JPS6364575A - Wiring pattern structure of load driving device - Google Patents

Abstract

PURPOSE:To make it hard to cause electric discharge between the wiring route by insulation deterioration, by interposing a wiring route opposite to the side connected to a load of a current limiting element between the wiring routes where the load is connected. CONSTITUTION:Terminals of a metal case B where a high voltage pulse generating circuit is enclosed are arranged in the order of terminals 9, 7, 8 and 10. Terminals 9 and 10 are separated to which an electric discharge lamp DL is connected. Between these terminals 9 and 10, terminals 7 and 8 are provided to connect to an inverter. By arranging terminals 7-10 the distance between terminals 9 and 10 is kept, so that there will be little possibility to start the electric discharge between terminals 9 and 10 by the insulation deterioration.

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a power conversion circuit that converts a DC power supply output to an AC voltage, a current limiting element that regulates the current flowing to a load, and a current limiting element that regulates the current flowing to the load, and The present invention relates to a trace of a wiring pattern of a load drive device including a new circuit element that is disconnected when a flow occurs.

BACKGROUND TECHNOLOGY] As this type of load driving device, the discharge lamp D shown in the second flash
There is a discharge lamp illumination lamp Vc that lights up the L. This discharge lamp lighting device includes a rectifying and smoothing circuit 1 that full-wave rectifies and smoothes a commercial power source AC, and a discharge lamp DL that converts the DC voltage created by this rectifying and smoothing circuit into an AC voltage of a predetermined frequency. It consists of an inverter 2 as a power source for lighting the lamp, and a high-voltage pulse generating circuit 3 for starting the discharge lamp I).

More specifically, the 1 ml passage in FIG. 2 will be explained.

Commercial power supply■^. The filter coil l'' C, and 1 capacitor C, are connected through the power supply fuse as new circuit elements.
A π water filter consisting of C2 is connected, and the aftereffects are rectified and smoothed by a circuit 1 that rectifies the commercial power supply VAC that has passed through the π water filter. The rectifying and smoothing circuit 1 includes diodes D, , D2 and capacitors C, , C,
A voltage doubler rectifier circuit formed in Impark 2 is a switching element, which is a transistor Q1 to Q.
4. It has a full bridge configuration consisting of transistors D to D, and is equipped with a switching control circuit IC2 that controls switching of transistors Q1 to Q. Note that the switching control circuit IC2 includes transistors Q, ,Q
, the current flowing through the discharge lamp DL is detected by the resistor R0 inserted on the emitter side of the transistor Q.
It has a function of controlling the switching of inverters 1 to Q to keep the output of inverter 2 constant. In addition, this switching control circuit C2 uses a transformer to step down the commercial power supply VAC as a power source, rectify this step-down voltage by a diode DB, and further stabilize the voltage by a three-terminal regulator IC. I am using it. In this discharge lamp lighting device, the connection point of transistors Q, ,Q, and the transistor Q2
．． Between the connection point of the discharge lamp DLI: the choke coil Cl as a current limiting element that regulates the flowing current, and the capacitor C3, C, which series circuit is connected, and the capacitor C
A discharge lamp DL is connected to both ends of 3 and C. In addition,
The capacitors Cs and Ca also have the role of a bypass filter, that is, the role of bypassing the high frequency component of the output of the inverter 2 applied to the discharge lamp DL. An igniter is used as the high-voltage pulse generation circuit 3, and the discharge lamp D
a pulse transformer PT that applies a high-voltage pulse to the discharge lamp DL in order to start the discharge lamp DL; a resistor R charged with the voltage applied across the discharge lamp DL; and a capacitor C8.
a charging circuit consisting of a charging circuit, and a high voltage that causes a current to flow through the primary Sim n of the pulse transformer PT by discharging the charge charged in the capacitor C6 and starting the discharge lamp DL at the secondary winding port. It consists of a bidirectional thyristor Q5 (like a triac) that induces pulses, a trigger element Q6 that controls conduction of the thyristor Q, and the like.

Hereinafter, the operation of the above-described discharge lamp lighting device will be schematically explained. The diode D2 and capacitors c, , C of the rectifying and smoothing circuit 1 double voltage rectify the commercial 'N M V Ac, and when this DC voltage is applied to the inverter 2, the inverter 2 converts the above voltage into an AC voltage. Convert and apply to discharge lamp 1) L. This inverter 2 includes transistors Q3. Q, is turned on and off alternately at a low frequency (about 1201(z)), transistor Q, is turned on and off at a high frequency (about 40 to 11z) only when transistor Q3 is on, and transistor Q2 is turned on and off at a high frequency (about 40 to 11z) only when transistor Q is on. ,
The choke coil C has transistors Q, Q2 whose current direction changes at low frequencies due to the switching of transistors Q, Q2, which turn on and off when either transistor Q, Q2 is on. A pulsating current flows due to switching. This current is the discharge lamp 1)
The current is divided into L and capacitors C, , C, and flows separately. In addition,
As mentioned above, since the capacitors Cs and C@ act as bypass filters, the lamp current in the discharge lamp DI- has a substantially rectangular waveform determined by the switching frequency of the transistors Q, , Q, from which high frequency components are almost removed. flows.

