JP2014229829A - Electronic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently dissipate the heat of any electronic component belonging to any circuit block, by a common pattern, while avoiding generation of noise due to interference of the ground potential between the circuit blocks configured on a circuit board.SOLUTION: In an electronic device including a circuit board (100) and a connector (102), the circuit board includes a heat transmission pattern (116) formed in a state of being electrically independent of an electronic circuit configured on the circuit board. The heat transmission pattern is thermally connected with at least one electrical component (e.g., 118a) constituting the electronic circuit, and mechanically connected with the connector pin (134) of the connector.

Description

  The present invention relates to an electronic device using an electrical component that generates heat, such as a transistor, and more particularly to an electronic device that can efficiently dissipate heat generated from the electrical component to the outside of the device.

  Conventionally, as a device that can dissipate heat from an electrical component that generates heat such as a transistor to the outside of the housing, an electrical component that constitutes an electronic circuit, and a connector that connects the electronic circuit to a wire harness outside the device itself , And a heat conduction pattern (an endothermic pattern and a heat transfer pattern) formed on the printed board to transmit heat generated from the electrical component to the vicinity of the connector pin of the connector. A control device is known (see Patent Document 1).

  In this control device, the heat conduction pattern is connected to the ground, and a capacitor is mounted between the heat conduction pattern and the connector pin. Thereby, the heat of the heat conduction pattern is transmitted to the connector pin via the capacitor and the printed board material, and noise flowing from the connector is removed to the ground line via the capacitor and the heat conduction pattern. Then, the heat conducted to the connector pin is finally conducted to the wire harness outside the device casing, and is radiated toward the outside of the device.

  However, although the heat conduction pattern in the control device is formed independently of the wiring pattern, it is electrically connected to the ground line and connected to the connector pin connected to the signal line via an AC capacitor. It is part of the electric circuit because it is connected to. For this reason, a certain restriction is imposed on the arrangement and configuration of the heat conduction pattern as the ground pattern from the viewpoint of noise reduction of the electronic circuit formed on the printed circuit board.

  In general, an electronic circuit is composed of various functionally independent circuit blocks such as an analog circuit, a digital circuit, and a power supply circuit. For example, a control circuit that controls a large current load such as an actuator according to an input from a sensor normally has a small signal analog circuit that amplifies a small signal input from the sensor and a digital signal that is the amplified analog signal. A digital circuit that performs conversion and arithmetic processing, and an analog drive circuit that converts the digital signal after the calculation into an analog signal to drive the actuator. In order to reduce signal interference between these multiple circuit blocks, a signal ground (SG, Signal Ground) for a small signal analog circuit and a logic ground (LG for a digital circuit) are usually provided on a printed circuit board. , Logic Ground) and a power ground (PG, Power Ground) for an analog drive circuit are individually provided.

  For this reason, when it is intended to apply the above-described conventional heat dissipation configuration to a device composed of a plurality of circuit blocks as described above, a heat conduction pattern connected to any type of ground is connected to any connector pin via a capacitor. From the viewpoint of noise reduction, depending on the type of ground to which the heat conduction pattern is connected, the heat conduction pattern is connected to a connector pin that transmits a signal according to the type of the ground. (For example, when a heat conduction pattern is connected to SG, it is connected to a sensor signal connector pin, when connected to LG, it is connected to a logic signal connector pin, and when connected to PG, it is a drive signal. The heat conduction pattern is connected to the connector pin for use).

  On the other hand, from the viewpoint of heat dissipation, for example, in a digital circuit, heat from a processor (which generates larger heat as the processing speed increases) is required, and in a drive circuit, heat from a power transistor is required. In some cases, even in a small-signal analog circuit, for example, heat dissipation (temperature stabilization) of the operational amplifier may be necessary to stabilize the characteristics of the operational amplifier.

  In this case, for example, if the heat conduction pattern connected to the PG for the drive circuit through which a large current flows is formed to the immediate vicinity of the processor or the operational amplifier for heat dissipation of the processor or the operational amplifier, the potential variation of the PG causes the There may occur a situation in which noise is induced in a signal handled by a processor or an operational amplifier. Further, if the heat conduction pattern connected to SG is formed to the vicinity of the power transistor for heat dissipation of the power transistor constituting the drive circuit, a large current signal handled by the power transistor causes the SG to pass through the heat conduction pattern. A situation that induces noise can occur.

  For this reason, from the viewpoint of noise reduction, it is necessary to form a dedicated heat conduction pattern for radiating electric components related to each ground for each type of ground.

  As a result, the number of heat conduction patterns formed on the printed circuit board increases, and as described above, the connector pins to be connected via the capacitors are also limited for each heat conduction pattern. The degree of freedom of arrangement of wiring patterns and electrical parts is greatly limited.

  If the capacitor that connects the heat conduction pattern and the connector pin is removed to avoid the above-mentioned noise problem, the heat flow from the heat conduction pattern to the connector pin is the heat conduction through the printed circuit board material. Will depend only on. As a result, the thermal resistance between the heat conduction pattern and the connector pin is greatly increased, the heat radiation efficiency is greatly reduced, and the heat conduction pattern formed up to occupying the corresponding area becomes meaningless. Things can happen.

JP 2001-68879 A

  Due to the above background, the heat generated from any electrical component belonging to any circuit block is reduced to the common heat while avoiding the generation of noise due to interference of ground potential between circuit blocks configured on the printed circuit board. Realization of an electronic device that can efficiently dissipate heat by a transmission pattern is desired.

