Power supply device, power receiving device, and power supply and receiving method

Abstract

In one aspect, a device is adapted to transmit power to or receive power from a remote device via a first communication line (DALI+) and a second communication line (DALI-), and to communicate with the remote device via the first and second communication lines. A first driver implements a first communication protocol that includes coupling the first and second communication lines together to encode a first signal level, and isolating the first and second communication lines from each other to encode a second signal level. This can be the DALI protocol. A second driver implements a second communication protocol that includes modulating the first communication line with a signal having a low modulation depth. The second communication protocol means that there is always a voltage difference between the two communication lines, enabling continuous power harvesting. A second aspect relates to efficient power transfer achieved by disabling the current limiter function when possible.

Description

Technical Field

[0001] The present invention relates to a power supply device, a power receiving device and a power supply and receiving method, and is particularly used for supplying power to a device through a communication line. Background Art

[0002] Powering devices via the communication lines of a communication bus is a well-known method. One example is the use of the DALI bus to power sensors within the lighting infrastructure. The deployment of sensors integrated into luminaires and powered by a power supply integrated with the LED driver is becoming an acceptable technical solution. This leverages the full potential of the Internet of Things (IoT) in the lighting sector.

[0003] As an example, the applicant has introduced a so-called sensor ready extension to the basic DALI signaling technology. A driver equipped with this technology can power sensors integrated with luminaires or with ceilings.

[0004] One of the challenges of transmitting power in this manner stems from the DALI signaling scheme. This scheme involves shorting two wires of the bus to encode the digital zero. This short-circuit function stops power from being supplied to the sensor. This results in a 50% reduction in power transfer during the time that communication is occurring.

[0005] It is desirable for devices to be able to communicate using a DALI (or similar) communication protocol, but avoid interruption of power delivery over the communication bus.

[0006] Another challenge with delivering power in this manner is enabling the lowest possible standby mode in the power receiving device and / or enabling maximum functionality in a low power standby mode. Summary of the Invention

[0007] The invention is defined by the claims.

[0008] According to an example according to the first aspect of the present invention, there is provided a device for transmitting power to a remote device via first and second communication lines and for communicating with the remote device via the first and second communication lines, the device comprising:

[0009] a power supply, configured to provide power to the first and / or second communication line;

[0010] a first driver for implementing a first communication protocol, the first communication protocol comprising: coupling the first and second communication lines together to encode a first signal level, and isolating the first and second communication lines from each other to encode a second signal level; and

[0011] A second driver is configured to implement a second communication protocol, the second communication protocol including modulating the first communication line with a signal having a modulation depth lower than 100%.

[0012] According to an example according to a second aspect of the present invention, there is provided a device for receiving power from a remote device via first and second communication lines (DALI+, DALI-) and for communicating with the remote device via the first and second communication lines, comprising:

[0013] a power collection circuit, configured to collect power from the first and / or second communication lines;

[0014] a first driver for implementing a first communication protocol, the first communication protocol comprising coupling first and second communication lines together to encode a first signal level and isolating the first and second communication lines from each other to encode a second signal level;

[0015] A second driver is configured to implement a second communication protocol, the second communication protocol including modulating the first communication line with a signal having a modulation depth lower than 100%.

[0016] The present invention thus provides a device for transmitting power via a communication bus, and a device for receiving power via a communication bus. In each case, the devices can communicate using a protocol in which a signal level (e.g., a digital 0) is encoded by shorting two lines. Another signal level (a digital 1) is encoded by the supply voltage on one communication line and the ground level on the other communication line. Additionally, however, encoding with a lower modulation depth is possible, i.e., such that there is always a voltage difference between the two communication lines, which enables continuous power harvesting.

[0017] The modulation depth is below 100%, i.e. the two lines are never at the same voltage. The modulation depth can be below 50%, below 25% or below 10%.

[0018] Modulation depth refers to the difference between (i) the differential communication line voltage encoding a logic low and (ii) the differential communication line voltage encoding a logic high, as a percentage of the differential communication line voltage encoding a logic high. For example, for 8V and 10V, the modulation depth is 2 / 10 = 20%. For conventional DALI, the differential line voltage can be 0V and 10V, so the modulation depth is 10 / 10 = 100%.

[0019] A bit may be encoded by a coded signal level, or else a set of signal level transitions may encode a single bit, such as in the case of Manchester encoding.

[0020] Power delivered over the communication bus to a remote device, for example in the form of a sensor, is not affected by the second communication protocol.

[0021] In each case, the device may include a controller, wherein the controller is adapted to send a request to the remote device using the first communication protocol to determine whether the remote device has the capability to use the second communication protocol.

[0022] In this way, one device may request another device whether it can switch to the second communication protocol.The first communication protocol may be a default protocol that is compatible with all devices used in the system.

[0023] The controller may then be adapted to request the remote device to switch to the second communication protocol if it is determined that the remote device has the capability.

[0024] This request can be sent in either direction, i.e. either the power supply side or the power harvesting side can ask the other side if it can use the second communication protocol. In fact, it is the power harvesting side that benefits from the second communication protocol and therefore the request usually originates from the power harvesting side.

[0025] In each case, the controller of the device may be adapted to:

[0026] In response to a request from a remote device using a first communication protocol, using the first communication protocol indicates that the device has the capability to use a second communication protocol.

[0027] The capability indication is a response to the above request.The controller is then adapted to switch to the second communication protocol in response to an activation request from the remote device.

[0028] These features provide a capability discovery mode where one device (typically a power harvesting device) identifies whether a connected power delivery device can communicate using the second communication protocol. If this is not the case, communication defaults to the first communication protocol, allowing backward compatibility.

[0029] Thus, power harvesting devices such as sensors become compatible with existing power delivery devices such as lighting drivers, but also with modified lighting drivers that have capabilities for both communication protocols.

