DE4023412A1 - Inductive coupling for electrical energy of signals - uses bandpass filter with periodic short-circuiting of secondary oscillation circuit - Google Patents

Abstract

The inductive coupling comprises a bandpass filter with primary and secondary oscillation circuits (26). The secondary oscillation circuit (6) is periodically short-circuited by a diode switched between its conductive and non-conductive states. Pref. the periodic short-circuiting of the secondary oscillation circuit (6) is effected in the LF range, the HF current in the secondary oscillationm circuit used during the blocking condition of the diode for providing the current supply for the secondary oscillation circuit (6). USE - For supplying electrical energy from primary to secondary unit and feeding signals back from secondary to primary unit, e.g. for window or door glass breaking alarm.

Description

The invention relates to a method for contactless, induc tive transfer of both electrical supply energies from a primary unit to a secondary unit as well as from Sig from the secondary unit to the primary unit using a a primary-side and a secondary-side resonant circuit having band filter. The invention further relates to a contactless, inductive transformer for performing the Procedure.

DE-C-30 29 543 is a contactless, inductive over known carrier, which is the opposite transfer of energy and signals. Via a first 2-circuit band file ter is the electrical supply energy and over a two tes 2-circuit band filter are signals in the opposite direction transfer. The special feature of this arrangement is there rin that the bandpass filter is coupled critically or supercritically are. As a result, it is no longer necessary to use the primary or second keep the unit constant in their positions relative to each other, so that the manufacturing tolerances with similar transformers can be relatively large or a change in position in buying genome men can be. Another advantage is that the The voltage on the secondary circuit is then also essentially constant remains when the distances of the primary and secondary coils in vary to a certain extent. Although this scarf has well proven arrangement, it still has the disadvantage  that a band filter for both the energy transfer transmission as well as for signal transmission is required which leads to increased circuit complexity and especially in certain applications regarding the Space is demanding.

From EP-A-3 16 872 an alarm transmitter arrangement with a Contactless, inductive transformer known in which the over carrying both the electrical supply energy into one Direction as well as the signals in the other direction over one only band filter is done. For this, the band filter is in ner function from the supply energy transfer to the Signal transmission and vice versa periodically switched. Next a still relatively high circuit complexity due to the need to use electronic switches this circuit arrangement has the disadvantage that during the time in which the signal transmission is switched over, the energy transfer from the primary to the secondary side the filter is interrupted so that no continuous, continuous animal energy transfer is possible.

In the unpublished DE-A-40 11 941 thereof The applicant is a method for contactless, inductive Transmission as well as a contactless, inductive transformer for Proposed implementation of the procedure in which the secondary circuit is periodically short-circuited. This ensures a continuous, uninterrupted energy transfer also during signal transmission, and vice versa, with low circuit complexity possible. With this Method or transmitter, which or preferably together is used with an alarm device arrangement, the Energy absorbed by the secondary unit on the alarms sensor, for example a glass break detector, and on the scarf divided part of the secondary unit, which for retransfer signals from the secondary unit to the primary unit  is provided. The secondary resonant circuit switched diode is the first rectifier stage from which the secondary unit and the sensor are supplied. The on this diode consumed power passes in the energy wear lost. The sensor needs - as well conventional, known arrangements of this type - a minimum Supply voltage of approximately 4 volts due to its own Rectifier stage, a possibly provided light diode and a thyristor to turn the lights on and off diode and a current limiting resistor. This means, that only a small fraction of that from the primary unit consumed power can be used.

The invention is therefore based on the object of a method and a circuit arrangement for contactless, inductive To transmit electrical energy and / or signals give or create, in which or on which the Se customer unit transmitted power can be optimally used can.

This object is achieved in that the secondary-side resonant circuit of the bandpass filter via a diode, which periodically in the conductive or non-conductive state is brought, is short-circuited periodically.

In other words, the secondary-side resonant circuit a diode periodically placed in parallel. This makes the be required voltage in the secondary unit and thus the Loss of power much less than this conventional methods and circuit arrangements is the case. In this case, the diode itself acts as a rectifier used.

It is particularly advantageous if the periodic short close the secondary-side resonant circuit in the low  frequency range.

According to a particularly advantageous embodiment of the Erfin This is done via the band filter on the secondary unit transmitted high-frequency current of the secondary-side vibration circle during a low frequency half period, during the the diode does not conduct power to the secondary side circuitry used. During the low frequency half-period during which the diode does not conduct, so The no-load voltage increases via the diode to relatively high values (5 to 15 volts). This will turn on simple way a sufficiently high supply voltage and sufficient supply power for electricity or Power supply to the circuit arrangement of the secondary part achieved.