The present invention is an electronic device including a circuit board and a connector, and the circuit board includes a heat transfer pattern formed electrically independent from the electronic circuit configured on the circuit board. The heat transfer pattern is thermally connected to at least one electrical component constituting the electronic circuit and mechanically connected to a connector pin of the connector.
One aspect of the present invention is an electronic device further including a housing that houses the circuit board, and the heat transfer pattern is further thermally connected to a screw that fixes the circuit board to the housing. Alternatively, the heat transfer pattern portion on the circuit board is thermally connected to the casing by being gripped by the casing.
Another aspect of the present invention is an electronic device including at least two of the heat transfer patterns, and each of the heat transfer patterns is mechanically connected to a different connector pin of the connector, and at least the adjacent heat heat patterns. The transfer patterns are thermally connected by a heat conductive member having a predetermined electric resistance value that limits a current flowing between the adjacent heat transfer patterns or a heat conductive member having electrical insulation. Yes.
According to another aspect of the present invention, the thermally conductive member is made of ceramic.
According to another aspect of the present invention, a ground pattern connected to the ground of a power source is formed on the circuit board, and a part of the outer periphery of the heat transfer pattern and a part of the outer periphery of the ground pattern However, it is formed to run in parallel at a predetermined distance over a section having a predetermined length.
According to another aspect of the present invention, a part of the outer periphery of the heat transfer pattern running in parallel in the section and a part of the outer periphery of the ground pattern are each formed in a sawtooth shape that meshes with each other.
According to another aspect of the present invention, a part of the outer periphery of the heat transfer pattern running in parallel in the section and a part of the outer periphery of the ground pattern are formed in a comb shape that meshes with each other.
According to another aspect of the invention, the heat transfer pattern is thermally connected to thermally passive electrical components that make up the electronic circuit.
According to another aspect of the invention, the thermally passive electrical component is an electrolytic capacitor.
According to another aspect of the invention, the electronic device is an electronic control device that controls the operation of the vehicle.

  According to the present invention, heat generated from any electrical component belonging to any circuit block can be shared while avoiding the generation of noise due to the interference of the ground potential between the circuit blocks configured on the printed circuit board. The heat transfer pattern can efficiently dissipate heat.

It is a figure which shows the structure of the electronic device which concerns on the 1st Embodiment of this invention. It is a figure which shows the structure of the electronic device which concerns on the 2nd Embodiment of this invention. It is a figure which shows the structure of the electronic device which concerns on the 3rd Embodiment of this invention. It is a figure which shows the structure of the electronic device which concerns on the 4th Embodiment of this invention. It is a figure which shows the structure of the electronic device which concerns on the 5th Embodiment of this invention. It is a figure which shows the structure of the electronic device which concerns on the 6th Embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the drawings.

[First Embodiment]
FIG. 1 is a diagram showing a configuration of an electronic device according to the first embodiment of the present invention.
The electronic device 10 is, for example, an electronic control unit (ECU, Electronic Control Unit) that is mounted on a vehicle and controls the operation of the vehicle, and a circuit board 100 that is a printed circuit board on which electronic components that constitute an electronic circuit are mounted. A connector 102 mounted on the circuit board 100, and a housing 104 that houses the circuit board 100 and the connector 102. Note that since the circuit board 100 is accommodated in the housing 104, the circuit board 100 cannot be visually recognized from the outside of the housing 104. However, in FIG. The part shown is also shown using a solid line.

  The circuit board 100 can be, for example, a double-sided board in which a circuit pattern is formed on the front and back of a single board, or a multilayer board in which a plurality of boards are stacked. Note that the surface of the circuit board 100 shown in FIG. 1 is the front surface (front surface) of the circuit board 100.

  The housing 104 is provided with flanges 106 and 108 on the outer surface thereof. The housing 104 and the flanges 106 and 108 are made of a conductive material such as metal (for example, aluminum). The housing 104 is mechanically fixed to the vehicle body 110 by the flanges 106 and 108 and is attached to the vehicle body 110. It is electrically connected. The vehicle body 110 is connected to a ground terminal of a power supply device (not shown) (hereinafter also simply referred to as “power supply”) that supplies power to an electronic circuit on the circuit board 100.

  An external connector 112 fitted to the connector 102 is connected to the connector 102 mounted on the circuit board 100. As a result, the electronic circuit on the circuit board 100 is electrically connected to, for example, a power source or other equipment placed outside the electronic device 10 via the external connector 112 and the wire harness 114 connected to the external connector 112. Connected.

  On the circuit board 100, for example, resistors 118a and 118b, regulators 120a and 120b, logic ICs 122a and 122b, and a processor 124 are mounted. Note that these electrical components are examples of electrical components that constitute an electronic circuit on the circuit board 100, and any electrical component can be used depending on the function or application of the electronic circuit.

  A heat transfer pattern 116 is formed on the circuit board 100, and the resistors 118 a and 118 b and the logic ICs 122 a and 122 b are mounted such that part of their outer surfaces are in contact with the heat transfer pattern 116. Further, the regulators 120a and 120b are mounted on the circuit board 100 so that the heat radiator and the heat transfer pattern 116 provided therein are in contact with each other. The contact between each electrical component and the heat transfer pattern 116 is an example of a means for thermally connecting each electrical component and the heat transfer pattern 116, as long as the thermal connection is established. 2, a method other than contact (for example, application of heat radiation grease to a gap portion between the heat conduction pattern 116 and each electrical component) can be used in combination or alternatively.

