Smart Electrical Power Supply Cal(IT)

1
Smart Electrical Power SupplyCal(IT)²Sponsor
Douglas Palmer

• Every new electronic gadget purchased today seems
  to come with its own external power supply, more
  commonly known as a 'wall wart'. It's a hassle to
  keep these organized and associated with their
  respective devices when you are at home, and when
  you're on a trip, the problem can grow
  enormously. On a typical business trip, it would
  not be unusual to take a laptop computer, a PDA,
  a CD and/or MP3 player, and a digital camera
  each one requiring its own wall wart. The power
  supplies can easily outweigh the devices they
  power, to say nothing of the rat's nest of
  tangled cords and confusing connectors. Thus the
  need for SmartPower The one-size-fits-all
  external power supply.
• The concept for SmartPower is to establish a
  technology and a standard for powering (nearly)
  all devices using an external power supply. One
  universal power supply can be created. The
  benefits could be enormous. Device manufacturers
  could use the same supply for all their designs,
  or for economy, could choose not to included a
  power supply with their device, counting on the
  consumer to already have at least one SmartPower
  supply at home. Consumers can plug any SmartPower
  device into any SmartPower supply, without
  concern for accidentally blowing something up. If
  they own a few SmartPower supplies, then they can
  recharge any device in any room of the house. On
  trips, only one SmartPower supply needs to be
  taken along, to be shared among all the devices.
  Soon, hotels and motels will start providing
  SmartPower supplies built into their rooms.
• Technically, the SmartPower system should work
  like this Each SmartPower device will have a
  single power-control chip built into it. When the
  device is first connected to the supply, no
  appreciable power flows. The device chip
  communicates with the supply to tell it how many
  volts and how many amps it requires. It may
  supply additional information such as expected
  charging time, or a current versus time schedule.
  The supply then provides precisely what the
  device needs. The device chip monitors the
  supplied power, and can cut it off if the wrong
  voltage or current is supplied. However, the
  device chip does not regulate the power, so heat
  does not have to be dissipated at the device.
  Power regulation all occurs in the SmartPower
  supply. Older devices that don't have SmartPower
  chips can use small external adapter plugs with a
  chip built in.
• For this project, the requirements are
• Design the method of communication between the
  SmartPower chip and and SmartPower supply. The
  supply may provide a very small amount of power
  for the chip initially, in case the device
  battery is completely discharged. Ideally, the
  same two wires used for power and ground can be
  used for communication. Also, it is desirable if
  additional communication can take place after
  power begins flowing. Though no specific
  application currently exists, it is also
  desirable to allow for communication from the
  supply to the chip.
• Design and build the digital and analog
  electronics for the SmartPower chip. Obviously, a
  custom chip is not required for this project.
  Instead discrete electronic parts may be used.
  Optionally, a PLD may be used for the digital
  portion. The design should allow for selection of
  different voltages and currents.
• Design and build the digital and analog
  electronics for the SmartPower supply. Again,
  discrete electronics may be used. The goal for
  the supply is 24 volt-Amps. In other words, it
  should be able to provide 24 volts at 1 amp, 1
  volt at 24 amps, and other selections in between.
  It should also have a cut off feature so that if
  a device draws more current at a given voltage
  than it specified, all power is cut off. Though
  DC voltage is more common, ideally AC should be
  available too if required.
• Design and implement a test procedure to
  demonstrate the functionality and features of the
  SmartPower system.
• Deliverables will include schematics, parts
  list, suppliers, cost, any code for processors or
  PLDs, and written documentation.
• Sponsor Cal(IT)2 Mentor Douglas Palmer,
  dpalmer_at_cox.net