Abstract:
The enhanced power supply adds a control circuit and rechargeable battery to the prior art transformer. The enhanced power supply uses an internal rechargeable battery in standby mode, so that the power supply does not draw AC power when the attached device is not in use. Control contacts on the power supply receptacle act as a communication channel allowing the attached device to power requirements to the power supply. The power supply has the ability to detect the power draw and switch between power modes, even when there is no communication with the attached device.

Description:
FIELD OF THE INVENTION 
       [0001]    The enhanced power supply relates generally to electrical power conversion systems, and specifically to an AC to DC adaptor using a microprocessor controller, an internal rechargeable battery and intelligent control contacts to reduce power consumption. 
       BACKGROUND OF THE INVENTION 
       [0002]    Many of the home electronic products, particularly electronics such as small appliances, cordless phones and laptop computers use external power supplies called “wall-packs” or “bricks.” These power supplies convert 120 volts of alternating current (AC) to the low voltage direct current (DC) used by most home electronic products. The DC voltage used by most target devices is commonly between 3V-14V. Most external power supplies are a linear power supply that use a transformer comprising two coils of wire and a magnetic field to lower voltage to the desired level. A bridge rectifier then converts the low voltage AC to DC. Other circuitry smoothes and filters the current to product a flat DC waveform. In operation, the transformer coils produce heat contributing to lost energy and a reduction in the effective life of the linear power supply. 
         [0003]    Linear power supplies continue to draw power after the attached device using the power supply has been turned off. The amount of energy used by a power supply when the attached device is turned off is called the “standby power load.” The standby power load generates waste heat which adds to the cooling load of a structure, and shortens the life of the power supply. 
         [0004]    Chris Caldwell and Travis Reeder, in a May 2002 National Resources Defense Council publication, “Power Supplies: A Hidden Opportunity for Energy Savings,” described the standby power load problem and known solutions to the problem. One known solution for dealing with the problem of standby power load eliminates the standby power load by manually turning off the power supply. Power supplies can be used on a power strip with a switch, or the power supply can have an integrated power switch so that consumers of electronic devices can turn off or unplug the power supply when it is not in use. While this solution may work for infrequently used devices such as battery chargers, it is not practical for other devices, such as a fax machine or an answering machine, that need to be ready to operate at any time. 
         [0005]    Another known solution for addressing standby power load involves “switching” power supplies that use internal solid state electronics to switch between high (peak) load and low (standby) load modes depending on the needs of the attached device. Switching between high and low load modes can be achieved either by using multiple transformers corresponding to the different power demands, or by using “pulse width modulation.” Pulse width modulation delivers power in a series of brief pulses. The switching power supply creates only the number of pulses necessary to meet the power demand, and skips pulses when demand is low. These switching power supplies reduce the standby power load, but do not totally eliminate the standby power load. Power supplies with pulse width modulation can increase peak load efficiency by supplying only the amount of power needed at any given time. 
         [0006]    While switching between peak and standby modes can reduce the standby power load, a need exists for an intelligent power supply that automatically eliminates standby power load so that no AC power is drawn when the attached device is turned off. 
       SUMMARY OF THE INVENTION 
       [0007]    The enhanced power supply adds a control circuit and rechargeable battery to the prior art transformer. The enhanced power supply uses an internal rechargeable battery in standby mode, so that the power supply does not draw AC power when the attached device is not in use. Control contacts on the power supply receptacle act as a communication channel allowing the attached device to power requirements to the power supply. The power supply has the ability to detect the power draw and switch between power modes, even when there is no communication with the attached device. 
     
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0008]    The novel features believed characteristic of the invention are set forth in the appended claims. The invention itself, however, as well as a preferred mode of use, further objectives and advantages thereof, will be understood best by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings, wherein: 
           [0009]      FIG. 1  is an external power supply attached to a computer; 
           [0010]      FIG. 2 . shows components of the power supply; and 
           [0011]      FIG. 3  is a flowchart of the power supply&#39;s switching logic. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0012]    Referring to  FIG. 1 , Enhanced Power Supply  200  is connected to outlet  105  is a 110 v 60 Hrz AC power outlet. Enhanced Power Supply  200  is an AC to DC converter plugged into power outlet  105 . Power cord  205  is a power cord carrying DC power to receptacle  270  which plugs into target device  115  (shown here as a laptop computer.) Often, target device  115  has an internal battery for portable applications. The internal battery on target device  115  will be referred to as the “target battery.” The actual configuration of receptacle  270  varies by model and manufacturer. A common configuration uses a coaxial pair of metal contacts extending from a plastic housing. 
