hp calculator power supplies -...
TRANSCRIPT
HP Calculator Power Supplies
from
HP-35 to HP Prime
Presentedby:JimJohnsonHPHandheldConference2016–FortCollins,CO
September17-18,2016
HP Calculator Power Supplies – HP35 to Prime
Synopsis:Thechallengesofprovidingpowertoahandhelddevicestretchesthedesignersimaginationandcreativity.Firstyoumustprovideenoughpowertolast,atminimum,afulldayofnormalusage(preferablymonthsofuse),poweringalltheIC’sandthedisplay.Secondly,youmustmeetagencyrequirements(i.e.FCC/CE/EMI/RFI/USB,etc).Thirdly,ifthedevicehasrechargeablebatteries,youmustbeabletosafelyrechargethem.Oralternatively,youmustuselowcost,disposablebatteries.Andfinally,thehandhelddevicepcboardmustaccommodatemanysmallpowerconversiondevicesintoarelativelysmallspaceanddothisefficientlyinpcboardcm2,powerandcost.
HP Calculator Power Supplies – HP35 to Prime
A WORD OF
This is what could happen if you don’t exercise caution in your power system design
FirereportedlycausedbychargingaSamsungGalaxyNote7
HP Calculator Power Supplies – HP35 to Prime
PowerBudgetfor:•Displaysandbacklighting•Highpowered,highspeedmicrocontrollers•Wirelesscommunications(WiFiorBluetoothLE)•Wiredcommunications(USB)•Piezotransducers/SounddevicesBatterySizeandWeight:•Smalllithium-ionbatteries(NiCadsinthepast)•SizeversusPower(mAH)versusCostRechargeableversusDisposable•Lithium-ionbatteries•Lithium/ManganeseDioxide(Li/MnO2)–(i.e.CR2032)CostConsiderations:•Chargingcircuitryandcharger•Replacementofdisposablebatteries•Replacementofrechargeablebatteries
PowerConsiderationsforaHandheldDevice
HP Calculator Power Supplies – HP35 to Prime
Notagoodendresult
ConsiderationsinUsingLithiumIonBatteries
HP Calculator Power Supplies – HP35 to PrimeWhatKindofPowerSupplies?
HPPRIME
HP Calculator Power Supplies – HP35 to PrimeHP-35PowerSupply
PhotoCredit:JacquesLaporteandDanWeed
Schematiccredit:KeesVandersanden
HP Calculator Power Supplies – HP35 to PrimeComponentsofHP-29CPowerSupply
3.3uF,10vNPNTransistor
NPNTransistor Tankoscillatorcircuit330pfcap.&15uHcoil
68Ω10KΩ 10uF,16v
6.8uF,10v
2.2uF,6v
15uF,10v
2.2KΩ
22uF,10v
330pf
100pf
diodediode
diode
diode diode
HP29CPowerSupplyPCB(DaughterBoard)
2
HP Calculator Power Supplies – HP35 to Prime
Tankoscillatorcircuit
Vss=+6.3vdc Vdisp=+4.4vdc
Vram=+6.5vdc
Vgg=-12.5vdcVbatt-IN=+2.4vdc
(switched)
HP-21,25and29CPowerSupply
Schematiccredit:JacquesLaporte
HP Calculator Power Supplies – HP35 to Prime
PowerSections
PowerNeedsuC:MultiplepowerrailsMemoryDisplayBacklightUSBChargingCircuit+3.7vdcLithiumIonbattery
HP Calculator Power Supplies – HP35 to PrimeHPPrimeMicrocontroller
MicrocontrollerPowerSupplyRequirements2-DC-DCswitchingregulators4–LDOregulators
HP Calculator Power Supplies – HP35 to Prime
HP35 PrimeContrastandComparePastwithPresent
4differentvoltagesVbatt= +3.6vdcVgg= -12vdcVcc= +8.2vdcVss= +6.2vdc
+10differentvoltagesVbatt= +3.7vdcVddalive= +1.2vdcVddarm= +1.3vdcVrtc= +3.3vdcVdda33usb=+3.3vdcVddi_udev=+1.2vdcVddsram= +1.8vdcVdisp= +??Vbklight= +??Vcharger= +3.7vdc
Components2PNPtransistors7diodes1multiwoundtransformerHandfullofpassives
ComponentsMultipleswitchingregulatorsMultiplelowdrop-outregulatorsMultipleinductorsMultipletransistorsMultiplediodesManysurfacemountpassives
HP Calculator Power Supplies – HP35 to Prime
Summary and Conclusions•Ashandheldelectronicsbecomemorecomplex,sodoesthepowersupplycircuitrythatpowersthem.•Storagedevices(batteries)andtheirchargingcircuitshavebeenandarebecomingamoreimportantpartofhandhelddevices.Monitoringthestatusandadjustingthechargeofthelithium-ionbatteryiscritical.•Newerpowerintegratedcircuitswillbemoreefficientandnewwallchargersmustmeetlowpowerregulations
Neverleaveunchargedbatteriesinyourcalculatorsforlongperiodsoftimeorriskbatteryleakage,outgassingandcorrosionofothercircuits.
HP Calculator Power Supplies – HP35 to Prime
AcknowledgementsandCredits
1. TonyDuell(UK)–InformationonMoHPCsiteandemailexchangein2012.2. JacquesLaporte(r.i.p.)–HPCalculatorForum(www.jacques-laporte.org/
forum)emailexchangeandthepapers“The‘Woodstock’generation”and“TheHP-35PowerUnit”.
3. MuseumofHPCalculators–(http://hpmuseum.org)4. GeoffQuickfall–EmailexchangeregardingHPcalculators,particularlythe
HP19C.5. DaveColver(UK)–EmailexchangeregardingHP29Cschematics.6. RandySloyer–(www.fixthatcalc.com)emailexchangein2012.7. EricSmith–EmailandpostsonMoHPC.8. KatieWasserman–emailexchangeregardingHP29C.9. WoodbankCommunications,Ltd.–Electropaedia10. KeesVandersanden.Calculator/powersupplywebsite.
PersonalCollection:HP01,HP10bII,HP12C,HP15CLE,HP17bII+,HP19C,HP21,HP25,HP29C,HP30b,HP32E,HP32SII,HP34C,HP35S,HP41CX,HP42SHP45,HP67,HP97,WP34S,HPPrime
HP Calculator Power Supplies – HP35 to Prime
Thank you!
©2016Allrightsreservedregardingtheinformationcontainedinthispresentation.IfyouhaveanyquestionsyoumaycontactJimJohnson.Email:[email protected]