DE3345449C2 - - Google Patents

Description

The invention relates to a solid-state AC voltage Relay of the type mentioned in the preamble of claim 1.

In a known solid-state AC voltage relay of this type (DE-OS 29 32 969) are two antiparallel Thyri interfere each with an associated control circuit and an associated light emitting diode in a common semiconductor housing, the light emitting diodes both the thyristors and the control circuits control that contain photo transistors. The phototransistors in turn control the base-emitter path of bipolar control transistors, the output circuits of which are connected to the gate control circuit of the thyristors, the control circuits being designed in such a way that the control transistors are switched through when the phototransistors are not illuminated, and thus the voltage of the gate Hold the control circuit of the thyristors at such a low value that they cannot ignite. With the photo transistor, a further transistor is connected, the base electrode of which is acted upon by a capacitor with the AC voltage to be controlled, and which is switched on when voltage peaks occur and blocks the phototransistor, so that the control transistor of the thyristor is turned on. The base electrode of an additional transistor is connected to the AC voltage via a voltage divider and forms a zero voltage switch, the output circuit of this additional transistor also being connected to the gate control circuit and allowing ignition only at AC voltages below a window. The known control circuit thus has a large number of components for which a separate operating voltage is obtained from the AC voltage via a Zener diode, so that the voltage drop across the thyristors must be relatively large and the solid-state AC voltage relay thus has a high power loss. The individual components are difficult to manufacture in the form of a single integrated control circuit, possibly also together with the thyristors, so that there is a high outlay, in particular due to the mixture of high-voltage and high-power components with control signal-carrying components. Here, it is still difficult to manufacture the multitude of resistors required for the operating voltage supply and the voltage divider circuits in an integrated form. On the other hand, this large number of components and individual Steuertran sistors is necessary to ensure switching on the one hand only at the zero crossing and on the other hand to achieve that no settling or switching off occurs in transient conditions with a high value of dV / dt .

A solid-state AC voltage relay is also known (US-PS 42 95 085), in which the gate control circuit of a thyristor controlled by a depletion type field effect transistor becomes. Here too, both the field effect transistor and the thyristor controlled by light radiation, being continued Photosensitive diodes with the gate electrode of the field effect transistor are connected. If switching in the span voltage zero crossing and / or protection against voltage peaks is to be achieved is also a variety of additional Chen components required that are poor in the form of a umpteenth integrated circuit are to be united.

The invention has for its object to provide a solid-state alternating voltage relay of the type mentioned, which, with a simple structure and easy to integrate, has to be switched on only when the voltage passes through zero and has a perfect switching behavior even when transient conditions occur with a high value of dV / dt .

This task is accomplished by the in the characterizing part of the patent claims 1 specified features solved.

Advantageous refinements and developments of the invention result from the subclaims.

Due to the inventive design of the solid-state alternating voltage relay, it is possible to achieve a simple structure with only a few components, with switching on only at zero voltage crossing and reliable protection against interference voltage peaks by means of a single MOS field-effect transistor associated with a respective thyristor with associated capacitive voltage divider is achieved with a high dV / dt value. Both the MOS field-effect transistors and the capacitors can be formed using techniques in a semiconductor die, as are required in any case for the production of the thyristors.

By shorting the gate control circuits according to the invention, a reduction in the sensitivity of the thyristors responsive to lighting is not necessary, so that a single light-emitting diode is sufficient to drive two semiconductor chips, the respective thyristors of which are connected in anti-parallel and which at the same time include the control circuits. The control circuit can prevent turn-on even when the surface is illuminated when the voltage across the solid-state AC relay exceeds a value greater than any predetermined window value, or when pulses having a high value of dV / dt along the AC voltage relay occur.

A particularly simple structure results from the fact that one of the capacitors of the capacitive voltage divider by the distributed capacitance of the control transistor can be formed.

This means that the AC voltage relay is also strong for switching suitable for inductive loads.  

