DE102007009520B4 - Interface for digital signals and mains voltage signals, with switchable constant current source - Google Patents

Abstract

Interface comprising an input terminal (K-K ') for selectively receiving mains AC signals (U network) or digital low-voltage signals (U BUS), characterized in that the input terminal is connected to a mains voltage-proof switch (T1) operating in receive mode upon application of a Mains voltage signal or a high-level digital signal at the input terminal a current source (KSQ) turns on, the primary side of a potential separation element (OKE) feeds, on the secondary side of the interface provides output signals that in a transmission mode, the mains voltage-proof switch (T1) selectively the input terminal (K- K ') short circuits.

Description

The present invention relates to an interface with an input port for selectively receiving AC power or low voltage digital signals. Moreover, the present invention relates to a dimmable operating device required for operating at least one light source, which has a corresponding interface for data exchange with a control device via a bus.

Various multifunctional interfaces for controlling dimmable lamp or LED operating devices connected to a bus are known from the prior art. Among other things, there are interfaces for dimming one or more discharge lamps or LED modules controlled via an operating device. In this case, the interface can optionally be controlled via push-button or switch signals or via digital control signals. A connected lamp operating device can be such. B. by a short press on or off and be dimmed by a long key press or. In addition to the pushbutton or switch operation, unidirectional or bidirectional operation is also possible with these interfaces, in which digital control commands, which represent, for example, setpoint values for a brightness control, are transmitted from the control device connected to the bus to the operating device or status feedback of the operating device become.

Multifunctional interfaces must be able to pass both digital signals from a low voltage range between, for example, -10 V and +30 V on the one hand and mains voltage signals on the other hand usable to the lamp operating device, the interface must not be damaged even with a long-lasting concern of a mains voltage signal. This means that a line voltage-proof reception branch as well as a transmission branch designed only for digital low-voltage signals must be provided.

In this context, especially in the WO 2006/010417 A1 disclosed bidirectional interface having a transmission branch with an RF power transformer.

The published patent application of the international application WO 2005/004552 A1 discloses an interface for a driver device for a lamp. The interface has two input-side terminals for connecting bus lines or for connection to a switch or pushbutton, an evaluation logic for processing signals arranged at the input-side terminals and for generating output-side signals for controlling the driver device for the lamp, and at least one galvanic separating element. to electrically isolate the input side terminals from the driving device for the lamp. The Auswertelogik is arranged on the side of the galvanic separating element, which is assigned to the input-side terminals, and which is supplied with a voltage from the input-side terminals with voltage.

The European patent application EP 1 473 976 A1 discloses an interface for driving electronic devices such as electronic ballasts. The interface has two input-side terminals U _IN1 , U _IN2 , to which either a digital signal or a mains voltage signal is applied. The two input-side terminals U _IN1 , U _IN2 are connected to a potential separation element GT. Between one of the two input-side terminals U _IN1 , U _IN2 and the potential separation _element GT is a series circuit consisting of an ohmic resistor R1 and a PTC element PTC provided.

The publication WO 00/69044 shows a 0-10 V dimming interface protection circuit. The 0-10V dimming interface protection circuit includes a first device for limiting a current serially between a mains voltage source and the first terminal of the dimming interface, a second device connected to the first and second terminals for detecting the presence of a mains voltage and generating a control signal, and a third device capable of increasing the resistance of the first device so as to limit a light output of a lamp.

The international publication WO 2006/010416 A2 discloses a method for controlling transmissions of a bidirectional interface. The interface comprises a transmission branch and a reception branch connected to the transmission branch. The method comprises steps of transmitting information by means of the transmission branch and determining defined features of the transmitted information by the reception branch of the same interface. Parameters of the transmission branch are adapted in accordance with the evaluated transmitted information in such a way that subsequently transmitted information is transmitted using the adapted parameters.

