Heater device

Abstract

To provide a vehicle heater device 1 in which the generation of emission noise is suppressed while the quick warming performance is secured.SOLUTION: Upon the reception of a heater operation command, a central processing unit 21 continuously keeps a transistor Tr2 off while keeping a transistor Tr1 fully on continuously. Current can be continuously supplied to a heater element R from a power source VB through the transistor Tr1. The transistor Tr1 is continuously kept fully on and the transistor Tr2 is continuously kept off and then when it is determined that the temperature of a heater main body part 30 is more than or equal to a target temperature, the central processing unit 21 controls the transistors Tr1 and Tr2 as follows: the central processing unit 21 continuously keeps the transistor Tr1 off and continuously keeps the transistor Tr2 fully on. Current can be continuously supplied to the heater element R from a power source VC through the transistor Tr2.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a heater device. [Background technology]

[0002] Conventionally, a heater device has been proposed that includes a transistor disposed between a DC power supply and a heater, and a control circuit that controls the power supplied from the DC power supply to the heater by switching the transistor (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-347213 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, there has been a demand for heater devices that can quickly heat an object to be heated by the heater at startup. To achieve this, it is necessary to lower the heater's resistance and supply a large amount of power to the heater at startup by switching the transistor. This increases emission noise, i.e., electromagnetic noise, due to changes in the current flowing from the DC power supply through the transistor to the heater as the transistor switches.

[0005] In view of the above, an object of the present disclosure is to provide a heater device that ensures fast heating while suppressing the generation of emission noise. [Means for solving the problem]

[0006] According to one aspect of the present disclosure, a heater device includes: a heater main body (30) having a heater element (R) that generates heat when a current flows through it; a first transistor (Tr1) disposed between a first DC power supply (VB) that outputs a first DC voltage and the heater element; a second transistor (Tr2) disposed between a second DC power supply (VC) that outputs a second DC voltage lower than the first DC voltage and the heater element; a temperature detection unit (32) for detecting the temperature of the heater main body; a temperature determination unit (S110) that determines whether the temperature of the heater main body is equal to or higher than a target temperature based on the temperature detected by the temperature detection unit; a first switch control unit (S100) that, upon receiving a command to start the operation of the heater main body, keeps the first transistor fully on to continuously flow a current from the first DC power supply through the first transistor to the heater element, and keeps the second transistor off to continuously open the connection between the second DC power supply and the heater element; and a second switch control section (S120) that, when the temperature determination section determines that the temperature of the heater main body is equal to or higher than a target temperature after the first switch control section has continuously kept the first transistor fully on and continuously kept the second transistor off, keeps the first transistor continuously off to continuously open the first DC power supply and the heater element, and keeps the second transistor continuously full on to continuously flow current from the second DC power supply to the heater element through the second transistor.

[0007] Therefore, when the temperature of the heater main body is below the target temperature, more power is supplied to the heater main body than when the temperature of the heater main body is at or above the target temperature. Therefore, when the temperature of the heater main body is below the target temperature, the amount of heat generated per unit time from the heater main body can be increased compared to when the temperature of the heater main body is at or above the target temperature. In addition, the first transistor and the second transistor are not switched to supply power from the first DC power source and the second DC power source to the heater main body. This makes it possible to provide a heater device that ensures fast heating while suppressing emission noise.

[0008] According to another aspect of the present disclosure, a heater device includes: a heater main body (30) having a first heater element (R1) that generates heat when a current flows through it, and a second heater element (R2) that has a larger electrical resistance than the first heater element and generates heat when a current flows through it; a first transistor (Tr1) disposed between a DC power supply (VB) and a first heater element; a second transistor (Tr2) disposed between the DC power supply and the second heater element; a temperature detection unit (32) for detecting the temperature of the heater main body; a temperature determination unit (S100) that determines whether the temperature of the heater main body is equal to or higher than a target temperature; a first switch control unit (S100A) that, upon receiving a command to start the operation of the heater main body, keeps the first transistor fully on to continuously flow current from the DC power supply to the first heater element through the first transistor, and keeps the second transistor off to continuously open the DC power supply and the second heater element; and a second switch control unit (S120A) that, when the temperature determination unit determines that the temperature of the heater main body is equal to or higher than a target temperature after the first switch control unit has continuously kept the first transistor fully on and continuously kept the second transistor off, keeps the first transistor continuously off to continuously open the connection between the DC power supply and the first heater element, and keeps the second transistor fully on to continuously flow current from the DC power supply to the second heater element through the second transistor.

[0009] Therefore, when the temperature of the heater main body is below the target temperature, more power is supplied to the heater main body than when the temperature of the heater main body is at or above the target temperature. Therefore, when the temperature of the heater main body is below the target temperature, the amount of heat generated per unit time from the heater main body can be increased compared to when the temperature of the heater main body is at or above the target temperature. In addition, the first and second transistors are not switched to supply power from the DC power source to the heater main body. This makes it possible to provide a heater device that ensures fast heating while suppressing emission noise.

