JPH0469058A - Switching power supply device - Google Patents

Abstract

PURPOSE:To improve heat radiation and also set the interval between insulated metallic boards accurately and simplify the manufacturing process by mounting the circuit on the primary side and the circuit on the secondary side of first and second insulated metallic boards, and coupling them by a photocoupler. CONSTITUTION:The circuit on the primary side and the circuit on the secondary side are formed on insulated metallic boards, which are united by a bridge, and thereon integrated circuits, elements, etc., are mounted. A photocoupler 50 is fixed to straddle a rectangular extra hole. For a variable resistance element 52, a variable resistance element for surface mounting is used, and a hole is made in a casing 10, or through an extra hole it is fixed in such arrangement that the adjustment is possible. Next, the bridge part is stamped out and removed by a press, thereby dividing it in two sheets of hybrid integrated circuit boards 20 and 20, and the margins are fixed to the step of the casing 10. The coupling with a transformer is performed through leads 56 and 58, and the feedback of a signal is performed by the photocoupler 50.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial Application Field The present invention relates to a converter-type switching power supply device in which high pressure is insulated. The present invention relates to a switching power supply device in which a side circuit and a secondary side circuit are respectively mounted.

(b) Prior Art FIG. 6 shows a flyback type switching power supply circuit.

In the illustrated switching power supply circuit, the primary winding and the secondary winding have opposite polarities, and the human power V I N and the output V. Transformer T that insulates UL, switching element Q that controls the current flowing from input V I N to transformer T, such as a transistor or power MOSFET, several tens of kilometres.
A PWM circuit (60) that outputs a pulse with a constant frequency of Hz and whose duty is changed by a feedback signal to the control electrode of the switching element Q, and a snubber circuit that releases the energy accumulated in the leakage inductance of the transformer T. (66), a current detector (64) that monitors the current of the switching element Q and provides overcurrent protection, a temperature detector (62) that prevents thermal runaway in the power supply circuit, and a rectifier and smoother that rectify and smooth the output voltage of the transformer T. diode D3,
Capacitor C2, output V. A voltage detector (68) that performs constant voltage control and overvoltage control of L12, this voltage detector (
It is composed of a photocoupler (70), etc., which insulates back the output of (68).

Next, the operation of the switching power supply circuit configured as described above will be explained.

When the output pulse of the PWM circuit (60) becomes high level and the switching element Q turns on, a closed circuit of the primary winding of the transformer T and the switching element Q is formed, and the primary winding of the transformer T A current that increases linearly flows. At this time, the secondary winding output of the transformer T is blocked by the diode D3, so no power is transmitted through the transformer T, and all the energy supplied to the primary winding is stored in the transformer T. And PWM times 16
When the output pulse of 0) becomes low level and the switching element Q is turned off, a back electromotive force is generated in the primary winding, and the secondary winding output based on this back electromotive force is transferred to the capacitor C2 via the diode D3. Charged and output ■. It becomes OL.

The switching power supply circuit that performs the above operations is highly efficient, so if it has a relatively small capacity, it is possible to create a hybrid integrated circuit on an insulating substrate such as ceramics. It is suitable as a power supply device for equipment. However, since insulating substrates such as ceramics generally have low thermal conductivity, there is a problem that it is not possible to form a large-capacity switching power supply circuit that generates a large amount of heat into a hybrid integrated circuit.

(c) Problems to be solved by the invention On the other hand, when converting a switching power supply circuit into a hybrid integrated circuit by using an insulated metal substrate as the substrate, the problem of heat dissipation is solved, but due to safety standards, switching power supply Since it is said that the primary side circuit and the secondary side circuit of the circuit should not be formed on a single metal substrate, there is a problem that the manufacturing process becomes complicated.

In addition, especially in switching power supply devices, there are a large number of needs such as current capacity, high pressure voltage, power capacity, etc., so the burden of development to meet some of these needs becomes heavy.

Therefore, the present invention has a structure that can simplify the circuit (circuit) < turn formation process, element mounting process, etc. to the same level as using a single board, and can quickly respond to the needs of a large number of users without increasing the development burden. The purpose of this company is to provide switching power supply devices.

(d) Means for Solving the Problems The present invention has been made in view of the above problems, and provides a method for disposing a primary side circuit and a secondary side circuit of a switching power supply circuit on first and second insulated metal substrates. The first and second insulated metal substrates are coupled by a photocoupler that insulates and returns voltage signals and overvoltage signals from the secondary circuit to the primary circuit, thereby connecting the primary circuit of the switching power supply circuit. This solves the problem of insulation distance between secondary circuits and the problem of manufacturing process.