The operation of the high-voltage pulse generation circuit 3 for starting the discharge lamp DL will now be described. High pressure pulse generation date v! 3, when the above-mentioned inverter 2 operates and a voltage is applied to the discharge lamp DI-, the capacitor C8 is connected to the resistor R, at the voltage across the discharge lamp DL.
, R3, and the resistors R, , R5, R
, to charge the capacitor C5. Then, with the capacitor C3 sufficiently charged, the electric charge charged in the capacitor C9 turns on the trifling element Q6, thereby turning on the thyristor Q5, and the current-limiting capacitor C
2 and the tli column tm path of the fill L and the primary winding 111 of the pulse transformer PT. With this discharge current, pulse transformer PT
A high voltage pulse boosted to the secondary 8an= is induced, and this voltage is applied to the discharge lamp DL via the capacitor C5HC6 to start the discharge lamp DI-.

By the way, in the discharge lamp lighting device having the above-described configuration, the high-frequency high-voltage pulse generated in the pulse transformer P'r is used as noise in the switching control circuit IC2 of the inverter 2.
There was a risk that the current would go around to the inside and cause a co-operation such as simultaneous on state of the transistor Q1 and the Flannostar Q or the simultaneous on state of the transistor Q2 and the transistor Q3.

Therefore, at least the pulse transformer PT of the high-voltage pulse generation circuit 3, the transistors Q, -Q, and the switching control circuit IC2 are divided into separate metal cases A and B.
There is one in which the choke coil CI+ is housed in the metal case B side where the pulse transformer PT1 is housed. That is, in FIG. 2, the circuit indicated by the broken line frame is housed separately from other circuits such as the inverter 2, and as shown in FIG. 3, the metal case A is used.

Connect B with terminal 7.8, and connect terminal 9.1 of metal case B.
A discharge lamp DL is connected to 0. In this way, at least the pulse transformer PT and the transistors Q1 to Q4
By housing the pulse transformer PT and the switching control circuit IC2 in separate metal cases A and B, the pulse transformer PT
, transistors Q, ~Q4, and switching control circuit IC2 of inverter 2 are electromagnetically shielded by metal cases A and 13, and electromagnetic noise due to high voltage pulses generated in pulse transformer PT is transmitted through space to the switching control circuit of inverter 2. In addition, since the choke coil C1l is housed on the metal case B side, the high voltage pulse generated in the pulse transformer PT due to the current limiting action of the choke filter CH is transferred to the inverter 2 and the high voltage pulse. It is possible to reduce the amount of lead wires connected to the generating circuit 3 that go around to the metal case A side. Therefore, transistors Q1 to Q of inverter 2
4 or switching control I and 2 pulse transformers P
Therefore, the switching control circuit IC, is not affected by the high voltage pulse generated in T,
This prevents malfunctions such as being turned on at the same time.

However, as mentioned above, the discharge lamp lighting circuit is installed in a separate metal case A.
, terminal 7 of metal case B when stored separately in B,
The terminal arrangement of terminals 8 and 1, 9 and 10 is as shown in Figure 3. , 9, 10.8, terminal 9
If dust or the like grows between terminals 9 and 10, the insulation may deteriorate and discharge may start between terminals 9 and 10. At this time, since energy was supplied to this discharge portion via the choke coil CH, the discharge was maintained and there was a risk that this discharge portion 1i would catch fire. Similarly, the terminal arrangement is 9.8
, 10.7, if insulation deterioration occurs at terminals 8 and 9 and a discharge starts, energy is supplied via the choke coil CH, so the discharge is maintained and there is a risk of ignition. There is sex. Note that in the above explanation, terminals 7 to 10 were partially explained as an example, but these terminals 7 to 10 have i! t
The same can be said of the entire wiring path including the wiring pattern portion formed of continuous copper foil. For this reason, conventionally, it has been necessary to apply an insulation protection material (for example, silicone) to improve insulation properties.

[Objective of the Invention 1 The present invention has been made in view of the above-mentioned points, and its object is to provide a load drive device that prevents fires due to deterioration of insulation between terminals or wiring paths such as wiring patterns. The purpose of this invention is to provide a wiring pattern structure.

[Disclosure of the Invention 1 (Structure) The present invention provides a power conversion circuit that converts a DC power output into an AC voltage by switching a switching element, a load operated by the output of the power conversion circuit, and a power conversion circuit connected in series with the load. It is equipped with a current-limiting element that regulates the current flowing to the connected load, and a disconnecting element that disconnects the circuit when an excessive current flows in the load current-carrying path, and a current-limiting element that connects the load to the current-limiting element between the wiring and the path. By interposing a wiring route on the opposite side to the connected side and separating the wiring route to which the load is connected, discharge due to insulation deterioration is less likely to occur between the wiring routes. If insulation deterioration occurs due to an open circuit between the peaks and a discharge occurs between the wiring paths, the output of the power conversion circuit is supplied to the load without passing through the current limiting element, and a large output current is caused to flow through the power conversion circuit. te, cut l1
The operation of the power converter circuit is stopped by destroying the eight elements or the switching elements of the power converter circuit.