[0010] According to yet another aspect of the present disclosure, a heater device includes: a heater main body (30) having a first heater element (R1) disposed between a DC power supply (VB) and ground, which generates heat when a current flows through it, and a second heater element (R2) disposed between the first heater element and ground, which generates heat when a current flows through it; a first transistor (TR1) disposed between the DC power supply and the first heater element; When a terminal to which the first heater element and the second heater element are commonly connected is defined as a common connection terminal (51), a second transistor (TR2) is arranged between the common connection terminal and ground; a temperature detection unit (32) for detecting the temperature of the heater main body; a temperature determination unit (S100) that determines whether the temperature of the heater main body is equal to or higher than a target temperature; a first switch control unit (S100B) that, upon receiving a command to start the operation of the heater main body, continuously turns on the first transistor and the second transistor so that current continues to flow from the DC power supply to ground through the first transistor, the first heater element, and the second transistor; a second switch control section (S120B) that, when the temperature determination section determines that the temperature of the heater main body is equal to or higher than a target temperature after the first switch control section has continuously turned on the first transistor and the second transistor, continuously turns on the first transistor and continuously turns off the second transistor in order to continuously flow a current from the DC power supply to ground through the first transistor, the first heater element, and the second heater element; When the power supplied from the DC power supply to the first heater element when the first switch control unit keeps the first transistor and the second transistor continuously fully on is defined as first power, and the power supplied from the DC power supply to the first heater element and the second heater element when the second switch control unit keeps the first transistor continuously fully on and the second transistor continuously off is defined as second power, the first power is larger than the second power.

[0011] Therefore, when the temperature of the heater main body is below the target temperature, more power is supplied to the heater main body than when the temperature of the heater main body is at or above the target temperature. Therefore, when the temperature of the heater main body is below the target temperature, the amount of heat generated per unit time from the heater main body can be increased compared to when the temperature of the heater main body is at or above the target temperature. In addition, the first and second transistors are not switched to supply power from the DC power source to the heater main body. This makes it possible to provide a heater device that ensures fast heating while suppressing emission noise. The reference symbols in parentheses attached to each component indicate an example of the correspondence between the component and the specific components described in the embodiments described below. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is an electric circuit diagram showing an electric circuit configuration of a vehicle heater device according to a first embodiment of the present disclosure. [Figure 2]FIG. 2 is a schematic diagram showing the overall configuration of a heater main body of the vehicle heater device in the first embodiment of FIG. 1, and is a diagram for assisting in the detailed description of a heater element constituting the heater main body. [Figure 3] 4 is a flowchart showing details of heater control processing by a central processing unit of the vehicle heater device in the first embodiment of FIG. 1. [Figure 4] FIG. 6 is an electric circuit diagram showing an electric circuit configuration of a vehicle heater device according to a second embodiment of the present disclosure. [Figure 5] 5 is a schematic diagram showing the overall configuration of a heater main body of the vehicle heater device according to the second embodiment of FIG. 4, and is a diagram for assisting in the detailed description of a heater element constituting the heater main body. FIG. [Figure 6] 5 is a flowchart showing details of heater control processing by a central processing unit of the vehicle heater device in the second embodiment of FIG. 4. [Figure 7] FIG. 10 is an electric circuit diagram showing an electric circuit configuration of a vehicle heater device according to a third embodiment of the present disclosure. [Figure 8] 8 is a schematic diagram showing the overall configuration of a heater main body of the vehicle heater device according to the third embodiment of FIG. 7, and is a diagram for assisting in the detailed description of a heater element constituting the heater main body. FIG. [Figure 9] 8 is a flowchart showing details of heater control processing by a central processing unit of the vehicle heater device in the third embodiment of FIG. 7. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the following embodiments, identical or equivalent parts are denoted by the same reference numerals in the drawings to simplify the description.

[0014] (First embodiment) A first embodiment of a vehicle heater device 1 in which a heater device of the present disclosure is applied to an automobile will be described with reference to Figs. 1, 2, etc. Fig. 1 is an electric circuit diagram showing the electric circuit configuration of the vehicle heater device 1. Fig. 2 is a perspective view showing the configuration of a heater main body 30 of the vehicle heater device 1. The vehicle heater device 1 is an electric heater that generates heat by receiving DC power from a power source VB or a power source VC. The power source VB is a first DC power source that is mounted on the automobile and outputs a DC voltage. The power source VC is a second DC power source that is mounted on the automobile and outputs a DC voltage.

[0015] The vehicle heater device 1 is used to radiate radiant heat in the thickness direction of the heater main body 30 to warm an object located in that direction. The vehicle heater device 1 is installed so as to radiate radiant heat, for example, to the feet of an occupant seated in a seat in a vehicle interior. As shown in FIG. 1, the vehicle heater device 1 includes a gate driver 10, a microcomputer 20, the heater main body 30, a resistive element 40, a power supply VC, and transistors TR1 and TR2. The output voltage of the power supply VC is smaller than the output voltage of the power supply VB. The output voltage of the power supply VB is defined as a first DC voltage, and the output voltage of the power supply VC is defined as a second DC voltage. The power supply VC is a step-down circuit (i.e., a DC-DC converter) that converts the first DC voltage output from the power supply VB into the second DC voltage and supplies the second DC voltage to the source terminal of the transistor TR2.

[0016] The gate driver 10 is an electronic circuit controlled by a central processing unit 21 and outputs gate signals to the gate terminals of transistors TR1 and TR2 to turn transistors TR1 and TR2 fully on or off. Here, "fully on" refers to a state in which the on-resistance between the source terminal and the drain terminal of transistor TR1 or TR2 is at its smallest. The microcomputer 20 includes the central processing unit 21, an AD converter 22, and a memory 23.

[0017] The central processing unit 21 executes a computer program pre-recorded in the memory 23 to perform heater control processing. In executing the heater control processing, the central processing unit 21 turns transistors TR1 and TR2 fully on or off based on the temperature detected by the temperature sensor 32. The AD converter 22 converts the detected temperature voltage Vk output from the common connection terminal 41 into a digital signal and outputs it to the central processing unit 21. The memory 23 is composed of a DRAM, a non-volatile memory, etc., and stores data such as the computer program.

