JP4474765B2 - Chip-type composite electronic components, temperature sensors, and electronic equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a chip-type composite electronic component including an NTC thermistor, a temperature sensor using the same, and an electronic apparatus.
[0002]
[Prior art]
With reference to FIGS. 7 to 9, an example of using an NTC (negative characteristic) thermistor having a characteristic (NTC characteristic) in which the resistance value decreases as the temperature rises will be described.
[0003]
FIG. 7 shows an internal circuit of an electronic device that detects and displays a temperature and compensates for the temperature. 1 is a temperature detection circuit, 2 is an A / D converter, and 3 is a liquid crystal drive. A circuit 4 is a liquid crystal display circuit. The temperature detection circuit 1 has a fixed resistor 5 connected to the power supply side and an NTC thermistor 6 connected to the ground side, and the fixed resistor 5 and the NTC thermistor 6 are connected in series to form a voltage dividing circuit. The divided voltage Vout can be input to the A / D converter 2 from the voltage dividing point 7. The divided voltage Vout from the temperature detection circuit 1 decreases as the temperature rises due to the NTC characteristics of the NTC thermistor 6 as shown in FIG. 8, and includes temperature information.
[0004]
The divided voltage Vout from the temperature detection circuit 1 is converted into a digital signal by the A / D converter 2 as temperature information and input to the liquid crystal drive circuit 3 and displayed on the liquid crystal display circuit 4. Here, the A / D converter 2, the liquid crystal drive circuit 3, and the liquid crystal display circuit 4 constitute a temperature signal processing circuit that performs processing using the divided voltage Vout from the temperature detection circuit 1 as a temperature signal.
[0005]
And in the said electronic device, among the electronic components which comprise the temperature detection circuit 1, in the component structure, while mounting the NTC thermistor 6 on the sub-substrate 8 side, it is another electronic component which comprises the temperature detection circuit 1. The fixed resistor 5 and the electronic components constituting the A / D converter 2, the liquid crystal drive circuit 3, and the liquid crystal display circuit 4 are mounted on the parent substrate 9 side, and the temperature between the two substrates 8 and 9 is drawn by wiring. The child board 8 on which the electronic components for the detection circuit 1 are mounted can be arranged in the vicinity of the object to be temperature-detected so that accurate temperature information for the temperature detection object can be obtained as much as possible. .
[0006]
By the way, as shown in FIG. 9, in the case of the NTC thermistor 6 mounted on the sub-board 8, the NTC thermistor 6 is exposed to ESD (electrostatic discharge) exceeding 10 kV in order to be placed near the temperature detection target. In order to prevent the characteristics from deteriorating, a protective element such as a varistor 10 is connected in parallel to the NTC thermistor 6. Further, a bypass capacitor 11 is provided in parallel with the NTC thermistor 6 in order to suppress transient fluctuations in the divided voltage Vout and to absorb fluctuations in input impedance accompanying the integration operation of the A / D converter 2. Connected.
[0007]
In this case, in general, the varistor 10 is mounted on the child board 8 side and the bypass capacitor 11 is mounted on the parent board 9 side.
[0008]
[Problems to be solved by the invention]
In the case of the above conventional example, each of the NTC thermistor 6, the varistor 10, and the bypass capacitor 11 is configured as an individual component. Therefore, the number of components is at least three, resulting in an increase in component costs and the number of components. Therefore, the mounting work of components on the boards 8 and 9 is increased, the mounting cost is increased, and the mounting space is further increased, thereby inhibiting the downsizing of the electronic device.
[0009]
Therefore, this invention makes it the subject which should be solved to reduce the number of parts of the varistor and bypass capacitor connected to an NTC thermistor.
[0010]
[Means for Solving the Problems]
(1) The chip-type composite electronic component of the present invention includes a first chip body that imparts NTC thermistor characteristics, and a relative dielectric constant that is necessary for forming a capacitance that imparts varistor characteristics and corresponds to a bypass capacitor. At least a second chip body having a structure in which both chip bodies are laminated, and an NTC thermistor, a varistor, and a bypass capacitor are connected in parallel by an electrical equivalent circuit by the laminated structure. It constitutes an integrated part.
[0011]
According to the chip-type composite electronic component of the present invention, the NTC thermistor, the varistor, and the bypass capacitor each have a function as a single unit. Therefore, the number of components is one as compared with the conventional individual component configuration having these functions. Parts cost can be greatly reduced. In addition, since the number of parts is small, the mounting work of the parts on the board can be reduced, and the mounting cost can be greatly reduced. Furthermore, the mounting space can be reduced, and the electronic equipment for mounting them can be downsized. Can promote. In particular, in the case of the chip-type composite electronic component of the present invention, the second chip body has two functions, that is, a varistor function and a bypass capacitor function by electrostatic capacity. Therefore, it is possible to further reduce the size of an electronic device on which these are mounted.
