JP2002043067A - Lighting system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely transmit the digital data, without lowering the transmission rate or without generating bit errors, when ringing of a frequency near the carrier wave is generated in a lighting system for transmitting the control signal among plural luminaires with the rectangular carrier wave ASK- modulated by the digital data. SOLUTION: In a transmitting circuit, having a pulse transformer PT connected to a transmission line, means A1, A2 for ASK-modulating the rectangular carrier wave with the control signal formed of a time series of the digital data 1 or 0, switching elements Q1, Q2 to be driven by the ASK-modulated carrier wave, and a drive voltage source connected to the pulse transformer PT via the switching elements Q1, Q2, the voltage Vp of the drive voltage source is changed synchronously with the timing of the changeover of the digital data 1 and 0.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lighting device using a plurality of lighting fixtures.

[0002]

2. Description of the Related Art An outline of a conventional lighting device will be described with reference to FIG. In the figure, U1, U2, U3,...
L2, L3, ... are lamps, C1, C2, C3, ... are control units, and S1, S2, S3, ... are sensors. For example, the luminaire U1 is provided with a human sensor S1, which, when detecting a human body, illuminates the luminaire U1 and, at the same time, transmits the luminaire U from a signal transmission unit of the control unit C1 via a transmission line.
2, a human body detection signal is sent to the control units C2 and C3 of U3. In response to this, the control units C2 and C3 switch the lamps L2 and L3.
An operation such as turning on 3 is performed.

[0003] Here, if there are other luminaires in the system other than the above, and there are luminaires that react to the human sensor S1 and luminaires that respond to other sensors, the sensor signal Is transmitted with an identification number (ID) assigned thereto, and each control section determines this and performs lighting control. When an ID is assigned as described above, it is general that a signal is transmitted using a digital signal, and the ID and the content of the transmission are coded.

FIG. 9 shows a circuit example of a signal transmission unit used in a conventional example.
Shown in In this example, a digital signal is transmitted by ASK modulation using a rectangular wave carrier. The pulse transformer PT is used to insulate between the lighting equipment and the transmission line. The pulse transformer PT on the transmission side is driven by the carrier waveform, and the pulse transformer PT on the reception side is driven via the transmission line. The section 3 demodulates the reception waveform that appears upon receiving the signal. The receiving section 3 is a circuit as shown in FIG. 10 and performs demodulation by a comparator 31 for comparing the amplitude of the received waveform with a predetermined threshold value Vt and a peak hold circuit 32 for peak holding the result of the magnitude comparison judgment. It is.

FIG. 11 shows waveforms at various parts. In this example,
The carrier wave oscillates / stops in response to 1/0 of the digital signal. When the digital signal switches from 1 to 0, it is desirable that the carrier wave stops and the amplitude of the received waveform becomes 0 at the same time. For realization, means for inserting a terminating resistor r into the receiving end of the transmission line is used.

Without such impedance matching, the transmission path becomes particularly long and the capacitance component increases. At the same time, vibration occurs between the pulse transformer and the ringing waveform in the received waveform after the carrier wave stops. May appear. FIG. 12 shows the waveform at that time.

[0007]

When the waveform as shown in FIG. 12 appears as a received waveform, when the receiving section demodulates by the amplitude of the waveform as described above, the output is inverted also by the ringing waveform. Therefore, a demodulated waveform as shown in FIG. 13 is obtained. As a result, the digital signal cannot be demodulated correctly.
As shown in FIG. 3, a bit error occurs in which data on the transmission side and data on the reception side are different.

When the ringing waveform is largely deviated from the carrier frequency, this can be removed by inserting a filter circuit in the carrier frequency band, but it may not be completely removed when the frequency band is close. In addition, it is conceivable to increase the bit width to shorten the period during which the output of the receiver becomes abnormal due to the ringing waveform with respect to the bit width, and to lower the error rate. This increases the time required for data transmission, which is not desirable.