  A heat transfer pattern 126 indicated by a dotted-line rectangle is formed on the circuit board 100 (surface (front surface)) immediately below the processor 124, and the processor 124 has a part of the lower surface thereof in the heat transfer. It is mounted so as to be in contact with the pattern 126. Furthermore, the heat transfer pattern 126 is thermally connected to the heat transfer pattern 130 indicated by a dashed line in the figure formed on the back surface of the circuit board 100 through five vias 128 indicated by a dotted circle in the figure. The heat transfer pattern 130 is thermally connected to the heat transfer pattern 116 through five vias 132 indicated by black circles in the drawing. Thus, the heat generated from the processor 124 is transferred to the heat transfer pattern 116 formed on the surface of the circuit board 100 through the heat transfer pattern 126, the via 128, the heat transfer pattern 130, and the via 132.

  The heat transfer pattern 116 is connected to a connector pin 134 of the connector 102 that is electrically independent of an electronic circuit on the circuit board 100 (that is, does not constitute the electronic circuit) by, for example, soldering. The soldering is an example of a configuration for mechanically coupling (connecting) the heat transfer pattern 116 and the connector pin 134 to reduce thermal resistance and establish good heat transfer. In other words, other methods (for example, pressing contact using the spring property of the connector pin, fitting with a metal sleeve mounted on the heat transfer pattern 116, etc.) can be used.

  A lead wire 136 is connected to the connector pin 134 via a connector pin (not shown) of the corresponding external connector 112, and the lead wire 136 is pulled out from an intermediate portion of the wire harness 114 to the outside via the terminal 140. And connected to the vehicle body 110.

  As a result, the heat generated from the resistors 118a and 118b, the regulators 120a and 120b, the logic ICs 122a and 122b, and the processor 124 flows into the connector pins 134 from the heat transfer pattern 116, and then corresponds to the external connector 112. The heat is radiated by flowing into a heat transfer path (the dotted line portion denoted by reference numeral 138) formed by the connector pin and the lead wire 136 in the wire harness 114. Further, the heat flowing into the lead wire 136 is finally radiated toward the vehicle body 110.

  Here, each of the heat transfer patterns 116, 126, and 130 formed on the circuit board 100 is formed electrically independently from the electronic circuit configured on the circuit board 100. That is, the heat transfer pattern 116 is not directly or indirectly connected to any of the electrical terminals of the electrical components constituting the electronic circuit, and is connected to both the DC and the AC. Absent. In other words, the heat transfer pattern 116 does not constitute a DC current path of the electronic circuit and does not constitute an AC current path.

  That is, the heat transfer patterns 116, 126, and 130 in the electronic device 10 are connected via the capacitors to the connector pins connected to the signal lines as in the heat transfer pattern in the conventional heat dissipation configuration described above. It does not constitute a part of the alternating current path. For this reason, in this electronic device 10, electric components that require heat dissipation are provided for all circuit blocks configured with different ground patterns, such as power supply circuits, analog circuits, digital circuits, and drive circuits configured on the circuit board 100 Regardless of which circuit block it belongs to, a common heat transfer pattern 116 (more precisely, a series of heat transfer patterns 116, 126, 130).

  The heat transfer pattern 116 is electrically connected to a ground terminal of a power source (not shown) via the lead wire 136 and the vehicle body 110, but the connector pin and the electric circuit constituting the electronic circuit on the circuit board 100 are electrically connected. The terminal of the component is not connected at all in direct current or alternating current. For this reason, although the heat transfer pattern 116 has the same potential as the vehicle body 110, it does not constitute a DC current path of the electronic circuit and does not constitute an AC current path.

  Further, in the electronic device 10, as described above, the heat transfer pattern 116 is mechanically connected to the connector pin 134 by soldering or the like. That is, in this electronic apparatus 10, the heat transfer pattern is formed to the vicinity of the connector pin as in the conventional case, and the heat of the heat transfer pattern is not transferred to the connector pin via the capacitor or the printed circuit board material. The heat of 116 is directly transmitted to the connector pin 134 through the mechanical connection portion, and is radiated toward the lead wire 136 of the wire harness 114. For this reason, in this electronic device 10, the heat dissipation effect can be enhanced in each stage as compared with the conventional one.

  In the present embodiment, the heat transfer pattern 116 is connected to the vehicle body 110 and connected to the power supply ground as described above. However, the present invention is not limited to this, and the heat transfer pattern 116 is electrically connected to the power supply. It can also be connected to an independent structure. In this case, the connector pin 134 to which the heat transfer pattern 116 is connected may constitute a part of the electronic circuit on the circuit board 100. Even in such a configuration, the heat transfer pattern 116 does not constitute a direct current path of the electronic circuit, nor does it constitute an alternating current path. However, from the viewpoint of reducing noise applied to the electronic circuit, it is generally desirable to avoid connecting a heat transfer pattern to a connector pin through which an input signal is propagated, for example.

  In the present embodiment, one connector pin 134 is connected to the heat transfer pattern 116. However, the number of connector pins to be connected is not limited to one and may be plural. However, each connector pin to which the heat transfer pattern 116 is connected needs to satisfy the condition that it does not electrically form part of the electronic circuit.

  Further, in the present embodiment, the heat transfer patterns 116, 126, and 130 are provided on the front surface or the back surface of the circuit board 100. However, the present invention is not limited to this, and the heat transfer pattern may be formed on the inner layer of the circuit board. Good. If a heat transfer pattern is formed on the front or back surface of the circuit board 100 as in this embodiment, heat can be released by heat radiation from the heat transfer pattern to the air, but the temperature inside the housing 104 is increased. It becomes. On the other hand, when a heat transfer pattern is provided in the inner layer of the circuit board 100, a heat dissipation effect due to heat radiation to the air cannot be expected, but the temperature rise inside the housing 104 is reduced and the housing 104 is exposed to the outside. Heat can be dissipated.

