Power Switching System

Abstract

A power switching system for controlling power supply to electronic devices, wherein each of a plurality of electronic devices includes a power supply unit. The power switching system includes a plurality of power switching modules, each configured to control power supply to one of the electronic devices by a respective one of the power supply units. Each power switching module has a module output connected to a power supply unit of a respective one of the electronic devices, a control input for receiving a control signal, and, upon receiving the control signal, activates an electrical connection between the module output and the respective power supply unit, thereby switching on a switch that causes the power supply unit to supply power to a respective one of the plurality of electronic devices. The power switching system further includes at least one delay module for each power switching module configured to initiate a time delay, each power module configured to activate a switch after the time delay has elapsed. At least two of the time delays have different durations, such that the durations of the time delays are different for at least two of the power switching modules.

Description

[Technical Field]

[0001] The present invention relates to a power supply switching module and a power supply switching system for controlling power supply to an electronic device, and to a method for controlling power supply to an electronic device. In particular, the present invention also relates to a power supply switching system and a method for controlling power supply to an LED display screen. [Background technology]

[0002] Electronic devices can be powered using a switched-mode power supply (SMPS), which converts the output from an input power source or power supply (e.g., an AC power source) into an output power supply suitable for the electronic device (e.g., a DC output at a voltage lower than the input voltage). For example, the SMPS may contain one or more capacitors (i.e., capacitors) to store the output and smooth the effects of fluctuations (e.g., surges) in the input, intermediate input, and output. It is commonly accepted practice and good design to use a discharge circuit to ensure that the capacitors return to a discharged state when the SMPS is not in use, leaving the device in a safe state when an electrician chooses to operate it. Thus, when the input power source or power supply to an SMPS is first switched on, all capacitors are typically discharged, resulting in an initial current surge known as inrush current, starting current, or switch-on surge, while the capacitors charge. This inrush current can be much larger than the steady-state supply current to the SMPS, causing unwanted current spikes or power surges in the power supply to the electronic equipment when the electronic device connected to the SMPS is initially switched on.

[0003] This problem is exacerbated when a device or system (such as a series of electronic devices) contains multiple SMPSs, as the combined inrush currents of the SMPSs can result in power surges and the "tripping" or switching (sometimes called nuisance tripping) of circuit breakers and other devices designed to protect the circuit from excessive current. One solution to this problem involves dividing the device or system into discrete units, each containing many multiple SMPS-based power devices, and using heavy-duty switching equipment to power on each of these units (usually manually, at a location remote from the location of the electronic devices).

[0004] Another approach to the problem of nuisance tripping involves the use of "oversized" circuit breakers or other safety devices, for example, configured to withstand inrush currents significantly better than the steady-state operating current of the electronic device. However, this approach has the problem that such safety devices are insensitive and may not be triggered in a safe and appropriate manner by a ground fault in the electronic device, allowing the electronic device to continue to receive power even in the event of a catastrophic failure or fire.

[0005] An LED display screen (also known as an LED video screen, LED video wall, or direct-view LED (DVLED) screen) can be composed of multiple modular LED panels configured to display messaging, images, and video content as if they were a single screen. Each LED panel can be composed of multiple LED tiles. For example, a single LED screen might have a controller card that manages data transmission to multiple driver integrated circuits (ICs) for each LED panel. In this case, each driver IC regulates the current to the LED pixels in that LED panel to display the desired image. Power to each LED panel is typically controlled by an SMPS, which regulates the voltage and current supplied to the components within each panel. While a single LED display screen can thus be composed of multiple SMPSs, switching on an LED display screen can result in undesirable inrush currents. For this reason, power to LED displays is rarely switched off. Switching it on again can result in nuisance tripping, requiring (often manually and repeatedly) resetting the power supply or power subsystem powering an area of ​​the screen.

[0006] In practice, LED display screens are made to appear "powered off," for example by displaying a dark or black image or video on the screen, giving the appearance of being powered off, when in reality the screen continues to consume power. This approach is used when a display screen needs to be rendered inoperable, for example, to address light pollution, urban planning, or advertising regulations. An LED display screen displaying a black image consumes approximately 20% or less of the maximum power it would consume when displaying a colored image or video. Therefore, the display screen typically remains powered on, potentially resulting in significant wasted power consumption, which can be costly both economically and environmentally.

[0007] SUMMARY OF THE INVENTION It is an object of the present invention to overcome at least one of the problems of the prior art pointed out herein or elsewhere. Summary of the Invention

[0008] According to a first aspect of the present invention, there is provided a power switching system for controlling power supply to an electronic apparatus comprising a plurality of electronic devices, each having a power supply unit. The power supply switching system includes a plurality of power supply switching modules, Each power supply switching module is configured to control one power supply unit that supplies power to one of the electronic devices; Each of the power supply switching modules comprises: a module output for connecting to the power supply unit of each of the electronic devices; a control input configured to receive a control signal; a switch configured to activate an electrical connection between the module output and a respective power supply unit in response to receiving a control signal, thereby switching on power supplied by the power supply unit to at least each of a plurality of electronic devices; and the power source switching system including a delay module configured to initiate a time delay for each of the power source switching modules, each of the power source switching modules activating the switch after the time delay has elapsed; At least two of the time delays have different durations, the durations of the time delays differ for at least two of the power switching modules, and the durations of at least two of the time delays are independent of each other.