It is an object of the present invention to reliably transmit a digital signal without lowering the transmission rate and without causing a bit error even when ringing occurs at a frequency close to the carrier frequency.

[0010]

According to the present invention, in order to solve the above-mentioned problem, as shown in FIG. 8, a plurality of lamps L1, L2, L3,.
A plurality of lighting load controllers C1, C for controlling lighting of L3,.
, C3,... And the respective lighting load control units C1, C2, C3.
And a signal transmission unit for transmitting a control signal via a transmission line between the transmission lines. The signal transmission unit includes a pulse transformer PT connected to the transmission line and a rectangular wave carrier, as shown in FIG. Means A1 and A2 for ASK modulation with a control signal consisting of a time series of digital data of 1 or 0, and switch elements Q1 and Q2 driven by the ASK-modulated carrier wave
And a transmission circuit unit 1 having at least a driving voltage source connected to the pulse transformer PT via the switching elements Q1 and Q2, and comparing the amplitude of the carrier waveform received via the transmission line with a predetermined threshold. As shown in FIGS. 1 to 7, in a lighting device having a receiving circuit unit 2 for demodulating the digital data to the original digital data according to the magnitude relation, as shown in FIGS. Then, the voltage Vp of the driving voltage source is changed.

[0011]

(Embodiment 1) FIG. 1 shows a configuration of a transmission circuit unit according to Embodiment 1 of the present invention. Drive voltage control circuit 5
Is a circuit that outputs a voltage Va as a drive voltage Vp when a data signal is at a high level, and outputs a voltage Vb as a drive voltage Vp when a data signal is at a low level. The drive voltage Vp is a pulse transformer. It is supplied to the center tap of the primary winding of the PT. One end of the primary winding of the pulse transformer PT is connected to the resistor R1 and the switch element Q1.
, And the other end of the primary winding is grounded via a series circuit of a resistor R2 and a switch element Q2. The outputs of the AND circuits A1 and A2 are connected to the gates of the switch elements Q1 and Q2. A data signal is inputted to one input terminal of the AND circuits A1 and A2, and a carrier wave and a signal obtained by inverting the carrier wave by the inverter N1 are inputted to the other input terminals.
A terminating resistor r is connected in parallel to the secondary winding of the pulse transformer PT, and is connected to a transmission line via a coupling circuit 4. The configuration of the receiving circuit unit is the same as that of the conventional example shown in FIGS.

FIG. 2 is a timing chart showing the transmission data, the carrier wave waveform, the driving voltage of the pulse transformer, the transmission waveform, the reception waveform, the comparator output, and the demodulation waveform of this embodiment. As is clear from the timing chart of FIG. 2, the drive voltage Vp is switched and lowered by a predetermined time earlier than the 1/0 switching timing of the transmission data, so that the output of the carrier wave when the transmission data is switched is stopped. The ringing waveform becomes smaller. As a result, it is possible to prevent the amplitude of the received waveform from being detected by the comparator 31 of the receiving unit 3 as being equal to or larger than the threshold value, thereby enabling correct demodulation.

(Embodiment 2) FIG. 3 is a circuit diagram of a transmission circuit according to Embodiment 2 of the present invention. In the first embodiment described above, the drive voltage Vp is switched in two steps in a stepwise manner, but in the present embodiment, the drive voltage Vp is switched with a predetermined time constant. The configuration of the drive voltage control circuit 5 will be described.
In the figure, 6 is a drive voltage source, 7 is an electrolytic capacitor, S
Is a switch element. The switch element S switches between ON and OFF in accordance with the switching of 1/0 of the data signal supplied to the drive voltage control circuit 5.

