DE102005048889A1 - Interface arrangement with electrical isolation for connection to an electrical device, in particular home appliance - Google Patents

Abstract

In the case of an interface circuit arrangement with electrical isolation between one or more signal output devices and / or signal receiving devices of an electrical device, in particular a domestic device, on the one hand and a control and evaluation device connecting to the device in question, on the other hand, the control device has its input and output levels on the output side or on the input side, level-adapted driver stages (T11, T12) are provided, which are connected via galvanic isolating devices (Op1, Op2) to driver stages (T12, T21) arranged on the side of the signal output devices and signal receiving devices mentioned, which are connected to the input and output levels of the Signal output and signal reception devices are capable of delivering or receiving adapted signal levels and which are set with regard to their operating points in such a way that they receive signals from signal delivery devices with output resistors on the input side able to process between a few tens of ohms and a few kiloohms and that on the output side they allow signal reception devices with input resistances between a few tens of ohms and one or more ten kilohms to be controlled.

Description

The The invention relates to an interface circuit arrangement with galvanic isolation for the connection between one or more signaling devices and / or signal receiving devices of an electrical device, in particular a household appliance on the one hand and a control and evaluation device to be connected to the relevant device on the other hand.

Interface circuitry is used for level and impedance adjustments between electrical devices and devices to be interconnected. In a known interface arrangement for automatic level adjustment ( DD 218 237 A1 For example, two optocouplers are used for the galvanic separation of the electrical devices or devices to be connected to each other. An impedance matching taking into account the impedances of the electrical devices or devices to be connected on the input side and the output side is not provided in this known interface arrangement.

Incidentally, optocouplers are also used in transmitting and receiving branches of electrical devices for galvanic isolation of these devices from a line arrangement ( US 6,272,220 B1 ). The relevant optocouplers, which are located both in the transmitting branch and in the receiving branch of the known circuit arrangement, are adapted on the input side and output side only to the level and impedances to be processed with this known circuit arrangement.

In addition, will Optocouplers in feedback branches used by switching power supplies to on the respective switching power supply load side determined voltage changes to translate into control signals on the network side of the respective Switching power supply to changes the switching frequency of a switching element provided there used become. In such a known switching power supply (see Siemens circuit examples, 1974/75, pages 127, 128, Figure 6.4.) Is one with the load or secondary side the relevant switching power supply connected driver stage in the form a transistor for the Control of an optocoupler provided on the output side a Transistor driver stage drives, with the one on the primary side of the concerned switching power supply provided switching transistor in his Switching frequency is controlled. By this scarf processing arrangement takes place Such a control of the voltage output from the relevant switching power supply, that is practically independent of load fluctuations constant output voltage is delivered. The input side with the relevant optocoupler and output driver stages are connected to the on their Side each present level and impedance conditions customized.

Of the The invention is based on the object, an interface circuit arrangement of the type mentioned above to make that with galvanic Separation as practically universal and bidirectional operable interface circuitry between one or a plurality of signal output devices and / or signal receiving devices an electrical device, in particular a household appliance on the one hand and a control device to be connected to the relevant device or evaluation is to use on the other hand.

Around to specify the above task even further noted that it is in the just mentioned signal output devices or signal receiving devices, for example, the signal output part or the signal receiving part of so-called standardized diagnostic or customer interfaces in electrical household appliances act can be connected to the control or evaluation equipment, each over an interface circuit arrangement with galvanic isolation. The requirement for the relevant galvanic separation results from the fact that the relevant tax or evaluation facilities on the one hand and the standardized diagnostic and customer interfaces on the other or the connected household appliances on the other hand with completely different from each other be operated different voltages or even mains AC voltage to lead can and that a direct coupling with all these voltages avoided for safety reasons must become. It can the signal levels as well as the input and output resistors in the Signaling devices and / or signal receiving devices and with it on the side of the mentioned Customer interface have a very large variance, which means covered by a single interface circuitry should.