[0018] As shown in Figure 1, the heater main body 30 includes a flexible substrate 31, a temperature sensor 32, and a heater element R. The flexible substrate 31 is an electrically insulating plastic film formed into a thin film. The flexible substrate 31 is also called an FPC, which is a flexible circuit board. FPC is an abbreviation of the English term Flexible Printed Circuits.

[0019] The temperature sensor 32 is a temperature detection unit that detects the temperature of the heater main body 30. The temperature sensor 32 is, for example, an NTC-type thermistor whose electrical resistance decreases as the temperature increases. NTC is an abbreviation of the English term "Negative Temperature Coefficient." The temperature sensor 32 is disposed on one surface of the flexible substrate 31, close to the heater element R.

[0020] The temperature sensor 32 is disposed between the power supply VD and ground. The temperature sensor 32 outputs a detected temperature voltage Vk, which indicates the temperature of the heater main body 30 (specifically, the heater element R), from a common connection terminal 41 to the AD converter 22. The common connection terminal 41 is a terminal to which the resistance element 40 and the temperature sensor 32 are commonly connected. The power supply VD is a power supply device mounted on an automobile and outputs a DC voltage. The output voltage of the power supply VD is lower than the output voltage of the power supply VB. The resistance element 40 is disposed between the positive terminal of the power supply VD and the temperature sensor 32.

[0021] The heater element R is a radiant heater formed in a linear shape extending from one end Ra to the other end Rb. The heater element R is formed in a thin film shape along one surface of the flexible substrate 31. For example, as shown in FIG. 2, the heater element R is formed in a serpentine shape on one surface of the flexible substrate 31. The heater element R is made of a conductive metal material such as copper. Note that the heater element R may be a PTC heater instead of an electric heater made of copper or the like. The heater element R generates heat when a current flows through it. One end Ra of the heater element R is connected to the drain terminals of the transistors TR1 and TR2. The other end Rb of the heater element R is connected to ground.

[0022] The transistor TR1 is a first transistor disposed between the power supply VB and the heater element R. The transistor TR1 is turned fully on or off based on a gate signal provided by the gate driver 10. The transistor TR2 is a second transistor disposed between the power supply VC and the heater element R. The transistor TR2 is turned fully on or off based on a gate signal provided by the gate driver 10. For example, p-channel metal oxide semiconductor field effect transistors are used as the transistors TR1 and TR2.

[0023] Next, the operation of the vehicle heater device 1 of this embodiment will be described with reference to Fig. 3. Fig. 3 is a flowchart showing details of the heater control process by the central processing unit 21. The central processing unit 21 executes the heater control process in accordance with the flowchart of Fig. 3. When the central processing unit 21 receives a command to start the operation of the heater main body 30 (i.e., a heater operation command) from the electronic control device, it starts executing the heater control process.

[0024] First, in step S100 (i.e., the first switch control unit), the central processing unit 21 controls the gate driver 10 to output gate signals to the gate terminals of the transistors TR1 and TR2. As a result, the transistor TR1 remains fully on and the transistor TR2 remains off. As a result, the transistor TR2 continuously opens the connection between the positive terminal of the power supply VC and the heater element R. A direct current continuously flows from the power supply VB to ground through the transistor TR1 and the heater element R. As a result, the heater element R generates radiant heat based on the direct current flowing from the power supply VB.

[0025] Next, in step S110 (i.e., the temperature determination section), the central processing unit 21 determines whether the temperature of the heater main body 30 (i.e., the heater temperature) is equal to or higher than the target temperature based on the digital signal output from the AD converter 22. For example, 100°C is used as the target temperature. At this time, if the temperature of the heater main body 30 is lower than the target temperature, the central processing unit 21 determines "NO" in step S110. Accordingly, the central processing unit 21 continues to execute the energization process for the heater element R in step S100. Therefore, as long as the central processing unit 21 determines "NO" in step S110, the central processing unit 21 continues to execute the energization process for the heater element R in step S100. Therefore, the heater element R generates radiant heat based on the DC current flowing from the power supply VB.

[0026] Thereafter, in step S110, the central processing unit 21 determines YES when the temperature of the heater main body 30 reaches or exceeds the target temperature. Accordingly, in step S120 (i.e., the second switch control unit), the central processing unit 21 controls the gate driver 10 to output gate signals to the gate terminals of the transistors TR1 and TR2. This keeps the transistor TR2 fully on, and the transistor TR1 continuously off. Therefore, with the transistor TR1 in an open state between the positive terminal of the power supply VB and the heater element R, a direct current continues to flow from the power supply VC to ground through the transistor TR2 and the heater element R. This causes the heater element R to generate radiant heat based on the direct current flowing from the power supply VC.

[0027] As described above, when the temperature of the heater main body 30 is below the target temperature, DC power is supplied from the power supply VB to the heater element R, and when the temperature of the heater main body 30 reaches or exceeds the target temperature, DC power is supplied from the power supply VC to the heater element R. The DC power supplied from the power supply VB to the heater element R is greater than the DC power supplied from the power supply VC to the heater element R.

[0028] According to the present embodiment described above, the vehicle heater device 1 includes a heater element R that generates heat when a direct current flows through it, and a transistor Tr1 that is arranged between the heater element R and the positive electrode of a power supply VB that outputs a direct current voltage. The vehicle heater device 1 further includes a transistor Tr2 that is arranged between the heater element R and a power supply VC that outputs a direct current voltage lower than the output voltage of the power supply VB, and a temperature sensor 32 that detects the temperature of the heater main body 30.