[0009] Configured in this manner, the power supply switching system limits the maximum starting current, which is the sum of the individual starting currents for each of the power supply units at any one time in the mains supply.

[0010] The durations of at least two of the time delays are preferably independent of one another. All of the time delays are preferably independent of one another. The duration of each time delay is preferably independent and independent of the respective durations of the other time delays. The duration of each time delay is preferably independent of and / or independent of the characteristics of each power switching module and / or each electronic device in the power switching system. For example, the duration of each time delay is preferably independent of and / or independent of the location of each power switching module in the power switching system. The duration of each time delay can be independent of and / or independent of the individual identifier, location, and / or function of each power switching module and / or each electronic device in the power switching system.

[0011] Each power switching module preferably has a module power input for connection to a main power supply of the electronic device, the module output preferably has a module power output, and the switch is preferably arranged to connect the module power input to the module power output to power the respective power supply unit, where the switch activates the electrical connection by switching on the power supply to the power supply unit.

[0012] In other embodiments, the switches and / or module outputs of each power switching module can send a secondary control signal to a respective power supply unit, causing the power supply unit to power at least one electronic device. In this case, sending the secondary control signal activates the electrical connection (rather than switching on power to the power supply unit). In such embodiments, each power supply unit can be connected (directly) to the main power supply of the electronic device, and a secondary signal (trigger signal) can activate the power supply unit to power the electronic device. For example, the secondary control signal can switch the power supply unit from a "standby" or "sleep" mode (where it does not power the electronic device) to an active or "awake" mode where it powers the electronic device. In such embodiments, each power switching module need not be connected to the main power supply or power supply of the electronic device.

[0013] Preferably, each power switching module is configured to initiate a time delay upon receipt of a control signal by the control input, the delay module being configured to operate a switch after the time delay has elapsed, and preferably, at least two of the plurality of power switching modules initiate time delays of different durations, the duration of the time delay being different for at least two of the power switching modules. Preferably, each delay module is configured to initiate a time delay of a different duration than the time delay initiated by any other delay module. Preferably, the time delays for each power switching module initiate substantially simultaneously.

[0014] In some embodiments, multiple such power switching modules are connected to a single delay module that initiates a time delay for each of the power switching modules connected to it and transmits a control signal to each of the power switching modules at the end of each time delay, causing the power switching modules to activate the switch. In this configuration, the control signals are sent to the power switching modules at different times. In such embodiments, the delay module may be configured as a single central delay module (or hub) to which each of the power switching modules is connected. Preferably, each of the time delays initiated by the delay modules has a different duration.

[0015] Preferably, the or each delay module comprises a random time delay module configured to initiate a time delay of random duration.

[0016] The time delay module is preferably a digital time delay module, and preferably includes a microcontroller unit (MCU).

[0017] The time delay module may comprise an analog time delay module, in which case the time delay module may comprise an analog time delay circuit that generates a time delay depending on the time to reach a threshold voltage or current.

[0018] Preferably, at least one of the delay modules includes a random time delay module configured to initiate a time delay of random duration upon receiving a control signal and to activate a switch when the (random) time delay has elapsed. The random time delay module can include a pseudorandom number generator to generate the duration of the random time delay. Alternatively, analog components such as resistors, capacitors, and inductors can be used to generate analog voltage or current threshold-induced time delays. For example, the time delay module can comprise an analog time delay circuit (such as a resistor-capacitor circuit) that generates a time delay based on the time it takes to reach a threshold voltage or current. In such an embodiment, inherent variability in the characteristics of the components can create random differences in the duration of the time delay between different power switching modules. For example, inaccuracies in the exact values ​​of the component resistances, capacitances, or inductances and / or other variables in the time delay inherent to each analog circuit can be used to introduce randomness in the device-to-device variations.

[0019] In these configurations, the time delays are different for each power switching module, thereby minimizing the maximum mains current. The system is advantageous because it is scalable. If the time delays are of random duration, it is not necessary to compare the time delay of any one power switching module with the time delays of other power switching modules in the system (e.g., when adding modules to increase the size of the system). The duration of each delay is preferably independent of the number of modules in the system.

[0020] The duration of each time delay is preferably 0 to 60 seconds, more preferably 1 to 30 seconds, and even more preferably 5 to 15 seconds after receiving the control signal. For example, 5 to 15 seconds after receiving the control signal. In this configuration, the total time required to switch on all of the power switching modules for their respective electronic devices can be kept substantially constant regardless of the number of modules in the system. The duration of each time delay can be set to at least 0.5 seconds, at least 1 second, at least 2 seconds, at least 3 seconds, or at least 4 seconds.

[0021] Preferably, each power supply switching module is connected to a common control line, and each power supply switching module is configured to receive a control signal substantially simultaneously. In the power supply switching system, a single control signal is preferably used to turn on the power supply to the power supply unit. Preferably, each power supply switching module is connected to a common control signal source, and a single control signal is used to activate each switch. In this configuration, electronic devices can be switched with a single operation, such as pressing a trigger button or switching a web relay, rather than multiple operations such as operating multiple switches.

