JP3654073B2 - Electronic block and discharge lamp lighting device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electronic block, such as a switching power source, and a discharge lamp lighting device, which are composed of a large number of electronic components.
[0002]
[Prior art]
There is a switching power supply as an electronic block for generating a DC voltage from an AC power supply, and its circuit configuration and overall configuration diagram are shown in FIGS. The switching power supply 1 includes an AC power supply, a rectifier circuit 2, a step-up chopper circuit 3 including an inductance L, a switching element SW, a diode D, and a capacitor C, a control circuit 4, and a print on which circuit elements constituting each circuit are mounted. It is comprised by the board | substrate 5 and the case 6 (the cover 6a and the accommodating part 6b) which covers the whole circuit. The switching power supply 1 converts an output obtained by full-wave rectification of an AC power supply using a rectifier circuit 2 into a high DC voltage using a boost chopper circuit 3 and a control circuit 4. The control circuit 4 controls the ON / OFF frequency and duty of the switching element SW so that the detected voltage across the capacitor C becomes a predetermined voltage value.
[0003]
[Problems to be solved by the invention]
However, since the switching element SW in the boost chopper circuit 3 is normally switched at a high frequency of several tens of kHz or more in order to make the inductance L as small as possible, a high-frequency current flows through the switching element SW and the inductance L, and the ON / Severe heat is generated due to switching loss or the like that occurs at the time of OFF. As described above, there is a problem that heat is trapped inside the switching power supply 1 due to the heat generated by each component, which hinders circuit operation. In order to solve this problem, there is a method of attaching the heat radiating plate 7 to each circuit element 8 with screws 9 as shown in FIG. 9, but this method cannot secure a sufficient heat radiating area, and the heat radiating effect is not so much. Did not go up. Further, in the method of attaching the heat radiating plate 7 to the housing portion 6b of the case 6 as shown in FIG. 10, a heat radiating area can be secured as compared with the above method, but it is not possible to radiate heat from the lid 6a side of the case 6 and is sufficient. Heat dissipation could not be performed. Further, there is a method of attaching the heat sink 7 as shown in FIG. 11 to both the lid 6a and the housing 6b of the case 6, but this method has a high heat dissipation effect, but the structure of the heat sink 7 is not simple and is costly. The problem had occurred.
[0004]
Accordingly, an object of the present invention is to efficiently dissipate heat generated by the circuit elements constituting the electronic block such as a switching power supply by the structure of the case and the heat sink, thereby suppressing a temperature rise of the circuit elements and performing a stable operation. An object of the present invention is to provide a low-cost electronic block and discharge lamp lighting device that can be maintained.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the present invention stores a printed circuit board on which a circuit element that is a heat generating component is mounted and a heat radiating plate that radiates heat from the circuit element in a case having a lid and a storage portion, and In the electronic block formed by connecting the heat sink to the case, the position of the screw for attaching the circuit element to the heat sink by bringing the flat heat sink into direct contact with both the lid and the housing of the case And the abutment position between the case lid and the storage portion is the same, and the tip of the screw is aligned with the indentation position of the storage portion .
[0006]
The invention according to claim 2 is characterized in that, in the invention according to claim 1, circuit elements having similar calorific values are collectively attached to the same heat radiating plate.
[0008]
In a third aspect of the invention, the discharge lamp lighting device comprises the electronic block according to the first or second aspect.
[0009]
The invention according to claim 4 is characterized in that, in the invention according to claim 3 , a high-pressure discharge lamp is used as a load of the discharge lamp lighting device.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
(First embodiment)
A first embodiment of the present invention will be described with reference to FIG. FIG. 1 shows a heat sink 7 and an electronic block 10 according to a first embodiment of the present invention, where (a) is a front view, (b) is a side view, and (c) is a top view. . The electronic block 10 is configured such that the lid 6a and the storage portion 6b of the case 6 abut on one side. In the present embodiment, one side surface of the case 6 is used, but this can also be applied to other side surfaces. A circuit element 8 constituting an electronic block 10 is mounted on a printed circuit board 5 installed inside the storage unit 6b. A heat radiating plate 7 is attached to the circuit element 8 by screws 9, and the heat radiating plate 7 is planar. And is arranged so as to directly contact both the lid 6a and the storage portion 6b of the case 6.
The lid 6a and the storage portion 6b of the case 6 in the present embodiment are in a positional relationship with a certain distance on a single plane, but this is applicable even when both are in contact. is there.
