and a single diode D1.

[0040] The current flowing through the single diode D1 is adjusted to N / M times the reference current by the first adjustment circuit 1B and the second adjustment circuit 2. M and N are both greater than 1. The reference current is the current that flows through the single diode D1 when one of the switches SW1_1 to SW1_n (described later) is turned on and a bias voltage Vbias (described later) is set to the minimum value of its adjustment range.

[0041] The first adjustment circuit 1B has P-channel MOS field effect transistors Q1 and Q2_1 to Q2_n, an N-channel MOS field effect transistor Q3, a bias voltage adjustment circuit 4, and a resistor R1. The P-channel MOS field effect transistors Q1 and Q2_1 to Q2_n are transistors of the same size.

[0042] A power supply voltage Vcc is applied to the sources of the P-channel MOS field effect transistors Q1 and Q2_1 to Q2_n.

[0043] The gates of the P-channel MOS field effect transistors Q1 and Q2_1 to Q2_n are connected to the drain of the P-channel MOS field effect transistor Q1 and the drain of the N-channel MOS field effect transistor Q3. A bias voltage Vbias output from the bias voltage adjustment circuit 4 is supplied to the gate of the N-channel MOS field effect transistor Q3.

[0044] The resistor R1 is provided between the source of the N-channel MOS field effect transistor Q3 and the constant potential end.

[0045] The second adjustment circuit 2 has a plurality of switches SW1_1 to SW1_n. A first terminal of the switch SW1_i is connected to the drain of the P-channel MOS field effect transistor Q2_i, and a second terminal of the switch SW1_i is connected to the anode of a single diode D1, where i is a natural number between 1 and n. The anode of the single diode D1 is connected to a constant potential terminal.

[0046] A constant voltage lower than the power supply voltage Vcc is applied to the constant potential end, which may be, for example, a ground voltage.

[0047] Here, the temperature sensor 12 turns on N switches among SW1_1 to SW1_n and adjusts the bias voltage Vbias so that the current flowing through the resistor R1 becomes 1 / M times the reference voltage. At this time, the anode voltage of the single diode D1, i.e., the forward voltage Vf_ref after repair, is given by the same formula as in the case of the temperature sensor 10.

[0048] The temperature sensor 12 can easily adjust N by controlling the switches SW1_1 to SW1_n, and can easily adjust M by adjusting the bias voltage Vbias. Therefore, the output accuracy of the temperature sensor 12 can be easily improved.

[0049] The temperature sensor 12 has a single diode D1, which can prevent an increase in the circuit area.

[0050] 6 is a diagram showing a temperature sensor 13 according to a third embodiment of the present invention. The temperature sensor 13 includes a first adjustment circuit 1C, a second adjustment circuit 2, and a single diode D1.

[0051] The current flowing through the single diode D1 is adjusted to N / M times the reference current by the first adjustment circuit 1C and the second adjustment circuit 2. M and N are both greater than 1. The reference current is the current that flows through the single diode D1 when one of the switches SW1_1 to SW1_n (described later) is turned on and all of the switches SW4_1 to SW4_kn (described later) are turned on.

[0052] The first adjustment circuit 1C includes P-channel MOS field effect transistors Q1, Q2_1 to Q2_n, and Q4_1 to Q4_k, switches SW4_1 to SW4_k, an N-channel MOS field effect transistor Q3, a constant voltage generation circuit 3, and a resistor R1. The P-channel MOS field effect transistors Q1, Q2_1 to Q2_n, and Q4_1 to Q4_k are transistors of the same size.

[0053] A power supply voltage Vcc is applied to the sources of the P-channel MOS field effect transistors Q2_1 to Q2_n and Q4_1 to Q4_k. The drains of the P-channel MOS field effect transistors Q4_1 to Q4_a are connected to a first terminal of a switch SW4_a, where a is a natural number between 1 and k.

[0054] The gates of the P-channel MOS field effect transistors Q2_1 to Q2_n and Q4_1 to Q4_k are connected to the drain of the P-channel MOS field effect transistor Q1, the second terminals of the switches SW4_1 to SW4_k, and the drain of the N-channel MOS field effect transistor Q3. The constant voltage Vconst output from the constant voltage generating circuit 3 is supplied to the gate of the N-channel MOS field effect transistor Q3.

[0055] The resistor R1 is provided between the source of the N-channel MOS field effect transistor Q3 and the constant potential end.