[0022] The power switching system preferably comprises control lines. The control signals are preferably transmitted over the control lines. The control lines preferably comprise wired connections. The control lines preferably comprise twisted pair cables. The control lines preferably comprise Ethernet cables. The control signals are preferably transmitted over a Power over Ethernet connection. This Power over Ethernet (PoE) connection may comprise, for example, a Cat5e, Cat6 or Cat8 twisted pair cable (or other twisted pair cable), sometimes referred to as an "Ethernet" cable.

[0023] Each power switching module is preferably connected to other power switching modules by control lines. At least one of the power switching modules preferably has a control output connected to a control input of another power switching module for transmitting control signals between the power switching modules. In such an embodiment, control signals may be transmitted between adjacent power switching modules. The power switching modules are preferably connected in a daisy chain arrangement. The power switching system may include control lines.

[0024] The control signal can be transmitted to the electronic device by a data transmission means. The control signal can be transmitted to the electronic device together with data. For example, the control signal can be transmitted to the electronic device by a data cable. If the electronic device has an LED display screen, the control signal can be transmitted together with and / or by the same means as the images and / or videos transmitted to the LED display screen.

[0025] The control signal can be transmitted from a control signal source. The power switching system can have a control signal source. The control signal source can comprise a web relay. The control signal source can comprise a control-over-IP device or system. The control signal source can comprise a manual push button trigger or a switch (e.g., a dry contact). The control signal source can be a remote control signal source.

[0026] At least one of the power switching modules may include a zero-cross function solid-state relay configured to control power delivery to the module power output. The switch may include a zero-cross function solid-state relay. In these configurations, the zero-cross function solid-state relay limits maximum current (e.g., inrush current) when the switch is activated.

[0027] At least one of the power switching modules can include a negative temperature coefficient (NTC) thermistor configured to control the power supply to the module power output, where the NTC thermistor at least partially limits the maximum current (e.g., inrush current) when the switch is activated.

[0028] The power switching system can include an electronic device. The electronic device can include a light-emitting diode (LED) display screen. The plurality of electronic devices can include a plurality of LED panels. Each power supply unit can include a switchable power supply.

[0029] Preferably, a power supply switching module is connected to each power supply unit. Preferably, a single power supply switching module is connected to each power supply unit (only one). A power supply switching module can be provided in each electronic device.

[0030] If the electronic device is an LED display screen, a power switching module can be provided for each LED panel.

[0031] The electronic device may comprise a lighting system, and multiple electronic devices may comprise lights or light modules, for example, the system of the present invention may be used to control the power supply to a lighting system in a building or a system comprising lights such as floodlights.

[0032] The electronic device may comprise an information technology (IT) or telecommunications system, and each of the plurality of electronic devices may comprise an IT or telecommunications device or module. For example, the system of the present invention may be used to control power to servers in a building's IT system, or to control power to systems in an IT installation such as a server farm, or, as another example, to control power to systems in an audio-visual / communications installation in an outside broadcast van.

[0033] Each power supply switching module can be connected to one or more power supply units. Each power supply unit can be configured to control power supply to multiple power supply units. For example, multiple electronic devices can be configured as a group of electronic devices, and each power supply switching module can be connected to each electronic device within one of the groups of electronic devices.

[0034] In some embodiments, the power switching system is also suitable for controlling power to an electronic system that includes multiple electronic devices. For example, the power switching system can be used to control power to multiple lights, heating devices, motors, etc. The power switching system can be comprised of electronic devices.

[0035] A second aspect of the present invention relates to a power supply switching module used in the power supply switching system of the first aspect. The power supply switching module can be configured in the form of a board or a card.

[0036] According to a third aspect of the present invention, there is provided a method for controlling power supply to an electronic apparatus comprising a plurality of electronic devices, each having a power supply unit, comprising: providing a plurality of power supply switching modules, each configured to control power supply to each of the electronic devices for each of the power supply units; a delay module initiates a time delay for each of the power supply switching modules, and when the time delay expires, a switch is activated to establish an electrical connection between the power supply switching module and each of the power supply units, causing the power supply units to turn on power to at least a respective one of the plurality of electronic devices; At least two of the time delays have different durations, and the durations of the time delays differ for at least two of the power switching modules.

[0037] Preferably, each power switching module has a delay module that initiates a time delay upon receipt of the control signal by the control input and that activates the switch after the time delay has elapsed, and at least two of the delay modules of a plurality of power switching modules initiate time delays of different durations, the durations of the time delays being different for at least two of the power switching modules.

[0038] In some embodiments, multiple such power switching modules are connected to a single delay module that initiates a time delay for each of the power switching modules connected to it and transmits a control signal to each of the power switching modules at the end of each time delay, causing the power switching modules to activate the switch.

[0039] Preferably, the duration of each time delay is random.

[0040] The method of the present invention allows existing electronic devices to be retrofitted with a power switching module.