(Example) Figure 11 is a diagram showing an example of the present invention, and in this example, as described above, the circuits within the broken line frame in Figure ff12 are individually divided and housed in metal cases L to B. The terminal arrangement of the metal case B in which the high-voltage pulse generating circuit 3 is housed is arranged in the order of terminals 9, 7, 8, and 10. Note that the configuration of each part is the same as that described in the conventional example.

In this way, by separating the terminals 9 and 10 to which the discharge lamp DI- is connected, and providing the terminals 7 and 8 connected to the inverter 2 between these terminals 9 and 10, and arranging the terminals 7 to 10, The distance between the terminals 9 and 10 is increased, and the occurrence of discharge between the terminals 9 and 10 becomes less likely due to deterioration of the insulation.

In addition, if a discharge begins due to insulation deterioration between terminals 7 and 9 due to adhesion of dust, etc., power will be supplied to the inverter 2 as a power conversion circuit through the choke filter C1 (as a current limiting element). Therefore, a large output current flows to the inverter 2, and the power supply fuse F as a new circuit element is disconnected or the transistors Q1 to Q of the inverter 2 are destroyed. The inverter 2 output is not applied between terminals 7 and 8, and the discharge is not maintained.Furthermore, if discharge is started between terminals 7 and 8, the inverter 2 output becomes almost short-circuited.
Naturally, power supply fuse F is disconnected or transistors Q1 to Q4 of inverter 2 are destroyed. In addition, in the above explanation, only the terminal arrangement was explained, but these terminals 7 to 7
It goes without saying that the wiring pattern constituting the wiring #a route connected to 10 must also be formed so as not to disrupt the same arrangement. Wait, separate case A by dividing the high-voltage pulse generation circuit 3 from the inverter 2 and other circuits.
, In B, we have explained the case where they are separated by 5>, but even if they are not separated, if the wiring pattern is formed in the same manner as described above, the risk of fire caused by discharge between the wiring patterns due to insulation deterioration can be prevented. can. ζ7. In the above explanation 1, the discharge lamp lighting device was explained as an example.
A power conversion circuit such as an inverter that converts a DC power output into an AC voltage by switching a switching element, and a load that operates on the output of the power conversion circuit.
A load driver equipped with a current limiting element such as a choke fill that is connected in series to this load and regulates the current flowing to the load. J.J.
The present invention can be similarly applied to any device.

[Effects of the Invention] As described above, the present invention includes a power conversion circuit that converts a DC power output into an AC voltage by switching a switching element, a load operated by the output of the power conversion circuit, and a power conversion circuit connected in series with the load. A current-limiting element that is connected to the wiring path to regulate the current flowing to the load, and a disconnecting element that disconnects the circuit when an excessive current flows through the load current-carrying path. Since the CI wiring path #a is interposed on the side opposite to the side connected to the wiring path, discharge due to edge deterioration to which the load is connected is unlikely to occur. If electrical discharge occurs between the wiring paths due to insulation deterioration between the The operation of the power converter circuit can be stopped by destroying the switching element of the power converter circuit or the switching element of the power converter circuit, and therefore the energy for sustaining the discharge is not supplied, which has the effect of eliminating the risk of fire caused by maintaining the discharge. Since there is no risk of ignition due to insulation deterioration, there is also an effect that there is no need to apply a special insulation protection material between the wiring paths.

[Brief explanation of the drawing]

Between Pt51 is an explanatory diagram showing the terminal arrangement of one embodiment of the present invention, FIG. 12 is a specific circuit diagram showing a conventional example, and the third bacterium is an explanatory diagram showing the terminal arrangement of the same as above. 2 is an inverter, 7-10 are terminals, Q1-Q are transistors, DL is a discharge lamp, CI+ is a choke block u-V
i-) 9j', buttocks I --- Butchi transfer Figure 1 A Figure 3 Δ

Claims (2)

[Claims] (1) A power conversion circuit that converts DC power output into AC voltage by switching switching elements, a load that operates with the output of this power conversion circuit, and a current that is connected in series with this load and regulates the current flowing to the load. a current limiting element;
A disconnecting element that disconnects the circuit when an excessive current flows in the load current-carrying path, and a wiring path on the opposite side of the current-limiting element from the side connected to the load is interposed between the wiring paths to which the load is connected. A wiring pattern structure of a load driving device characterized by: (2) In a load drive device that is equipped with a terminal connected to the wiring path and to which a load is connected, there is a reflection between the terminals connected to the load and the side connected to the load of the current limiting element. The wiring pattern structure of a load driving device according to claim 1, characterized in that a side wiring route or a terminal connected to the wiring route is interposed.