[0056] The second adjustment circuit 2 has a plurality of switches SW1_1 to SW1_n. A first terminal of the switch SW1_i is connected to the drain of the P-channel MOS field effect transistor Q2_i, and a second terminal of the switch SW1_i is connected to the anode of a single diode D1, where i is a natural number between 1 and n. The anode of the single diode D1 is connected to a constant potential terminal.

[0057] A constant voltage lower than the power supply voltage Vcc is applied to the constant potential end, which may be, for example, a ground voltage.

[0058] Here, the temperature sensor 13 turns on N of the switches SW1_1 to SW1_n and adjusts the number of switches SW4_1 to SW4_k to be turned on so that the current flowing through the resistor R1 is 1 / M times the reference voltage. At this time, the anode voltage of the single diode D1, i.e., the forward voltage Vf_ref after repair, is expressed by the same formula as in the case of the temperature sensor 10. The mirror ratio of the current mirror circuit is adjusted by adjusting the number of switches SW4_1 to SW4_k to be turned on. The current mirror circuit includes P-channel MOS field-effect transistors Q1, Q2_1 to Q2_n, and Q4_1 to Q4_k, and switches SW4_1 to SW4_k.

[0059] The temperature sensor 13 can easily adjust N by controlling the switches SW1_1 to SW1_n, and can easily adjust M by adjusting the mirror ratio of the current mirror circuit, thereby easily improving the output accuracy of the temperature sensor 13.

[0060] The temperature sensor 13 has a single diode D1, which can prevent an increase in the circuit area.

[0061] <Use> Fig. 7 is an external view of a vehicle X. The vehicle X of this configuration example is equipped with various electronic devices X11 to X18 that operate by receiving a supply of voltage output from a battery (not shown). Note that the installation positions of the electronic devices X11 to X18 in this figure may differ from the actual positions for convenience of illustration.

[0062] The electronic device X11 is an engine control unit that performs engine-related controls (injection control, electronic throttle control, idling control, oxygen sensor heater control, auto-cruise control, etc.).

[0063] The electronic device X12 is a lamp control unit that controls the turning on and off of a high intensity discharged lamp (HID) or a daytime running lamp (DRL).

[0064] The electronic device X13 is a transmission control unit that performs control related to the transmission.

[0065] The electronic device X14 is a braking unit that performs control related to the movement of the vehicle X (ABS (anti-lock brake system) control, EPS (electric power steering) control, electronic suspension control, etc.).

[0066] The electronic device X15 is a security control unit that controls the driving of door locks, security alarms, and the like.

[0067] The electronic devices X16 are electronic devices that are installed in the vehicle X at the factory as standard equipment or manufacturer options, such as wipers, power door mirrors, power windows, dampers (shock absorbers), power sunroofs, and power seats.

[0068] The electronic device X17 is an electronic device that is optionally installed in the vehicle X as a user option, such as an in-vehicle A / V (audio / visual) device, a car navigation system, and an ETC (electronic toll collection system).

[0069] The electronic device X18 is an electronic device equipped with a high-voltage motor, such as an in-vehicle blower, an oil pump, a water pump, or a battery cooling fan.

[0070] Each of the electronic devices X11 to X18 has a power supply circuit. For example, one of the temperature sensors 11 to 13 is provided inside the power supply circuit, and the power supply circuit performs overheat protection based on the output of a comparator that compares the output of the temperature sensor with a reference voltage. Also, one of the temperature sensors 11 to 13 may be used as an outside air temperature detection sensor for the vehicle X. Also, one of the temperature sensors 11 to 13 may be used as an interior temperature detection sensor for the vehicle X.

[0071] The temperature sensors 11 to 13 may be mounted not only on vehicles but also on industrial equipment, consumer equipment, and the like.

[0072] <Others> In addition to the above-described embodiments, various modifications can be made to the configuration of the invention without departing from the spirit of the invention. The above-described embodiments are illustrative in all respects and should be considered not to be limiting. The technical scope of the present invention is defined by the claims, not by the description of the above-described embodiments, and should be understood to include all modifications that fall within the meaning and scope of the claims.

[0073] At least two of the first to third embodiments may be combined. For example, when the second and third embodiments are combined, the constant voltage generating circuit 3 in the temperature sensor 13 is replaced with the bias voltage adjusting circuit 4.