The publication US 2004/0140777 A1 shows a digital addressable lighting interface (DALI) that is powered by a high voltage circuit when the digital addressable lighting interface is in standby. The DALI interface remains in the Standby mode until a signal is detected on a DALI bus, or the DALI interface is periodically switched from standby mode to active mode to detect activity on the DALI bus. If no activity is detected on the DALI bus, the DALI interface returns to standby mode. If an activity is detected, the DALI interface remains in active mode. The DALI interface remains in active mode as long as a power controller delivers power to an electrical device.

OBJECT OF THE PRESENT INVENTION

In view of this prior art, the object of the present invention is that of the WO 2006/010417 A1 To simplify known interface circuit technology so that a cost saving is given. Of course, the requirements for the interface with regard to the strength against voltage spikes or a permanent concern of the mains voltage should be met.

SUMMARY OF THE INVENTION

According to the invention, this object is solved by the features of the independent claims. The dependent claims form the central idea of the invention in a particularly advantageous manner on.

The present invention according to a first aspect relates to a unidirectional interface having an input terminal for selectively receiving a mains AC voltage or a digital low-voltage bus voltage and a transmitting branch provided for transmitting digital low-voltage signals to a bus.

According to the invention, the input terminal is connected to a mains voltage-proof switch which, when receiving a mains voltage signal or a high-level digital signal at the input terminal, switches on a current source which feeds the primary side of a potential separation element (OK _E ) to the secondary side of which the interface provides output signals. In a transmission mode according to the invention, the mains voltage-proof switch selectively closes the input terminal (K-K ') for a short time.

In this case, a controllable power switch serving for the selective temporary short-circuiting of the bus voltage is provided in the transmitting branch, which is preferably the only mains voltage-resistant semiconductor switching element of the interface. The mains voltage-proof circuit breaker is part of a switchable constant current source which feeds an optocoupler on the primary side in the receive mode, for example.

The transmission branch is fed via a galvanically isolated from the interface external power supply of a switching power supply with a supply voltage.

In addition, the interface according to the invention has means for potential-free coupling via the reception branch recorded signals in which it is z. B. can act on the primary side via the constant current source with a current of an approximately constant current supplied optocouplers.

An included in the interface circuit, non-line voltage solid designed controllable semiconductor switch is used to cause the through-connection operation by switching the mains voltage fixed designed controllable circuit breaker in a low-resistance state. This controllable semiconductor switch which is not designed for line voltage can be, for example, a MOS field-effect transistor connected on the drain side to the receiving branch and the base of a bipolar transistor connected to the collector side of a control electrode of the mains voltage-proof circuit breaker. The bipolar transistor of the constant current source can be z. B. are operated in an emitter circuit with current negative feedback, the emitter electrode is connected to the primary side of the integrated opto-coupler in the receiving branch.

Furthermore, it can be provided according to the invention that the switching behavior of the semiconductor switch in transmission mode is delayed by a suitable external circuit. This can be z. Example, with the aid of a switched between the source of this semiconductor switch and the ground node of the interface circuit ohmic resistance (source resistance), by which the source voltage of the controllable semiconductor switch is raised relative to the ground potential of the interface, and with the help of one with the Gate electrode of this semiconductor switch and the ground node of the interface connected, consisting of the parallel connection of a charging capacitor (gate capacitance) and a discharge resistor charging / discharging circuit, which are provided according to the invention for adjusting the edge slopes of the interface digital low-voltage signals sent.

According to a second aspect, the present invention relates to a bidirectional interface which has an input terminal for optionally, receiving a mains alternating voltage signal, for example from a pushbutton or switch or a digital low-voltage bus voltage signal and for transmitting digital low-voltage signals by means of a transmission branch. In the transmitting branch, a controllable circuit breaker is provided for selectively short-circuiting the bus voltage. This is designed as mains voltage resistant semiconductor switching element. The mains voltage-resistant power switch is part of a switchable constant current source, which keeps the current strength of a current flowing in a receiving mode through the receiving branch upon receipt of a signal at a stable, approximately constant level.

Like the unidirectional interface described above, the bidirectional interface according to the invention also has means for potential-free coupling via the reception branch of transmitted signals to a bus line of the bus, in which it is z. B. is a primary side via the constant current source supplied with a current optocoupler.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following, further features and embodiments of the present invention will be explained in more detail with reference to the accompanying drawings.