The object is achieved in an interface circuit arrangement of the type mentioned in the present invention that on the output side and the input side level control adapted driver stages are provided to the side of the control and evaluation towards the input and output levels on the side of said signal output devices via galvanic separation devices and signal receiving means connected to the driver stages are connected, which at the input and output levels of the signal output and signal receiving devices able to output or receive matched signal levels and which are adjusted in terms of their operating points so that they are able to process signals from signal output devices with output resistances between tens of ohms and a few kilohms and on the output side signal receiving devices with input resistances between tens of ohms and one or more allow signal control of ten kiloohms.

The Invention brings with it the advantage that with relatively little circuit complexity a practically universally applicable and bidirectionally operable interface circuitry provided, in particular, for the connection of tax and evaluation devices to different household appliances or in these provided standardized customer interfaces with the mentioned huge Variance of input and output resistors is required.

Preferably are the mentioned ones Driver stages to the side of said signal output devices and signal receiving devices with regard to their operating points adjusted so that they input signals from signal output devices with output resistors be able to process between 68 ohms and 2 kOhms and that they are output side Signal receiving devices with input resistances between 68 ohms and 10 kOhm signal to control allow. In these resistance ranges of the output and input resistances of the relevant signal output devices or signal receiving devices operates the interface circuitry according to the present invention Invention impeccable.

Preferably are the mentioned ones galvanic isolation devices in the interface circuitry according to the invention formed by optocouplers. This will be a high dielectric strength with bringing galvanic isolation between the mentioned Signalabgabe- and Signal receiving equipment on the one hand and the tax and evaluation on the other hand with simple circuit components guaranteed.

Conveniently, contain the driver stages of the interface circuitry according to the present Invention each at least one transistor. This brings the advantage a particularly low circuit complexity with it. The concerned Otherwise, transistor driver stages can each be set to low Design input powers and short switching times and thus on required levels and currents one used as a control and evaluation, for example Adapt microcontroller.

Preferably point the driver stages to the side of the signal output devices and signal receiving devices on voltage limiting elements. This can be advantageously from these signal output devices and signal receiving devices forthcoming disturbing voltages, such as static overvoltages or increased Effectively limit the signal level.

The relevant voltage limiting elements are expediently each formed by a ZENER diode. This is a voltage limit easily accessible to a defined voltage level.

Preferably contain the driver stages to the side of the signal output devices or the signal receiving devices in each case at least one Tiefpassglied. This low-pass member may in individual cases preferably in addition to the respectively provided ZENER diode be provided; On the one hand, it serves as pulsed voltage relatively high amplitude immediately and strongly dampen, and on the other hand it serves to the possibly provided ZENER diode from destruction to protect by such voltage spikes.

Based In the drawing below, an interface circuit arrangement will be described according to a embodiment of the present invention.

at the interface circuit arrangement shown in the drawing according to the invention it is a practically universal and bidirectional operable interface circuitry that exists between a Control and evaluation (not shown) on the one hand and one or more signal output devices and / or signal receiving devices an electrical device and in particular a household electrical appliance connected on the other can be. As already mentioned above, the signal output devices or Signalempfangseinrich lines to a so-called standardized Diagnostic or customer interface of household electrical appliances belong. there This interface can be used in home appliances from different manufacturers a relatively large one Have variance of input and output resistors and levels. The output resistors the mentioned Signaling devices can between a few ten ohms and one or more kilo ohms, in particular between 68 ohms and 2 kohms, and the input resistances of the mentioned Signal receiving devices can between tens of ohms and one or more ten kilohms, in particular between 68 ohms and 10 kohms.

The interface shown in the drawing lenschaltungsanordnung according to the present invention is divided into two circuit parts by a shown in the middle of the drawing, running from top to bottom dashed line II. The on the ST (control side) designated left side of this dashed line II circuit parts of the relevant interface circuit arrangement are connected to the output or input side of a control and evaluation device not shown here. This control and evaluation device can be, for example, a microcontroller or a microprocessor. The on the GE (device side) designated right side of the respective dashed line II located circuit parts are to be connected to signal receiving devices or signal output devices not shown here or with the mentioned standardized customer interface of household appliances.

