Abstract:
A power saving device is described that is disposed in use between a further device and a mains power supply for supplying power to the further device. The power saving device includes: a communications channel input connected in operation to a communications channel output of the further device. The communications channel input is operable to receive control instructions from the further device. The power saving device also includes: a switch for disconnecting the further device from the mains power supply in response to the control instructions received from the further device; and an internal power source operable to provide power to the power saving device.

Description:
FIELD OF THE INVENTION 
       [0001]    This invention relates to a power saving device. More specifically, it relates to power saving devices that can be used with existing equipment in order to lower the overall power consumption of the equipment. 
       BACKGROUND OF THE INVENTION 
       [0002]    Some consumer electronics equipment has already been designed with power saving features. A “standby” mode is a power saving mode that reduces electrical power consumption when the electronic device is idle. Standby mode places the electronic device into a state of “waiting for a power-up command”. However, power consumption can still be considerable in such a “standby” mode, even though the equipment is not in active use. 
         [0003]    Canal+ introduced a digital set-to-box (STB) having a true power cutoff mode built into it meaning that the STB could be completely powered down, thus consuming no power. 
         [0004]    However, the majority of consumer electronics equipment currently marketed are not designed with such a power cutoff feature and therefore various after-market devices are available that provide some degree of power control. Such devices include the Standby Saver (www.standby-saver.co.uk/standby_saver_home.htm) and The Savasocket (www.thesavasocket.co.uk/savasocket.html). These are timer-based, mains-power control devices that the consumer equipment is plugged into. The device turns the power on or off according to a preset timer that forms part of the device. 
         [0005]    International patent application published as WO 2004/057862 describes an appliance, such as a set top box, that has an ON power mode and a STAND BY power mode and that is in communication with a television set. A parameter of an operating signal associated with the television set is monitored and the value of the parameter is compared with predetermined values at which the set top box is desired to be either operative (ON power mode) or inoperative (STAND BY power mode). When a predetermined value of the parameter is detected, the current power mode of the set top box is evaluated and, if necessary, changed. Power supply to the TV set, operating frequency of a local oscillator/mixer in the TV set or the presence of a line scan signal from the TV set rate can be monitored to determine whether the appliance should be turned on or off. 
         [0006]    U.S. Pat. No. 6,292,233 describes a device controller that controls access to a device, such as a television, and that has a power input for receiving power and a data input for receiving control data. When in standby mode, the device controller disconnects the device from a power source, such as the AC mains of the building in which the device is situated. As a result, in standby mode only the device controller is powered, which uses much less power than prior art devices in standby mode. The device controller includes an input device structured to provide control data based on control instructions received from a user, a power switch coupled between a power source and the device power input, and a data coupler coupled to the device data input and structured to convert electrical data into non-electrical data and back to the electrical data for delivery to the device data input. The device controller also includes a controller structured to cause the data coupler to provide the control data to the device data input, decode the control data, and if the control data indicates that the user desires to turn on the device when in standby mode, then causes the power switch to deliver power from the power source to the device power input. 
         [0007]    European patent application EP0975109 describes a digital broadcasting method for transmitting required information to minimize the stand-by power in an apparatus for receiving a digital broadcast, and the receiving apparatus. Before transmitting utilization data for an apparatus at the receiving end from a transmitting end, transmission schedule information including the kind of the utilization data, a receiver identifier indicating a target to which the utilization data is to be transmitted, and the transmission time at which the utilization data is to be transmitted, is multiplexed in a transport stream of a service (program) to be transmitted. 
       SUMMARY OF THE INVENTION 
       [0008]    Many items of mains powered, electronic equipment are designed for continuous operation and as such they consume power, even when placed in a “standby” power state. A typical example of this is a digital television set top box (STB), where the broadcast television operator requires that entitlement management messages (EMM) and schedule information are received by the STB even when the STB is put into “standby” state by the user in order to facilitate a fast “wakeup from standby” time for the STB. The STB may also have digital video recorder (DVR) functionality and in order to allow for features such as rewind of the live television broadcast, the STB may also be continually caching the television broadcast. This means that the STB has to be continually powered and have appropriate components operating at all times in order to retrieve the relevant information from the television broadcast. 
         [0009]    However, the requirement for such STBs to be in continuous operation is not fixed as changes to the broadcast system or a user preference to completely power down the STB may remove the requirement. Therefore, the situation can arise where an item of electronic equipment is consuming power unnecessarily as it was not designed to fully power down without user intervention. 
         [0010]    There is provided in accordance with embodiments of the present invention a power saving device disposed in use between a further device and a mains power supply for supplying power to the further device, the power saving device including: a communications channel input connected in operation to a communications channel output of the further device, wherein the communications channel input is operable to receive control instructions from the further device; a switch for disconnecting the further device from the mains power supply in response to the control instructions received from the further device; and an internal power source operable to provide power to the power saving device. 
         [0011]    In some embodiments the power saving device further includes a signal receiver operable to receive signals initiating the reconnection of the further device to the mains power supply and the powering up of the further device. 
         [0012]    In some embodiments, the signal receiver includes an infra-red receiver. 