[0029] In step S110 (i.e., in the temperature determination section), the central processing unit 21 determines whether the temperature of the heater main body 30 is equal to or higher than the target temperature based on the temperature detected by the temperature sensor 32. Upon receiving a command to start the operation of the heater main body 30, in step S100, the central processing unit 21 keeps the transistor Tr1 fully on to continuously flow current from the power supply VB to the heater element R through the transistor Tr1. In addition, the central processing unit 21 keeps the transistor Tr2 off to continuously open the connection between the positive electrode of the power supply VC and the heater element R.

[0030] After the central processing unit 21 has continuously kept transistor Tr1 fully on and transistor Tr2 continuously off, if it determines that the temperature of the heater main body 30 is equal to or higher than the target temperature, the central processing unit 21 controls transistors Tr1 and Tr2 in the following manner in step S120. That is, the central processing unit 21 continuously keeps transistor Tr1 off to continuously open the connection between the positive electrode bridge of power supply VB and the heater element R. In addition, the central processing unit 21 continuously keeps transistor Tr2 fully on to continuously flow current from power supply VC to the heater element R through transistor Tr2.

[0031] As a result, the first power is supplied from the power source VB to the heater element R until the temperature of the heater main body 30 reaches the target temperature. When the temperature of the heater main body 30 is equal to or higher than the target temperature, the second power is supplied from the power source VC to the heater element R. The first power is greater than the second power. Therefore, when the temperature of the heater main body 30 is below the target temperature, the amount of heat generated per unit time by the heater main body 30 can be increased compared to when the temperature of the heater main body 30 is equal to or higher than the target temperature. This ensures rapid heating by the heater element R. Here, rapid heating refers to the ability of the heater main body 30 to quickly heat the object to be heated.

[0032] In addition, in step S100, the central processing unit 21 keeps transistor Tr1 fully on and transistor Tr2 fully off. In step S120, the central processing unit 21 keeps transistor Tr1 fully off and transistor Tr2 fully on. This allows the power supplied to the heater element R by transistors Tr1 and Tr2 to be varied without switching them. This reduces the emission noise associated with the switching of transistors Tr1 and Tr2. This provides a vehicle heater device 1 that ensures rapid heating by the heater element R while reducing the emission noise. In this embodiment, a step-down circuit that converts a first DC voltage output from power source VB to a second DC voltage is used as the power source VC. This allows the vehicle heater device 1, which outputs a lower power than the power output from power source VB to the heater element R via transistor Tr2, to be configured with a simple electrical circuit.

[0033] Alternatively, to control the current flowing through the heater element R, it is possible to perform PWM control by switching a transistor disposed between the heater element R and the power supply VB. This allows for greater power to be supplied to the heater element R when the temperature of the heater main body 30 is below a target temperature than when the temperature of the heater main body 30 is at or above the target temperature. However, switching the transistor generates emission noise. Alternatively, it is possible to control the current flowing through the heater element R by performing analog control, which continuously changes the voltage between the drain and source terminals of a transistor disposed between the heater element R and the power supply VB. While this method can suppress emission noise, it also generates a lot of heat from the transistor. In contrast, in this embodiment, as described above, the transistors Tr1 and Tr2 are continuously turned on or off. This suppresses emission noise. In addition, it also suppresses heat generation from the transistors Tr1 and Tr2.

[0034] (Second embodiment) In the first embodiment, an example was described in which the power supplied to the heater element R (i.e., the heater main body 30) is switched using the power supplies VC and VB, which have different output voltages. However, instead of this, a second embodiment will be described with reference to FIGS. 4 and 5, which explains an example in which the power supplied from the power supply VB to the heater main body 30 is switched using the heater elements R1 and R2, which have different electrical resistance values.

[0035] The vehicle heater device 1 of this embodiment includes heater elements R1 and R2 in place of the heater element R in the heater main body 30. In FIG. 4, the same reference numerals as in FIG. 1 indicate the same components, and their explanations will be omitted. The heater element R1 is a first heater element disposed between the transistor Tr1 and ground. The transistor Tr1 is a first transistor disposed between the positive electrode of the power supply VB and the heater element R1. The heater element R2 is a second heater element disposed between the transistor Tr2 and ground. The transistor Tr2 is a second transistor disposed between the positive electrode of the power supply VB and the heater element R2.

[0036] As shown in Fig. 5, the heater element R1 is a radiant heater formed linearly extending from one end R1a to the other end R1b. Similarly, the heater element R2 is a radiant heater formed linearly extending from one end R2a to the other end R2b. The heater elements R1 and R2 are each formed as a thin film on one surface of the flexible substrate 31. The heater elements R1 and R2 are each formed in a serpentine shape on one surface of the flexible substrate 31. In this embodiment, the width dimension of the heater element R1 is larger than the width dimension of the heater element R2.

[0037] Therefore, the electrical resistance of heater element R2 is greater than that of heater element R1. Hereinafter, heater element R1 and heater element R2 will be collectively referred to as heater elements R1 and R2. In this embodiment, temperature sensor 32 is a temperature sensor that detects the temperature of heater main body 30. Specifically, temperature sensor 32 detects the average temperature of heater elements R1 and R2. Temperature sensor 32 is, for example, an NTC thermistor whose electrical resistance decreases as the temperature increases.

[0038] The temperature sensor 32 is disposed on one surface of the flexible substrate 31, close to the heater elements R1 and R2. The temperature sensor 32 is disposed between the power supply VD and ground. The temperature sensor 32 outputs a detected temperature voltage Vk indicating the temperature of the heater main body 30 from a common connection terminal 41 to the AD converter 22. The common connection terminal 41 is a terminal to which the resistance element 40 and the temperature sensor 32 are commonly connected. The power supply VD is a DC power supply mounted on an automobile that outputs a DC voltage. The resistance element 40 is disposed between the positive terminal of the power supply VD and the temperature sensor 32.