According to a preferred embodiment of the invention, the High-frequency current of the secondary-side resonant circuit during the half period during which the diode does not conduct sets up and buffered. In this way, there is an im substantial continuous power supply to the circuit arrangements of the secondary unit with a sufficiently high Voltage level above 2 volts due to buffering for example in an appropriately dimensioned capacitor during the half-period during which the diode lei tet.

The diode is preferably a light-emitting diode. On Because of the measure according to the invention, the diode to the secondary Periodically placing the resonant circuit in parallel flows a maximum current because the light emitting diode itself as equal judge acts and causes no further voltage drops devices between the light emitting diode and the driving voltage source, i.e. the secondary vibration circle lying. This means that the light emitting diode  glows considerably brighter than conventional arrangements. The tension breaks in the half-period during which the light-emitting diode conducts and lights up to 1.8 volts together, d. H. it falls under those for operating the the circuitry provided for the secondary unit voltage of approx. 2 volts. However, since the half period during which the light emitting diode does not conduct and does not light up for the generation of a sufficiently high one Supply voltage is exploited, as is already the case has been explained, the brief collapse of the Voltage to values below the required supply voltage no disadvantages for the function of the circuit arrangement.

According to a particularly advantageous embodiment of the Er periodic short-circuiting of the secondary takes place -sided resonant circuit depending on different signal states occurring in the secondary unit with under different frequencies and / or duty cycles. This be indicates that those to be transferred back to the primary unit Signals depending on their different signal states due to different frequencies and / or duty cycles, and so that the message to be transmitted can be encoded or can.

It is advantageous if the signal is evaluated statuses of the secondary unit - and thus the one to be transferred Message - by determining the different fre sequences and / or duty cycles in the primary unit follows. The different frequencies or the difference Lactations are namely different by one electricity consumption can be seen on the primary side. To how Avoid repetitions is based on the explanations in the DE-A-40 11 941 with regard to the signal evaluation in the Primary referenced.  

According to the invention, the object is also achieved with a Transmitter for contactless, inductive transmission both electrical supply energies from a primary unit to a secondary unit as well as signals from the secondary unit to the primary unit by means of a one on the primary side and a band-side film having a secondary-side resonant circuit ters by a first diode and a first oscillator circuit solved with a first oscillator frequency, the first Oscillator circuit the first diode to the secondary side Periodically sets the resonant circuit in parallel. The diode is in the Contrary to conventional circuit arrangements do not have a separate transistor, but according to the invention by one Oscillator driven, the diode itself being equal judge serves. As already described, with this feature a significantly lower voltage needed.

According to a preferred embodiment of the invention additionally at least one further diode and at least one another oscillator with a different oscillator frequency, such as a second diode and a second oscillator provided with a second oscillator frequency, the white tere or second diode the secondary-side resonant circuit pe periodically parallel. In this way, each result after which of the provided oscillators in the working Condition brought, different frequencies or tact conditions with which the secondary-side resonant circuit is short is closed, so that different messages can be transferred and evaluated in the primary unit. When using the circuit arrangement according to the invention in connection with an alarm arrangement can both the alarm as well as the non-alarm state are transmitted and he be known. In connection with a glass break detector arrangement on windows or doors, it is possible with one simple circuit arrangement the non-alarm state  Alarm state and in the event that no modulation occurs, also to recognize whether the window or the door is open or there is sabotage or the alarm arrangement is defective. Al Alternatively, it is also possible to provide only one diode and the diode by means of an oscillator on the secondary side Periodically lay the resonant circuit in parallel, the oszilla gate frequency according to the present and to be transmitted Signal state is selected differently.

It is particularly advantageous if the diode has a Push-pull output stage of the oscillator on the secondary side The oscillating circuit is periodically placed in parallel. The push-pull The output stage of the oscillator circuit then switches accordingly immediately after its activation, which means that only a very small voltage drop of 10 to 20 mV occurs, and the minimum operating voltage is kept low can be.

According to an advantageous embodiment of the invention the first oscillator frequency the alarm condition and the second Oscillator frequency to the non-alarm state of an alarm transmitter order assigned. This way there is a clear difference between the signal or alarm states and in the Primary unit due to the different frequency of the Change in power consumption recognizable.