1a FIG. 12 is a schematic diagram of a unidirectional interface that allows low voltage digital signals to be received over a bus. FIG.

1b shows a schematic diagram of a bi-directional interface that allows sending and receiving low-voltage digital signals over a bus,

2a shows a circuit realization of the unidirectional interface according to the invention,

2 B shows a circuit realization of the inventive bidirectional interface, and

3 shows a schematic view of 2 B

DETAILED DESCRIPTION OF THE INVENTION

In 1a is a schematic diagram of a one for receiving low-voltage digital _signals U _{SUout provided} by the bus BS unidirectional bus interface SU shown, for. B. can be used for dimming a controlled via an operating device BG bulb. In the aforementioned bulbs may be z. B. to act a gas discharge lamp or an LED module. The operating device can be, for example, an electronic ballast with an ASIC or μC as a central control unit.

It should be noted that the interface is used only for the transmission of control signals and the power supply of the lamps is provided separately via the operating device. In the case of dimming signals by the operating device, the power of the lighting means may, for example, be dependent on signals received via the interface.

The interface SU has an input terminal KK 'for selectively receiving an AC mains voltage U _network or the digital low-voltage _bus voltage U _bus with a voltage level, for example. In the order of the DALI / DSI interface standard for predetermined DC level.

In addition, the interface SU according to the invention has an additional input terminal, via which a supply voltage U _V required for the voltage supply of the interface is provided, which is referred to as a "high" level of a control voltage potential for a circuit breaker T ₁ integrated in the transmitting branch SZ (cf. 2a ) serves. The supply voltage U _V is a DC voltage with a low-voltage voltage level.

How out 1a can be seen, the output signal receiving branch EZ via a potential _{separation stage} PTS in the form of a digital low-voltage signal U _SUout potential free of a control device StE is transmitted, which converts the signal into a control signal for the operation of lamps.

In 1b is a schematic diagram of one for receiving no mains voltage _signals as well as for sending and receiving digital low-voltage _signals U _SBout U _SBin or via an interface SB according to a second embodiment of the present invention. The bidirectional interface SB has the same structure as that described above 1a described unidirectional interface SU via an input terminal KK 'for selectively receiving a mains AC voltage U _network or a digital low-voltage signal U _bus .

In contrast to the unidirectional interface SU, however, the bidirectional interface SB additionally has a transmission branch SZ which is capable of transmitting digital signals Low-voltage _signals U _{SBin is provided} by a control device StE via the bus BS.

Just like the unidirectional interface SU also has the in 1b shown bidirectional interface SB to an additional input terminal, via which a supply voltage for the interface required supply voltage U _{V is} provided, the required as a "high" level of a control voltage potential for an integrated in the transmitting branch SZ for selective short-circuiting of the _bus voltage U _Bus mains voltage-resistant circuit breaker T ₁ (cf. 2 B ) serves. The supply voltage U _V is again a DC voltage with a low-voltage voltage level.

In order to transmit a signal, this digital low-voltage signal U _{SBin is conducted potential-free to the transmitting branch} SZ in the form of a digital control signal U _G via a further potential _{separation stage} PTE in the form of a digital control signal U _G3 , wherein the control signal input of the power switch T ₁ in the case of a "high" level of U _{SBin is raised} to the level of the supply voltage U _V (the "high" level of the control voltage potential) so that the line of the bus BS is switched on and thus short-circuited.

In the case of a "low" level of the digital control signal U _SBin , the aforementioned power _switch T _1, on the other hand, remains in blocking operation, so that a mains voltage signal having a "high" level corresponding to the bit value "logic one" is transmitted to the line of the bus BS and U _SUout remains unchanged.

In 2a a suitable circuitry implementation of a unidirectional interface SU according to a first embodiment of the present invention is shown, which is designed for the transmission of digital data signals between the required for operating at least one discharge lamp or at least one LED module operating device BG and a bus BS.

The voltage U _SBout lies between the terminal K _S and the _{ground node} GND of the interface _circuit .