Further, on the first insulated metal substrate or the second insulated metal substrate, at least a variable resistor for setting the overcurrent detection level of the primary side circuit, a variable resistor for setting the voltage of the secondary side circuit, or a variable resistor for setting the overvoltage detection level of 8 levels is provided. The resistance can be adjusted on the user side or at least in the final stage of manufacturing by mounting a variable resistor 1 for the first and second insulated metal substrates or through a hole formed in the casing. By doing so, it meets the needs of many users.

(E) Function By coupling the first and second insulated metal substrates, on which the primary and secondary circuits of the switching power supply circuit are specially mounted, using a photocoupler, it is possible to treat them as the metal substrates of the body. , it becomes possible to simplify the element mounting process, lead fixing process, etc. to be equivalent to that of a single board. Furthermore, since the two metal substrates are coupled using a photocoupler, the distance between the first and second insulating metal substrates can be set with high precision.

Furthermore, it is possible to adjust at least 61 resistances of the variable resistor for setting the overcurrent detection level, the variable resistor for setting the voltage, or the variable resistor for setting the overvoltage detection level, so that it is possible to immediately respond to minute changes in specifications.

(F) Embodiments First, the outline and structure of the switching power supply device of the present invention will be explained with reference to FIGS. 4 and 5. Note that any converter-type switching power supply circuit including the switching power supply circuit described in the description of the conventional example can be used in the switching power supply device of the present invention, so a description of the circuit configuration will be omitted.

Referring to FIG. 4, the switching power supply device of the present invention includes two hybrid integrated circuit boards (1) each mounted with a primary side circuit and a secondary side circuit separated by an isolation transformer (not shown because it is externally connected). 20) (20), leads (56) (58) led out from the respective peripheral ends of the two hybrid integrated circuit boards (20) (20), two hybrid integrated circuit boards (20) (20); A photocoupler (
50) and a casing (10) which is generally frame-shaped and includes a step (12) serving as a guide for a spacer called a circon.

Two hybrid integrated circuit boards (20) (20) are arranged on the same plane with a predetermined distance apart, and their peripheral edges are connected to the casing (
10) is fixed to the stepped portion using an adhesive sheet or the like. The primary and secondary side circuits of the switching power supply circuit mounted on the hybrid integrated circuit board (20) (20) are independent seals formed by the hybrid integrated circuit board (20) (20) and the casing (10). The circuits are arranged in a space, and the circuits are coupled to the transformer through leads (56) and (58). Further, feedback of voltage and overvoltage signals from the secondary circuit to the primary circuit is performed by a photocoupler (50). Note that the n8 region where this photocoupler (50) is arranged is sealed with a cover (not shown).

FIG. 5 shows a modified example, which differs from the previous example only in that a hole (14) for adjusting the resistance of the variable resistance element (52) is formed in the casing (10). In the switching power supply shown in FIG. 4, the resistance of the variable resistance element (52) is adjusted through the gap between the first and second hybrid integrated circuit boards (20) (20). It is not possible to adjust the resistance after installation.

On the other hand, in this modification, the resistance can be adjusted at any time.

Next, the manufacturing process of an example will be explained in order to clarify the features of the present invention.

FIG. 1A shows a plan view of a circuit board just before circuit components are mounted to form a hybrid integrated circuit board. Note that FIG. 1B is a sectional view taken along line I-1.

The metal substrate (20) is made of aluminum or the like with a thickness of 0°5 mm.
A ~3 mm metal substrate is used and press punched into a rectangular shape with a rectangular cut hole (24) in its center, as illustrated in FIG. 1A.

When aluminum is used, an oxide film is formed by anodizing after this, and a copper foil with a thickness of 18 μm to 35 μm is laminated with an insulating resin layer (26) of polyimide or enamelled wood with a thickness of about 35 μm. The body is attached. This copper foil is then etched into a predetermined shape to form a circuit pattern (2
8), pads (30) and (32) for external leads, puff )' (34) for the photocoupler (50), )<rad (36) for the variable resistance element, etc. are formed.