[0041] According to another aspect of the present invention, there is provided a power switching system for controlling power supply to an electronic apparatus comprising a plurality of electronic devices, each having a power supply unit. The power switching system includes a plurality of power switching modules; each power supply switching module is configured to control power supply to a respective one of the power supply units; Each of these power switching modules: a module power input for connecting to the main power supply of the electronic device; a module power output for connecting to a power supply unit of a respective electronic device; a control input configured to receive a control signal; a switch connecting the module power input to the module power output for powering each of the power supply units; a start module configured to actuate the switch upon receipt of the control signal by the control input; and and a starting element configured to limit the initial current drawn by each of the power supply units upon actuation of the switch.

[0042] The starting element may be configured as a zero-cross function solid-state relay or as an NTC thermistor (negative temperature coefficient thermistor). [Brief explanation of the drawings]

[0043] The invention will now be described, by way of example only, with reference to the accompanying drawings, in which like parts are indicated by like reference numerals, and in which:

[0044] [Figure 1] FIG. 1 is a schematic diagram showing a power switching module according to a preferred embodiment of the present invention. [Figure 2] FIG. 2 is a schematic diagram showing an apparatus having the power switching module of FIG. 1 together with an LED panel and a power supply unit in which the power switching module can be used. [Figure 3] FIG. 3 is a schematic diagram showing the apparatus of FIG. 2 in which a control line connects the control input of the power switching module to a control signal source having a manual push button. [Figure 4] FIG. 4 is a schematic diagram showing the apparatus of FIG. 2 in which a control line connects the control input of the power switching module to a control signal source having a dry contact (no voltage) switch. [Figure 5] FIG. 5 is a schematic diagram showing the apparatus of FIG. 2 in which a control line connects the control input of the power switching module to a control signal source having a control system over an IP network. [Figure 6] FIG. 6 is a schematic diagram showing a power switching system according to a preferred embodiment of the present invention connected, in use, to an LED display screen having a plurality of LED display panels. [Figure 7] FIG. 7 is a schematic diagram showing a modification of the power supply switching system of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0045] The present invention provides a power switching system and a power switching module for use in the power switching system. In use, a plurality of power switching modules are configured to form the power switching system. Each power switching module is configured to control power supply to a power supply unit, such as a switched mode power supply (SMPS) unit. In particular, a power switching module may be configured to switch power supply to a power supply unit (such as an LED driver unit) of an LED panel. A power switching system having a plurality of power switching modules can power a plurality of LED panels that form part of an LED display screen. In this configuration, a power switching module is connected to the power supply unit of each of the LED panels to control the power supply to each LED panel. Each power switching module switches on power supply to (or from) a respective LED panel power supply unit when it receives a control signal.

[0046] 1 is a diagram illustrating a power switching module 10 according to a preferred embodiment of the present invention. The power switching module 10 has a power input 12, a power output 14, a control input 16, and a starter module 18.

[0047] In this embodiment, power switching module 10 includes a board 10 having a power input 12, a power output 14, a control input 16, and a start-up module 18. Power input 12 is configured to connect to an input power source 50, such as a mains power supply or other external power source. Power output 14 is configured to connect to a device to be powered, such as a power supply unit (e.g., SMPS) for an electronic device. Control input 16 is configured to connect to a control signal source 52 that receives control and trigger signals. The control input can be connected to the control signal source by control line 54. In this embodiment, control input 16 comprises an Ethernet connector.

[0048] The control signal source can be a control device (not shown in FIG. 1 ) that can be located remotely from the power switching module, as described in more detail below. In this embodiment, the control signal is transmitted over control lines 54 in the form of power via an Ethernet (Power over Ethernet, PoE) connection 54. In this embodiment, the switching module 10 further includes a control output 20 that transmits or relays the control signal to another power switching module 10. The control output 20 is configured to connect to a control input of another power switching module 10, for example, by another control line 54. In some embodiments, the control output is not used.

[0049] The start module 18 includes a switch (not shown). The start module 18 is configured to switch the connection between the power input 12 and the power output 14 to connect or disconnect power to the power supply unit. In this embodiment, the start module 18 includes a delay module. The switch is configured to switchably connect the power input 12 to the power output 14. The start module 18 is configured to activate the switch upon receiving a control signal from the control input 16. The start module 18 is configured to activate the switch to connect the power input 12 to the power output 14 (e.g., to turn the switch “on”). The start module 18 is also configured to activate the switch to disconnect the power input from the power output (e.g., to turn the switch “off”). The switch may comprise any suitable means, such as a relay, for turning power to the power output on or off.

[0050] In this embodiment, the start-up module 18 includes a random delay timer (delay module) and a switch (not shown). The random delay timer is configured to activate (or activate) a switch to connect (or disconnect) the power input 12 and the power output 14 upon activation of a control signal. The random delay timer is configured to activate (or activate) the switch to connect the power input 12 and the power output after a randomly-lengthened time delay. In this embodiment, the duration of the time delay is limited to 5 to 15 seconds after receipt of the control signal. The random delay timer generates a random time delay each time a control signal is received. In this embodiment, the delay timer is implemented by a microcontroller unit (MCU) configured to recall a random value. This configuration results in a substantially different length of time between receipt of the control signal and powering up the power output 14 (and therefore the connected power supply unit) each time a control signal is received. As will be explained in more detail below, in this configuration of multiple power switching modules 10 in the power switching system 100, each power switching module 10 powers up its respective power output 14 at different times after receiving a control signal (which occurs substantially simultaneously for each power switching module). This prevents a large initial current from being drawn by the input power source or main power source 50 powering up the power switching system 100. In this embodiment, the duration of each time delay is limited to a minimum of 5 seconds from the receipt of the control signal. This allows the MCU sufficient time to fully power up and reach a steady state before ending the time delay. Note that in some embodiments, the minimum time delay can be set to less than 5 seconds, or even less than 1 second. Alternatively, there can be no minimum time delay (e.g., the time delay can have a duration of zero).