An embodiment of the invention is particularly advantageous, in the case of the at least one diode, a light-emitting diode is. In this way there is an alarm on the secondary part easily arrange a visual display above the Alarm or non-alarm state, or also possible whether an alarm system works reliably.

It is particularly advantageous if at least one of the Oscillator frequencies in the frequency resolution range of humans  lichen eye, i.e. below about 20 Hertz. Since that human eye a discontinuous glow of a light better recognizes source even with relatively low light emission, it is possible to use a small light emitting diode To operate power consumption.

The invention will hereinafter be described with reference to the only one Circuit explained using the example of a glass break detector arrangement tert.

A transmission oscillator and evaluation circuit 1 is connected to a primary-side resonant circuit 2 of a bandpass filter 3 . The primary-side resonant circuit 2 consists of a primary-side coil 4 of the bandpass filter 3 and a parallel-connected primary-side resonant circuit capacitor 5 . A se secondary-side resonant circuit 6 consists of a secondary-side coil 7 of the bandpass filter 3 and a secondary-side resonant circuit capacitor 8 , the secondary-side coil 7 of the bandpass filter 3 being inductively coupled to the primary-side coil 4 .

The transmit oscillator and evaluation circuit 1 and the resonant circuits 2 and 6 and their inductive coupling via the bandpass filter 3 are described in detail in their functions and embodiments in DE-A-40 11 941, so that - to avoid repetition - reference is made to them becomes.

The anode of a rectifier diode 9 is connected to a connection point Ver of the secondary coil 7 and the secondary resonant circuit capacitor 8 , while its cathode with a connection of a filter and buffer capacitor 10 , a reset generator 11 , an alarm storage circuit 12 , the counter clock output stage of a first oscillator 13 and the counter clock output stage of a second oscillator 14 is connected. The filter and buffer capacitor 10 , the reset generator 11 , the alarm memory 12 , the other connection of the push-pull output stage of the first oscillator 13 and the other connection of the push-pull output stage of the second oscillator 14 are with the other, defined as ground connection of the secondary side resonant circuit 6 connected.

The inverting output of the reset generator 11 is connected to the alarm memory 12 . An output of the alarm memory 12 is connected to the control input of the first oscillator 13 . Another output of the alarm memory 12 is connected to the control input of the second oscillator 14 .

One connection of the secondary-side resonant circuit 6 , to which the anode of the rectifier 9 is connected, is connected to the respective anodes of diodes 17 and 18 , the cathode of the diode 17 at the output of the push-pull output stage of the first oscillator 13 and the cathode of the Diode 18 is connected to the output of the push-pull output stage of the second oscillator 14 .

The control input of the alarm memory 12 is connected to ground via a transistor 20 . This is controlled by a sensor circuit 21 , which may contain a glass break detector, for example.

The schematically illustrated embodiment of the fiction moderate circuit arrangement, as in connection with the An embodiment of an alarm arrangement is described works as follows:

When the alarm generator arrangement is switched on, the reset generator 11 , which is constructed in a manner known per se and is in the form of an integrated circuit, provides an inverted reset output signal which is fed to the circuit 12 and stores it in a defined manner in one of the two Non-alarm brings corresponding memory status.

The voltage transmitted from the primary unit via the bandpass filter 3 to the secondary-side oscillating circuit 6 is rectified by means of the rectifier diode 9 and sieved and buffered in the filter and buffer capacitor 10 , so that one for the reset generator 11 , the alarm storage circuit 12 and the oscillator circuits 13 and 14 essentially constant supply voltage is provided.

The operation of the circuit arrangement for the case in which no alarm occurs, ie when the sensor circuit does not emit an alarm signal, will first be described. In this case, the transistor 20 , which can also be seen in its function as a key switch, remains in the non-conductive state. Therefore, the alarm storage circuit 12 outputs a low-level output signal to the first oscillator circuit 13 so that it blocks. A high-level signal is therefore present at the output of the first oscillator circuit 13 , so that the diode 17 , which can be a light-emitting diode, is not conductive and therefore does not light up.

If there is no alarm, a high-level output signal from the alarm storage circuit 12 reaches the control input of the second oscillator circuit 14 . As a result, a low-frequency square-wave signal occurs at the output of the second oscillator circuit 14 or the push-pull output stage of the second oscillator circuit 14 is very low-impedance, so that the cathode of the diode 18 is periodically put at practically 0 volts or ground and current can flow through it . In the push-pull output stage of the second oscillator circuit 14 , the voltage drop is very small and in the order of magnitude of at most 20 mV. Thus, while current flows through the diode 18 , the resonant circuit is essentially short-circuited.