[0011]
According to the present embodiment, since the planar heat sink 7 attached to the circuit element 8 is arranged so as to contact both the lid 6a and the storage portion 6b of the case 6, the heat generated by the circuit element 8 Since the heat can be transmitted to both the lid 6a and the storage portion 6b of the case 6 via the surface, the heat can be efficiently radiated using the surface area of the entire case 6, and the temperature rise of the entire electronic block 10 can be reduced.
[0012]
The electronic block 10 described in the present embodiment can also be applied to a discharge lamp lighting device using a high pressure discharge lamp as a load, and even in the case of a high pressure discharge lamp that easily generates higher heat, the temperature of the heat generating component The rise can be reduced.
[0013]
(Second Embodiment)
A second embodiment of the present invention will be described with reference to FIGS. FIG. 2 shows an electronic block 10 according to a second embodiment of the present invention, where (a) shows a front view and (b) shows a side view. FIG. 3 shows a circuit diagram of a discharge lamp lighting device 11 using the electronic block 10. Details of the present embodiment will be described below.
[0014]
The discharge lamp lighting device 11 includes an AC power supply 12, a DC power supply circuit unit 13, an inverter circuit unit 14, and a lamp 15. The DC power supply circuit unit 13 includes a rectifier circuit 16, a boost chopper circuit having an inductance L1, a switching element SW1, a diode D1, and a capacitor C1, and a control circuit 17 that controls the boost chopper circuit. It has a function of converting the AC voltage into a predetermined DC voltage and improving the power factor of the input power source to a high power factor. The inverter circuit unit 14 includes a step-down chopper circuit 18, a control circuit 19, a polarity inversion circuit 20, and an igniter circuit 21. The step-down chopper circuit 18 is composed of a switching element SW2, a diode D2, an inductance L2, and a capacitor C2. A stable supply power to the lamp 15 is maintained by adjusting the ON time of the switching element SW2. It has a function. The polarity inversion circuit 20 is composed of a full bridge circuit having four switching elements SW3 to SW6, and the control circuit 19 alternately turns ON / OFF the switching elements SW3 and SW4 and SW5 and SW6 as a pair. The rectangular wave AC power is supplied to the lamp 15 repeatedly. The igniter circuit 21 includes a pulse transformer Tr, a capacitor C3, a switching element SW7, and a resistor R. The igniter circuit 21 receives the rectangular wave voltage generated by the polarity inverting circuit 20 and gradually charges the capacitor C3 by the time constant of the resistor R and the capacitor C3. When the charged voltage reaches the breakover voltage Vbo of the switching element SW3, the switching element SW3 is turned ON, and the charge accumulated in the capacitor C3 is discharged through the primary winding N1 of the pulse transformer Tr. At this time, the pulse voltage generated in the pulse transformer Tr is boosted, and a high voltage pulse voltage (several KV) is generated in the secondary winding N2 of the pulse transformer Tr. This high voltage pulse voltage causes the lamp 15 to start discharging and shift to a lighting state.
[0015]
In the discharge lamp lighting device 11 as described above, the circuit elements SW1, D1, SW2, and D2 operate at a high frequency, so the amount of heat generated is large, while SW3 to 6 operate at a low frequency. Therefore, the amount of generated heat is relatively small. Therefore, a circuit element group having a large amount of generated heat such as SW1, D1, SW2, and D2 and a circuit having a relatively small amount of generated heat such as SW3-6. As shown in FIG. 2, the element group is separately attached to the heat sinks 7a and 7b.
[0016]
According to the present embodiment, the circuit element 8 in the discharge lamp lighting device 11 is divided into those having a large amount of heat generation and those having a relatively small amount of heat generation, and the heat radiation plate 7a is compared with the circuit element group having a large amount of heat generation. Since the heat dissipation plate 7b is attached to the circuit element group having a small amount of generated heat, the circuit element group having a relatively small amount of heat generation is affected by the circuit element group having a large amount of heat generation, and the temperature rises excessively. Can be prevented.
[0017]
(Third embodiment)
A third embodiment of the present invention will be described with reference to FIGS. FIG. 4 is a configuration diagram when a large number of circuit elements 8 according to the third embodiment of the present invention are attached to the heat sink 7. FIG. 5 is a process diagram for attaching the printed circuit board 5 and the housing 6b of the case 6 in the prior art. FIG. 6 is an attachment process diagram of the printed circuit board 5 and the housing 6b of the case 6 in the present embodiment.