FIG. 4 is an operation waveform diagram of the present embodiment, and shows timing charts of transmission data, a carrier wave waveform, a driving voltage of a pulse transformer, a transmission waveform, a reception waveform, a comparator output, and a demodulation waveform. When the transmission data becomes 1,
When the switch element S is turned on, the voltage Vp of the electrolytic capacitor 7 increases with a predetermined time constant and reaches the output voltage Va of the drive voltage source 6. When the transmission data becomes 0, the switch element S is turned off, and the voltage Vp of the electrolytic capacitor 7 decreases with a predetermined time constant, and eventually becomes 0.

Also in this embodiment, 1/0 of transmission data is used.
Drive voltage Vp earlier than the switching timing by a predetermined time.
Is switched, the ringing waveform when the output of the carrier is stopped when the transmission data is switched becomes small. As a result, it is possible to prevent the amplitude of the received waveform from being detected by the comparator 31 of the receiving unit 3 as being equal to or larger than the threshold value, thereby enabling correct demodulation.

(Embodiment 3) FIG. 5 is a circuit diagram of a transmission circuit according to Embodiment 3 of the present invention. In the present embodiment, 1/0 of the data signal is switched by a CPU having a timer, and a voltage reference defining the drive voltage Vp is created using the CPU. The drive voltage source 6 of the drive voltage control circuit 5 controls charging and discharging of the electrolytic capacitor 7 in accordance with a voltage reference output from the CPU to generate a predetermined drive voltage Vp. By doing so, the drive voltage Vp output from the drive voltage control circuit 5 can be controlled as designed.

In the illuminating device, the input power fluctuates depending on the control state of other loads, so that it may be difficult to set a constant time constant in the configuration of the second embodiment. However, if the time constant is not kept constant, there arise problems such as the ringing not being completely eliminated or the timing of switching 1/0 of the transmission data being largely deviated. Therefore, as in the present embodiment, ringing can be surely eliminated by using means for controlling the rise and fall of the drive voltage Vp to have a constant time constant in accordance with data transmission. is there.

FIG. 6 is an operation waveform diagram of the present embodiment, and shows timing charts of transmission data, reference voltage, drive voltage, carrier waveform, transmission waveform, reception waveform, comparator output, and demodulation waveform. The rising slope and falling slope of the reference voltage are fixed by a timer built in the CPU, and the time constant of the rising and falling of the reference voltage is constant even if the input power fluctuates due to the control state of other loads. does not change.

(Embodiment 4) FIG. 7 is a circuit diagram of a transmission circuit according to Embodiment 4 of the present invention. In the above-described first to third embodiments, the timing of the change of the driving voltage is set to be earlier by a predetermined time than the timing of switching to 1/0 of the transmission data. Transmission data to be transmitted is supplied to AND circuits A1 and A2 via a delay circuit 8. With this configuration, the timing at which the switching elements Q1 and Q2 are switched is delayed by a predetermined time, so that the timing of the change of the drive voltage Vp can be relatively advanced by a predetermined time.

FIG. 7 shows an example in which the delay circuit 8 is added to the embodiment 2 shown in FIG. 3, but the delay circuit 8 is similarly applied to the embodiment 1 shown in FIG. 1 or the embodiment 3 shown in FIG. It is needless to say that can be added. Further, in the third embodiment shown in FIG. 5, since a CPU having a timer is used for creating the data signal and the voltage reference, the function of the delay circuit 8 for delaying the data signal is realized by the function of the CPU. I do not care.

Alternatively, in each of the embodiments shown in FIGS. 1, 3 and 5, AND circuits A1, A2 and switch elements Q1, Q
The delay time including the charging time of the gate capacitor 2 may be designed to be longer than the response time of the drive voltage control circuit 5.