[0051] In other embodiments, the start-up module includes an analog time delay circuit that generates the required time delay depending on the time it takes for the time delay to reach a threshold voltage or current. For example, a resistor-capacitor (RC) circuit can be used that, upon receiving a control signal, generates the time delay by charging a capacitor until a threshold voltage is reached, and activates a switch at the end of the time delay. In such an embodiment, inherent variability in component characteristics creates random differences in the duration of the time delay between different power switching modules, causing each power switching module to switch on its respective power supply unit at different times.

[0052] In some embodiments, the power switching module includes a control module configured to receive a control signal and activate the start module in response to the control signal. In this case, the control module is coupled to the control input. The control module may comprise a relay and / or one or more microprocessors. The control module processes the control signal and determines a characteristic of the control signal. For example, the control module may determine whether the control signal is an enabling "on" signal or a disabling "off" signal. The control module is coupled to the start module and configured to activate or activate the start module upon receiving the control signal. In some embodiments, the control module may be integrated with and / or comprise the start module.

[0053] FIG. 2 illustrates a power supply (power supply) unit 2 that includes a power switching module 10 and to which the module 10 can be connected. The power supply unit 2 is an SMPS configured to control power to an electronic device, which in this embodiment is an LED panel 4. The power input 12 is connected to a main power supply 50 that supplies power to the LED panel 4. The power output 14 is connected to the power supply unit 2 of the LED panel 4. The control input 16 is connected to a control signal source by a control line 54. In this embodiment, the control line is a PoE connection 54. Also in this embodiment, the control signal source 52 (not shown in FIG. 2) is located remotely from the power switching module 10. For example, the control signal source 52 can be located in a control room remote from the switching module 10 and the power supply unit 2 connected to it.

[0054] Continuing with reference to FIGS. 3, 4, and 5, the control signal source 52 can be a switch, such as a manual push button trigger 52a, a dry contact closure 52b, or can be implemented by a control-over-IP (internet protocol) control system 52c. However, other suitable control signal sources can also be used. When using IP control, the control signals can be initiated or controlled using a web-based interface or web relay. The control signals can be initiated using a web application and / or using an application on a remote device, such as a smartphone or tablet. In this embodiment, the control signal source comprises an IP control system or IP control element 52c. In this configuration, the control signals can be transmitted from any device connected to the same network as the control signal source 52, for example.

[0055] In this embodiment, the control signal or activation signal is a signal carried by PoE (e.g., 48V PoE). In other embodiments, the control signal can be a DC signal (e.g., 50V DC), or can be a relatively low voltage activation signal, such as a 12V or 5V signal.

[0056] In the above embodiment, the input power source 50 (e.g., mains power) can be left switched on at all times, and the power switching module 10 switches power to the LED panel power unit 2. This configuration eliminates the need to turn the input power source 50 on and off, eliminating the need for manually operated switches or, in high power applications, manually operated switchgear.

[0057] 6, the power supply switching module 10 can be used to configure a power supply switching system 100 having multiple power supply switching modules 10. The power supply switching system 100 can control the power supply to multiple power supply units 2 (e.g., multiple SMPSs) in a large and / or complex device such as an electronic device array.

[0058] In this embodiment, a power supply switching system 100 is used to control power supply to an LED display screen 6 having an array of multiple modular LED panels 4. Each LED panel 4 has a power supply unit 2 (e.g., an LED driver unit) that controls the voltage supplied to the LED panel 4. An input power supply 50 is provided to supply power to each LED panel 4 in the LED display screen 6.

[0059] The power source switching system 100 includes multiple power source switching modules 10. In this embodiment, one power source switching module 10 is provided for each LED panel 4. As can be seen from FIG. 6 , each power source switching module 10 is connected to an input power source 50. The power output 14 of each switching module 10 is connected to the power supply unit 2 of each LED panel 4 to which the module 10 is connected. The control input 16 of each switching module 10 is connected (directly or indirectly) to a control signal source 52. In this embodiment, the control input 16a of a first power source switching module 10a of the multiple power source switching modules is connected to a control line 54. The control line 54 is configured to transmit a control signal from a remote location. The control output 14a of the first switching module 10a is connected to the control input 16b of a second power source switching module 10b of the multiple power source switching modules 100. The control output 14b of the second power source switching module 10b is connected to the control input 16c of a third power source switching module 10c, and so on.