         [0013]      FIG. 2  depicts the components of enhanced power supply  200 . Prongs  220  plug into wall outlet  105 . In other embodiments of Enhanced Power Supply  200 , prongs  220  are replaced with a cord coupled with prongs for plugging into wall outlet  105 . Transformer  230  converts 110V 60 Hrz AC power into DC power with a voltage required by target device  115 , commonly between 6V-14V. Connector  240  delivers DC power to Switching Logic Component  300 . Connectors  250  deliver DC power between Switching Logic Component  300  and local battery  260 . In a preferred embodiment, Switching Logic Component  300  comprises a microprocessor, electronic switches and any necessary signal converters that enable the microprocessor to redirect current as required by the microprocessors programming. Switching Logic Component  300  may also include electrical measuring devices capable of detecting power load used by target device  115 . Local battery  260  may be either a battery, a capacitor, or any other suitable charge holding component that can store power as required by Switching Logic Component  300 . Switching Logic Component  300  charges local battery  260  when the charge decreases to a designated level. Local battery  260  supplies power to Switching Logic Component  300  when in standby mode, and can provide a trickle charge to recharge batteries in target device  115 . Power cord  205  provides DC power from enhanced power supply  200  to receptacle  270 . Metal contact  275  extends from receptacle  270  and plugs into to target device  115 . Cable  215  extends from Switching Logic Component  300  to control contact  280  mounted to receptacle  270 . Control contact  280  via cable  215  facilitate communication between target device  115  and Switching Logic Component  300 . Control contact  280  in its simplest form is an open circuit with a switch that closes when physically connected with target device  115 . The closed circuit indicates that enhanced power supply  200  is attached to target device  115 . Other embodiments of control contact  280  allow target device  115  to electronically communicate with Switching Logic Component  300 , to signal for increased or decreased power and to turn enhanced power supply  200  on or off. 
         [0014]      FIG. 3  depicts a flowchart of the Switching Logic Component  300 . Switching Logic Component starts when Enhanced Power Supply is plugged into an AC power source ( 310 ). Switching Logic Component  300  initializes the steady state power mode, converting the AC power into DC power to supply target device  115  and local battery  260 . ( 312 ). Switching Logic Component  300  then attempts to establish a communication link with target device  115  ( 314 ) via control contact  280  and cable  215 . If local battery  260  is fully charged or exceeds a preset threshold value ( 316 ), Switching Logic Component  300  stops supplying DC power to local battery  260  ( 318 ). 
         [0015]    Switching Logic Component  300  determines if target device  115  is attached ( 320 ) in two ways. First, Switching Logic Component  300  can determine that target device  115  is attached by detecting current drawn through metal contact  275  via power cord  205 . Otherwise, control contact  280  can signal via cable  215  whether target device  115  is connected to enhance power supply  200  by closing a circuit when receptacle  270  is physically plugged into target device  115 , or by establishing a communication link with target device  115 . 
         [0016]    If target device  115  is not connected to enhanced power supply  200 , then Switching Logic Component  300  stops supplying DC power through connector  205  ( 322 ). If target device  115  is connected to enhanced power supply  200 , then Switching Logic Component  300  determines if target device  115  is turned on ( 324 ). Target device  115  is turned on if DC power is being drawn through connector  205 . Switching Logic Component  300  can also use a communication link through connector  215  to determine if target device  115  is turned on. If target device  115  is turned off, Switching Logic Component  300  determines if the target battery on target device  115  is fully charged ( 326 ). If the target battery is fully charged, then Switching Logic Component  300  stops supplying DC power through connector  205  ( 322 ). If the target battery is not fully charged, Switching Logic Component  300  will continue to supply DC power through connector  205  to charge the target battery ( 328 ). 
         [0017]    If Switching Logic Component  300  determines target device  115  is turned on ( 324 ), then Switching Logic Component  300  checks whether enhanced power supply  200  is at “steady state” ( 330 ), turns the transformer back on and starts the supply of DC power to target device  115  if needed ( 332 ). Enhanced power supply  200  is at “steady state” whenever the transformer is turned on and is supplying DC power to target device  115  (and to local battery  260  if local battery  260  is not fully charged). If local battery  260  is not fully charged ( 334 ), DC power is supplied to charge local battery  260  ( 336 ). 
         [0018]    If target device  115  is not attached, or if target device  115  is turned off, Switching Logic Component  300  determines if enhanced power supply  200  is in “standby mode” ( 338 ). Standby mode occurs when transformer  230  is turned off and DC power is supplied by local battery  260 . Enhanced power supply  200  in standby mode can provide a trickle charge from local battery  260  to target battery when target device  115  is powered off. If enhanced power supply  200  is not in standby mode, Switching Logic Component  300  shuts off the AC transformer and uses local battery  260  to supply DC power ( 340 ). 
         [0019]    For as long as enhanced power supply  200  is plugged in or has AC power available ( 342 ), Switching Logic Component  300  will loop through steps ( 316 - 340 ) detecting the power requirements of target device  115 , and switching between steady state and standby modes. Whenever the AC power is no longer supplied, Switching Logic Component  300  will shut down communication with target device  115  via control contact  280  and cable  215  ( 344 ) and stop ( 346 ). 
         [0020]    In one embodiment of enhanced power supply  200 , the functions of Switching Logic Component  300  are performed by target device  115 . In this embodiment, control contact  280  and cable  215  acts as communication link between Switching Logic Component  300  and target device  115 . While the communication link is active, Switching Logic Component  300  acts as a slave to target device  115 . Whenever the communication link is lost, Switching Logic Component  300  reassumes control of enhanced power supply  200 . 
         [0021]    A preferred form of the invention has been shown in the drawings and described above, but variations in the preferred form will be apparent to those skilled in the art. The preceding description is for illustration purposes only, and the invention should not be construed as limited to the specific form shown and described. The scope of the invention should be limited only by the language of the following claims.