  Moreover, in the electronic device 10 according to the present embodiment, one continuous heat transfer pattern configured by the heat transfer patterns 116, 126, and 130 is used. A plurality of independent heat transfer patterns may be used. In this case, each of a plurality of “continuous heat transfer patterns” can collect heat from any of a plurality of electrical components belonging to different circuit blocks.

  In this case, the plurality of “continuous heat transfer patterns” can be commonly connected to one or a plurality of connector pins, and the plurality of “continuous heat transfer patterns” can be different from each other. Alternatively, it can be connected to a plurality of connector pins. In the latter case, restrictions on the connector pins to which the heat transfer pattern is to be connected are relaxed, so that the degree of freedom of arrangement of the heat transfer pattern on the circuit board can be improved.

[Second Embodiment]
Next, an electronic device according to a second embodiment of the present invention will be described.
In the electronic device according to the present embodiment, the independent continuous heat transfer pattern is formed so as to extend to the screw portion that fixes the circuit board to the housing, and the heat transfer pattern and the screw are thermally connected. By being connected to, the heat transfer pattern and the housing are thermally connected. As a result, the heat collected in the heat transfer pattern is dissipated toward the wire harness via the connector pins, and is also dissipated toward the housing via the screws, thereby improving the heat dissipation efficiency of the entire electronic device. improves.

  FIG. 2 is a diagram showing a configuration of an electronic device according to the second embodiment of the present invention. In the electronic device 20 shown in FIG. 2, the same components as those of the electronic device 10 according to the first embodiment shown in FIG. 1 are denoted by the same reference numerals as those shown in FIG. The description about FIG. 1 is used.

  The electronic device 20 includes a circuit board 200 instead of the circuit board 100 in the electronic device 10 according to the first embodiment. The circuit board 200 includes a heat transfer pattern 216 instead of the heat transfer pattern 116 according to the first embodiment. The heat transfer pattern 216 has the same configuration as the heat transfer pattern 116 according to the first embodiment, except that it extends to the screw 242 portion that fixes the circuit board 200 to the housing 104. The heat collected in the heat transfer pattern 216 is also transmitted to the housing 104 via the screw 242 in the vicinity of the connector pin 134 by the extended portion, and the heat dissipation efficiency is improved.

  The heat transfer pattern 216 may extend to any one or a plurality of positions of the screws 242 to 248 that fix the circuit board 200. In this case, the heat collected in the heat transfer pattern 216 is radiated to the housing 104 via one or more screws, and the heat radiation efficiency can be further improved.

  In the present embodiment, the heat transfer pattern 216 is thermally connected to the housing 104 via the screw 242. However, the circuit board 200 is not limited to this and is fixed by being gripped by the housing 104. The heat transfer pattern 216 on the circuit board 200 is gripped (sandwiched) by the housing 104, so that the heat transfer pattern 216 and the housing 104 are thermally connected. It is good. Such a structure can be applied, for example, when the housing 104 is configured by two separate upper and lower bodies (for example, a case and a cover) that sandwich the circuit board 200.

  More specifically, in the electronic device 20, the entire or a part of the outer peripheral region of the circuit board 200 is sandwiched between the two separate bodies (that is, grasped by the housing 104), and the circuit board 200 is the housing. It can be configured to be fixed to the body 104. In this case, by forming the heat transfer pattern 216 so as to extend to the portion (grip portion) gripped by the casing 104 in the outer peripheral region of the circuit board 200, the heat transfer pattern via the grip portion is formed. 216 and the housing 104 can be thermally connected. Note that the force with which the housing 104 grips the circuit board 200 can be ensured by the fastening force of the screws, for example, when the two separate bodies are fastened by screws outside the outer periphery of the circuit board 200. it can.

[Third Embodiment]
Next, an electronic device according to a third embodiment of the present invention will be described.
The electronic device 10 according to the first embodiment is configured to use one continuous heat transfer pattern configured by the heat transfer patterns 116, 126, and 130, whereas the electronic device according to the present embodiment. The difference is that two independent heat transfer patterns are used. The two independent continuous heat transfer patterns are connected to different connector pins that do not constitute an electronic circuit. As a result, heat from a plurality of heat generating components dispersed on the circuit board can be dissipated through the connector pins in the vicinity of the components, so that compared to the case where only one independent heat transfer pattern is used. In addition to reducing heat resistance and improving heat dissipation efficiency, it is possible to improve the degree of freedom of arrangement of the heat transfer pattern on the circuit board.

  Furthermore, in the electronic device according to the present embodiment, a heat conductive member having a predetermined electric resistance value that limits a current flowing through the two heat transfer patterns between two independent continuous heat transfer patterns. Alternatively, they are connected by a thermally conductive member having electrical insulation, for example, a ceramic block. This reduces the temperature difference between the two heat transfer patterns via the ceramic block, reduces the thermal stress of the circuit board material, reduces mechanical stress, and reduces the difference in operating temperature between electrical components. The operation of the electronic circuit can be stabilized.

  In addition, by using a ceramic block that is an electrical insulator, two independent continuous heat transfer patterns can be obtained by using two different external structures (for example, a vehicle body and an engine in a vehicle via different connector pins and lead wires). Even when connected to the housing, it is possible to avoid current from flowing between the heat transfer patterns due to the potential difference between the two structures, and to avoid generation of heat and noise due to the current.

  FIG. 3 is a diagram illustrating a configuration of an electronic device according to the third embodiment of the present invention. In the electronic device 30 shown in FIG. 3, the same components as those in the electronic device 10 according to the first embodiment shown in FIG. 1 are indicated by the same reference numerals as those shown in FIG. The description about FIG. 1 is used.