[0030] In either case, the device may include a current limiter circuit between a power terminal and the first communication line, wherein the second driver includes a shorting circuit for bypassing the current limiter circuit. The power terminal may be a power supply output for power supply purposes, or it may be a power harvesting circuit input for power harvesting purposes. Thus, the second communication protocol is based on bypassing the current limiter. The current limiter causes a voltage drop, and the second communication protocol therefore involves applying or not applying this voltage drop.

[0031] In each case, the equipment may include:

[0032] a first receiver for receiving data encoded by the first communication protocol; and

[0033] The second receiver is configured to receive data encoded by a second communication protocol.

[0034] Thus, the devices are able to perform bidirectional communication using a selected one of the two protocols.

[0035] The first receiver, for example, comprises a voltage source and a pull-down circuit for selectively coupling the voltage source to the output or pulling the output to ground according to the voltage on the first communication line. This is, for example, a standard DALI receiver.

[0036] The second receiver, for example, includes a high-pass filter for receiving the voltage on the first communication line, a voltage clamper, and a hysteresis comparator. The hysteresis comparator receives the clamped filtered voltage and generates an output of the second receiver.

[0037] The comparator enables detection between two levels of the second communication protocol.The high-pass filter removes any DC offset, thereby allowing detection of small modulation depth signals of the second communication protocol.

[0038] The first communication protocol is, for example, the DALI protocol.

[0039] The present invention also provides a lighting system, which includes: the power supply side device as defined above, which includes a lighting controller, and the power collection device as defined above, which includes a lighting device.

[0040] The present invention also provides a method for transmitting power to a remote device via first and second communication lines and communicating with the remote device via the first and second communication lines, comprising:

[0041] providing power to the first and / or second communication lines; and

[0042] Choose between:

[0043] a first communication protocol comprising coupling the first and second communication lines together to encode a first signal level, and isolating the first and second communication lines from each other to encode a second signal level; and

[0044] The second communication protocol includes modulating the first communication line with a signal having a modulation depth less than 100%.

[0045] The present invention also provides a method for receiving power from a remote device via first and second communication lines and for communicating with the remote device via the first and second communication lines, comprising:

[0046] harvesting power from the first and / or second communication lines; and

[0047] Choose between:

[0048] a first communication protocol comprising coupling the first and second communication lines together to encode a first signal level, and isolating the first and second communication lines from each other to encode a second signal level; and

[0049] The second communication protocol includes modulating the first communication line with a signal having a modulation depth less than 100%.

[0050] According to another aspect of the present invention, there is provided an apparatus for receiving power from a remote device via first and second communication lines, comprising:

[0051] a power collection circuit, configured to collect power from the first and / or second communication lines;

[0052] a current limiter circuit between the first communication line and the power transmission terminal;

[0053] A current limiter circuit is between the first communication line and the power terminal of the power collection circuit;

[0054] a bypass unit for bypassing the current limiter circuit; and

[0055] A controller is configured to determine whether the current limiter circuit can be bypassed and to control the bypass unit.

[0056] The device can select whether the current limiting function (described above) can be bypassed. This is of interest for reducing standby power consumption or enabling additional functionality to be maintained during standby mode due to more efficient energy harvesting in the power receiving device. These functions may include, for example, RF links for control and occupancy sensing.

[0057] The device may comprise a voltage sensor for measuring a voltage at the first communication line or at the power delivery terminal, wherein the controller is adapted to actuate the bypass unit in dependence on the measured voltage.

[0058] A drop in voltage (before or after the current limiter) indicates that the remote device (e.g., a DALI driver) is unable to deliver the required load current to keep the load voltage above a minimum level, i.e., the load is discharging the receiving device's buffer capacitor below the minimum limit.

[0059] Bypassing the current limiter circuit reduces losses, allowing the load to draw the desired current and power from the communication line.

[0060] If the voltage measured drops when the bypass unit is active, the controller may be adapted to change the settings of the device to reduce the power demand.

[0061] This indicates that even with more efficient power delivery to the load, the communication line may not be able to meet the current demands of the load. In this case, the functions performed by the device can be scaled down, again preventing a collapse of the communication line voltage.

[0062] This aspect also provides a method for receiving power from a remote device via first and second communication lines, comprising:

[0063] determining whether a current limiter circuit between the first communication line and the power terminal can be bypassed, and if so, controlling a bypass unit to bypass the current limiter circuit; and

[0064] Based on the determination, power is harvested from the first and / or second communication lines with the current limiter circuit being bypassed or not being bypassed.

[0065] The method may be implemented at least partially by software.

[0066] These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] For a better understanding of the present invention, and in order to show more clearly how it may be carried into effect, reference will now be made, by way of example only, to the accompanying drawings, in which:

[0068] Figure 1 shows the basic architecture of a luminaire equipped with a sensor-controller device powered by a known DALI driver;

[0069] Figure 2 The voltage level thresholds for DALI are shown;

[0070] Figure 3 A typical DALI data message is shown;

[0071] Figure 4 shows the DALI frame format;

[0072] Figure 5 The main components of the so-called sensor-ready power and communication solution are shown;

[0073] Figure 6 A system with a driver and a sensor controller according to the present invention is shown;

[0074] Figure 7 An example implementation of a circuit in a driver is shown;

[0075] Figure 8 An example implementation of a circuit in a sensor is shown;

[0076] Figure 9Shown is the receiving circuit on the sensor side for detecting normal DALI and bypass mode communications;

[0077] Figure 10 Shows the receiving circuit on the driver side that can be used to generate normal DALI and bypass mode communications;

[0078] Figure 11 shows the simulation results of bypass mode communication;

[0079] Figure 12 Shown for comparison with Figure 11 The waveform of normal DALI communication with the same load in ;

[0080] Figure 13 Power transmission and communication methods are shown.

[0081] Figure 14 shows a basic known configuration of a lighting device for explaining another aspect of the present invention; and

[0082] Figure 15 shows how the circuit can be modified to include a bypass unit for bypassing the current limiter circuit; and

[0083] Figure 16 Shown in more detail Figure 15 Implementation of the circuit. DETAILED DESCRIPTION

[0084] The present invention will be described with reference to the accompanying drawings.