[0074] In the first to third embodiments, the second adjustment circuit is provided between the first adjustment circuit and the diode, but the first adjustment circuit may be provided between the second adjustment circuit and the diode.

[0075] The temperature sensors (11 to 13) described above have a single diode (D1), a first adjustment circuit (1A to 1C), and a second adjustment circuit (2), and the current flowing through the single diode is adjusted to N / M times the reference current by the first adjustment circuit and the second adjustment circuit, the first adjustment circuit is configured to handle 1 / M times the reference current out of the N / M times the reference current, and the second adjustment circuit is configured to handle N times the reference current out of the N / M times the reference current, where M and N are each greater than 1 (first configuration).

[0076] The temperature sensor having the first configuration can improve the output accuracy while suppressing an increase in the circuit area.

[0077] In the temperature sensor of the first configuration described above, the second adjustment circuit may be configured (second configuration) to include a plurality of switches (SW1_1 to SW1_n) connected in series with the single diode and connected in parallel with each other.

[0078] In the temperature sensor of the second configuration, N can be easily adjusted by changing the number of switches that are turned on.

[0079] In the temperature sensor of the first or second configuration, the first adjustment circuit may be configured (third configuration) to include a plurality of resistors (R1_1 to R1_m) connected in series with each other.

[0080] In the temperature sensor of the third configuration, M can be easily adjusted by changing the number of resistors whose both ends are shorted.

[0081] In the temperature sensor of any of the first to third configurations described above, the first adjustment circuit may be configured (fourth configuration) to include a bias voltage adjustment circuit (4) configured to adjust a bias voltage, and a transistor (Q3) configured to supply the bias voltage to a control terminal.

[0082] In the temperature sensor of the fourth configuration, M can be easily adjusted by changing the bias voltage.

[0083] In the temperature sensor of any of the first to fourth configurations, the first adjustment circuit may include a current mirror circuit (Q1, Q2_1 to Q2_n, Q4_1 to Q4_k, SW4_1 to SW4_k) configured to supply a mirror current to the second adjustment circuit, and the mirror ratio of the current mirror circuit may be variable (fifth configuration).

[0084] In the temperature sensor of the fifth configuration, M can be easily adjusted by changing the mirror ratio of the current mirror circuit.

[0085] The vehicle (X) described above has a configuration (sixth configuration) that includes a temperature sensor having any one of the first to fifth configurations.

[0086] The vehicle having the sixth configuration can improve the output accuracy of the temperature sensor while suppressing an increase in the circuit area of ​​the temperature sensor.

[0087] 1A to 1C First adjustment circuit 2 Second adjustment circuit 3 Constant voltage generation circuit 4 Bias voltage adjustment circuit 10 to 13 Temperature sensor IS1 Constant current source D1_1 to D1_m Diode Q1, Q4_1 to Q4_n, Q2_1 to Q2_n P-channel MOS field effect transistor Q3 N-channel MOS field effect transistor R1, R1_1 to R1_m Resistor SW1_1 to SW1_n, SW2_1 to SW2_m, SW3_1 to SW3_m, SW4_1 to SW4_k Switch X Vehicle X11 to X18 Electronic device

Claims

1. A single diode; A first adjustment circuit; A second adjustment circuit, a current flowing through the single diode is adjusted to N / M times a reference current by the first adjustment circuit and the second adjustment circuit; The first adjustment circuit is configured to carry 1 / M times the reference current out of N / M times the reference current; the second adjustment circuit is configured to carry N times the reference current out of N / M times the reference current; M and N are each greater than 1. Temperature sensor.

2. The temperature sensor of claim 1 , wherein the second adjustment circuit includes a plurality of switches connected in series with the single diode and connected in parallel with each other.

3. The temperature sensor according to claim 1 , wherein the first adjustment circuit includes a plurality of resistors connected in series with each other.

4. The first adjustment circuit is a bias voltage adjusting circuit configured to adjust a bias voltage; a transistor configured to provide the bias voltage to a control terminal; The temperature sensor according to claim 1 or 2, comprising:

5. the first adjustment circuit includes a current mirror circuit configured to provide a mirror current to the second adjustment circuit; 3. The temperature sensor according to claim 1, wherein a mirror ratio of the current mirror circuit is variable.

6. A vehicle comprising the temperature sensor according to claim 1 or 2.