[0012]
Incidentally, in Japanese Patent Application No. 5-69666 (Japanese Patent Laid-Open No. 6-283301), a plurality of chip-type electronic components were selected from the group of chip-type resistors, chip-type thermistors, chip-type capacitors, and chip-type varistors. There is provided a chip-type composite electronic component that is two or more types of chip-type electronic components. However, there is no disclosure of the structure of the chip-type varistor regarding the chip-type composite electronic component according to this provision, and it is more like the present invention. Furthermore, there is no description or suggestion of a second element body having a relative dielectric constant that forms a required capacitance corresponding to a bypass capacitor.
[0013]
In the case of the present invention, although there are two chip bodies, it is possible to provide a component having a function equivalent to connecting an NTC thermistor, a varistor, and a bypass capacitor in parallel. It can be made thinner and smaller than the three-layered structure of the thermistor, varistor, and bypass capacitor, and can further contribute to the miniaturization of electronic equipment.
[0014]
(2) The temperature sensor of the present invention includes a chip-type composite electronic component and a sub-board on which the chip-type composite electronic component is mounted. The chip-type composite electronic component is a first that imparts NTC thermistor characteristics. A structure in which at least a chip body and a second chip body having a relative dielectric constant necessary for forming a capacitance corresponding to a bypass capacitor and having varistor characteristics are laminated. In addition, the laminated structure constitutes an integrated part in which an NTC thermistor, a varistor, and a bypass capacitor are connected in parallel in an electric equivalent circuit.
[0015]
According to the temperature sensor of the present invention, the chip-type composite electronic component has the functions of the NTC thermistor, the varistor, and the bypass capacitor based on the capacitance of the varistor. Compared with a conventional configuration using a substrate, the substrate size is reduced, and the electronic equipment on which the substrate is mounted can be reduced in size.
[0016]
(3) The electronic device of the present invention is an electronic device including a sub board and a parent board that is connected to the sub board by wiring and on which a temperature signal processing circuit is mounted. A chip-type composite electronic component is mounted. In this chip-type composite electronic component, an NTC thermistor and a varistor having a relative dielectric constant necessary for forming a capacitance corresponding to a bypass capacitor are electrically connected in parallel to each other. A fixed resistor that forms a voltage dividing circuit together with the NTC thermistor is mounted on the parent substrate by being connected in series with the NTC thermistor. The fixed resistor is connected to the power supply side, and the NTC thermistor mounted on the sub-board is connected to the ground side, and a temperature signal is sent from the voltage dividing point of the voltage dividing circuit to the temperature. Those that can be input configured to a signal processing circuit.
[0017]
According to the electronic device of the present invention, since the chip-type composite electronic component having the functions of the NTC thermistor, the varistor, and the bypass capacitor based on the capacitance of the varistor is mounted on the sub board, the varistor part is mounted on the sub board side. As a result, the number of bypass capacitor parts mounted on the parent board side is reduced, making it unnecessary to mount and reducing the mounting space, resulting in a compact overall configuration. Compared with this, it is possible to promote price reduction and downsizing.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, details of the present invention will be described based on embodiments shown in the drawings.
[0019]
1 to 3 relate to an embodiment of the present invention, FIG. 1 is a perspective view of a chip-type composite electronic component, FIG. 2 is a cross-sectional view of the chip-type composite electronic component shown in FIG. 1, and FIG. FIG. 2 is an electrical equivalent circuit diagram of the chip-type composite electronic component shown in FIG. 1.
[0020]
With reference to these drawings, the chip-type composite electronic component 20 of the present embodiment has a rectangular parallelepiped shape, the NTC thermistor chip body 21 as the first chip body, and the second disposed on both sides thereof. It has a laminated structure with two varistor chip bodies 22 and 23 as chip bodies.
[0021]
The NTC thermistor chip body 21 is a sheet-like sintered body composed of a plurality of types of oxides of transition metal elements such as nickel, cobalt, and copper.
[0022]
The varistor chip bodies 22 and 23 are semiconductor ceramic sheet-like sintered bodies containing zinc oxide as a main component, and zinc oxide as a constituent material thereof has a relative dielectric constant of about εr200. It has a capacitance of about 1000 pF corresponding to the capacitance.
[0023]
The first to fifth internal electrodes 24 to 28 are provided inside the NTC thermistor chip body 21 and both varistor chip bodies 22 and 23, and the first, third and fifth internal electrodes 24, 28 are provided. 26 and 28 are connected to the external electrode 29 on one side, and the second and fourth internal electrodes 25 and 27 are connected to the external electrode 30 on the other side.