A represented in the drawing, extending in the horizontal direction Dotted line II-II divides the above-mentioned circuit parts of the interface circuit arrangement according to the invention in circuit parts (upper part in the figure), which for one signal transmission from the mentioned Control and evaluation device to a signal receiving device a device or household appliance are provided, and in circuit parts (lower part in the relevant drawing figure), which for the recording of signals from a signal output device of a device or household appliance and the transfer to the mentioned Control and evaluation serve.

Before to the structure of the circuit arrangement shown in the drawing discussed in more detail be, be first noted that for the lying in the control-side area ST circuit parts a Power supply is used by the power supply for the in the device side Range GE provided scarf processing parts is different. This means, that the power supply connections and of course the ground connections in the range ST and the ground connections in the area GE are not identical, but different from each other, so are not connected. This measure is for through the dashed line I-I indicated galvanic separation between the two areas ST and GE required.

Now the circuit arrangement shown in the drawing is considered closer. This circuit contains in the upper part of the control-side area ST here with a the output side of a control and evaluation device, not shown npn-type bipolar transistor T11 to be connected. This one input-side control stage on the ST-side forming Transistor T11 has its base connected to an input terminal E1 connected to the relevant control and evaluation can deliver an output signal. As already mentioned, can this control and evaluation device is a microcontroller or a microprocessor act. The transistor T11 is base side furthermore about an ohmic resistor R11 and the collector side via a ohmic resistor R12 connected to a voltage terminal U1, which can result in a DC supply voltage of, for example, + 5V. This supply voltage is effective against a terminal U01, which is connected to the ST-side ground.

Of the Transistor T11 has a current limiting resistor with its emitter R13 with one end of an LED element of an opto-coupler Op1 connected, whose LED element with its other end also connected to the ST-side ground.

One Phototransistor of the optocoupler Op1 is on the one hand with the GE side Ground connection and the other with the base of an output side Tax level on the GE side forming npn conductivity type transistor T12 and with the one End of an ohmic resistor R14 connected. The collector of the Transistor T12 is at one end of an ohmic resistor R15 connected to the other end together with the other End of resistor R14 via an ohmic resistor R16 connected to a voltage terminal U2 is, to which a GE-side DC supply voltage is supplied, for example, + 5V with respect to the GE side ground can. The emitter of transistor T12 is at the GE side ground this DC supply voltage. Between the connection points the Wi derstates R14, R15 and R16 on the one hand and the GE-side mass on the other is a capacitor C11. This capacitor C11 forms together with the resistor R16 a Tiefpassglied, which for over the Voltage connection U2 possibly coupled interference voltages to their suppression is effective. Furthermore This capacitor C11 is used to smooth the voltage of the voltage connection U2 supplied DC supply voltage.

Between the collector of the transistor T12 and the GE-side ground connection is a ZENER diode Z1, which may have, for example, a ZENER voltage of 5.5V. Further, an ohmic resistor R17 is connected to the collector of the transistor T12, to which a Tiefpassglied is connected, which be of a resistor R18 and a capacitor C12 be stands. Here, this low-pass member fulfills a corresponding task, such as the low-pass filter consisting of the resistor R16 and the capacitor C11. The remote from the connection point with the capacitor C12 end of the resistor R18 is connected to an output terminal A of the illustrated circuit arrangement, from which output signals are deliverable with respect to a connected to the GE-side ground terminal U02.

Either by the low-pass element, consisting of the resistor R16 and the Capacitor C11, as well as through the ZENER diode Z1 in conjunction with the resistor R17 and by the low-pass filter, consisting of the resistor R18 and the capacitor C12, are in the in the Drawing shown interface circuit arrangement of the Side of the signal receiving device coming from and about connections U2 or A1 coupled interference pulses and static overvoltages attenuated or harmless made. In the case of between the output terminal A1 and the collector of the transistor T12 connected components first causes the Low-pass filter, consisting of the resistor R18 and the capacitor C12 a damping from above this output terminal A1 coupled interference pulses, and then optionally still left permanent overvoltage passes over the resistor R17 to the ZENER diode Z1 and is through this on a for the Transistor T12 harmless Voltage level limited.