[0022]

According to the first aspect of the present invention, a plurality of lamps, a plurality of lighting load control units for controlling the lighting of each lamp, and a control signal transmitted between the respective lighting load control units via a transmission line. A signal transmission unit for transmitting the signal, the signal transmission unit comprising: a pulse transformer connected to a transmission line;
A means for ASK modulation with a control signal consisting of a time series of 0 digital data, a switch element driven by the ASK-modulated carrier, and a drive voltage source connected to the pulse transformer via the switch element. And a receiving circuit unit for comparing the amplitude of the carrier waveform received via the transmission line with a predetermined threshold value and demodulating the original digital data according to the magnitude relationship. In the above, since the voltage of the drive voltage source is changed in synchronization with the switching timing of the digital data between 1 and 0, linking on the receiving side can be suppressed, and therefore, without lowering the transmission rate This has the effect of eliminating bit errors and enabling reliable signal transmission.

Further, if the voltage of the drive voltage source rises or falls with a predetermined time constant, rapid fluctuation can be suppressed, so that ringing is more unlikely to occur. Furthermore, if the delay circuit is used to delay the drive signal of the switch element rather than the voltage change of the drive voltage source, there is an effect that a transmission circuit with a simple configuration that does not easily generate ringing can be realized.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a transmission circuit according to a first embodiment of the present invention.

FIG. 2 is an operation waveform diagram according to the first embodiment of the present invention.

FIG. 3 is a circuit diagram of a transmission circuit according to a second embodiment of the present invention.

FIG. 4 is an operation waveform diagram according to a second embodiment of the present invention.

FIG. 5 is a circuit diagram of a transmission circuit according to a third embodiment of the present invention.

FIG. 6 is an operation waveform diagram according to a third embodiment of the present invention.

FIG. 7 is a circuit diagram of a transmission circuit according to a fourth embodiment of the present invention.

FIG. 8 is a block circuit showing the entire configuration of a conventional example.

FIG. 9 is a circuit diagram of a transmission circuit and a reception circuit in a conventional signal transmission circuit.

FIG. 10 is a circuit diagram showing a detailed configuration of a conventional receiving circuit.

FIG. 11 is an operation waveform diagram in a normal state in a conventional example.

FIG. 12 is a waveform diagram showing a ringing waveform generated in a reception waveform of a conventional example.

FIG. 13 is an operation waveform diagram when a transmission error occurs in a conventional example.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 transmission circuit 2 reception circuit 3 reception section 4 coupling circuit 5 drive voltage control circuit 6 drive voltage source 7 electrolytic capacitor 8 delay circuit

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masanao Okawa 1048 Kadoma Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Works, Ltd. (72) Inventor Shinsuke Nishioka 1048 Odaka Kadoma, Kadoma City, Osaka Matsushita Electric Works F-Term (Reference) 3K073 AA14 AA42 AA52 BA25 CC25 CE04 CE07 CE15 CE17 CF08 CF16 CG14 CG41 CG58 CJ05 CJ08 CJ22

Claims (4)

[Claims] 1. A lighting system comprising: a plurality of lamps; a plurality of lighting load control units for controlling lighting of each lamp; and a signal transmission unit for transmitting a control signal between the respective lighting load control units via a transmission line; The signal transmission unit includes a pulse transformer connected to a transmission line, a unit for ASK modulating a rectangular wave carrier with a control signal composed of a time series of 1 or 0 digital data,
A transmission circuit unit having at least a switch element driven by an SK-modulated carrier, a drive voltage source connected to the pulse transformer via the switch element, and an amplitude of a carrier waveform received via a transmission line And a receiving circuit for demodulating the digital data into the original digital data according to the magnitude relationship by comparing the driving voltage with a predetermined threshold value, wherein the drive voltage is synchronized with the switching timing of the digital data between 1 and 0. A lighting device characterized by changing a voltage of a source. 2. The lighting device according to claim 1, wherein the voltage of the drive voltage source rises or falls with a predetermined time constant. 3. The lighting device according to claim 2, further comprising means for controlling the time constant to be constant regardless of a load condition or a power supply condition. 4. A delay circuit for delaying a phase of an ASK-modulated carrier for driving the switch element, compared to a voltage change of a drive voltage source. The lighting device according to the above.