         [0013]    In some embodiments, the infra-red receiver is operable to receive infra-red signals from a remote control associated with the further device. 
         [0014]    In some embodiments, the infra-red receiver is enabled when the further device is disconnected from the mains power supply. 
         [0015]    In other embodiments, the signals include Ethernet signals. 
         [0016]    In other embodiments, the signals include PSTN signals. 
         [0017]    In other embodiments, the signals include RF signals. 
         [0018]    In some embodiments, the RF signals initiating the reconnection of the further device are modulated with standard RF signals being transmitted to the further device. 
         [0019]    In other embodiments, the RF signals initiating the reconnection of the further device are overlaid on standard RF signals being transmitted to the further device. 
         [0020]    In some embodiments, the RF signals are transmitted out of band to said standard RF signals. 
         [0021]    In some embodiments, the internal power source includes a battery. 
         [0022]    In other embodiments, the internal power source includes a rechargeable power source. 
         [0023]    In some embodiments, the power saving device reconnects the further device to the mains power supply in order to recharge the rechargeable power source. 
         [0024]    In some embodiments, the rechargeable power source includes a rechargeable battery. 
         [0025]    In other embodiments, the rechargeable power source includes a capacitor. 
         [0026]    In other embodiments, the internal power source includes a mains transformer. 
         [0027]    In some embodiments, the power saving device further includes a timer, and the control instructions include a time, measurable using the timer, at which the further device is to be reconnected to the mains power supply. 
         [0028]    In some embodiments, the communications channel input includes a serial communications channel input. 
         [0029]    In some embodiments, the serial communications channel input includes an RS-232 input. 
         [0030]    In other embodiments, the serial communications channel input includes a universal serial bus input. 
         [0031]    In some embodiments, the further device includes a digital television set top box. 
         [0032]    There is also provided in accordance with further embodiments of the present invention a power saving device disposed in use between a further device and a mains power supply for supplying power to the further device, the power saving device including: communications channel input means connected in operation to communications channel output means of the further device, wherein the communications channel input means are for receiving control instructions from the further device; switching means for disconnecting the further device from the mains power supply in response to the control instructions received from the further device; and internal power means for providing power to the power saving device. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         [0033]    The present invention will be understood and appreciated more fully from the following detailed description, taken in conjunction with the drawings in which  FIG. 1  is a simplified pictorial illustration of a power saving system constructed and operative in accordance with embodiments of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
       [0034]    Embodiments of the present invention will now be described with reference to a digital television set top box (STB). Referring to  FIG. 1 , a STB  101  is shown. STB  101  is software programmable and has a communication channel  103  (e.g. a serial RS232 communication channel, universal serial bus (USB), WiFi, Bluetooth etc.) enabling it to communicate with a power saving device  105 . STB  101  is connected to a mains power supply (sometimes also called an outlet power supply or line power supply) via power saving device  105 . 
         [0035]    Power saving device  105  contains a microcontroller  107  for controlling operation of power saving device  105 , a countdown timer  109 , an infra-red (IR) receiver port  111  enabling power saving device  105  to receive IR commands from an IR remote control, an internal power source  113  and a latching mains power switch relay  115 . Internal power source  113  provides the power that power saving device  105  needs to operate and could comprise, for example, a rechargeable battery connected via the communications channel, RF output or another connector on the back panel of the STB, a large capacity capacitor, a small mains transformer, a replaceable battery etc. Other internal power sources will be apparent to someone skilled in the art. Power relay  115  enables power saving device  105  to cut off STB  101  from a mains power supply  117 . Although described as a latching mains power switch relay, someone skilled in the art will realize that any form of switching means that can disconnect STB  101  from mains power supply  117  could be used. 
         [0036]    On reception of a power down event (e.g. a user of STB  101  pressing a standby button on a remote control associated with STB  101 ), the software of STB  101  makes itself ready for a clean power down by flushing any data and caching any essential information in non-volatile storage (as described, for example, in International Patent Application PCT/GB2007/001983 of NDS Technologies France (published as WO 2007/138306). STB  101  then ignores any further requests from the user except a request to cancel the power down. 
         [0037]    Then, the software of STB  101  sends power saving device  105  a sequence of commands via the communications channel. 
         [0038]    Then microcontroller  107  of power saving device  105  interprets the command sequence received from STB  101 . 
         [0039]    The command sequence may include a wake-up alarm time (e.g. if there are scheduled reminders in the software&#39;s viewing planner application of STB  101 ). In this case, microcontroller  107  sets countdown timer  109  to wake up (power up) STB  101  at the appointed time. 
         [0040]    Then microcontroller  107  powers down STB  101  by switching power relay  115  thereby cutting off the mains power to STB  101 . 
         [0041]    Then microcontroller  107  enables IR receiver  111  to detect requests from the user (e.g. the user pressing a power up button on the remote control.) 
         [0042]    Microcontroller  107  then puts itself into a power saving mode, but countdown timer  109  continues and IR receiver  111  remains active. 
         [0043]    Microcontroller  107  is reactivated on completion of the countdown timer, or if power saving device  105  receives an IR signal from the user&#39;s remote control indicating that the user wants to turn on STB  101 . 