[0085] It should be understood that the detailed description and specific examples, while indicating exemplary embodiments of the devices, systems, and methods, are for illustrative purposes only and are not intended to limit the scope of the present invention. These and other features, aspects, and advantages of the devices, systems, and methods of the present invention will become better understood from the following description, the appended claims, and the accompanying drawings. It should be understood that the drawings are merely schematic and not drawn to scale. It should also be understood that the same reference numerals are used throughout the drawings to indicate the same or similar components.

[0086] The present invention provides a device adapted to transmit power to or receive power from a remote device via first and second communication lines, and adapted to communicate with the remote device via the first and second communication lines. A first driver implements a first communication protocol comprising coupling the first and second communication lines together to encode a first signal level, and isolating the first and second communication lines from each other to encode a second signal level. This may be the DALI protocol. A second driver implements a second communication protocol comprising modulating the first communication line with a signal having a low modulation depth. The second communication protocol means that there is always a voltage difference between the two communication lines to enable continuous power collection.

[0087] On the other hand, the bypass function of the current limiter is utilized in order to increase the efficiency of the energy transfer, in particular in the standby operating mode.

[0088] Figure 1 The basic architecture of a luminaire 10 is shown which is equipped with a sensor controller device 12 powered by a known DALI sensor ready LED driver 14. The driver acts as a slave device, while the sensor-controller device acts as a master device.

[0089] Communication and power transmission take place over a pair of communication lines, DALI+ and DALI-, which form a two-wire differential bus. Drivers equipped with this technology can power sensors integrated with luminaires or with ceilings.

[0090] A conventional DALI network includes a controller serving as a master device and one or more lighting devices (e.g., electronic ballasts and dimmers) with a DALI interface. The controller monitors and controls each lighting device through bidirectional data exchange. The DALI protocol allows devices to be addressed individually or multiple devices to be addressed simultaneously. Data is transmitted between the controller and devices over a two-wire differential bus using an asynchronous, half-duplex, serial protocol. Such conventional DALI devices use a single pair of wires to form a bus for communicating with all devices on a single DALI network.

[0091] A DALI network can include various sensors and wireless receivers for receiving remote wireless commands. Such sensors can be provided as part of a specific lighting unit, i.e. within the luminaire housing, or they can be separate stand-alone sensors that also communicate with the DALI network via a two-wire differential bus or wirelessly.

[0092] The signaling in DALI communication is Figures 2 to 4 Shown in.

[0093] Figure 2 The voltage level thresholds and signal 20 conveying a signal level "1010" are shown. A logic high is defined as being above 9.5 V, while a logic low is defined as being below 6.5 V. In practice, the voltage between the communication lines is zero to encode a logic low.

[0094] Figure 3 A typical data message is shown. The encoding operates by shorting the bus to send Manchester coded bits. Therefore, each bit consists of two logic signal levels. In conventional applications, where long DALI lines are wired in a building, large signal swings (such as Figure 2 22.5V maximum) is provided to protect against interference.

[0095] Figure 4The frame format is shown, where s is the start bit, YAAAAAAS is the address period, and XXXXXXXX is the data byte. The last two bits are the stop bits.

[0096] Figure 5 The main components of the sensor-ready power and communication solution are shown.

[0097] Driver 50 (which is a slave device) includes a microcontroller 52, which includes a DALI encoder 54 and a DALI decoder 56. The DALI encoder provides a transmit signal TXD to a bus driver 58, which controls the short circuit of the communication line as explained above. Power is supplied to the DALI bus from a DALI power supply 60. Data is received by a threshold receiver 62, which then generates a receive signal RXD for the DALI decoder 56.

[0098] Sensor 70 (which is the main controller) has similar components to driver 50, namely, a controller 52' ​​with a DALI encoder 54' that drives a bus driver 58' using a transmit signal TXS. Controller 52' ​​has a DALI decoder 56' that receives a receive signal RXS from a DALI threshold receiver 62'. A DALI power harvester receives power from the DALI bus to power the sensor subsystem.

[0099] The LED is for example implemented as a slave device, as it acts as an actuator awaiting commands from a master device, ie a sensor or communication device hosting the various sensing and lighting control functions. However, the reverse configuration is also possible.

[0100] The driver 50 therefore comprises a low voltage power supply 60 to provide power to sensors connected to the DALI bus.

[0101] One of the challenges of delivering power in this manner stems from the DALI signaling scheme, which, as mentioned above, shorts the bus, removing power from the sensor. This results in a 50% reduction in available power during communication and, therefore, limits sensing and sensor data processing capabilities.

[0102] The sensor module needs to be designed with this limitation in mind and needs to continuously monitor the available energy. In addition to this, if significant computation is required while DALI communication is occurring, a large storage capacitor may be required to ensure that the bus voltage does not drop below the predetermined DALI "high" voltage level threshold (e.g. Figure 2 Besides increasing the cost, the large capacitor size has a significant impact on the sensor module size and subsequently on the illuminator mechanical design.

[0103] It is therefore desirable to maximize the available power on the DALI line. The present invention provides a signaling scheme in which the power delivered to the sensor is maintained at the maximum possible value. To enable this, a communication scheme is provided by which the sensor module identifies whether the connected driver is capable of communicating in this maximum power mode; if this is not the case, the communicating driver defaults to normal DALI operation, thus allowing backward compatibility.

[0104] Figure 6 A system with a driver and a sensor controller according to the invention is shown.

[0105] The system is shown to be Figure 5 The present invention relates to a modification of the system, and the same reference numerals are used for the same components.

[0106] The additional maximum power mode may be considered a bypass mode of operation, as it bypasses the normal short circuit encoding method of conventional DALI communication.

[0107] The driver 50 has an additional bypass driver 80. It is powered by the DALI power supply 60 and receives the bypass enable signal TXDB from the DALI encoder 54. The driver 50 also has a bypass detection receiver 82. It detects when the bypass function is activated and generates a bypass detection signal RXDB for the DALI decoder 56.