The oscillator frequencies of the oscillator circuits 13 and 14 are selected differently and are, for example, in a ratio of 1:10. The oscillator circuit 13 oscillates, for example, at a frequency of 1 Hz and the second oscillator circuit 14 is operated at a frequency of 10 Hz.

Due to the load on the secondary-side resonant circuit 6 by the periodically conductive in the case of non-alarm and thus constituting a short circuit 18 , a corresponding change in the frequency of the second oscillator circuit 14 results in a load change in the primary unit, which can be detected by the evaluation circuit thereof, whereby the proper functioning of the system can be determined.

Since the diode 18 serves as a rectifier in the case of the non-alarm or OK state and conducts only one half period of the low-frequency period of the secondary-side resonant circuit 6 , the output of the secondary-side resonant circuit 6 rises during the low-frequency half-period, during which the diode 18 does not conduct, the open circuit voltage to relatively high values of 5 to 15 volts, which are rectified in the rectifier diode 9 , buffered in the filter and buffer capacitor 10 and provided to the individual circuit stages of the secondary unit as a supply voltage. This means that a continuous supply voltage of sufficient level is also available for the low-frequency half-period during which the diode 18 conducts and represents a short circuit.

The functioning of the circuit arrangement for the case in which an alarm occurs, that is to say when the sensor circuit emits an alarm signal, is described below. In this case, the transistor 20 is at least briefly switched to the conductive state and the alarm storage circuit 12 , which can be a flip-flop, for example, stores this alarm state and emits a high-level signal at its output, which is sent to the control input of the second oscillator circuit 14 arrives and blocks, so that a high-level signal is present at the output. This means that no current can flow through the diode 18 in this case.

In contrast, the alarm storage circuit 12 provides the control input of the first oscillator circuit 13 with a high-level output signal, so that it begins to oscillate and provides a low-level signal at its output. The diode 17 , which can also be a light-emitting diode such as the diode 18 , is therefore periodically conductive in this case and represents a periodic short-circuit for the secondary-side resonant circuit 6. As a result, the frequency of the first oscillator circuit 13 or a given duty cycle occurs a change in load in the primary unit, which in turn can be determined in the evaluation circuit, as described in DE-A1-40 11 941 in an individual. Since the frequency of the first oscillator circuit 13 differs from the frequency of the second oscillator circuit 14 , the evaluation circuit of the primary unit is also able to distinguish between the two signal states of the secondary unit, that is to say between the non-alarm state and the alarm state.

With regard to the continuous provision of a sufficiently high supply voltage for the switching stages of the secondary unit, what has been said in connection with the case of the non-alarm applies accordingly and should not be repeated again. This means that regardless of which alarm state is present and which of the diodes 17 or 18 are periodically conductive, a continuous, stable voltage supply with a sufficiently high voltage is always ensured for the circuit arrangements of the secondary unit.

During the low frequency half period, during which Secondary resonant circuit is short-circuited, the diode is in a high-frequency half-cycle alternately not conductive. In the oscillating circuit can recover during this time. Under the In this context, the term low frequency is said to be a Frequency are understood to be less than the radio frequency with which the resonant circuits vibrate. In the illustrated Low frequencies are, for example, in the exemplary embodiment Range from 1 to 50 Hz. However, they can also be essential be chosen higher.

With the circuit arrangement according to the invention it is possible to significantly increase the efficiency of the secondary unit, d. that is, with significantly less power for the operation of the Se get along with the customer unit. This is particularly why Meaning because the secondary unit is about in the case of a house alarm arrangement with glass break detectors in the event of a power failure with a Battery must be supplied for at least 72 hours. Here Conventional circuit arrangements of this type have a current absorption from 10 to 20 mA. With the measures according to the invention and features, the current consumption could only be approx. 1 mA can be reduced to 1/10. Furthermore, with the invention a significant reduction in radio frequency radiation and this makes it easier to comply with postal regulations.