[0024]
In the case of the chip-type composite electronic component 20 having the above-described configuration, the NTC thermistor 6, the varistor 10, and the varistor 10 are equivalently composed of an NTC thermistor chip body 21 and both varistor chip bodies 22 and 23. The bypass capacitor 11 having electrostatic capacity is connected in parallel.
[0025]
In the case of the above-described chip-type composite electronic component 20, the NTC thermistor chip body 21 provides the function of the NTC thermistor 6 while being in the form of a single structure composed of two chip bodies, and the varistor chip body 22. , 23 can provide the functions of the varistor 10 and the bypass capacitor 11, so that only one component is required compared to the conventional individual component configuration having these functions, and the component cost is greatly reduced. Can do.
[0026]
With reference to FIG. 4, the configuration of an electronic device on which the chip-type composite electronic component 20 is mounted will be described. FIG. 4 shows an internal circuit of an electronic device that performs temperature display and temperature adjustment, and the same reference numerals are given to portions corresponding to those in FIG.
[0027]
In FIG. 4, 1 is a temperature detection circuit, 2 is an A / D converter, 3 is a liquid crystal drive circuit, and 4 is a liquid crystal display circuit.
[0028]
The temperature detection circuit 1 includes a fixed resistor 5 connected to the power supply side + Vcc and an NTC thermistor 6 connected to the ground side. The fixed resistor 5 and the NTC thermistor 6 are connected in series to form a voltage dividing circuit. The divided voltage Vout can be input to the A / D converter 2 from the voltage dividing point 7. The divided voltage Vout from the temperature detection circuit 1 decreases as the temperature rises as shown in FIG. 8 due to the NTC characteristics of the NTC thermistor 6.
[0029]
The divided voltage Vout from the temperature detection circuit 1 is converted into a digital signal by the A / D converter 2 as a temperature signal and input to the liquid crystal driving circuit 3 and displayed on the liquid crystal display circuit 4.
[0030]
A varistor 10 and a bypass capacitor 11 are connected in parallel to the NTC thermistor 6.
[0031]
In the case of this embodiment, as an electronic component constituting such a circuit configuration, the NTC thermistor 6, the varistor 10, and the bypass capacitor 11 are integrally configured by a single chip-type composite electronic component 20 to constitute a temperature sensor. On the other hand, the fixed resistor 5, the A / D converter 2, the liquid crystal drive circuit 3, and the liquid crystal display circuit 4 are mounted on the parent substrate 9 while being mounted on the sub-substrate 8.
[0032]
The boards 8 and 9 are connected by wiring 30 and the sub board 8 can be arranged as a temperature sensor in the vicinity of the object to be detected for temperature detection as much as possible. Accurate temperature information is obtained by the NTC thermistor 6 constituting all the chip-type composite electronic components 20.
[0033]
In the electronic device, a board device composed of the sub board 8 and the main board 9 is built in, and in terms of the circuit, the NTC thermistor 6, the varistor 10, and the bypass capacitor 11 have one component. Since it is mounted on the sub board 8, the sub board 8 reduces the mounting work and the mounting space of the varistor 10, and the main board 9 reduces the mounting work and the mounting space of the bypass capacitor, thereby greatly reducing the mounting cost. It is possible to reduce the mounting space, and to promote the reduction in price and size of the electronic device in which the mounting space is reduced.
[0034]
The present invention is not limited to the above-described embodiment, and various applications and modifications are possible.
[0035]
(1) The chip-type composite electronic component 20 of the above-described embodiment is configured by providing the varistor chip bodies 22 and 23 on both sides of the NTC thermistor chip base 21, but the chip-type composite electronic component shown in FIG. As in 20 ′, either one of the varistor chip bodies 22 may be provided, and the NTC thermistor chip bodies 21, 21 may be provided on both sides of the varistor chip body 22.
[0036]
The chip-type composite electronic component 20 ′ of FIG. 5 also has an electrical equivalent circuit similar to that of FIG. 3, and has the same effects as the chip-type composite electronic component 20 of the above-described embodiment.
[0037]
In each of the above-described embodiments, there are three chip bodies. Since two chip bodies are the same, the NTC thermistor and the varistor are substantially composed of two chip bodies. It is possible to provide a component having a function equivalent to that in which a bypass capacitor is connected in parallel, and it is possible to further reduce the thickness and size of the multilayer structure of an NTC thermistor, a varistor, and a bypass capacitor. This can further contribute to downsizing of electronic devices.