[0108] Sensor 70 has an additional bypass driver 80' powered by DALI power harvester 72. It receives the bypass enable signal TXSB from DALI encoder 54'. Sensor 70 also has a bypass detection receiver 82'. It detects when the bypass function is activated and generates a bypass detection signal RXSB for DALI decoder 56'.

[0109] The bypass drivers 80, 80' supplement the normal bus drivers, while the bypass detection receivers 82, 82' supplement the normal DALI threshold detectors.

[0110] In a preferred embodiment (which allows for backward compatibility), the additional module is only activated when both parties are capable of communicating in bypass mode. Otherwise, communication defaults to normal DALI using a standard bus driver and DALI threshold receiver. This normal DALI communication can be considered the first communication protocol, while bypass mode is the second communication protocol.

[0111] Drivers and sensors are therefore designed to operate in bypass communication mode and optionally also support normal DALI communication.

[0112] The bypass mode implemented by the bypass drivers 80, 80' comprises low swing signal modulation on the DALI+ line, rather than a short circuit function, thereby avoiding restrictions on the power consumption of the sensor during data communication.

[0113] Low-swing signal modulation means that one of the communication lines (e.g., the first communication line DALI+) is modulated with a signal with a modulation depth of less than 100%, as described above. Therefore, the voltage difference between the lines is never zero, i.e., they are never short-circuited together. This allows power to be harvested from both low and high signal levels.

[0114] The DALI bus voltage can fluctuate depending on the load current, so the logic 1 and 0 in bypass mode can have variable voltage levels. The voltage swing between the two logic levels is preferably 500mV or greater.

[0115] To achieve low-swing operation, the bypass driver exploits the voltage difference that exists across the DALI power source and the current limiter circuit in the DALI power harvester. This will be explained below.

[0116] The sensor is preferably able to query the driver about the availability of the bypass communication mode and activate it accordingly. The driver can then respond to the query command and activate the bypass mode in response to the request from the sensor. This is also explained further below.

[0117] Figure 7 An example implementation of circuitry in a driver, specifically a bypass driver 80 and a conventional bus driver 58, is shown. Also shown is a current limiter 90 that forms part of a DALI power supply 60. Current limiter 90 is connected in series between the input VIN and the DALI+ line. The input VIN is received from a power supply and can generally be considered a power supply terminal. Thus, current limiter circuit 90 is located between the power supply terminal VIN and the first communication line DALI+.

[0118] A conventional DALI bus driver includes a short-circuit switch Q7 and a base resistor R16 for short-circuiting the communication lines DALI+ and DALI-. It is controlled by the transmit signal TXD. The bus driver 58 is not activated during the bypass operation mode.

[0119] Bypass driver 80 includes a shorting switch Q12 between the input voltage VIN and the DALI+ line. This bypasses the current limiter. It is driven by an inverting level shifter formed by transistor Q11 and resistor R17. The inverting level shifter receives a bypass enable signal TXDB. Base resistors R20 and R18 limit the current flowing through the corresponding transistors.

[0120] The current limiter 90 includes a current limiting transistor Q5, whose base voltage is generated according to the current flowing through the series current sensing resistor R11. This current sensing voltage controls a transistor Q6, which in turn sets the base voltage of the current limiting transistor Q5.

[0121] Under normal operation, the current limiter 90 establishes a voltage difference between its input VIN and its output which is the DALI + line.The current limiter is used to guarantee the start-up time specification of DALI and is a standard component within DALI devices.

[0122] When the bypass switch Q12 is activated, that is, the signal TXDB is driven high, the DALI+ line will be pulled high to the level of VIN, and return to its lower level when TXDB goes low. In this way, the voltage of the DALI+ line can be modulated without preventing current from being supplied to the sensor side.

[0123] Figure 8 An example implementation of the circuitry in the sensor is shown, specifically the bypass driver 80' and the conventional bus driver 58', as well as a current limiter 90' forming part of the DALI power harvester 72. The current limiter is connected in series between the input VIS (from the DALI + line) and the voltage VOS provided to the sensor load (represented by resistor RLOAD and capacitor C4). Voltage VOS is the power supply to the load and can generally be considered a power supply terminal. Therefore, the current limiter circuit 90 is located between the power supply terminal VOS and the first communication line VIS.

[0124] The DALI power harvester includes a rectifier (not shown) for rectifying the voltage between the communication lines.

[0125] The rectifier is used to allow for polarity reversal during wiring. The communication line VIS is connected to the positive rectified output, i.e. it is connected to DALI+ via the rectifier. If the driver and sensor are equipped with polarity-correcting connectors (e.g. RJ45), the rectifier can be avoided and VIS will be connected directly to DALI+.

[0126] The conventional DALI bus driver 58' comprises a short-circuiting switch Q10 for connecting the input VIS and the base resistor R13 to ground. It is controlled by the transmit signal TXS. The bus driver 58' is not activated during the bypass mode of operation.

[0127] The bypass driver 80' comprises a short-circuit switch Q13 and a Zener diode D9 between the input voltage VIS and the output VOS. The diode D9 blocks the undesired discharge of the storage capacitor C4 through the collector-base PN junction of Q13.

[0128] Therefore, it bypasses the current limiter. It is driven by the inverting level shifter formed by transistor Q14 and resistor R23. The inverting level shifter receives the bypass enable signal TXSB. When data bits are being transmitted, TXSB is pulled high. Base resistors R24 and R22 allow the current to be limited to the corresponding transistors.

[0129] The current limiter 90' also includes a current limiting transistor Q8, whose base voltage is generated according to the current flowing through the series current sensing resistor R1. This current sensing voltage controls the transistor Q4, which in turn sets the base voltage of the current limiting transistor Q8.

[0130] Diode D7 blocks undesired discharge of storage capacitor C4 via the collector-base PN junction of Q8.