[0060] In this configuration, the switching system 100 comprises a control signal "daisy chain" that allows control signals to be transmitted to all of the switching modules 10. This daisy chain configuration forms a modular system of power switching modules 100. Advantageously, the system is therefore scalable; modules 10 can be added or removed, thereby allowing for resizing of the power switching system 100. The modules 10 can be connected in a parallel bus configuration. These control signal connections between the power switching modules 10 can be made using suitable wired connections (such as Ethernet cables or other twisted pair cables). In other embodiments, the switching modules 10 need not be in a daisy chain configuration; for example, each module 10 can be directly connected to a control line, or the system can employ a hub or multi-drop configuration that allows control signals to be transmitted to each module 10 individually.

[0061] In this embodiment of the invention, the control signal transmitted along control line 54 is received by each power switching module 10 substantially simultaneously. When each start module 18 receives the control signal, a random delay timer generates or invokes a random time delay. In this embodiment, the random time delay is 5 to 15 seconds in duration. After the time delay has elapsed, the start module 18 of each switching module 10 activates a switch to connect power input 12 to power output 14, thereby powering up (inputting) power supply unit 2. In this configuration, a single control signal can be used to turn on all of the LED panels.

[0062] Note that because the time delays generated by each starting module 18 are random, the duration of each time delay for each power switching module 10 is different and independent of the durations of the other time delays. Therefore, each power switching module 10 switches on its respective power supply unit 2 at a different time. Consequently, the power input times for each LED panel 4 are different. In this configuration, because the inrush currents associated with switching on each power supply unit 2 occur at different times (due to staggered or offsets), the maximum combined current draw at any one time is significantly less than if all power supplies 2 were simultaneously powered on. Thus, the combined effect of the multiple time delays provides a "soft start," limiting the maximum current draw from the input power source 50 and significantly reducing the risk of tripping a circuit breaker or other safety device connected to the input power source 50. Therefore, the power switching system 100 has a soft start configuration. In this particular embodiment, the soft start configuration includes multiple starting modules (delay modules).

[0063] In a variation or alternative to the power switching system 100 shown in Figure 7, the main power supply 50 does not connect directly to each power switching module 10. Instead, the power switching units connect to the main power supply 50 through the power supply units 2, in order to connect the power supply 50 to each power supply unit 2 and to connect each power switching module 10 to its respective power supply unit 2. In other respects, the variation of the system 100 shown in Figure 7 is substantially the same as the system 100 previously described and shown in Figure 6.

[0064] In the embodiments described above, the control signals are transmitted over control lines 54, which take the form of a wired PoE connection. However, the control signals may be transmitted to each power switching module and / or between power switching modules by any suitable means. In some embodiments, the control signals may be transmitted over the same cable that transmits image data (e.g., video) to the LED display screen. The trigger signal may be combined with the video data signal being transmitted to the display screen. The control lines may comprise twisted pair cable, and the control signals may be transmitted using any suitable protocol. For example, the control signals and / or image data may be transmitted using transmitters and / or protocols manufactured by Novastar, Brompton, Linsn, Colorlite, etc.

[0065] It should be noted that in the above embodiment, the main power supply 50 to the LED display screen or panel may remain on, but the or each power supply unit 2 is disconnected from the main power supply 50 by a switch in the start-up module 18, so that each power supply unit 2 does not consume power to power the unit or system when it is not switched on (i.e., until it receives a suitable control signal). This is therefore advantageous as it allows the LED display screen 6 to consume zero power when not in use (and the main power supply 50 to be switched off as appropriate).

[0066] In some embodiments, the power switching system includes a single central delay module connected to each of the power switching modules. In this case, each power switching module may not include a delay module, but is otherwise substantially the same as the power switching modules described above. In such embodiments, the delay module is configured to initiate a time delay for each power switching module to which it is connected. After the time delay intended for a particular power switching module has elapsed, the delay module sends a control signal to the respective power switching module, which activates its switch and applies power to each power supply unit to which it is connected. The time delay is initiated by the delay module upon receiving a control signal (e.g., from a control signal source, such as the control signal source described above). In preferred embodiments, the time delay initiated by the delay module is random, such that each connected switching module receives the control signal at a different, random time. The time delays may be initiated simultaneously, may be of random duration, and / or may be initiated at random times. In either case, the delay module is configured to send the control signal to each connected power switching module at different times, such that each module receives the control signal at a different time and powers up each power supply unit at a different time. The delay module is connected to each power switching module by suitable control lines such as those described above.

[0067] Note that the time delays do not need to have random durations. Thus, in some embodiments, the time delays initiated by the delay modules, or the delay modules within each switching module, may be the same each time a control signal is received. In such embodiments, the time delay modules in at least some of the switching modules may be set to a predetermined duration that differs from the durations of the delay modules of the other switching modules in the power switching system, for staggered or soft-start purposes. In this configuration, the switches operate at at least two different times after receiving the control signal, thereby reducing overall inrush current. In such embodiments, it is preferable to configure most or all of the delay modules to have different delay times. In these embodiments, the delay times can be preselected and compared for each switching module, preventing simultaneous switching of the switching modules and reducing the risk of tripping.