Connected to terminals K, K 'is a full-wave rectifier AC / DC.

The power supply of the interface SU can z. B. inductively via a built into a power supply circuit EKN interface secondary winding L _{S of} a transformer, which is connected on the primary side with a power supply to the operating device BG and / or the control device StE serving switching power supply. In this way, the power supply from the interface SU is galvanically isolated. In the coupled via the transformer winding L _S voltage is an AC voltage whose amplitude is given by the level of the supply voltage U _V. To provide the aforementioned power supply, this AC voltage is rectified and smoothed using a low-pass filter.

An optocoupler OK _E , which is located at the output end of a receiving branch EZ of the interface SU, is used for the potential-free decoupling of the digital low-voltage signal output terminal KE. This transmission-side opto-coupler OK _E is supplied with a constant current source KSQ, which can be connected via a controllable non-voltage-controllable semiconductor switch T ₃ , with a constant current. The signal connected via this semiconductor switch T ₃ thereby controls a controllable power switch T ₁ designed as a mains voltage-resistant switching element.

A threshold value switch connected to the optocoupler OK _{E on the} primary side in series (for example a Zener diode D _Z1 ) serves to set a voltage threshold value.

In 2 B a suitable circuit implementation of a bidirectional interface SB according to a second embodiment of the present invention is shown. The voltages U _SBin and U _SBout lie between the terminals K _E and K _S and the _{ground node} GND of the interface _circuit . Via the input terminal KK ', the interface SB is connected to an AC mains voltage U _network or to a digital signal-carrying bus line of the bus BS.

The voltage supply of the interface SB can be as in the above with reference to 2a described interface SU done.

In a transmission branch SZ provided for transmitting digital low-voltage signals, there is now a further optocoupler OK _S.

When sending a digital low-voltage signal via this transmitting side optocoupler OK _S flows through the secondary side and a series-connected constant current source KSQ _S, a current that ensures that the falling at the constant current source KSQ _S gate voltage U _{G3 of} the semiconductor switch T ₃ to a value above the level of its switching voltage increases and the semiconductor switch T ₃ turns on. As a result, no base current flows into the base of a counter-current bipolar transistor T ₂ connected to the gate of the mains voltage-proof power switch T _{1 on} the collector side, whereupon its collector-emitter voltage U _CE2 increases abruptly and the collector current I _C2 falls to zero, which means that the bipolar transistor T ₂ blocks and the gate of the line voltage fixed circuit breaker T _{1 is} pulled up to a formed by the level of the supply voltage U _V "high" level, for example, 12V. Due to the high level signal at the gate input of the mains voltage-resistant circuit breaker T ₁ , this switches into a low-resistance state, so that the bus line is short-circuited.

In the transmission of digital control signals for light control, according to the DALI standard, it is necessary for the bit durations and edge steepnesses of the digital low-voltage signals transmitted and received by the unidirectional (SU) or bidirectional interface (SB) according to the invention to be within a predetermined tolerance range. Moreover, when switching from a high voltage level to a low voltage level, or from a low voltage level to a high voltage level of a transmitted or received digital low voltage signal, the slew rate is limited upwards, which means that turn-on and turn-off delay times of a particular one Duration to take into account.

For this purpose, the switching through of the circuit breaker T ₁ in the low-resistance state according to the invention via a z. B. in the form of a self-locking n-channel MOS field effect transistor realized semiconductor switch T ₃ , the switching behavior is delayed in both embodiments of the interface according to the invention by a suitable external circuitry. This is done according to the invention by means of a negative feedback circuit AB.

By the upstream filter and the subsequent counter-coupled switch the edges of the control signal are adjusted (flattened). The edge profiles of the digital low-voltage signals transmitted or received by the interface SU or SB according to the invention can be adjusted by a suitable choice of parameter values, the switch-on and switch-off delay times being controlled by the upstream filter and the counter-coupled switch.