Referring to FIG. 2, the circuit board completed as described above includes a switching element (40), a PWM circuit (42), an overcurrent detection circuit (42), and an overcurrent detection circuit (42) constituting a switching power supply circuit.
4) Integrated circuits such as diodes (46) and overvoltage detection circuits (48), or elements such as resistors and capacitors are mounted in chip form. A photocoupler (50) is fixed to the puff l' (34) so as to straddle the rectangular hole (24), and a lead (56) (
58) is fixed by solder. The variable resistance element (52) may be of any type such as a dip type or trimmer type, and may be attached to the casing (10) as required.
A hole is formed in the hole or the hole is fixed in an adjustable manner through a hole (24).

By adopting a structure in which the resistance of this variable resistance element (52) can be adjusted on the user side, or at least in the final stage of manufacturing the hybrid integrated circuit device, the switching power supply device of the present invention can be achieved. It can immediately respond to the needs of an extremely large number of users. Thereafter, a predetermined electrode and a circuit pattern are connected by wire bonding.

These mounting steps and the circuit pattern etching steps described above are performed in the same manner as in the manufacture of a hybrid integrated circuit device using a single substrate.

Next, the bridge (22) and lead frame (54) connecting the circuit boards on the left and right sides of the left and right holes of the hybrid integrated circuit board (20 (20)) on which the element mounting and the fixing of the leads (46) have been completed are punched out by press punching. The two hybrid integrated circuit boards (20) are removed and completed as two hybrid integrated circuit boards that are connected only by the photocoupler (50) (see Figure 3).
0), the substrate spacing specified by safety standards is guaranteed even in the subsequent manufacturing process.

(1) Effects of the Invention As described above, according to the present invention, (1) Since an insulated metal substrate is used, heat dissipation characteristics are good and it can be applied to a large-capacity switching power supply device.

(2) Even though safety standards are met because the primary and secondary circuits of the switching power supply circuit are completely separated, etching and mounting processes are simplified to the same level as processing a single board. be able to.

(3) Since the variable resistance for setting the overcurrent detection level, the variable resistance for setting the voltage, or the variable resistance for setting the overvoltage detection level can be adjusted to a minimum of 1, it can quickly meet the needs of many users.

(4) Since the circuit pattern is formed on a single substrate with holes formed, the lead bands and photocoupler pads formed on each substrate are aligned.

[Brief explanation of the drawing]

1 to 4 are diagrams explaining the manufacturing process of an embodiment of the present invention, in which FIG. 1A is a plan view of a circuit board used in the embodiment, and FIG. 1B is a line II thereof. 2A is a plan view of the hybrid integrated circuit board on which circuit elements are mounted, FIG. 2B is a sectional view taken along line I-1, FIG. 3 is a plan view of the completed hybrid integrated circuit board, and FIG. 5 is a perspective view of an embodiment, FIG. 5 is a perspective view of a modified example, and FIG. 6 is a circuit diagram of a general switching power supply circuit. (10) - Casing, (12)... Circon guide, (20)... - Hybrid integrated circuit board, (22)
・-Bridge, (24)...Subhole, (28)・-
Circuit pattern, (30) (32) (34) (36
)···band.

Claims (1)

[Scope of Claims] (1) A first insulated metal substrate mounting a plurality of circuit elements such as a switching element constituting a primary side circuit of a switching power supply circuit and a circuit that controls the operation of this switching element; The second circuit is equipped with multiple circuit elements such as diodes and overvoltage detection circuits that constitute the secondary side circuit of the power supply circuit.
The insulated metal substrate and the first and second insulated metal substrates are coupled at a predetermined interval on the same plane, and voltage signals and overvoltage signals are insulated and fed back from the secondary side circuit to the primary side circuit of the switching power supply circuit. A casing comprising a photocoupler and a space for independently sealing a primary side circuit and a secondary side circuit of a switching power supply circuit mounted on the first and second insulated metal substrates, and a first insulated metal substrate. At least one variable resistor for setting the overcurrent detection level of the primary side circuit, the variable resistor for setting the voltage of the secondary side circuit, or the variable resistor for setting the overvoltage detection level is mounted on the substrate or the second insulated metal substrate. A switching power supply device characterized by: (2) The switching power supply device according to claim 1, wherein the first and second insulated metal substrates are formed by cutting a bridge of a single insulated metal substrate in which a rectangular cut hole is formed. (3) The switching power supply device according to claim 2, wherein the width of the cut hole is set to a size that satisfies a required insulation standard. (4) The leads led out from the first and second insulating metal substrates are fixed to one peripheral edge of the single insulating metal substrate before the single insulating metal substrate is separated by cutting the bridge. The switching power supply described.