[0068] It should be noted that the above-described embodiment, or a system in which each delay module includes a random delay timer, advantageously allows the system to be assembled and scaled without the need to check or compare the time delays of individual modules (or the time delays initiated by the central module). Because each time delay is random, the likelihood of two switches activating simultaneously (or closing long enough to cause an inrush current) is relatively low (compared to, for example, a system assembled by assembling modules each with one of several different predetermined time delays, some of which may have the same time delay). Because random time delays eliminate the need to check and compare module time delays, simultaneous switching is not required when assembling a power switching system. Furthermore, the use of random time delays further reduces the likelihood of, for example, three, four, or more switches activating simultaneously. Thus, multiple random time delay switching modules can be advantageously used in a power switching system without the need to carefully preselect or compare delay times between modules, while still minimizing the risk of simultaneous inrush currents.

[0069] In some embodiments, the power switching system includes at least one thermal cut-off element or protection element, such as a thermostatically controlled switch, an overheat protection fuse, or a pyrofuse. Each power switching module can include a thermal cut-off element. In the event of a fire or other overheating, for example, due to a failure of a portion of the LED display, power to the LED panel, or each LED panel, or the entire LED display screen can be cut off by activating the thermal cut-off element or elements. In this way, power to the LED display screen can be cut off without being activated by excessive current, for example, in the event of an electrical failure, a fire, or an overheating event.

[0070] In other embodiments of the present invention, each power supply switching module can be configured with a start-up element or a soft-start element. For example, a start-up module can be configured with a soft-start component or element. In such embodiments, the or each power supply switching module is individually configured to provide a soft start upon switching power to the power supply unit. This configuration allows a single power supply switching module to limit the maximum current draw (e.g., inrush current) by the power supply unit during a switching operation. The start-up element may or may not be used in conjunction with a time delay module.

[0071] For example, in some embodiments, the soft-start element may comprise a negative temperature coefficient thermistor (NTC thermistor) connected in circuit to the power supply output. Thus, when the power supply switching module receives a control signal and activates the switch to power the power supply output, the NTC thermistor initially has a relatively high resistance, limiting the initial current to the power supply unit. As current flows through the thermistor, its temperature increases, causing the thermistor's resistance to decrease (compared to when the switch is first activated and an initial current flows through the thermistor). This configuration may prevent potentially undesirable inrush current levels from being drawn by the power supply switching module to the power supply unit (e.g., an SMPS).

[0072] In some embodiments, the soft-start element may comprise a zero-crossing solid-state relay. In such embodiments, following receipt of a control signal, the or each power switching module is configured to switch on and power the power supply unit only when the AC current connected to the switch is at zero amplitude. Such embodiments may be used with AC mains power and / or may comprise an inverter that supplies AC. When a power supply is connected to a power supply output, the current amplitude is zero, thereby limiting the initial current that can be drawn by the power supply.

[0073] In such embodiments having soft start devices, a plurality of such power switching modules are assembled to form a power switching system (e.g., as described above), and multiple such soft start devices have a compounding effect, reducing the overall initial current draw when multiple power supply units are switched on, helping to prevent tripping, etc.

[0074] In some embodiments, the power switching module of the present invention is configured to be retrofitted to an existing assembly or device, such as an existing LED display screen, such that after the power switching module is retrofitted, the LED display screen's conventional main power source can remain on and the switching of power to the LED display screen can be controlled by the power switching module.

[0075] The power switching module and system of the present invention advantageously allow a modular electronic device, such as an LED display screen, to remain powered by a main power source, but the power consumption of the electronic device can be completely reduced (i.e., reduced to zero) by the switching action of the power switching module when the electronic device is not in use. Furthermore, because the power on / off switching action occurs within or at the electronic assembly, the need to switch the main power source (possibly remote from the electronic device) is avoided. The electronic device's power supply to the electronic device can be switched on and off without generating a large inrush current that could cause a safety device to trip. Similarly, in the event of a power outage or an emergency or maintenance situation that requires the main power source to be switched off, the LED display screen can be switched on again without the problems associated with large combined inrush currents. [Explanation of symbols]

[0076] 10 Power Switching Module 10a First power supply switching module 10b Second power switching module 10c Third power switching module 100 Power Switching System 12 Power input section 14 Power output section 14a, 14b Control output section 16, 16b, 16c Control input section 18 Starting Module 2 power supply units 20 Control output section 4 LED panels 50 Input power or mains 52 Control signal source 52a Manual Push Button Trigger 52b Dry Contact Closure 52c IP Control System 54 Control Line 54 Connection 6 LED display screens

Claims

1. 1. A power supply switching system for controlling power supply to an electronic apparatus comprising a plurality of electronic devices, each having a power supply unit, comprising: The power supply switching system includes a plurality of power supply switching modules; Each power supply switching module is configured to control one power supply unit that supplies power to one of the electronic devices; Each of the power supply switching modules comprises: a module output for connecting to the power supply unit of each of the electronic devices; a control input configured to receive a control signal; a switch configured to activate an electrical connection between the module output and a respective power supply unit in response to receiving a control signal, thereby switching on power supplied by the power supply unit to at least each of a plurality of electronic devices; and the power source switching system including at least one delay module configured to initiate a time delay for each of the power source switching modules, each of the power source switching modules activating the switch after the time delay has elapsed; and at least two of the time delays have different durations, the durations of the time delays differ for at least two of the power switching modules, and the durations of at least two of the time delays are independent of one another. A power supply switching system comprising:

2. 2. The power supply switching system of claim 1, wherein each said power supply switching module has a module power input for connecting to a main power supply of the electronic device, said module output having a module power output, and said switch configured to connect said module power input to said module power output to power each said power supply unit.