The function of this circuit of the transmission branch can therefore be as follows with reference to 3 be summarized:
A constant current source KSQ _S is driven (via an optocoupler) with pulsed signals from a control unit StE (for example, an operating device for lighting means), these signals being to be transmitted in standard compliant manner with respect to their edge characteristics on a bus. This constant current source KSQ _{S is} followed by a filter (low-pass filter, eg an LR or RC low-pass filter), which is designed to set the switching edge. This filtered signal drives a counter-clocked switch, which thus generates a trapezoidal control signal (with the desired standard-compliant edge steepnesses), which controls the switch T1. The counter-clocked switch generates the trapezoidal signal by smoothing the filter signal above and below a threshold value, in between the edge is maintained. But it can also be influenced by the wiring of the counter-clocked switch the switching edges.

Claims (16)

Interface comprising an input terminal (K-K ') for selectively receiving mains AC signals ( U _network ) or digital low-voltage signals ( U _BUS ), characterized in that the input terminal is connected to a mains voltage-proof switch (T ₁ ) which is in receive mode when in contact a mains voltage signal or a high-level digital signal at the input terminal a power source (KSQ) turns on, the primary side of a potential separation element (OK _E ) fed to the secondary side of the interface provides output signals that in a transmission mode of the line voltage proof switch (T ₁ ) selectively the input terminal (K-K ') shorts. Interface according to claim 1, characterized by a galvanically isolated from the interface external power supply (U _V ) of a switching power supply. Interface according to Claim 1 or 2, in which the potential-separating element (OK _E ) is an optocoupler. Interface according to one of the preceding claims, in which the mains voltage-proof switch (T1) switches on the current source (KSQ) by means of output of a signal to a control input of a further switch. Interface according to one of the preceding claims, wherein in the transmission mode, a control input of the mains voltage-proof switch (T ₁ ) by means of a transmitting-side potential separation element (OK _S ) is controlled. Interface according to one of the preceding claims, in which an edge steepness of the mains voltage-proof switch (T ₁ ) in the transmission mode is adjustable. Interface according to one of the preceding claims, wherein a switching behavior of the mains voltage-proof switch (T ₁ ) is delayed in the transmission mode by an external circuit (AB). Interface according to Claim 7, in which the external circuit (AB) has a charge / discharge circuit (LES) whose time constants specify the slope. Interface for transmitting digital signals from an operating device for lighting means via a connected bus line, characterized by having a mains voltage-proof switch (T ₁ ), which selectively short-circuits the bus line connection (K-K ') of the interface for transmitting an edge of a digital signal in a transmission mode, wherein the edge steepness of the mains voltage-proof switch (T ₁ ) by an external circuit (AB) is adjustable. Interface according to Claim 9, in which the mains voltage-proof switch (T ₁ ) is counter-coupled. Circuit according to Claim 9 or 10, in which the external circuit (AB) has a filter circuit (LES) whose time constants predetermine the edge steepness. Operating device for lighting means, comprising an interface according to claim 1 or claim 9 and a digital control unit connected thereto, which controls the operation of the lighting means. Operating device according to claim 12, which is an electronic ballast for gas discharge lamps, high-pressure lamps or light-emitting diodes. Operating device according to one of Claims 12 or 13, in which the digital control unit is an ASIC or a microcontroller. A method for operating an interface, comprising an input terminal (K-K ') for selectively receiving mains AC signals ( U _network ) or digital low-voltage signals (U _BUS ), and characterized in that a mains voltage resistant switch (T1) in the receive mode upon application of a mains voltage signal or a high-level digital signal at the input terminal (K-K ') turns on a power source (KSQ) which feeds the primary side of a receiving-side potential separation element (OK _E ), at the secondary side of which the interface provides output signals, and in a transmission mode the mains voltage-proof switch (T ₁ ) selectively short-circuits the input terminal (K-K '). Method for operating an interface for transmitting digital signals from a lighting device via a connected bus line, wherein a mains voltage-proof switch (T1) selectively short-circuits the bus line terminal (K-K ') of the interface for transmitting the edge of a digital signal, wherein the edge steepness of the mains voltage fixed switch (T1) by an external circuit (AB) is set.

Images