Each of the anti-parallel thyristors is preferred on a separate semiconductor die in the form of a number of partial thyristors connected in parallel, each with associated gene MOS field effect transistors formed, their gate electro with each other and with a common capacitive voltage divider and optionally a common Zener diode the. The partial thyristors are on the semiconductor chip preferably designed as lateral thyristors.

The solid-state chip with two semiconductor chips voltage relay is arranged in a housing that heats up tendes, but electrically insulating substrate with suitable conductive patterns or traces that the two Pick up semiconductor wafers and a common light emitting diode. The housing also has a plastic cap made of radiation reflective material on which the light from the light emitting diode conducts on the semiconductor wafers.

An embodiment of the invention is described below of the drawings explained in more detail. In the drawing shows

Fig. 1 is a circuit diagram of an embodiment of the fixed body AC relay;

FIG. 2 shows an embodiment of the attachment of the two semiconductor chips according to FIG. 1 and a light-emitting diode on a ceramic substrate;

Fig. 3 is a side view of Fig. 2;

Fig. 4 is a view of the assembly of Figure 2 with a cap that encloses the light emitting diode and the semi-conductor plate.

Fig. 5 is a top view of Fig. 4;

Fig. 6 shows a more detailed circuit diagram of a semiconductor chip.

In Fig. 1, a circuit diagram of an embodiment of a solid-state AC relay is shown. The relay of FIG. 1 uses two identical thyristors 210, 211 , which are connected in anti-parallel to each other and are switched between two mains AC power connections 212, 213 .

These thyristors 210, 211 are formed on respective separate semiconductor chips, each semiconductor chip having a plurality of thyristors connected in parallel and each having MOS field-effect transistors formed in the semiconductor chips for each thyristor. This plurality of thyristors with associated MOS field effect transistors is shown in Fig. 1 only schematically in the form of a single MOS field effect transistor Darge, but the control circuit to be explained with the voltage dividers and the Zenerer diode for all thyristors and MOS field effect transistors of a semiconductor ge is common, as can be seen from Fig. 6, which shows the circuit device of a semiconductor chip in more detail.

The thyristors have gate control connections 216, 217 . The thyristor semiconductor chip 210 has on its upper surface an anode electrode pad 220 and a cathode electrode pad 221 , while the semiconductor chip 211 has an identical anode pad 222 and a cathode pad 223 ( FIG. 2).

The thyristors 210 and 211 are electrically connected to one another in such a way that the anode 220 of one thyristor is connected to the cathode 223 of the other thyristor and the anode 222 of one thyristor is connected to the cathode 221 of the other thyristor. Accordingly, the semiconductor components are connected to one another in the anti-parallel relationship shown in FIG. 1.

A single light emitting diode 225 , which can be a conventional commercially available gallium aluminum arsenide component with connections 226 and 227 according to FIG. 1, is arranged in such a way that it photosensitive surfaces of the semiconductor plates 210 in the manner yet to be described and 211 illuminated to enable the semiconductor dies to turn on if the other circuit conditions are appropriate. Good electrical insulation is formed between the input circuit connected to terminals 226 and 227 and the AC power circuit connected to terminals 212 and 213 .

Identical control circuits, as will be described in more detail with reference to FIG. 6, are provided for controlling the switching on of the thyristors 210 and 211 and include respective MOSFET transistors 230 and 231 , Zener diodes 232 and 233 , resistors 234 and 235 and Capacitors 236 and 237 . The capacitors 236 and 237 serve similarly to the capacitors 60 and 61 according to FIG. 6 as a construction part of respective capacitive voltage dividers. The second component of the capacitive voltage divider consists of the distributed capacitance 238 and 239 of the MOSFET transistors 230 and 231, respectively.

The circuit components 230 to 239 could be designed as discrete components. However, these components are preferably designed to be integrated with the semiconductor chips which form the thyristors 210 and 211 .