Now becomes the one below the dashed line shown in the drawing II-II illustrated circuit part of the interface circuit arrangement according to the present Invention closer considered.

This Circuit part contains on his input page on the right in the drawing figure an input-side control stage on the GE side with a transistor T21 of npn conductivity type, the one with his base over an ohmic resistor R21 connected to an input terminal E2 and in the present case with its collector over two ohmic resistances R22, R23 is connected to a voltage terminal U2 at which the same DC supply voltage of, for example, + 5V may be on the GE side ground, as on the GE side in the upper part the drawing figure shown voltage terminal U2 is supplied. With U02 here is also a connection with the same ground connection illustrated on the GE side.

Between is the junction of the two resistors R22 and R23 and the GE side ground a capacitor C21 which together with the resistor R23 is a low-pass filter forms and on the one hand as the capacitor C11 for smoothing over the Voltage connection U2 supplied DC supply voltage is used and the other together with the resistor R23 for an effective damping from above provides this voltage terminal U2 coupled interference voltages.

Between the base of the transistor T21 and the GE side ground are still a capacitor C22 and a ZENER diode connected in parallel therewith Z2 connected, which has a ZENER voltage of 5.5V, for example like to own. That of resistor R21 and capacitor C22 existing low-pass filter and the Zener diode Z2 meet here each have the same tasks as the already mentioned low-pass filter, consisting of the resistor R18 and the capacitor C12, and the ZENER diode Z1. In any case, here is a double protection function implemented to protect the respective transistor T12 or T21.

Of the Transistor T21 has an ohmic resistance with its emitter R24 with one connection of the LED element of an optocoupler Op2 connected, its LED element with its other connection on the GE side ground.

One belonging to the optocoupler Op2 Phototransistor is with its a connection with the ST-side Mass connected, and with his other connection he is with the Base of a transistor T22 connected npn conductivity type. This to an output-side control stage of below the in the drawing shown Strichpunktli never II-II provided circuit part belonging Transistor T22 has an ohmic resistance with its base R25 and with his collector over an ohmic resistor R26 connected to a voltage terminal U1, which may be the same voltage connection as he has been mentioned above in connection with the transistor T11.

Of the Transistor T22 is collector side with an output terminal A2 connected, over an ohmic resistor R27 is on the ST side ground. Between the output terminal A2 and one on the ST-side ground Connection U01 can be the one mentioned above Control and evaluation device to be connected on the input side.

Of the Emitter of the transistor T2 is in the present case directly on the ST-side mass.

The above-mentioned transistors T11 and T21 constitute, as mentioned, in each case an input-side driver stage for the respective optocoupler Op1 or Op2. The driver stage comprising the transistor T11 is at a control and off value device (not shown) connected, which, as mentioned, may be formed by a microcontroller or microprocessor. By contrast, the driver stage comprising the transistor T21 can be connected to a signal output device of an electrical appliance or domestic appliance and in particular to the above-mentioned standardized customer interface of such a domestic appliance.

The Transistors T12 and T22 each provide an output driver stage for the respective optocouplers Op1 and Op2, and they are output side on the one hand with a signal receiving device of an electrical equipment or household appliance or the mentioned Control and evaluation connected by the mentioned microcontroller or microprocessor can be formed. The ST-side, the transistors T11 and T22 comprehensive driver stages are by appropriate dimensioning their base and collector side provided resistors R11, R12 and R25, R26 on the input side or output side to the input level or Adjusted output level of the control and evaluation. These Control and evaluation works in the present case also with a supply voltage of + 5V, so like the transistors T11 and T22.