[0131] Because there is a voltage difference between the current limiter input VIS and output VOS, activation of the bypass switch has the effect of pulling the DALI+ line down to the VOS level. When TXSB is pulled low, switch Q13 opens and the DALI+ line returns to its high level. This modulation process allows continuous current to be supplied to storage capacitor C4 during DALI communication.

[0132] Figure 9 The receiving circuitry on the sensor side is shown which can be used to detect both normal DALI (output RXS) and bypass mode communications (output RXSB).

[0133] The bypass detection receiver 82' includes two stages of high pass filters (C2, R15 and C3, R25), a voltage clamp (Zener diode D8) and a hysteresis comparator U2.

[0134] The high-pass filter helps extract the modulating pulses and blocks the DC bus voltage that may vary with the load.

[0135] To limit the voltage swing at the input of comparator U2, a Zener diode D8 is placed at the output of the first filter stage. The filtered signal VISF is ultimately compared to a reference value set by ground and hysteretic feedback (resistors R28, R29 forming the positive feedback loop of comparator U2) to convert the modulated pulses to the appropriate logic voltage levels.

[0136] The output of the comparator U2 is the bypass detection signal RXSB.

[0137] The typical voltage levels for logic 1 and 0 at the comparator input are 250mV and -250mV, respectively, with corresponding threshold voltages of 100mV and 7mV.

[0138] Figure 9A conventional DALI threshold receiver 62' is also shown. Zener diode D1 is used to set the base voltage of pull-down transistor Q3 so that output RXS is pulled down if input VIS is above a threshold voltage of 7.5V and is pulled up if VIS is below the threshold.

[0139] Figure 10 The receiving circuitry on the driver side is shown which can be used to generate both normal DALI (output RXD) and bypass mode communications (output RXDB).

[0140] These circuits are similar to Figure 9 Therefore, the bypass detection receiver 82 includes two stages of high pass filters (C5, R30 and C7, R31), a voltage clamp (Zener diode D6) and a hysteresis comparator U3.

[0141] The filtered signal VDALIF is compared to a reference value set by ground and hysteresis feedback (resistors R32, R33 forming a positive feedback loop of comparator U2) to convert the modulated pulses to the appropriate logic voltage level.

[0142] The output of the comparator U2 is the bypass mode detection signal RXDB.

[0143] The DALI threshold receiver 62 has a Zener diode D25 to set the base voltage of the pull-down transistor Q9 so that the normal DALI output RXD is pulled down if the input DALI+ is above the threshold voltage of 7.5V, and is pulled up if the input is below the threshold.

[0144] Figure 11 The simulation results for bypass mode communication are shown. The equivalent load is set to RLOAD = 250 ohms, so that the current drawn at 12V is about 48mA.

[0145] The top graph shows the DALI+ line signal.

[0146] The second graph shows the output voltage VOS to the load after the current limiter.

[0147] The third graph shows the drive signal TXSB to the bypass driver in the sensor. This is the signal sent by the sensor.

[0148] The fourth graph shows the corresponding receive signal RXDB at the driver.

[0149] The sixth (bottom) graph shows the drive signal TXDB to the bypass driver in the driver. This is the signal sent by the driver.

[0150] The fifth graph (the one from the bottom up) shows the received signal RXSB at the sensor corresponding to the drive signal TXDB.

[0151] The initial transmit and receive pulse 110 involves transmission from the driver and reception at the sensor. The subsequent pulse 112 involves transmission from the sensor and reception at the driver.

[0152] It can be seen from the waveforms of the DALI bus voltage DALI+ and the collected sensor voltage VOS that the bypass communication scheme keeps the bus voltage high (12 V or higher) and provides the required load power.

[0153] The other signal traces show how pulses sent from one side are received on the other side as described above.The actual frame format may be arranged to follow any suitable protocol (DALI or other single wire communication technology).

[0154] As a comparison, Figure 12 The waveform of normal DALI communication for the same RLOAD value is shown in FIG.

[0155] The top graph shows the DALI + line signal.

[0156] The second graph shows the output voltage VOS to the load after the current limiter.

[0157] The third graph shows the drive signal TXS to the (conventional) bus driver in the sensor. This is the signal sent by the sensor.

[0158] The fourth graph shows the corresponding receive signal RXD at the driver.

[0159] The sixth (bottom) graph shows the drive signal TXD to the (conventional) bus driver in the driver. This is the signal sent by the driver.

[0160] The fifth graph (the one from the bottom up) shows the received signal RXS at the sensor corresponding to the drive signal TXD.

[0161] The initial transmit and receive pulse 120 involves transmission from the driver and reception at the sensor. The subsequent pulse 122 involves transmission from the sensor and reception at the driver.

[0162] The bus voltage DALI+ and the sensor voltage VOS drop as communication progresses, indicating that the sensor cannot draw the specified current when DALI communication is occurring. In simulations, VOS drops from 12V to 6V—corresponding to a 4x drop in power consumption. The sensor requires additional control schemes to reduce its power consumption, which complicates the overall solution and effectively reduces the sensor's capabilities (i.e., the functions it can perform and when). Another option is to add a storage capacitor, which has an impact on sensor size.

[0163] The bypass operation mode of the present invention avoids this limitation of DALI.

[0164] When operating in the bypass mode, the voltage between the communication lines is switched between voltages that are close to each other as described above.

[0165] When the power harvesting device is transmitting (in this example, the sensor and host controller), the switched voltages are the input bus voltage (VIS) and the storage capacitor voltage (VOS).

[0166] When the power supply device is transmitting (in this example, the driver), the switched voltages are the supply voltage (VIN) and the bus voltage (DALI+).

[0167] At any given moment, there is at least one current limiter in place to prevent excessive current from flowing, as only the current limiter on the transmitting side is bypassed. Therefore, the second communication protocol does not cause safety issues.

[0168] Figure 13 Power transmission and communication methods are shown. Figure 13 (a) shows the method implemented in the driver (i.e., the power supply side), Figure 13 (b) shows the method implemented in the sensor (ie, the power collection side).