  The electronic device 30 includes a circuit board 300 instead of the circuit board 100 in the electronic device 10 according to the first embodiment. The circuit board 300 has two heat transfer patterns 316a and 316b formed on the surface thereof. These heat transfer patterns 316a and 316b are formed electrically independent of the electronic circuit configured on the circuit board 300, similarly to the heat transfer pattern 116 in the electronic device 10 according to the first embodiment. . That is, the heat transfer patterns 316a and 316b are not directly or indirectly connected to any of the electrical terminals of the electrical components constituting the electronic circuit, and are connected either directly or indirectly. It has not been. Therefore, the heat transfer patterns 316a and 316b do not constitute a DC current path of the electronic circuit and do not constitute an AC current path.

  For this reason, each of the heat transfer patterns 316a and 316b is similar to the heat transfer pattern 116 in the electronic device 10 according to the first embodiment, regardless of which circuit block the electrical component that requires heat dissipation belongs to. Heat from any of a plurality of electrical components belonging to different circuit blocks formed on the substrate 300 can be collected.

  Further, the heat transfer pattern 316a is connected to the connector pins 134 of the connector 102 by, for example, soldering, similarly to the heat transfer pattern 116 of the electronic device 10 according to the first embodiment. Thereby, the heat collected in the heat transfer pattern 316a is radiated toward the lead wire 136, and further radiated to the vehicle body 110 to which the lead wire 136 is connected.

  On the other hand, the heat transfer pattern 316b is connected to another connector pin 334 of the connector 102 that does not constitute an electronic circuit, for example, by soldering. A lead wire 336 is connected to the connector pin 334 via a connector pin (not shown) of the corresponding external connector 112, and the lead wire 336 is pulled out from an intermediate portion of the wire harness 114 and is different from the vehicle body 110. A terminal 340 is connected to an external structure, for example, an engine housing 344.

  As a result, the heat collected in the heat transfer pattern 316b flows into the connector pin 334, and then the heat transfer path (reference numeral 338) configured by the corresponding connector pin of the external connector 112 and the lead wire 336 in the wire harness 114. It flows into the illustrated dotted line part) and is dissipated. Further, the heat flowing into the lead wire 336 is finally radiated toward the engine housing 344.

  With the above configuration, the heat generated from the electrical components mounted on the circuit board 300 is generated from the heat transfer pattern 316a to the vehicle body 110 via the connector pin 134 and the lead wire 136, and from the heat transfer pattern 316b to the connector pin. Since heat is dissipated by two heat transfer paths, that is, a heat transfer path reaching the engine housing 344 via 334 and the lead wire 336, the heat dissipation efficiency is improved as compared with the electronic device 10 according to the first embodiment.

Further, the heat transfer patterns 316a and 316b are thermally connected to each other while ensuring electrical insulation by a thermally conductive member having electrical insulation, for example, a ceramic block 342.
As a result, the temperature difference between the heat transfer patterns 316a and 316b is reduced, the thermal distortion of the circuit board 300 is reduced, and the difference in operating temperature between the electrical components is also reduced, thereby ensuring stable operation of the electronic circuit. .

  In addition, even if there is a potential difference between the vehicle body 110 connected to the heat transfer pattern 316a and the engine casing 344 connected to the heat transfer pattern 316b due to the electrical insulation as described above. The current due to the potential difference does not flow through the heat transfer patterns 316a and 316b, and the generation of Joule heat due to the current is avoided.

  Note that the electrically conductive thermally conductive member for thermally connecting the two heat transfer patterns is not limited to the ceramic block 342, and other members such as heat radiation grease can be used. When the ceramic block 342 is used, for example, a chip capacitor can be used as the ceramic block 342. Further, in place of the ceramic block which is a heat conductive member having electrical insulation, a heat conductive member having a predetermined electric resistance value for limiting the current flowing through the two heat transfer patterns 316a and 316b, for example, the predetermined block A ceramic block having a specific electric resistance value, more specifically, a chip resistor can be used.

  Here, the predetermined electric resistance value is caused by a current flowing through the heat transfer patterns 316a and 316b according to a potential difference assumed between the two external structures to which the heat transfer patterns 316a and 316b are connected. The Joule heat can be set to a resistance value such that the Joule heat is substantially negligible (for example, several percent or less) as compared with the heat generated from the electrical components on the circuit board 300.

  As described above, when a chip capacitor or chip resistor is used as a thermally conductive member having electrical insulation, the chip capacitor or chip resistor is connected to a chip mounter or chip resistor in the same manner as other chip components constituting an electronic circuit. Since it can be automatically mounted using a solder reflow device, it is advantageous in terms of manufacturing cost.

[Fourth Embodiment]
Next, an electronic device according to a fourth embodiment of the present invention will be described.
In the electronic apparatus according to the present embodiment, the heat transfer pattern formed electrically independent from the electronic circuit configured on the circuit board is mechanically connected to the connector pin, and the electronic circuit is configured. It is thermally connected to the ground pattern to ensure electrical insulation.

  Thereby, in the electronic device according to the present embodiment, the heat collected in the heat transfer pattern is dissipated toward the wire harness, and is also dissipated to the air via the ground pattern, or the housing connected to the ground pattern. The heat dissipation efficiency of the entire electronic device can be improved.

  Here, the thermal connection between the heat transfer pattern and the ground pattern is performed, for example, by bringing a part of the outer periphery of the heat transfer pattern and a part of the outer periphery of the ground pattern close to each other with a predetermined distance therebetween. It can be performed by running parallel over the length of. Alternatively, in addition to or instead of this, the thermal connection may be performed by applying heat radiation grease between a part of the outer periphery of the heat transfer pattern and a part of the outer periphery of the ground pattern. it can.