Transistors 230 and 231 are connected to gate electrodes 216 and 217 of thyristors 210 and 211 , respectively. As long as the transistors 230 and 231 conduct or are switched through, the lighting of the surfaces of the components 210 and 211 by the light-emitting diode 225 cannot turn on the component. Transistors 230 and 231 turn on when their respective gate electrodes 240 and 241 are appropriately charged to an appropriate threshold voltage V _th . Accordingly, when nodes 242 and 243 reach the turn-on threshold voltage of transistors 230 and 231 and when there is sufficient drain-source voltage, the devices conduct and clamp the respective gate electrodes 216 and 217 of thyristors 210 and 211 .

The voltage at each of nodes 242 and 243 , designated V ₀, is:

V ₀ = V _cc C _p / ( C ₁ + C _p ).

In this equation, V _{cc is} the voltage across connections 212 and 213 , C _{p is} the capacitance of distributed capacitors 238 and 239, and C ₁ is the capacitance of capacitors 236 and 237 .

From the foregoing, it can be seen that the voltage V ₀ at nodes 242 or 243 is greater than the threshold voltage of transistors 230 and 231 when the instantaneous AC voltage between terminals 212 and 213 is more positive or negative than any particular "window""-Value. Correspondingly, the transistors 230 and 231 clamp the thyristors 210 and 211 when this window voltage is exceeded. This arrangement then forms a zero voltage switch without the need for a resistor which extends between the main terminals of the component.

The capacitive voltage divider circuit is also useful for suppressing the firing of components 210 and 211 due to rapidly increasing pulses, such as spikes or signals with a high dV / dt value. Such high interference pulses with a short duration apply a sufficiently high voltage across the parasitic or stray capacitances 238 and 239 so that the transistors 230 and 231 switch on and clamp the respective thyristor. Accordingly, the thyristor is not ignited due to such rapidly increasing interference pulses.

In the case of relatively slowly rising pulses, such as those caused by strongly inductive loads, which are connected to the relay connections 212 and 213 , these pulses are not sufficiently fast to switch on the control transistors and thus undesirably the thyristors 210 and 211 to be clamped so that a single-phase operation or a bouncing of the relay is avoided with strongly inductive loads. It should also be noted that this is achieved without the need to reduce the optical sensitivity of the component. The thyristors 210 and 211 can therefore be designed so that they have an optimal optical sensitivity for the ignition process without the risk of erroneous operation due to relatively slow rising transient pulses.

The resistors 234 and 235 serve to compensate for the temperature dependency of the sensitivity of the respective thyristor.

An arrangement for receiving the semiconductor chips 210 and 211 and the light-emitting diode 225 according to FIG. 1 is described below with reference to FIGS . 2 to 5. In FIGS. 2 and 3, a ceramic substrate carrier is showing 260 ge, which may consist of alumina, but may also consist of any desired electrically insulating ther mixed conducting material. For example, the alumina board 260 may have a thickness of 0.635 mm, a length of approximately 22.9 mm and a width of approximately 6.35 mm. A plurality of conductor track patterns are formed on a surface of the substrate 260 including conductor tracks 261 to 267 . Each of these conductor tracks can be formed by a gold plating on the substrate, the gold plating having a thickness of more than approximately 0.00381 mm. Each of the thyristor semiconductor platelets 210 and 211 is then suitably soldered to conductive pads 265 and 264, respectively, or otherwise secured so that the circuit boards are in good thermal contact with the alumina substrate 260 . Each of the dies 210 and 211 can be approximately 2.08 x 2.95 mm in size for a typical size device. The light-emitting diode semiconductor plate 225 is attached at one end to the conductor pattern 262 .