3. each power switching module having a delay module configured to initiate a time delay upon receipt of the control signal by the control input, and to activate the switch after the time delay has elapsed; 3. The power supply switching system of claim 1 or claim 2, wherein at least two of the delay modules of a plurality of power supply switching modules initiate time delays of different durations, and the durations of the time delays are different in at least two of the power supply switching modules.

4. 4. The power supply switching system of claim 3, wherein the power supply switching system includes a plurality of delay modules, each of the delay modules configured to initiate a time delay of a different duration, with the time delay initiated by each delay module being different from the other.

5. 3. The power supply switching system of claim 1, wherein a plurality of said power supply switching modules are connected to a single delay module, said delay module initiating a time delay for each of said power supply switching modules connected thereto and transmitting a control signal to each of said power supply switching modules at the end of each time delay, said power supply switching modules actuating said switches.

6. 6. The power switching system of claim 5, wherein each of said time delays initiated by said delay module is of a different duration.

7. A power supply switching system according to any preceding claim, wherein the or each delay module comprises a random time delay module configured to initiate a time delay of a random duration.

8. A power supply switching system according to any one of claims 1 to 7, wherein the duration of each time delay is between 5 and 15 seconds.

9. A power supply switching system according to any one of claims 1 to 8, comprising a control line, and said control signal is transmitted over said control line.

10. 5. A power supply switching system according to claim 3 or claim 4, wherein each power supply switching module is connected to a common control signal source, and a single control signal causes operation of the switches in each power supply switching module.

11. 5. The power supply switching system of claim 3, wherein each power supply switching module is connected to a common control line, and each power supply switching module receives the control signal substantially simultaneously.

12. A power supply switching system according to any one of claims 9 to 11, wherein the control lines comprise twisted pair cables.

13. A power supply switching system according to any one of claims 9 to 12, wherein said control signals are transmitted by a Power over Ethernet connection.

14. 14. The power supply switching system of claim 1, wherein at least one of the power supply switching modules has a control output connected to a control input of another of the power supply switching modules for transmitting control signals between the power supply switching modules.

15. A power supply switching system according to any one of claims 1 to 14, comprising the electronic device.

16. 16. The power supply switching system of claim 15, wherein a separate power supply switching module is connected to each power supply unit.

17. 17. The power switching system of claim 15 or claim 16, wherein the electronic device has an LED display screen and a plurality of the electronic devices have a plurality of LED panels.

18. 18. The power supply switching system of claim 2, wherein at least one of the power supply switching modules includes a zero cross function solid state relay configured to control the supply of power to the module power output, or a negative temperature coefficient thermistor configured to control the supply of power to the module power output.

19. A power supply switching module for use in a power supply switching system according to any one of claims 1 to 18.

20. 1. A method for controlling power supply to an electronic apparatus comprising a plurality of electronic devices, each having a power supply unit, comprising: providing a plurality of power supply switching modules, each configured to control power supply to each of the electronic devices for each of the power supply units; a delay module initiates a time delay for each of the power supply switching modules, and when the time delay expires, a switch is activated to establish an electrical connection between the power supply switching module and each of the power supply units, causing the power supply units to turn on power to at least a respective one of the plurality of electronic devices; At least two of the time delays have different durations, the durations of the time delays differ for at least two of the power switching modules, and the durations of at least two of the time delays are independent of one another. A method characterized by:

21. each power switching module having a delay module configured to receive a control signal via a control input to initiate a time delay, and the delay module configured to activate the switch after the time delay has elapsed; At least two of the delay modules of a plurality of the power source switching modules initiate time delays of different durations, the durations of the time delays being different for at least two of the power source switching modules; or a plurality of said power supply switching modules are connected to a single delay module, said delay module initiating a time delay for each of said power supply switching modules connected thereto and transmitting a control signal to each of said power supply switching modules at the expiration of each time delay, said power supply switching modules actuating said switches; 21. The method of claim 20.

22. 22. The method of claim 20 or claim 21, wherein the duration of each time delay is random.

23. The method of any one of claims 20 to 22, wherein an existing electronic device is retrofitted with the power switching module.

24. 1. A power supply switching system for controlling power supply to an electronic apparatus comprising a plurality of electronic devices, each having a power supply unit, comprising: The power supply switching system includes a plurality of power supply switching modules; each power supply switching module is configured to control power supply to a respective one of the power supply units; Each of these power switching modules: a module power input for connecting to the main power supply of the electronic device; a module power output for connecting to a power supply unit of a respective electronic device; a control input configured to receive a control signal; a switch connecting the module power input to the module power output for powering each of the power supply units; a start module configured to actuate the switch upon receipt of the control signal by the control input; and a starting element configured to limit an initial current drawn by each of the power supply units upon actuation of the switch; A power supply switching system comprising:

25. 25. The power switching system of claim 24, wherein the starting element comprises a zero crossing function solid state relay or a negative temperature coefficient thermistor.

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