  FIG. 4 is a diagram showing a configuration of an electronic device according to the fourth embodiment of the present invention. In the electronic device 40 shown in FIG. 4, the same components as those of the electronic device 10 according to the first embodiment shown in FIG. 1 are indicated by the same reference numerals as those shown in FIG. The description about FIG. 1 is used.

  The electronic device 40 includes a circuit board 400 instead of the circuit board 100 in the electronic device 10 according to the first embodiment. A heat transfer pattern 416 and a ground pattern 450 are formed on the surface of the circuit board 400.

  Similar to the heat transfer pattern 116 in the electronic device 10 according to the first embodiment, the heat transfer pattern 416 is formed electrically independent of the electronic circuit configured on the circuit board 400. That is, the heat transfer pattern 416 is not directly or indirectly connected to any of the electrical terminals of the electrical components constituting the electronic circuit, and is connected to both DC and AC. Absent. Therefore, the heat transfer pattern 416 does not constitute a DC current path of the electronic circuit and does not constitute an AC current path.

  For this reason, the heat transfer pattern 416 is formed on the circuit board 400 regardless of which circuit block the electrical component requiring heat dissipation belongs to, like the heat transfer pattern 116 in the electronic device 10 according to the first embodiment. It is possible to collect heat from any of a plurality of electrical components belonging to different configured circuit blocks.

  The heat transfer pattern 416 is connected to the connector pins 134 of the connector 102 by, for example, soldering, similarly to the heat transfer pattern 116 of the electronic device 10 according to the first embodiment. Thereby, the heat collected in the heat transfer pattern 416 is radiated toward the lead wire 136 and further radiated to the vehicle body 110 to which the lead wire 136 is connected.

  The ground pattern 450 is electrically connected to the housing 104 via screws 460 and 462 for fixing the circuit board 400 to the housing 104. As a result, the ground pattern 450 is connected to the ground terminal of the power source (not shown) via the housing 104, the flanges 106 and 108, and the vehicle body 110.

  A part of the outer periphery of the heat transfer pattern 416 and a part of the outer periphery of the ground pattern 450 are formed so as to run in parallel in a section 454 having a predetermined length with a predetermined distance therebetween. . As a result, the heat transfer pattern 416 and the ground pattern 450 are thermally coupled while ensuring electrical insulation, and the heat collected in the heat transfer pattern 416 passes through the ground pattern 450 and the housing 104 and the ground pattern 450. Heat is also radiated to the vehicle body 110, and the heat dissipation efficiency is improved.

  Here, the predetermined length can be set as long as possible within a range that does not substantially limit the degree of freedom of other wiring patterns on the circuit board 300, for example. Further, the predetermined distance (that is, the interval) is, for example, that the heat transfer pattern 416 and the ground pattern 450 are thermally coupled to each other with a desired thermal resistance value and are not capacitively coupled (coming to the heat transfer pattern 416). Of the external radiation noise that does not enter the ground pattern 450).

  In addition, heat radiation grease 456 can be applied between the heat transfer pattern 416 and the ground pattern 450. Thereby, the thermal coupling between the heat transfer pattern 416 and the ground pattern 450 can be further strengthened while ensuring the electrical insulation with respect to each other, and the heat dissipation efficiency can be further improved.

[Fifth Embodiment]
Next, an electronic device according to a fifth embodiment of the present invention will be described.
Similar to the electronic device 40 according to the fourth embodiment, the electronic device according to the present embodiment has a heat transfer pattern and a ground pattern on the circuit board, and a part of the outer periphery of the heat transfer pattern and the ground pattern A part of the outer periphery is formed so as to run in parallel with each other at a predetermined distance over a predetermined length section. Further, in the present electronic device, in particular, the shape of the part of the outer periphery of the heat transfer pattern and the part of the outer periphery of the ground pattern in the above section has a saw-tooth shape and / or a comb shape.

  Thus, in the electronic device according to the present embodiment, the heat transfer pattern and the ground pattern are thermally connected to each other by the parallel running section, and the heat collected in the heat conductive ground pattern is enclosed via the ground pattern. Heat is also radiated to the body and the vehicle body, and the heat dissipation efficiency of the entire electronic device can be improved.

  FIG. 5 is a diagram showing a configuration of an electronic device according to the fifth embodiment of the present invention. In the electronic device 50 shown in FIG. 5, the same components as those of the electronic device 10 according to the first embodiment shown in FIG. 1 are denoted by the same reference numerals as those shown in FIG. The description about FIG. 1 is used.

  The electronic device 50 includes a circuit board 500 instead of the circuit board 100 in the electronic device 10 according to the first embodiment. A heat transfer pattern 516 and a ground pattern 550 are formed on the surface of the circuit board 500.

  The heat transfer pattern 516 is formed electrically independent of the electronic circuit configured on the circuit board 500, like the heat transfer pattern 116 in the electronic device 10 according to the first embodiment. That is, the heat transfer pattern 516 is not directly or indirectly connected to any of the electrical terminals of the electrical components constituting the electronic circuit, and is connected to both DC and AC. Absent. Therefore, the heat transfer pattern 516 does not constitute a DC current path of the electronic circuit and does not constitute an AC current path.

  For this reason, the heat transfer pattern 516 is formed on the circuit board 500 regardless of which circuit block the electrical component requiring heat dissipation belongs to, like the heat transfer pattern 116 in the electronic device 10 according to the first embodiment. It is possible to collect heat from any of a plurality of electrical components belonging to different configured circuit blocks.