The GE side driver stages are with their transistors T12 and T21 to the input or output levels the one to be connected to it Signal receiving or signaling devices adapted. Besides, they are the relevant driver stages with the transistors T12 and T21 in terms of their operating points by appropriate dimensioning their base and collector side provided resistors R14, R15 and R21, R22 are set to output signal receiving equipment with input resistors between tens of ohms and one or more ten kilohms, in particular between 68 ohms and 10 kOhms allow safe driving and that on the input side signals from signal output devices with output resistors between a few tens of ohms and a few kilohms, especially between 68 ohms and 2 kOhm to receive, so signalially secure to allow capture. This is the consideration the relatively large one Variance in the input and output resistors of the GE side of the interface circuitry according to the invention to be connected Signal receiving or signaling devices considered.

In conclusion, be yet noted that the interface circuitry according to the invention also with other supply voltages and also with other semiconductor devices can be operated as in the previously explained embodiment have been specified. So can the in the mentioned Driver stages used npn transistors by transistors of a other conductivity types or by thoroughly be replaced with other transistors or other semiconductor devices. Furthermore can the mentioned Optocoupler formed by other galvanic separation devices be such as by transformers. Finally, the two low-pass filters, consisting of the resistor R16 and the Capacitor C11 on the one hand and from the resistor R23 and the capacitor C21 on the other hand, by a single, a resistance and a Capacitor existing low-pass filter to be replaced. In any case is thus a reliable operating interface circuit arrangement with galvanic isolation between their two sides available, the on their device connection side a relatively high variance of input resistances and output resistances of to be connected electrical appliances, in particular of household appliances to take into account is.

A1

output port

A2

output port

C11, C12, C21, C22

capacitors

E1

input port

E2

input port

GE

device-side circuit parts

I-I

Chain line

II-II

Chain line

op1, op2

optocoupler

R11, R12, R13, R14, R15, R16, R17,

resistive resistors

R 18, R21, R22, R23, R24, R25, R26,

R27

ST

the control side circuit parts

T11, T12, T21, T22

transistors

U01

connection

U02

connection

U1

voltage connection

U2

voltage connection

Z1, Z2

Zener diodes

Claims (7)

Interface circuit arrangement with galvanic isolation between one or more signal output devices and / or signal receiving devices of an electrical device, in particular a domestic appliance on the one hand and a device to be connected to the control and evaluation device on the other hand, characterized in that the side of the control device out at their input and output levels Output-level or input-side adjusted drivers stages (T11, T12) are provided, which are connected via galvanic isolation devices (Op1, Op2) to the side of said signal output devices and signal receiving devices arranged towards the driver stages (T12, T21), which adapted to the input and output levels of the signal output and signal receiving devices Able to output signal level and which are adjusted in terms of their operating points so that they are able to process signals from signal output devices with output resistances between tens of ohms and a few kiloohms and that they output side signal receiving devices with input resistances between tens of ten and one or more tens Allow signal to drive Kiloohm signal. Interface circuit arrangement according to claim 1, characterized in that the driver stages (T12, T21) to the side said signal output means and signal receiving means in terms of their operating points are set so that they input side Signals from signal output devices with output resistors between 68 ohms and 2 kOhm capable of processing and that they output side Signal receiving devices with input resistances between 68 ohms and 10k Ohm signal to drive allow. Interface circuit arrangement according to claim 1 or 2, characterized in that the galvanic separation devices (Op1, Op2) are formed by optocouplers (Op1, Op2). Interface circuit arrangement according to one of claims 1 to 3, characterized in that the driver stages (T11, T22, T12, T21) in each case at least one transistor (T11, T22, T12, T21) contain. Interface circuit arrangement according to one of claims 1 to 4, characterized in that the driver stages (T12, T21) to the side of the signal output devices and signal receiving devices Voltage limiting elements (Z1, Z2) have. Interface circuit arrangement according to Claim 5, characterized in that the voltage limiting elements (Z1, Z2) are each formed by a ZENER diode (Z1; Z2). Interface circuit arrangement according to one of claims 1 to 6, characterized in that the driver stages (T12, T21) to the side of the signal output devices and the signal receiving devices in each case at least one low-pass element (R18, C12, R16, C11, R21, C22) contain.