[0039] Next, the operation of the vehicle heater device 1 of this embodiment will be described with reference to Fig. 6. Fig. 6 is a flowchart showing details of the heater control process by the central processing unit 21. The central processing unit 21 executes the heater control process according to the flowchart of Fig. 6, which replaces Fig. 3. When the central processing unit 21 receives a command to start the operation of the heater main body 30 (i.e., a heater operation command) from the electronic control device, it starts executing the heater control process.

[0040] First, in step S100A (i.e., the first switch control unit), the central processing unit 21 controls the gate driver 10 to output gate signals to the gate terminals of transistors TR1 and TR2. This keeps transistor TR1 fully on and transistor TR2 off. Transistor TR2 keeps the positive terminal of power supply VB and heater element R2 open. A direct current ID1 flows continuously from power supply VB to ground through transistor TR1 and heater element R1. As a result, heater element R1 generates radiant heat based on the direct current ID1 flowing from power supply VB.

[0041] Next, in step S110 (i.e., the temperature determination unit), the central processing unit 21 determines whether the temperature of the heater main body 30 is equal to or higher than the target temperature based on the digital signal output from the AD converter 22. The target temperature is, for example, 100°C. At this time, if the temperature of the heater main body 30 is lower than the target temperature, the central processing unit 21 determines "NO" in step S110. Accordingly, the central processing unit 21 continues to execute the energization process for the heater element R1 in step S100A. Therefore, as long as the central processing unit 21 determines "NO" in step S110, the central processing unit 21 continues to execute the energization process for the heater element R1 in step S100A. As a result, the heater element R1 generates radiant heat based on the DC current ID1 flowing from the power supply VB.

[0042] Thereafter, in step S110, the central processing unit 21 determines YES when the temperature of the heater main body 30 reaches or exceeds the target temperature. Accordingly, in step S120A (i.e., the second switch control unit), the central processing unit 21 controls the gate driver 10 to output gate signals to the gate terminals of the transistors TR1 and TR2. This keeps the transistor TR2 fully on and the transistor TR1 off. Therefore, with the positive terminal of the power supply VB and the heater element R1 open by the transistor TR1, a direct current ID2 continues to flow from the power supply VB to ground through the transistor TR2 and the heater element R2. Therefore, the heater element R2 generates radiant heat based on the direct current ID2 flowing from the power supply VB.

[0043] Here, the DC current ID1 flowing through the heater element R1 when the temperature of the heater main body 30 is below the target temperature is larger than the DC current ID2 flowing through the heater element R2 when the temperature of the heater main body 30 is equal to or higher than the target temperature. Therefore, when the temperature of the heater element R is below the target temperature, the DC power supplied from the power source VB to the heater main body 30 is larger than when the temperature of the heater element R is equal to or higher than the target temperature.

[0044] According to the present embodiment described above, the vehicle heater device 1 includes a heater main body 30 having a heater element R1 that generates heat when a direct current flows through it, and a heater element R2 that has a larger electrical resistance than the heater element R1 and generates heat when a direct current flows through it. The vehicle heater device 1 also includes a transistor Tr1 arranged between a power supply VB and the heater element R1, a transistor Tr2 arranged between the power supply VB and the heater element R2, and a temperature sensor 32 that detects the temperature of the heater main body 30.

[0045] In step S110, the central processing unit 21 determines whether the temperature of the heater main body 30 is equal to or higher than the target temperature based on the temperature detected by the temperature sensor 32. When the central processing unit 21 receives a command from the electronic control unit to start operation of the heater main body 30 in step S100A, the central processing unit 21 keeps transistor Tr1 fully on to continuously flow current from power supply VB to heater element R1 through transistor Tr1. In addition, in step S100A, the central processing unit 21 keeps transistor Tr2 off to continuously open the connection between power supply VB and heater element R2.

[0046] When the central processing unit 21 determines that the temperature of the heater main body 30 is equal to or higher than the target temperature after continuously keeping transistor Tr1 fully on and transistor Tr2 continuously off, it controls transistors Tr1 and Tr2 in the following manner in step S120A. That is, the central processing unit 21 continuously keeps transistor Tr1 off to continuously open the connection between the power supply VB and the heater element R1. In addition, the central processing unit 21 continuously keeps transistor Tr2 fully on to continuously flow current from the power supply VB to the heater element R2 through transistor Tr2.

[0047] As a result, when the temperature of the heater main body 30 is below the target temperature, the power supplied from the power source VB to the heater main body 30 is greater than when the temperature of the heater main body 30 is equal to or greater than the target temperature. Therefore, when the temperature of the heater main body 30 is below the target temperature, the amount of heat generated per unit time by the heater main body 30 can be increased compared to when the temperature of the heater main body 30 is equal to or greater than the target temperature. This ensures rapid heating by the heater main body 30. Additionally, in step S100A, the central processing unit 21 keeps transistor Tr1 fully on and transistor Tr2 fully off. In step S120, the central processing unit 21 keeps transistor Tr1 fully off and transistor Tr2 fully on. This reduces emission noise associated with switching between transistors Tr1 and Tr2. Therefore, a vehicle heater device 1 can be provided that ensures rapid heating by the heater elements R1 and R2 while suppressing emission noise.