  The heat transfer pattern 516 is connected to the connector pins 134 of the connector 102 by, for example, soldering, similarly to the heat transfer pattern 116 of the electronic device 10 according to the first embodiment. Thereby, the heat collected in the heat transfer pattern 516 is radiated toward the lead wire 136 and further radiated to the vehicle body 110 to which the lead wire 136 is connected.

  The ground pattern 550 is electrically connected to the housing 104 via screws 560 and 562 for fixing the circuit board 500 to the housing 104. As a result, the ground pattern 550 is connected to the ground terminal of the power source (not shown) via the housing 104, the flanges 106 and 108, and the vehicle body 110.

  A part of the outer periphery of the heat transfer pattern 516 and a part of the outer periphery of the ground pattern 550 are formed in a sawtooth shape that meshes with each other in a section 554 having a predetermined length, and are adjacent to each other with a predetermined distance therebetween. It is formed to run in parallel. Further, a part of the outer periphery of the heat transfer pattern 516 and a part of the outer periphery of the ground pattern 550 are formed in a comb shape that meshes with each other in a section 556 having a predetermined length, and are close to each other with a predetermined distance therebetween. And are formed to run side by side.

  As a result, the heat transfer pattern 516 and the ground pattern 550 are thermally coupled in the sawtooth-shaped portion and the comb-shaped portion. In addition, since the length of the thermal coupling portion is longer than the linear distance between the sections 554 and 556, the thermal resistance between the heat transfer pattern 516 and the ground pattern 550 is the electronic device 40 according to the fourth embodiment. It is reduced compared with the structure which mutually parallelly parallels like. As a result, the heat collected in the heat transfer pattern 516 can be more efficiently transferred to the ground pattern 550 and dissipated to the housing 104 and the vehicle body 110, and the heat dissipation efficiency of the electronic device 50 as a whole is improved. To do.

[Sixth Embodiment]
Next, an electronic device according to a sixth embodiment of the present invention will be described.
In the electronic device in each of the embodiments described above, the outer surface of the electrical component that generates heat is thermally connected to the heat transfer pattern, and the heat generated from the electrical component is collected by the heat transfer pattern via the connector pin. Dissipates heat outside the electronic device. On the other hand, in the electronic device according to the present embodiment, the outer surface of the thermally passive electrical component is thermally connected to the heat transfer pattern.

  Here, the “thermally passive electrical component” is an electrical component that generates less heat than the surrounding electrical component and increases its temperature when the heat generated from the surrounding electrical component is transmitted. This refers to a component, for example, a capacitor, resistor, coil or the like that generates less heat than a semiconductor component, or an operational amplifier that generates less heat than a power transistor used in a power amplifier.

  With the above configuration, in the electronic device, the temperature of the thermally passive electrical component is brought close to the temperature outside the electronic device via the connector pin and the heat transfer pattern, and the temperature of the passive electrical component is changed to the surrounding electrical component. To prevent the heat from rising. As a result, it is possible to stabilize the characteristics of the passive electrical component and to avoid shortening the lifetime (or accelerating degradation) of the electrical component due to a temperature rise.

  For example, electrolytic capacitors widely used in power supply circuits are known to have an exponential shortening of the lifetime as the operating temperature rises, and the lifetime of the capacitor is a major factor that limits the lifetime of electronic devices. It has become one of the. In the electronic device of the present embodiment, for example, the temperature of such an electrolytic capacitor can be prevented from rising due to heat generated from the surrounding electrical components, and the life of the electronic device can be prevented from being shortened.

  FIG. 6 is a diagram showing a configuration of an electronic device according to the sixth embodiment of the present invention. In the electronic device 60 shown in FIG. 6, the same components as those of the electronic device 10 according to the first embodiment shown in FIG. 1 are indicated by the same reference numerals as those shown in FIG. The description about FIG. 1 is used.

  The electronic device 60 includes a circuit board 600 instead of the circuit board 100 in the electronic device 10 according to the first embodiment. The circuit board 600 has heat transfer patterns 116 and 616 formed on the surface thereof. In FIG. 6, in order to facilitate understanding of the relationship between the shape of the heat transfer patterns 616 and 116 and the electrical components, the electrical components mounted on the circuit board 600 are indicated by dotted lines.

  Similar to the heat transfer pattern 116, the heat transfer pattern 616 is formed electrically independent of the electronic circuit configured on the circuit board 600. That is, the heat transfer pattern 616 is not directly or indirectly connected to any of the electrical terminals of the electrical components constituting the electronic circuit, and is connected to both the DC and the AC. Absent. Therefore, the heat transfer pattern 616 does not constitute a DC current path of the electronic circuit and does not constitute an AC current path.

  The heat transfer pattern 616 is connected to the connector pin 634 of the connector 102 that does not constitute an electronic circuit, for example, by soldering. In addition, a lead wire 636 is connected to the connector pin 634 via a connector pin (not shown) of the corresponding external connector 112, and the lead wire 636 is pulled out from the intermediate portion of the wire harness 114 to the terminal 640. For example, it is connected to the vehicle body 110.

  For example, a pattern for mounting a radial type aluminum electrolytic capacitor 642 is formed in the heat transfer pattern 616. That is, the heat transfer pattern 616 has a circular region 644 from which the metal foil portion is removed. Through holes 646 a and 646 b are formed in the circular region 644, and the through-holes on the back side of the circuit board 300 are formed. Lands are formed around the holes 646a and 646b (not shown). The two lead wires of the radial type aluminum electrolytic capacitor 642 pass through the through holes 646a and 646b, respectively, and are soldered to the lands formed on the back surface of the circuit board 300.