[0169] exist Figure 13 In (a), the method starts in normal DALI mode in step 130, ie, the default first communication protocol.

[0170] A command is waited for at step 132. When a command is received, a determination is made at step 134 whether it is a request from a connected remote device regarding whether the device has the capability to use the second communication protocol. If so, information is sent at step 136 (using the first communication protocol) confirming that the device has the capability.

[0171] If the command is not a capability request, then a determination is made at step 138 whether it is a request from a remote device to switch to a second communication protocol. If so, then bypass mode is enabled at step 144. The second communication protocol is then used for subsequent communications.

[0172] Once both parties agree to use the second protocol, they remember that operating mode as long as they remain powered on. On power up, they need to renegotiate via normal DALI.

[0173] If the command is not a handover request, the command is processed in step 140 using the first communication protocol.

[0174] The reply is then sent in step 142 in the normal manner.

[0175] exist Figure 13 In (b), the method also starts in step 150 in normal DALI mode, ie, the default first communication protocol.

[0176] In step 152, a request is made to the connected remote device (powered driver) whether the driver has the capability to use the second communication protocol. Therefore, in step 154, it is determined whether the remote device has the capability to use the second communication protocol.

[0177] If the driver does not have this capability, then normal DALI mode (ie the first communication protocol) is maintained in step 160 .

[0178] If the drive does have the capability, then a switch request is made in step 156 (using the first communication protocol).

[0179] In step 158, the device switches to a second communication protocol.

[0180] DALI is an example of a system where there is communication and power delivered by a shared bus. This is an example of a power line communication system.

[0181] This aspect of the invention can be applied to any power line communication system which uses a short circuit of the power line to encode one of the possible bits. Examples are the Digital Serial Interface DSI from Tridonic (trademark) and the 1-Wire Interface from Dallas Semiconductor / Maxim Integrated Products (trademark).

[0182] The above examples utilize selectively bypassing and coupling the current limiter 90 to achieve voltage modulation.

[0183] Another aspect of the invention relates to bypassing the current limiter to reduce the associated power consumption, thereby enabling a more power efficient standby mode, or allowing increased functionality in the power receiving device for the same amount of power transferred from the power source to the power receiver in standby mode.

[0184] Figure 14 The basic known configuration of a luminaire is shown. Driver 14 includes driver controller 58 and bus driver 52, all as described above. Also as described above, sensor controller 12 includes controller 52', current limiter 90', and DALI power harvester 72'. Power harvester 72' includes a full-bridge rectifier as shown. Modules driven by the harvested power, such as sensor modules, are shown as 140. Current limiter 90' is located between one of the communication lines and the power delivery terminal, i.e., the power supply Vcc of module 140.

[0185] As an example, for standby mode, the driver can deliver a minimum of 52 mA at a minimum of 12 V at its output.

[0186] Figure 15 It is shown how the circuit may be modified to include a bypass unit (switch) 150 for bypassing the current limiter circuit. A controller (eg, controller 52') determines whether the current limiter circuit can be bypassed and controls the bypass unit 150 accordingly.

[0187] The control of the bypass unit is explained in detail below. It can be hardware or firmware (i.e. software and controller), while the current limiting circuit is a permanent hardware feature.

[0188] Figure 16 Shown in more detail Figure 15 Implementation of the circuit.

[0189] It shows that the bypass circuit 150 includes a short-circuiting transistor M1 controlled by a bypass control signal BPC from the controller 52'. The bypass control signal BPC is applied to the base of the transistor Q1.

[0190] In a preferred embodiment, the bypass control signal BPC is generated by the power receiving device alone without communication with other DALI devices. Such communication may exist in more complex systems.

[0191] In the above example, the power receiving device is the master device. As a result, it controls the communication and therefore knows when the DALI bus is used for communication and when it is not used for communication. For example, there is no communication during standby mode.

[0192] The BPC signal activates and deactivates the bypass switch 150 .

[0193] In the example shown, voltage VOS is applied to one end of a resistor divider R1, R2, R3 including transistor Q1. When transistor Q1 is on, the gate voltage of transistor M1 is defined by the resistor divider, turning on transistor M1. When Q1 is off, transistor M1 is off.

[0194] Therefore, the power receiving device has a bypass switch to achieve a reduction in power losses of the DALI circuit and increased sensor functionality by optimizing power transfer of the available power from the driver.

[0195] Figure 16 Also shown are different designs of current limiter circuits 90' with different arrangements of Zener diodes D4, D7 (see FIG. Figure 8 compared to).

[0196] To ensure that the system still operates according to the full DALI specification, the output voltage from the driver at node VIS should remain above a certain level. This can be measured, for example, at the input of the current limiter circuit downstream of the rectifier. This measurement can be performed when there is no DALI communication or during high bit levels of DALI communication. Alternatively, the voltage at the node after the current limiter, VOS, can be measured, in which case the voltage drop between the communication line and Vcc is taken into account.

[0197] The current limiter is used to prevent the load from drawing too much current at any one time. If the current exceeds a designed threshold (e.g., 52mA), the bus voltage collapses. Taking into account the losses in the current limiter, the current limiter can be set to, for example, 40mA to be delivered to the load, thereby limiting the current on the DALI bus to, for example, 50mA.

[0198] A device sourcing current (a driver) can supply current exceeding the value of the current limiter, but with more devices connected to the DALI bus, the driver current is divided among multiple consumers.

[0199] If the current drawn by the load is less than the current limiter's hardware allows, there is no problem. In other words, the voltage at the load can be maintained by charging the load capacitance using the DALI bus current.

[0200] However, if the load profile changes and the load requires more current, the current can reach the maximum allowed by the current limiter. In other words, the load attempts to draw more current than the current limiter allows. When this maximum current limiter current is reached, no additional current can flow to the load, even if more current is available from the DALI driver.