[0048] (Third embodiment) In the second embodiment, an example was described in which the heater elements R1 and R2 were arranged in parallel between the positive electrode of the power source VB and ground. However, instead of this, a third embodiment in which the heater elements R1 and R2 are arranged in series between the positive electrode of the power source VB and ground was described with reference to Figures 7 and 8. Figure 7 is a circuit diagram showing the electrical circuit configuration of the vehicle heater device 1 of this embodiment. In Figure 7, the same reference numerals as in Figure 4 indicate the same components, and their description will be omitted.

[0049] As shown in FIG. 7, the vehicle heater device 1 of this embodiment includes a microcomputer 20, transistors Tr1 and Tr2, gate drivers 10 and 10A, and a heater main body 30. The transistor Tr1 is a first transistor disposed between the positive electrode of a power supply VB and a heater element R1. The source terminal of the transistor Tr1 is connected to the positive electrode of the power supply VB. When the transistor Tr1 is turned on, it connects the positive electrode of the power supply VB to the heater element R1. When the transistor Tr1 is turned off, it disconnects the positive electrode of the power supply VB from the heater element R1. Note that, for example, a p-channel metal oxide semiconductor field effect transistor is used as the transistor Tr1.

[0050] The heater element R1 is a first heater element, with one end R1a connected to the drain terminal of the transistor Tr1. The other end R1b of the heater element R1 is connected to one end R2a of the heater element R2. The heater element R2 is a second heater element, with the other end R2b connected to ground. When the sum of the electrical resistance values ​​of the heater elements R1 and R2 is taken as the combined resistance value, the electrical resistance value of the heater element R1 is smaller than the combined resistance value of the heater elements R1 and R2. In this embodiment, the electrical resistance value of the heater element R1 is smaller than the electrical resistance value of the heater element R2.

[0051] As shown in FIGS. 7 and 8, in the heater body 30, a terminal to which the heater elements R1 and R2 are commonly connected is defined as a common connection terminal 51. The transistor Tr2 is disposed between the common connection terminal 51 and ground. The drain terminal of the transistor Tr2 is connected to the common connection terminal 51. In the heater body 30 of this embodiment, the heater elements R1 and R2 are each formed along one surface of the flexible substrate 31, as in the second embodiment. The heater elements R1 and R2 are each made of copper. The heater element R2 may constitute a PTC heater.

[0052] The transistor Tr2 is a second transistor whose source terminal is connected to ground. When turned on, the transistor Tr2 connects the common connection terminal 51 to ground. When turned off, the transistor Tr2 opens the gap between the common connection terminal 51 and ground. The gate driver 10 is an electronic circuit controlled by the central processing unit 21 of the microcomputer 20 to turn the transistor Tr1 fully on or off. The gate driver 10A is also an electronic circuit controlled by the central processing unit 21 to turn the transistor Tr2 fully on or off.

[0053] Next, the operation of the vehicle heater device 1 of this embodiment will be described with reference to Fig. 9. Fig. 9 is a flowchart showing details of the heater control process by the central processing unit 21. The central processing unit 21 executes the heater control process according to the flowchart of Fig. 9, which replaces Fig. 6. The central processing unit 21 starts executing the heater control process when it receives a command to start the operation of the heater main body 30 (i.e., a heater operation command) from the electronic control device.

[0054] First, in step S100B (i.e., the first switch control unit), the central processing unit 21 controls the gate driver 10 to output a gate signal to the gate terminal of transistor TR1. This keeps transistor TR1 fully on. In addition, in step S100B, the central processing unit 21 controls the gate driver 10A to output a gate signal to the gate terminal of transistor TR2. This keeps transistor TR2 fully on. As a result, a direct current ID1 continues to flow from the power supply VB to ground through transistor TR1, heater element R1, and transistor TR2. This causes the heater element R1 to generate radiant heat based on the direct current ID1 flowing from the power supply VB.

[0055] Next, in step S110 (i.e., the temperature determination section), the central processing unit 21 determines whether the temperature of the heater main body 30 is equal to or higher than the target temperature based on the digital signal output from the AD converter 22. For example, 100°C is used as the target temperature. At this time, if the temperature of the heater main body 30 is lower than the target temperature in step S110, the central processing unit 21 determines "NO." Accordingly, the central processing unit 21 continues to execute the energization process for the heater element R1 in step S100B. Therefore, as long as the determination in step S110 is "NO," the central processing unit 21 continues to execute the energization process for the heater element R1 in step S100B.

[0056] Thereafter, in step S110, the central processing unit 21 determines YES when the temperature of the heater main body 30 reaches or exceeds the target temperature. Accordingly, in step S120B (i.e., the second switch control unit), the central processing unit 21 controls the gate drivers 10 and 10B to output gate signals to the gate terminals of the transistors TR1 and TR2, respectively. This causes the transistor TR1 to remain fully on and the transistor TR1 to remain off. Therefore, with the common connection terminal 51 open to the ground by the transistor TR1, a direct current ID2 continuously flows from the power supply VB to the ground through the transistor TR1 and the heater elements R1 and R2. Therefore, the heater elements R1 and R2 generate radiant heat based on the direct current ID2 flowing from the power supply VB. The direct current ID1 is larger than the direct current ID2.

[0057] That is, the power supplied from the power supply VB to the heater element R1 when the temperature of the heater main body 30 is below the target temperature is greater than the power supplied from the power supply VB to the heater elements R1 and R2 when the temperature of the heater main body 30 is equal to or higher than the target temperature. Here, the power supplied from the power supply VB to the heater elements R1 and R2 is the sum of the power supplied from the power supply VB to the heater element R1 and the power supplied from the power supply VB to the heater element R2.

