Difference between revisions of "Gps1"

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m (Battery charger)
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**, need to watch for cell reversal and over discharge.  indefinite charge at C/300, but a C/10 charge can be used for limited time.  [[http://en.wikipedia.org/wiki/Nickel-metal_hydride_battery#Charging]]   
 
**, need to watch for cell reversal and over discharge.  indefinite charge at C/300, but a C/10 charge can be used for limited time.  [[http://en.wikipedia.org/wiki/Nickel-metal_hydride_battery#Charging]]   
 
** probably can just use a CV charger and use the CPU to monitor cell voltage.  Will use USB to make it easy.
 
** probably can just use a CV charger and use the CPU to monitor cell voltage.  Will use USB to make it easy.
 +
** LT3684 36V 2A 2.8 MHz buck : [[http://www.linear.com/pc/productDetail.jsp?navId=H0,C1,C1003,C1042,P37361]]
  
 
==LCD display==
 
==LCD display==

Revision as of 21:40, 16 July 2009

power management

  • 3 to 4.2 LiPo (1.3 Ahr) - 26 hrs @ 50mA
  • Need upower LV cutoff.

Battery charger

  • LIPO : LT3650-8.2 [[1]]
  • NiMh
  • NImi - charge at upto 1C
    • charge voltage of 1.4-1.6V / cell, fully charged cell of 1.35 to 1.4, discharged at 1.0 to 1.1 V / cell
    • , need to watch for cell reversal and over discharge. indefinite charge at C/300, but a C/10 charge can be used for limited time. [[2]]
    • probably can just use a CV charger and use the CPU to monitor cell voltage. Will use USB to make it easy.
    • LT3684 36V 2A 2.8 MHz buck : [[3]]

LCD display

  • 5V @ 1.5mA
  • TPS61220 boost converter - very efficient at lite load

LCD back light

  • 3.8 - 4.2V @ 240mA max,
  • LTC3454 - LED driver.


dsPICsupply

  • 3.0V @ upto 100mA GPS
  • TPS63030 (buck - boost)

GPS

  • direct to LiPo,
  • or through LDO - TPS780xx Iq=500nA, 150mA output.
  • TPS735xx 25mW @ 50mA, 500mA max, IQ 46uA
  • TPS734xx 25mV @ 50mA, 250mA IQ 44ua
  • TPS799xx 25mV @ 50mA, 200mA, 40uA
  • LOCOSYS LS20031/33 - direct Lipo connections! (41/44 mA)