[0201] The demand for more current causes the voltage at the load to drop. Specifically, the limited current delivered may not be sufficient to maintain the load capacitor at the desired voltage. For example, if a power-intensive function (such as a radar sensor) is activated, the load voltage is monitored. If this voltage drops, it is determined that the current limiter is operating at its maximum level.

[0202] The voltage (at VIS or VOS) is thus detected and the way it rises and falls is used to control the bypass switch. For example, if the voltage exceeds a first threshold voltage (e.g., 10V), this indicates that the bypass switch can be closed for more efficient power transfer.

[0203] If the buffer capacitor C4 connected at the output of the current limiter circuit 90' has been charged above the minimum specified DALI logic 'high' voltage level, the bypass switch should be turned on. It is then safe to operate in bypass mode. A 50mA current on the load side might, for example, experience a 1V voltage drop in the current limiter, resulting in a 50mW power loss. By bypassing the current limiter, this additional 40mW can be delivered to the load.

[0204] A more efficient use of the current delivered by the driver may be sufficient to drive the load and maintain the load voltage.

[0205] The sensor module draws current from both buffer capacitor C4 and the DALI driver. The maximum current drawn from the DALI driver is given by the minimum DALI driver specification of 52mA, but in practice, more current is available depending on the DALI driver circuit implementation. For short periods, the total current drawn from C4 plus the DALI current can be much greater than 52mA.

[0206] If the load draws a large current (without the protection of the current limiter), there is a risk of the bus voltage collapsing. Therefore, the voltage continues to be monitored so that a drop in the bus voltage can be detected. This can be detected as a second voltage threshold, which is applied when the bypass function is active. The bypass switch is then opened.

[0207] In this case, the bypass function is then switched off, causing the current limiter to become active, resulting in a lower load current but a stable DALI bus voltage.

[0208] During DALI communication, less power may be available due to a bus short caused by DALI drivers and sensor modules encoding a logic 0. Intensive communication or multiple modules on the DALI bus may cause a temporary power shortage, causing the bypass switch to close again. Power will be restored when there is no or less communication or when there is less power consumption by other modules.

[0209] Thus, there is a resulting loop control of the bypass switch. If current limiting is required due to a collapsed bus voltage, the bypass switch is opened. The bypass switch is closed when possible to avoid the power loss associated with the current limiter circuit.

[0210] If closing the bypass switch does not result in excessive current being drawn, the system may be stable in this state. However, if excessive current is drawn, leading to the onset of bus voltage collapse as described above, the bypass switch is opened again to reactivate the current limiter function.

[0211] Another measure that can be taken is to adapt to the needs of the load. Depending on the state and function of the load, the load may draw different current / power depending on its profile. Therefore, in response to a decrease in voltage towards or exceeding the first (10V) threshold (i.e., even if power is saved by disabling the current limiter, too much current is required to meet the load demand), the sensor functions can be turned off in a staggered manner to adjust the current demand of the load. For example, an IR sensor or an optical sensor can be turned off to reduce the overall current demand. In this way, the power consumed at the load is regulated. For example, this may be required when communicating on a DALI bus, which results in a 50% reduction in the available harvested power.

[0212] In this way, the functionality of the load is switched to a less power-consuming profile to avoid total power failure at the load and loss of functionality. For example, a sensor can be configured for minimal power load. In this case, the voltage will not drop any lower (because the current demand can be met by the current-limited value even during communication).

[0213] After the power consumption of the sensor module has been reduced to this minimum level by reducing the sensor functionality, the bypass switch is opened and the voltage level still decreases, for example to the above-mentioned second (lower) threshold.

[0214] The voltage will only drop further in this way if the DALI bus is short-circuited for a very long time, but this indicates a DALI bus fault, which will in any case cause the sensor to switch off.

[0215] The operation of the circuit is thus summarized as follows:

[0216] start

[0217] When the DALI driver's mains power up, the sensor module will be powered by the DALI line. During mains power up, the sensor module bypass switch is open. The sensor module current limiter is active. This is to ensure a minimum high-level DALI voltage (>9V) at power up.

[0218] On power up, the sensor module functionality is set to a reduced level to ensure that the DALI supply can adequately power the sensor module.The sensor module buffer capacitor C4 at the output of the current limiter circuit 90' is charged.

[0219] When the voltage VOS at the output of the current limiter circuit 90' exceeds a first threshold (e.g., 10V), the capacitor C4 is fully charged and the bypass switch is closed for optimal power transfer and minimum circuit losses. Because the voltage on C4 is above the minimum DALI voltage, the bypass switch is allowed to close.

[0220] Additionally, when the bypass switch is closed, the voltage at, for example, VOS continues to be monitored.

[0221] Depending on the DALI driver, the voltage of VOS may for example still increase to a nominal 12 V level or higher, reaching a maximum of approximately 19 V. The sensor module functionality is added to the full functionality in a staggered manner.

[0222] When all functions are realized, the normal operating condition of the sensor module is reached.

[0223] If, during normal operating conditions (and with the bypass switch closed), the voltage VOS drops below a first threshold voltage, e.g., 10 V, due to a lack of power delivered by the DALI driver, the sensor module functionality is reduced until the voltage VOS is again above a higher threshold voltage, e.g., 11 V. When the voltage VOS exceeds this higher threshold voltage (e.g., 11 V), the sensor module functionality is increased again, while still monitoring the voltage level VOS. This control loop and voltage measurement are performed by the main control unit.

[0224] Therefore, there is a looped control of the sensor function when the bypass switch is closed to provide the most efficient power transfer.

[0225] A lack of available DALI power may occur when there is (temporarily) strong DALI traffic or when other devices connected to the DALI temporarily overload the DALI bus.

[0226] In an unexpected situation, when the minimum sensor module function has been selected and the voltage VOS still drops below the aforementioned second threshold (e.g., 9.5V), the bypass switch is opened. Opening the bypass switch ensures that the DALI load current is below the maximum DALI load current of the sensor module current limiter. In this way, the minimum DALI driver voltage is observed and the DALI operates within the DALI specification.