[0058] According to the present embodiment described above, the vehicle heater device 1 includes a heater main body 30 having a heater element R1 disposed between a power supply VB and ground and a heater element R2 disposed between the heater element R1 and ground. The vehicle heater device 1 also includes a transistor TR1 disposed between the power supply VB and the heater element R1, and a transistor TR2 disposed between a common connection terminal 51 to which the heater elements R1 and R2 are commonly connected and ground.

[0059] In step S110, the central processing unit 21 determines whether the temperature of the heater main body 30 is equal to or higher than the target temperature based on the temperature detected by the temperature sensor 32 that detects the temperature of the heater main body 30. When the central processing unit 21 receives a command to start the operation of the heater main body 30 in step S100B, it keeps the transistors Tr1 and Tr2 fully on. This allows a direct current ID1 to continuously flow from the power supply VB to ground through the transistor Tr1, heater element R1, and transistor Tr2.

[0060] After continuously keeping the transistors Tr1 and Tr2 fully on, if the central processing unit 21 determines that the temperature of the heater main body 30 is equal to or higher than the target temperature, in step S120B, the central processing unit 21 controls the transistors Tr1 and Tr2 as follows: In other words, the central processing unit 21 continuously keeps the transistor Tr1 fully on and keeps the transistor Tr2 off so that a direct current ID2 continuously flows from the power supply VB to ground through the transistor Tr1 and the heater elements R1 and R2.

[0061] The power supplied from the power supply VB to the heater element R1 when the central processing unit 21 keeps transistors Tr1 and Tr2 fully on in step S100B is defined as the first power. The power supplied from the power supply VB to the heater elements R1 and R2 when the central processing unit 21 keeps transistor Tr1 fully on and transistor Tr2 fully off in step S120B is defined as the second power. In this embodiment, the first power is greater than the second power. Therefore, when the temperature of the heater main body 30 is below the target temperature, the amount of heat generated per unit time by the heater main body 30 can be increased compared to when the temperature of the heater main body 30 is equal to or higher than the target temperature. This ensures rapid heating by the heater main body 30.

[0062] In addition, in step S100B, the central processing unit 21 keeps transistors Tr1 and Tr2 fully on. In step S120B, the central processing unit 21 keeps transistor Tr1 fully on and transistor Tr2 fully off. This makes it possible to suppress the generation of emission noise associated with the switching of transistors Tr1 and Tr2. Therefore, it is possible to provide a vehicle heater device 1 that ensures fast heating by heater elements R1 and R2 while suppressing the generation of emission noise.

[0063] (Other embodiments) (1) In the above first to third embodiments, examples have been described in which p-channel metal oxide semiconductor field effect transistors are used as the transistors TR1 and TR2. However, instead of this, n-channel metal oxide semiconductor field effect transistors may be used as the transistors TR1 and TR2. Furthermore, junction field effect transistors, bipolar transistors, or insulated gate bipolar transistors may also be used as the transistors TR1 and TR2.

[0064] (2) In the second embodiment, the width dimension of the heater element R1 is larger than the width dimension of the heater element R2 in order to make the electrical resistance of the heater element R2 larger than the electrical resistance of the heater element R1. However, instead of this, the longitudinal dimension of the heater element R2 may be larger than the dimension of the heater element R2 in order to make the electrical resistance of the heater element R2 larger than the electrical resistance of the heater element R1.

[0065] (3) In the second embodiment, the width dimension of heater element R1 is larger than the width dimension of heater element R2 to make the electrical resistance of heater element R2 larger than the electrical resistance of heater element R1. However, heater element R1 and heater element R2 may be made of different materials. For example, heater element R1 may be made of a conductive metal material such as copper. Heater element R2 may be made of a PTC paste. PTC heaters have the characteristic that their electrical resistance increases as their temperature increases. That is, as the temperature increases, current becomes less likely to flow through the PTC heater, and as the temperature decreases, current becomes more likely to flow through the PTC heater. Therefore, the PTC heater automatically controls its temperature, eliminating the need to use a temperature sensor to control the temperature of the PTC heater.

[0066] (4) In the first to third embodiments described above, the vehicle heater device 1 is an example in which the heater device of the present disclosure is applied to an automobile. However, instead of this, the heater device of the present disclosure may be applied to a home heating device or industrial heating device that heats a room other than the passenger compartment of the automobile. Furthermore, the heater device of the present disclosure may be applied not only to home heating devices and industrial heating devices, but also to a heating device that heats an unheated object other than a human.

[0067] (5) In the above first to third embodiments, an NTC thermistor whose electrical resistance decreases as the temperature increases is used as the temperature sensor 32 of the present disclosure. However, instead of this, a PTC thermistor whose electrical resistance increases as the temperature increases may be used as the temperature sensor 32 of the present disclosure. PTC is an abbreviation for Positive Temperature Coefficient.

[0068] (6) In the first embodiment, an example was described in which one heater element R was used in the heater main body 30. However, instead of this, two or more heater elements R may be used in the heater main body 30. In the second and third embodiments, an example was described in which two heater elements R1 and R2 were used in the heater main body 30. However, instead of this, three or more heater elements may be used in the heater main body 30.

[0069] (7) In the first to third embodiments, the heater main body 30 is configured using the flexible substrate 31. However, instead of this, the heater main body 30 may be configured using an electrically insulating material such as a substrate instead of the flexible substrate 31. Alternatively, the heater main body 30 may be configured without using a substrate that supports the heater elements R, R1, and R2. In this case, the temperature sensor 32 is configured independently by the flexible substrate 31.