The die 210 and 211 are attached so that their anode and cathode lines are generally aligned with each other and with one end of the traces 266 and 267 . Accordingly, a single wire 270 is conveniently used to electrically connect the conductive pads 223 of the thyristors 211 and 220 of the thyristor 210 and the ends of the trace 267 . This can be achieved with the aid of a relatively simple type of binding method which, due to its nature, is suitable for automatic high-speed techniques. Accordingly, a tack head is simply pressed onto the wire 270 to electrically secure the wire at three spaced apart locations that correspond to the location of the pads 223, 220 and the end of the trace 267 . Similarly, a second parallel wire 271 is tacked to the conductive pads 222 , 221 and the end of the trace 266 . The booklet connection of the wire 271 is shown in FIGS. 2 and 3 ge. Each conductive wire 270 and 271 can be an aluminum wire approximately 0.15 mm in diameter.

As a result of these connections, the power connections 212 and 213 are connected to the thyristor components 210 and 211 in FIG. 2 in the manner shown in FIG. 1, the thyristors being connected in anti-parallel relation to one another. It should be noted that because the dies 210 and 211 also contain their respective control circuits, the control circuits are also connected in their place using this single link connection process.

As shown, the light emitting diode 225 is arranged over one end of the conductor track 262 , which is connected to a circuit 226 . The other electrode of the light emitting diode 225 is electrically connected to one end of the conductor track 261 via a wire 280 . The wire 280 , which may be a lead of the light emitting diode 225 , is connected to the end of the trace 261 in any desired manner.

The conductor track 261 is then electrically connected to the conductor track 263 arranged with from either a direct short-circuit connection through a wire 281 or via a resistor 282 . The selection of the short-circuit wire 281 or the resistor 282 depends on the power available at the connections 226 and 227 and on the characteristic of the light-emitting diode 225 . The wires 280 and 281 can be gold wires approximately 0.0254 mm in diameter. It can be seen that the terminals 212, 213, 226 and 227 extend from the periphery of the substrate 260 such that they form a semiconductor package of the dual-in-line connector type.

An optical cap or a housing 291 is then put on via the light-emitting diode 225 and the thyristors 210 and 211 and encloses the area which is indicated in FIG. 2 by the dashed line 290 . This cap is shown in FIGS. 4 and 5 as cap 291 and can be made of any desired reflective plastic material that is able to withstand the temperatures that occur during operation of the component. A white colored plastic material was used. The plastic material selected can be a disulfo plastic. The plastic material is preferably white before, so that light is reflected from the inner surfaces of the cap. The cap can also be made of a suitable silicone material, such as RTV, to which titanium oxide powder has been mixed. The titanium oxide powder clearly remains in dispersion in the silicone material. This mixture can be cured in an oven at about 115 ° C for about 15 minutes.

The cap 291 has an inclined side surface 292 above the position of the light-emitting diode 225 , this inclined edge reflecting light in the direction of the region of the semiconductor plates 210 and 211 , as can be seen in FIG. 4.

The cap 291 can be glued in place as shown in Fig. 4, or it can be designed to overlap the substrate and snap over the edge of the substrate. A clear silicone material is then introduced into the interior of the cap 292 via the fill bores 293 and 294 according to FIGS . 4 and 5 in order to encapsulate all the semiconductor chips 225, 210 and 211 and their connecting lines, while the lighting from the light emitting diode 225 can reach photosensitive surfaces of the thyristor semiconductor chips 210 and 211 .

After the cap 291 is secured in place and filled with silicone, the entire substrate 260 can be secured together with the cap 291 in a lead frame which provides leads 212, 213, 226 and 227 . The component can then be arranged completely in a molded housing, which can be formed, for example, by a transfer molding process or the like. Terminals 212, 213, 226 and 227 extend from this semiconductor package to form a dual in-line semiconductor package of relatively small size and volume. The component can still withstand a constant current load of 1½ A or more at voltages of 240 V AC.