         [0044]    Microcontroller  107  then disables IR receiver  111  on power saving device  105  and powers up STB  101  by switching power relay  115  and reapplying mains power to STB  101 . 
         [0045]    STB  101  boots up (restarts) as it would normally do when mains power is applied to it after having been in a powered down state. 
         [0046]    The software on STB  101  determines the reason for the wake up by examining the schedule information and the current time. The software on STB  101  may also interrogate microcontroller  107  for this information. 
         [0047]    In cases where internal power source  113  comprises an ephemeral, rechargeable source of power, power saving device  105  wakes up STB  101  in order to recharge internal power source  113 . 
         [0048]    STB  101  attached to power saving device  105  may also be connected to related equipment. For example, a display device  119  could also be attached to STB  101 . In this case, the display device  119  may also be connected to a mains power supply  117  via power saving device  105  so that both STB  101  and the display device  119  are powered down simultaneously. The display device  119  may remain powered down while STB  101  is active. For example, in the case where STB  101  was powered up to perform a recording based on a preset time, the display device  119  may remain powered down until the user presses a remote control button to signify that the display device  119  should be powered up again. 
         [0049]    Additional sources of stimuli  121  may exist aside from a remote control for STB  101 , IR receiver  111 , or internal countdown timer  109 . 
         [0050]    For example, a PSTN or Ethernet line may be used to signal to power saving device  105  that it should wake up STB  101  in order to allow STB  101  to receive appropriate signaling from an external third party. This can allow, for example, a television broadcaster to signal STB  101  that new entitlement data is about to be delivered or to add a new recording event to the recording schedule of STB  101 . When a PSTN line is used, a Caller ID (also called caller identification, CID, or calling number identification, which is a telephone service that transmits a caller&#39;s number to the called party&#39;s equipment during the ringing signal or when the call is being set up but before the call is answered) can be used to identify the external third party. In this way, only certain, predetermined telephone numbers can be made to wake up the STB without causing all telephone calls to wake up the STB. 
         [0051]    An RF feed may be used in a similar manner to signal a wakeup from an external third party. A standard RF signal may be further modulated or overlaid with additional signaling (e.g. an out of band signal) which does not affect the standard signal. The additional signaling can be used by an external third party in a similar manner to a PSTN or Ethernet line but may not require any additional wiring to power saving device  105 . 
         [0052]    According to embodiments of the present invention, a power saving device  105  has been described that can be used with electronic equipment that was not originally designed to be fully powered down without user intervention. Using an existing communications channel of the electronic equipment, the power saving device  105  can power down the electronic equipment. Power saving device  105  contains more than simply a preset timer as a stimulus for waking up the electronic equipment. Power saving device  105  offers an after market means of totally powering down electronic equipment. 
         [0053]    According to embodiments of the present invention, an add-on device that can be used with mains powered electronic equipment (such as STBs) to provide a power saving solution has been described. The device is controllable by the electronic equipment that is plugged into it and can be operated using other stimuli and/or a preset timer. The device can be connected to the electronic equipment via a communications channel (e.g. serial (RS232), USB, etc.) to allow the electronic equipment to program the device. 
         [0054]    The device can provide a controlled electrical means for the electronic equipment to fully power down by cutting of the mains supply to the electronic equipment on request via the communications channel. The device allows reactivation of the electronic equipment by re-establishing the mains power supply to the electronic equipment. The reactivation can take place at a known time or through another source of stimulus, such as infra-red remote control or power recharge cycle (in the case where the device is powered by a rechargeable battery or a capacitor), or other mechanisms (as were described above). The electronic equipment is typically quick to boot (start/restart) from a completely powered down state in order to obtain the optimal power saving. 
         [0055]    The device can be programmed by the connected electronic equipment rather than via a remote control associated with the electronic equipment. The device can enable a controlled shutdown of the electronic equipment, and can also allow a controlled wake-up alarm timer to be set. The device can also allow interruption of the wake-up alarm timer by a stimulus such as remote control, PSTN line, Ethernet, RF signaling, etc. An external supplier (e.g. a television broadcaster in the case where the electronic equipment is a STB) can ‘stimulate’ the electronic equipment in order to initiate the controlled wake-up (e.g. to indicate data for the electronic equipment is due to be delivered and the electronic equipment needs to be active in order to receive it.) 
         [0056]    It is appreciated that software components of the present invention may, if desired, be implemented in ROM (read only memory) form. The software components may, generally, be implemented in hardware, if desired, using conventional techniques. It is further appreciated that the software components may be instantiated, for example: as a computer program product; on a tangible medium; or as a signal interpretable by an appropriate computer. 
         [0057]    It is appreciated that various features of the invention which are, for clarity, described in the contexts of separate embodiments may also be provided in combination in a single embodiment. Conversely, various features of the invention which are, for brevity, described in the context of a single embodiment may also be provided separately or in any suitable subcombination. 
         [0058]    It will be appreciated by persons skilled in the art that the present invention is not limited by what has been particularly shown and described hereinabove. Rather the scope of the invention is defined by the appended claims and equivalents thereof.