[0227] Opening the bypass switch in this situation may cause the sensor module to lose power. When sufficient DALI power is supplied again, the sensor module will start up.

[0228] The bypass function allows additional power to be available to the sensor module 140. For example, for operation at a minimum of 12V and 52mA, the conventional circuit allows for approximately 230mW of power draw, while the bypass function allows for an increase to approximately 300mW.

[0229] Figure 16 An additional option shown is to use a current sense resistor 152 to detect a dynamic current sense (CS) voltage. This can provide additional information about the current being delivered from the driver. This enables the bypass function to shut down in the event of excessive current under fault conditions.

[0230] The examples above relate to the use of a power system for lighting. However, the same approach can be used for non-lighting applications.

[0231] By studying the drawings, the disclosure and the appended claims, those skilled in the art can understand and implement variations of the disclosed embodiments when practicing the claimed invention. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. A single processor or other unit can perform the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not mean that a combination of these measures cannot be used to advantage. If a computer program is discussed above, it may be stored / distributed on a suitable medium, such as an optical storage medium or solid-state medium provided with or as part of other hardware, but may also be distributed in other forms, for example via the Internet or other wired or wireless telecommunications systems. If the term "suitable for" is used in a claim or description, it should be noted that the term "suitable for" is intended to be equivalent to the term "configured to". Any figure marks in the claims should not be interpreted as limiting the scope.

Claims

1. A device (50) for transmitting power to a remote device (70) via a first communication line (DALI+) and a second communication line (DALI-) and for communicating with the remote device via the first communication line and the second communication line, comprising: a power supply (60) for providing power to the first communication line and / or the second communication line; a first driver (58) for implementing a first communication protocol, the first communication protocol comprising: coupling the first communication line and the second communication line together to encode a first signal level, and isolating the first communication line and the second communication line from each other to encode a second signal level; as well as A second driver (80) is used to implement a second communication protocol, wherein the second communication protocol is configured to modulate the first communication line with a signal having a modulation depth lower than 100%, so that the voltage difference between the first communication line (DALI+) and the second communication line (DALI-) is never zero during the modulation of the first communication line.

2. A device (70) for receiving power from a remote device (50) via a first communication line (DALI+) and a second communication line (DALI-) and for communicating with the remote device via the first communication line and the second communication line, comprising: A power collection circuit (72) for collecting power from the first communication line and / or the second communication line; a first driver (58') for implementing a first communication protocol, the first communication protocol comprising: coupling the first communication line and the second communication line together to encode a first signal level, and isolating the first communication line and the second communication line from each other to encode a second signal level; as well as A second driver (80') is used to implement a second communication protocol, wherein the second communication protocol includes modulating the first communication line with a signal with a modulation depth lower than 100%, so that the voltage difference between the first communication line (DALI+) and the second communication line (DALI-) is never zero.

3. The device according to claim 1 or 2, comprising a controller (52; 52'), wherein the controller is adapted to: sending a request to the remote device using the first communication protocol to determine whether the remote device has the capability to use the second communication protocol; and If it is determined that the remote device has the capability, the remote device is requested to switch to the second communication protocol.

4. The apparatus according to any one of claims 1 to 2, comprising a controller (52, 52'), wherein the controller is adapted to: In response to a request from the remote device using the first communication protocol, indicating using the first communication protocol that the device has the capability to use the second communication protocol; and In response to an activation request from the remote device, switching to the second communication protocol.

5. The apparatus according to any one of claims 1 to 2, comprising: Current limiter circuit (90; 90'), located between the power terminals (VIN; VOS) and the first communication line (DALI+; VIS), wherein the second driver includes a shorting circuit (Q12; Q13), and the shorting circuit (Q12; Q13) is used to bypass the current limiter circuit.

6. The apparatus according to any one of claims 1 to 2, comprising: The first receiver (62; 62'), for receiving data encoded by the first communication protocol; as well as The second receiver (82; 82'), for receiving data encoded by the second communication protocol.

7. The apparatus according to claim 6, wherein: The first receiver (62; 62') includes a voltage source and a pull-down circuit (Q9; Q3), the pull-down circuit (Q9; Q3) is used to communicate with the first communication line (DALI+; VIS) selectively couples the voltage source to the output or pulls the output to ground; as well as The second receiver (82; 82') includes a high pass filter for receiving the voltage on the first communication line, a voltage clamper (D8) and a hysteresis comparator (U2), the hysteresis comparator (U2) receiving the clamped filtered voltage and generating an output of the second receiver.

8. The device according to any one of claims 1, 2 and 7, wherein the first communication protocol is the DALI protocol.

9. A lighting system comprising: The apparatus of claim 1, comprising a lighting controller; as well as The apparatus of claim 2, comprising an illuminator.

10. A method for transmitting power to a remote device via a first communication line (DALI+) and a second communication line (DALI-) and for communicating with the remote device via the first communication line and the second communication line, comprising: providing power to the first communication line and / or the second communication line; as well as Choose between: a first communication protocol comprising coupling the first communication line and the second communication line together to encode a first signal level, and isolating the first communication line and the second communication line from each other to encode a second signal level; as well as The second communication protocol includes modulating the first communication line with a signal having a modulation depth lower than 100%, so that the voltage difference between the first communication line (DALI+) and the second communication line (DALI-) is never zero.

11. A method for receiving power from a remote device via a first communication line (DALI+) and a second communication line (DALI-) and for communicating with the remote device via the first communication line and the second communication line, comprising: collecting power from the first communication line and / or the second communication line; as well as Choose between: a first communication protocol comprising coupling the first communication line and the second communication line together to encode a first signal level, and isolating the first communication line and the second communication line from each other to encode a second signal level; as well as The second communication protocol includes modulating the first communication line with a signal having a modulation depth lower than 100%, so that the voltage difference between the first communication line (DALI+) and the second communication line (DALI-) is never zero.

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