[0018]
As shown in FIG. 5, in the prior art, when the normal circuit element 8 is attached to the heat radiating plate 7, the tip of the screw 9 may protrude from the heat radiating plate 7, so that the printed circuit board 5 and the housing 6b of the case 6 At the time of mounting, the printed board 5 is inserted to the lowermost part of the storage portion 6b with a certain distance a so that the tip of the screw 9 protruding from the heat dissipation plate 7 does not hit the storage portion 6b, and the heat dissipation plate 7 is attached. The two-step mounting operation of bringing the storage portion 6b to the inner surface of the storage portion 6b has to be performed, and extra labor is required.
[0019]
In the present embodiment, the position of the screw 9 for attaching the circuit element 8 to the heat radiating plate 7 and the contact position of the case 6 with the lid 6a of the case 6 and the storage portion 6 are the same, as shown in FIG. The tip of the protruding screw 9 coincides with the position of the recess of the storage portion 6b, and the printed circuit board 5 can be easily attached to the storage portion 6b in only one step of placing the printed circuit board 5 in the lowermost portion of the storage portion 6b. be able to.
[0020]
【The invention's effect】
Thus, the present invention has the following effects.
[0021]
According to the first aspect of the present invention, the heat generated in the circuit element can be efficiently radiated to both the case lid and the housing, and the temperature rise of the circuit element can be suppressed and stable operation can be maintained. Furthermore, there is an effect that the printed circuit board on which each circuit element is mounted can be smoothly attached to the case .
[0022]
According to the second aspect of the present invention, since circuit elements having similar calorific values are collectively attached to the same heat radiating plate, a circuit element group having a relatively small calorific value is influenced by a circuit element group having a large calorific value. Therefore, there is an effect that it is possible to prevent a problem that the temperature rises excessively.
[0024]
According to the third aspect of the present invention, since the discharge lamp lighting device is provided with the electronic block, an increase in the temperature of the semiconductor element can be reduced even in the discharge lamp lighting device having many circuit elements.
[0025]
According to the fourth aspect of the present invention, since the high pressure discharge lamp is used as the load, there is an effect that the temperature rise can be reduced even when the high pressure discharge lamp that easily generates high heat is used.
[Brief description of the drawings]
FIG. 1 is an electronic block diagram showing a first embodiment of the present invention, in which (a) is a front view, (b) is a side view, and (c) is a top view.
FIG. 2 is an electronic block diagram showing a second embodiment of the present invention, where (a) is a front view and (b) is a side view.
FIG. 3 is a circuit diagram of a discharge lamp lighting device using an electronic block according to a second embodiment of the present invention.
FIG. 4 is a configuration diagram of a circuit element and a heat radiating plate showing a third embodiment of the present invention.
FIG. 5 is a process diagram of attaching a printed circuit board and a case storage portion according to the prior art.
FIG. 6 is an attachment process diagram of a printed circuit board and a case storage portion according to a third embodiment of the present invention.
FIG. 7 is a circuit configuration diagram of a switching power supply showing the prior art.
FIG. 8 is an overall configuration diagram of a switching power supply showing a conventional technique.
FIG. 9 is a front view, a top view, and a side view of a heat sink showing the prior art.
FIG. 10 is an electronic block diagram showing a conventional technique, in which (a) is a front view, (b) is a side view, and (c) is a top view.
FIG. 11 is an electronic block diagram showing a conventional technique, in which (a) is a front view, (b) is a side view, and (c) is a top view.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Switching power supply 2 Rectifier circuit 3 Boost chopper circuit 4 Control circuit 5 Printed circuit board 6 Case 6a Cover 6b Storage part 7 Heat sink 7a Heat sink 7b Heat sink 8 Circuit element 9 Screw 10 Electronic block 11 Discharge lamp lighting device 12 AC power supply 13 DC Power circuit section 14 Inverter circuit section 15 Lamp 16 Rectifier circuit 17 Control circuit 18 Step-down chopper circuit 19 Control circuit 20 Polarity inversion circuit 21 Igniter circuit

Claims (4)

An electronic device comprising: a printed circuit board on which a circuit element as a heat generating component is mounted; and a heat radiating plate for radiating heat of the circuit element is housed in a case having a lid and a housing portion, and the heat radiating plate is connected to the case. In the block, the flat heat sink is directly brought into contact with both the case lid and the housing, and the position of the screw for attaching the circuit element to the heat sink, the case lid and the housing An electronic block characterized in that the contact position is the same, and the tip of the screw coincides with the position of the recess of the storage portion .   2. The electronic block according to claim 1, wherein circuit elements having similar calorific values are collectively attached to the same heat sink. A discharge lamp lighting device comprising the electronic block according to claim 1 . 4. The discharge lamp lighting device according to claim 3 , wherein a high pressure discharge lamp is used as a load.

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