  The circular region 644 is formed to be smaller than the diameter of the cylindrical main body portion of the aluminum electrolytic capacitor 642 (the diameter of a circle indicated by a dotted line in the drawing). When the aluminum electrolytic capacitor 642 is mounted, the circular region 644 is formed. A part of the bottom surface of the main body portion is in thermal contact with the heat transfer pattern 616 in contact with the metal foil portion of the heat transfer pattern 616 around the circular region 644.

  As a result, the heat generated from the electrical components inside the electronic device 60 and transmitted to the aluminum electrolytic capacitor 642 (due to thermal radiation, heat conduction through the material part of the circuit board 600 (for example, the glass epoxy part), etc.) Heat is dissipated to the vehicle body 110 through the heat transfer pattern 616, the connector pin 634, and the lead wire 636. As a result, the body temperature of the aluminum electrolytic capacitor 642 approaches the external temperature of the electronic device 60, and the degree of shortening of the life of the aluminum electrolytic capacitor 642 due to the increase in the body temperature is reduced.

  In the present embodiment, the heat transfer pattern 616 is formed so that the main body portion of the aluminum electrolytic capacitor 642 and a part of the heat transfer pattern 616 are in contact with each other. The thermal connection between the electrical component and the heat transfer pattern can be performed by another method, for example, application of heat dissipation grease.

  In the present embodiment, the lead wire 636 is connected to the vehicle body 110. However, the present invention is not limited to this, and the lead wire 636 can be connected to any structure as long as the purpose of heat dissipation is met. For example, when the main body portion of the aluminum electrolytic capacitor is made of metal and the potential of the main body portion is to be floating, the lead wire 636 is not electrically connected to the ground terminal of the power source or the like. Further, it may be connected to a heat sink provided outside the electronic device 60.

  As described above, the electronic device according to the first to sixth embodiments has a circuit board and a connector, and the circuit board is electrically connected to the electronic circuit configured on the circuit board. An independent heat transfer pattern is formed. As a result, in this electronic device, heat from any of a plurality of electrical components belonging to different circuit blocks is dissipated by one common heat transfer pattern regardless of which circuit block the electrical component requiring heat dissipation belongs to. can do. As a result, in this electronic device, since it is not necessary to provide a heat transfer pattern for each circuit block, the number of heat transfer patterns formed on the circuit board can be reduced, and electrical components and wiring on the circuit board can be reduced. The degree of freedom of arrangement of patterns and the like can be improved.

  The heat transfer pattern is mechanically connected to a connector pin that does not constitute an electronic circuit, and is thermally connected to a wire harness outside the device itself via the connector pin. Thereby, in this electronic device, the heat collected by the heat transfer pattern can be efficiently radiated toward the outside of the device itself.

  10, 20, 30, 40, 50, 60 ... electronic device, 100, 200, 300, 400, 500, 600 ... circuit board, 102 ... connector, 104 ... housing, 106, 108 ... Flange, 110 ... Car body, 112 ... External connector, 114 ... Wire harness, 116, 126, 130, 216, 316a, 316b, 416, 516, 616 ... Heat transfer pattern, 118a 118b ... resistors, 120a, 120b ... regulators, 122a, 122b ... logic ICs, 124 ... processors, 128, 132 ... vias, 134, 334, 634 ... connector pins, 136 336, 636 ... lead wire, 140, 340, 640 ... terminal, 242, 244, 246, 248, 460, 4 2, 560, 562... Screw, 342... Ceramic block, 344... Engine housing, 450, 550... Ground pattern, 456. ... Circular regions, 646a, 646b ... through holes.

Claims (10)

In an electronic device comprising a circuit board and a connector,
The circuit board includes a heat transfer pattern formed electrically independent of the electronic circuit configured on the circuit board,
The heat transfer pattern is thermally connected to at least one electrical component constituting the electronic circuit and mechanically connected to a connector pin of the connector.
Electronic equipment. A housing for housing the circuit board;
The heat transfer pattern is further thermally connected to a screw that fixes the circuit board to the housing, or the heat transfer pattern portion on the circuit board is gripped by the housing, Thermally connected to the housing,
The electronic device according to claim 1. Comprising at least two heat transfer patterns;
Each of the heat transfer patterns is mechanically connected to a different connector pin of the connector,
A heat conductive member having a predetermined electric resistance value or a heat conductive member having electrical insulation between at least the adjacent heat transfer patterns to limit a current flowing between the adjacent heat transfer patterns. Thermally connected,
The electronic device according to claim 1.   The electronic device according to claim 3, wherein the thermally conductive member is made of ceramic. On the circuit board, a ground pattern connected to the ground of the power source is formed,
A part of the outer periphery of the heat transfer pattern and a part of the outer periphery of the ground pattern are formed so as to run in parallel at a predetermined distance over a section of a predetermined length.
The electronic device according to claim 1. A part of the outer periphery of the heat transfer pattern running in parallel in the section and a part of the outer periphery of the ground pattern are each formed in a sawtooth shape that meshes with each other.
The electronic device according to claim 5. A part of the outer periphery of the heat transfer pattern running in parallel in the section and a part of the outer periphery of the ground pattern are each formed in a comb shape that meshes with each other.
The electronic device according to claim 5.   The electronic device according to any one of claims 1 to 7, wherein the heat transfer pattern is thermally connected to thermally passive electrical components constituting the electronic circuit.   The electronic device of claim 8, wherein the thermally passive electrical component is an electrolytic capacitor.   The electronic device according to claim 1, wherein the electronic device is an electronic control device that controls operation of a vehicle.

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