[0038]
(2) The chip-type composite electronic component 20 of the above-described embodiment is composed of three chip bodies of the NTC thermistor chip base 21 and the varistor chip bases 22 and 23. As shown by the component 20 ″, a two-layer structure of an NTC thermistor chip body 21 and an NTC thermistor chip body 21 may be used.
[0039]
The chip-type composite electronic component 20 ″ of FIG. 6 also has an electrical equivalent circuit similar to that of FIG. 3, and has the same effect as the chip-type composite electronic component 20 of the above-described embodiment.
[0040]
(3) In the case of the chip-type composite electronic component 20 of the above-described embodiment, the NTC thermistor chip body 21 has a room temperature resistance value of 10 kΩ and the varistor chip bodies 22 and 23 have a capacitance of 1000 pF. With the cutoff frequency of kHz, it is possible to configure a filter that removes noise generated during input switching in the successive approximation A / D converter 2 and switching noise in the power supply line.
[0041]
【The invention's effect】
As described above, according to the chip-type composite electronic component of the present invention, the ratio of the first chip body that imparts the characteristics of the NTC thermistor and the capacitance that imparts the characteristics of the varistor and that corresponds to the bypass capacitor. It has at least a second chip body having a dielectric constant, and has a structure in which both chip bodies are stacked in a state of being electrically connected in parallel with each other. Therefore, an NTC thermistor, a varistor, and a bypass capacitor are used alone. Each function can be provided, and the number of parts can be reduced to one compared with the conventional individual part configuration having these functions, thereby significantly reducing the part cost. In addition, since the number of parts is small, the work for mounting each of these NTC thermistors, varistors and bypass capacitors on the board can be reduced, and the mounting cost can be greatly reduced, and the mounting space for the parts is also reduced. Therefore, the downsizing of electronic devices equipped with these can be promoted.
[Brief description of the drawings]
1 is a perspective view of a chip-type composite electronic component according to an embodiment of the present invention. FIG. 2 is a sectional view of the chip-type composite electronic component of FIG. 1. FIG. 3 is an electrical equivalent of the chip-type composite electronic component of FIG. 4 is a circuit diagram of an electronic apparatus using the chip-type composite electronic component of FIG. 1. FIG. 5 is a cross-sectional view of a chip-type composite electronic component according to another embodiment of the present invention. FIG. 7 is a circuit diagram of a conventional electronic device. FIG. 8 is a voltage-temperature characteristic diagram of the NTC thermistor in FIG. 7. FIG. 9 is a varistor for the NTC thermistor in FIG. And parallel circuit diagram of bypass capacitor [Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Temperature detection circuit 2 A / D converter 5 Fixed resistor 6 NTC thermistor 7 Voltage dividing point 8 Sub board 9 Parent board 20 Chip type composite electronic component 21 NTC thermistor chip body (first chip body)
22, 23 Varistor chip body (second chip body)

Claims (3)

At least a first chip element that imparts the characteristics of an NTC thermistor and a second chip element that imparts the characteristics of a varistor and has a relative dielectric constant necessary for forming a required capacitance corresponding to a bypass capacitor. In addition, both chip bodies are structured to be laminated, and the laminated structure constitutes an integrated part in which an NTC thermistor, a varistor, and a bypass capacitor are connected in parallel by an electric equivalent circuit. A chip-type composite electronic component. A chip-type composite electronic component and a sub-board on which the chip-type composite electronic component is mounted. The chip-type composite electronic component provides a first chip body that provides NTC thermistor characteristics, and varistor characteristics. And at least a second chip element having a relative dielectric constant necessary for forming a capacitance corresponding to the bypass capacitor, and the two chip elements are laminated, and the laminated structure A temperature sensor characterized by comprising an integrated part in which an NTC thermistor, a varistor, and a bypass capacitor are connected in parallel in an electrical equivalent circuit. In an electronic device comprising a daughter board and a mother board that is connected to the daughter board by wiring and on which a temperature signal processing circuit is mounted,
A chip-type composite electronic component is mounted on the sub-board. The chip-type composite electronic component includes an NTC thermistor and a varistor having a relative dielectric constant necessary for forming a required capacitance corresponding to a bypass capacitor. And have a structure in which they are electrically connected in parallel to each other and stacked and integrated,
A fixed resistor that constitutes a voltage dividing circuit together with the NTC thermistor is mounted on the parent substrate in series with the NTC thermistor, and the fixed resistor is connected to the power source side, and An electronic device characterized in that an NTC thermistor mounted on the sub-board is connected to the ground side, and a temperature signal can be input to the temperature signal processing circuit from a voltage dividing point of the voltage dividing circuit. .

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