In Fig. 6, the circuit diagram of a semiconductor wafer is shown Licher execution. The first capacitor of the voltage divider is designed for easy integration in the form of two capacitors 60, 61 connected in parallel, while the second capacitor is formed by the distributed capacitance 75 of the individual MOS field-effect transistors 76 to 79 . The first capacitors 60, 61 are between the anodes of the partial Thyristo ren 64 a to 64 d and the gate electrodes of the control MOS field effect transistors 76 to 79 . The thyristors 64 a to 64 d are connected in parallel and have common cathodes and anodes.

With the semiconductor wafer of FIG. 3 is further integrally and in one piece, a 100 K resistor 70 ausgebil formed of polysilicon of and electrically connected between the cathodes and gates of each of the thyristors 64 a, 64 b, 64 c and 64 is turned on d .

Furthermore, with the semiconductor die of FIG. 6 made in one piece and to additionally integrally a Zener diode 71, which is switched in series with the capacitors 60 and 61 between the anode and cathode terminals 51 and 50 of the thyristors shown. Furthermore, in Fig. 6 the naturally predetermined ver divided capacitance 75 is shown, which is parallel to the Zener diode 71 .

The number of control MOSFETs 76, 77, 78 and 79 according to FIG. 6 is also formed on the semiconductor wafer and cooperate with the thyristors 64 a , 64 b , 64 c and 64 d . Each control MOSFET is arranged immediately adjacent to its respective partial thyristor on the semiconductor wafer, so that operating delay times are limited and the symmetry of the circuit is ensured.

It should be noted that although the embodiment described here uses four parallel thyristor elements 64 a , 64 b , 64 c and 64 d , any desired number of elements could be used.

Claims (4)

1. Solid-state AC voltage relay with two antiparallel connected, ignitable thyristors, each having AC anode and cathode electrodes and a gate control circuit, with lighting devices for switching on the thyristors, and with respective control circuits with control transistors whose output circuits are connected to the gate control circuits of the associated thyri and in the connected state clamp the gate control circuits to the cathode potential of the respective thyristor in order to prevent the thyristors from igniting when the voltage between the AC voltage connections exceeds a predetermined value or when brief Im Pulse occur, which have a value of dV / dt , which is greater than a predetermined value, characterized in that the respective control circuits ( 230, 241 ) are formed by MOS field-effect transistors ( 240, 241 ) of the enhancement type, the source-Drai n output circuit is connected to the gate control circuit of the associated thyristor and the gate electrode of which is connected to the connection node of an associated capacitive voltage divider ( 236, 238/237, 239 ), the free connections of which in turn are connected to the AC connections ( 212, 213 ) forming anode or cathode connections of the thyristors, and that the respective capacitor ( 238, 239 ) of the capacitive voltage divider connected to the cathode connection of the associated thyristor is formed by the internal capacitance of the MOS field-effect transistors. 2. Solid-state AC voltage relay according to claim 1 or 2, characterized in that each control circuit ( 230, 231 ) includes a Zener diode ( 232, 233 ) which between the connection node ( 242, 243 ) of the capacitive voltage divider and the source electrode of the MOS field effect transistor ( 240, 241 ) is switched on in order to prevent overvoltage on the internal capacitance of the MOS field effect transistor. 3. Solid-state AC voltage relay according to one of the preceding claims, characterized in that the first and two th antiparallel connected thyristors ( 210, 211 ) are each formed with their associated control circuits on first and second semiconductor chips, that each thyristor on the semiconductor chip in the form a number of parallel-connected partial thyristors ( 64 a - 64 d ) is formed and that each partial thyristor ( 64 a - 64 d ) is assigned a MOS field-effect transistor ( 76-79 ), the gate electrodes of the MOS Field effect transistors of a semiconductor wafer are connected to one another and to a common capacitor ( 60, 61 ) which forms the capacitor of the voltage divider connected to the anode connection of the thyristor. 4. Solid-state AC voltage relay according to claim 3, characterized in that the first and second semiconductor chips and the illuminating devices are attached to the same surface of a ceramic substrate ( 260 ), and that the illuminating devices are formed by a common light-emitting diode ( 225 ).