If a light-emitting diode is used as the diode 17 and / or 18 , the power consumption for the optical display of the alarm state and / or the non-alarm state is substantially lower than in conventional arrangements, without the display intensity suffering as a result. This is because the diodes are only operated for half a period and the flashing frequency can be selected in the visible range in which the eye can better perceive a flashing light source even with less light emission. This further helps to manage with a low power consumption of the secondary unit and this has the additional advantage that the transmission quality of the bandpass filter 3 can be lower than in conventional arrangements of this type, so that greater tolerances with regard to the variable distance between the coils of the bandpass filter 3 are allowed.

The oscillator circuits can, for example, CMOS scarf arrangement, such as Schmitt trigger. The sensor scarf tion is also of conventional design and not an object of the present invention.

Since the secondary unit men and features can be constructed much simpler and more compact due to the measures and features of the invention, it is possible to parts, namely Sen sensor, for example glass breakage detectors, high-frequency circuit parts, rectifiers and the circuit stages, for example in the form of Logic circuit parts can be present in the housing of the sensor, such as the glass break detector itself, which was previously not possible. It now only needs a cable for the connection of the secondary unit with the secondary coil 7 of the bandpass filter 3 be used ver.

The invention has been described in a preferred embodiment described in connection with an alarm device arrangement ben. However, refinements and modifications are known to the person skilled in the art possible without leaving the inventive idea becomes. For example, instead of just two diodes for the Short circuit and accordingly only two oscillator circuits with  different frequencies also other diodes and Oszilla Gate circuits can be used to receive more than two signals determine the status and be able to evaluate it in the primary unit nen.

Claims (15)

1. A method for contactless, inductive transmission both of electrical supply energies from a primary unit to a secondary unit and of signals from the secondary unit to the primary unit by means of a band filter having a primary-side and a secondary-side resonant circuit, characterized in that the secondary-side resonant circuit of the bandpass filter via a diode , which is brought into the conductive or non-conductive state periodically, is periodically short-circuited. 2. The method according to claim 1, characterized in that the periodic short-circuiting of the secondary Resonant circuit is in the low frequency range. 3. The method according to claim 1 or 2, characterized in that the high frequency current of the secondary side oscillation circle during the low frequency half period, during which does not conduct the diode, to power the secondary circuit arrangement is used. 4. The method according to any one of the preceding claims, characterized characterized in that the high frequency current of the secondary side resonant circuit during the half period, during that does not conduct the diode, rectified and buffered becomes. 5. The method according to any one of the preceding claims, characterized characterized in that the diode is a light emitting diode is. 6. The method according to any one of the preceding claims, characterized  characterized in that the periodic short-circuiting of the se customer-side resonant circuit depending on below different signal appearing in the secondary unit conditions with different frequencies and / or under different duty cycles. 7. The method according to any one of the preceding claims, characterized characterized by the use in connection with a Alarm device arrangement. 8. The method according to any one of the preceding claims, characterized characterized that the different signal states the non-alarm state and the alarm state are. 9. The method according to any one of the preceding claims, characterized characterized in that the evaluation of the signal states of the Secondary unit by identifying the different Frequencies and / or duty cycles in the primary unit he follows. 10. Transmitter for contactless, inductive transmission both of electrical supply energies from a primary unit to a secondary unit and of signals from the secondary unit to the primary unit by means of a band filter having a primary-side and a secondary-side resonant circuit, characterized by a first diode ( 17 and 18 ) and one first oscillator circuit ( 13 or 14 ) with a first oscillator frequency, the first oscillator circuit ( 13 or 16 ) periodically placing the first diode ( 17 or 18 ) in parallel with the secondary-side resonant circuit ( 6 ). 11. Transformer according to claim 10, characterized by a second diode ( 18 or 17 ) and a second oscillator circuit ( 14 or 13 ) with a second oscillator frequency, the second oscillator circuit ( 14 or 13 ) the second diode ( 18th or 17 ) periodically places the secondary-side resonant circuit ( 6 ) in parallel. 12. Transformer according to one of claims 10 or 11, characterized in that the diode ( 17 or 18 ) is periodically parallel to the oscillating circuit ( 6 ) on the secondary side via a push-pull output stage of the oscillator ( 13 or 14 ). 13. Transformer according to one of claims 10 to 12, characterized characterized in that the first oscillator frequency Alarm state and the second oscillator frequency the Non-alarm state assigned to an alarm device arrangement is. 14. Transformer according to one of claims 10 to 13, characterized in that at least one diode ( 17 , 18 ) is a light-emitting diode. 15. Transformer according to one of claims 10 to 14, characterized characterized in that at least one oscillator frequency in Frequency resolution range of the human eye.