[0070] (8) The present disclosure is not limited to the above-described embodiments and can be modified as appropriate within the scope of the claims. Furthermore, the above-described embodiments are not unrelated to each other and can be combined as appropriate unless the combination is clearly impossible. It goes without saying that, in each of the above embodiments, the elements constituting the embodiments are not necessarily essential unless specifically stated as essential or clearly considered essential in principle. Furthermore, in each of the above embodiments, when numerical values ​​such as the number, values, amounts, and ranges of components of the embodiments are mentioned, they are not limited to the specific numbers unless specifically stated as essential or clearly limited to a specific number in principle. Furthermore, in each of the above embodiments, when the shape, positional relationship, etc. of components, etc. are mentioned, they are not limited to the shape, positional relationship, etc., unless specifically stated or clearly limited to a specific shape, positional relationship, etc. in principle. [Explanation of symbols]

[0071] 1 Vehicle heater device 10 Gate Drivers 20 Microcomputer 30 Heater body 32 Temperature Sensor R heater element Tr1 transistor Tr2 transistor VC power supply VB power supply

Claims

1. a heater main body (30) having a heater element (R) that generates heat when a current flows therethrough; a first transistor (Tr1) disposed between a first DC power supply (VB) that outputs a first DC voltage and the heater element; a second transistor (Tr2) disposed between a second DC power supply (VC) that outputs a second DC voltage lower than the first DC voltage and the heater element; a temperature detection unit (32) for detecting the temperature of the heater main body; a temperature determination unit (S110) that determines whether the temperature of the heater main body is equal to or higher than a target temperature based on the temperature detected by the temperature detection unit; a first switch control unit (S100) that, upon receiving a command to start the operation of the heater main body, continuously turns on the first transistor to continuously flow current from the first DC power source to the heater element through the first transistor, and continuously turns off the second transistor to continuously open the second DC power source and the heater element; a second switch control unit (S120) that, when the temperature determination unit determines that the temperature of the heater main body is equal to or higher than a target temperature after the first switch control unit has continuously turned on the first transistor and continuously turned off the second transistor, continuously turns off the first transistor to continuously open the first DC power source and the heater element, and continuously turns on the second transistor to continuously flow a current from the second DC power source to the heater element through the second transistor; A heater device comprising:

2. 2. The heater device according to claim 1, wherein the second DC power supply is a step-down circuit that steps down the first DC voltage and outputs the second DC voltage.

3. The heater device according to claim 1 , wherein the heater element generates radiant heat when the current flows through it.

4. a heater body (30) having a first heater element (R1) that generates heat when a current flows through it, and a second heater element (R2) that has a larger electrical resistance than the first heater element and generates heat when a current flows through it; a first transistor (Tr1) disposed between a DC power supply (VB) and the first heater element; a second transistor (Tr2) disposed between the DC power supply and the second heater element; a temperature detection unit (32) for detecting the temperature of the heater main body; a temperature determination unit (S100) that determines whether the temperature of the heater main body is equal to or higher than a target temperature; a first switch control unit (S100A) that, upon receiving a command to start the operation of the heater main body, continuously turns on the first transistor to continuously flow current from the DC power supply to the first heater element through the first transistor, and continuously turns off the second transistor to continuously open the DC power supply and the second heater element; a second switch control unit (S120A) that, when the temperature determination unit determines that the temperature of the heater main body is equal to or higher than a target temperature after the first switch control unit has continuously turned on the first transistor and continuously turned off the second transistor, continuously turns off the first transistor to continuously open the DC power supply and the first heater element, and fully turns on the second transistor to continuously flow a current from the DC power supply to the second heater element through the second transistor; A heater device comprising:

5. a heater main body (30) including a first heater element (R1) disposed between a DC power supply (VB) and ground, and generating heat when a current flows through it, and a second heater element (R2) disposed between the first heater element and ground, and generating heat when a current flows through it; a first transistor (TR1) disposed between the DC power supply and the first heater element; When a terminal to which the first heater element and the second heater element are commonly connected is defined as a common connection terminal (51), a second transistor (TR2) is arranged between the common connection terminal and ground; a temperature detection unit (32) for detecting the temperature of the heater main body; a temperature determination unit (S100) that determines whether the temperature of the heater main body is equal to or higher than a target temperature; a first switch control unit (S100B) that, upon receiving a command to start the operation of the heater main body, continuously keeps the first transistor and the second transistor fully on so that current continues to flow from the DC power supply to ground through the first transistor, the first heater element, and the second transistor; a second switch control unit (S120B) that, when the temperature determination unit determines that the temperature of the heater main body is equal to or higher than a target temperature after the first switch control unit continuously turns on the first transistor and the second transistor, continuously turns on the first transistor and continuously turns off the second transistor in order to continuously flow a current from the DC power supply to ground through the first transistor, the first heater element, and the second heater element, a first power being the power supplied from the DC power supply to the first heater element when the first switch control unit keeps the first transistor and the second transistor continuously fully on; and a second power being the power supplied from the DC power supply to the first heater element and the second heater element when the second switch control unit keeps the first transistor continuously fully on and the second transistor continuously off, wherein the first power is greater than the second power.

6. 6. The heater device according to claim 4, wherein the second heater element is a PTC heater whose electrical resistance increases as the temperature increases.

7. 6. The heater device according to claim 4, wherein the first heater element and the second heater element are each made of copper.

8. A flexible substrate (31) having flexibility is provided.

6. The heater device according to claim 4, wherein the first heater element and the second heater element are each formed along one surface of the flexible substrate.

9. 6. The heater device according to claim 4, wherein the first heater element and the second heater element each generate radiant heat when the current flows through them.

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