www.德州仪器.com
V
输出
V
交流
I
CHG
I
输出
V
输出
reg. @ 4.4 v (bq24032)
V
DPPM
−
输出
= 4.26 v, dppm 模式
V
输出
V
BAT
, bat supplement 模式
bq24030,bq24031,bq24032,
bq24032a,bq24035,bq24038,bq24039
SLUS618C–AUGUST2004–REVISEDJUNE2005
0ato~2.2aandbackto0aasshowninthebottomwaveform.asthei
输出
loadreaches0.5a,alongwiththe
1-achargecurrent,theadaptorstartstocurrentlimit,theoutputvoltagedropstothedppm-outthresholdof
4.26v.thisisdppmmode.theacinputtrackstheoutputvoltagebythedropoutvoltageoftheacfet.这
batterychargecurrentisthenadjustedbackasnecessarytokeeptheoutputvoltagefromfallinganyfurther.
oncetheoutputloadcurrentexceedstheinputcurrent,thebatteryhastosupplementtheexcesscurrentandthe
outputvoltagefallsjustbelowthebatteryvoltagebythedropoutvoltageofthebatteryfet.thisisthebattery
supplementmode.whentheoutputloadcurrentisreduced,theoperationdescribedisreversedasshown.ifthe
dppm-outvoltagewassetbelowthebatteryvoltage,duringinputcurrentlimiting,theoutputfallsdirectlytothe
电池'svoltage.
underusboperation,whentheloadsexceedstheprogrammedinputcurrentthresholdsasimilarpatternis
observed.iftheoutputloadexceedstheavailableusbcurrent,theoutputinstantlygoesintothebattery
supplementmode.
figure5.dppmandbatterysupplementmodes
Figure6illustrateswhenpselistoggledlowfor500µs.powertransfersfromactousbtoac;channel1
(ch1)vac=5.4v;channel2(ch2)v
(usb)
=5v;channel3(ch3)v
输出
;outputcurrent,i
输出
=0.25a;频道
4(ch4)v
BAT
=3.5v;andi
(pgm-chg)
=1a.whenthepselwentlow(1
st
div),theacfetopened,andthe
outputfelluntiltheusbfetturnedon.turningofftheactivesourcebeforeturningonthereplacementsourceis
referredtoas
破裂-在之前-制造
切换.therateofdischargeontheoutputisafunctionofsystem
capacitanceandload.notethecableirdropintheacandusbinputswhentheyareunderload.atthe4
th
分隔,theoutputhasreachedsteady-stateoperationatthedppmvoltagelevel(chargecurrenthasbeen
reducedduetothelimitedusbinputcurrent).atthe6
th
分隔,thepselgoeshighandtheusbfetturnsoff
followedbytheacfetturningon.theoutputreturnstoitsregulatedvalue,andthebatteryreturnstoits
programmedcurrentlevel.
16
: 点此下载
