www.德州仪器.com
V
交流
V
USB
V
输出
V
BAT
dppm 模式
V
交流
V
USB
V
输出
V
BAT
破裂 在之前 制造
dppm 模式
V
输出
returns 至 规章制度 (4.4 v, bq24032)
charging 电流 returns 至 i
pgm
bq24030,bq24031,bq24032,
bq24032a,bq24035,bq24038,bq24039
SLUS618C–AUGUST2004–REVISEDJUNE2005
Figure8illustrateswhenac(lowbattery)isremoved,powertransferstousb;psel=h;channel1(ch1)vac
=5.4v;channel2(ch2)v
(usb)
=5v;channel3(ch3)v
输出
;outputcurrent,i
输出
=0.25a;channel4(ch4)
V
BAT
=2.25v;andi
(pgm-chg)
=1a.thisfigureisthesameaswherethebatteryhasmorecapacity.notethat
theoutputdropstothebatteryvoltagebeforeswitchingtousbpower.aresistordividerbetweenacandground
tiedtopselcantogglethepowertransferearlierifnecessary.
figure8.removeac(lowbattery)–pwrxfertousb
Figure9illustrateswhenacisapplied,powertransfersfromusbtoac;psel=h;channel1(ch1)vac=5.4
v;channel2(ch2)v
(usb)
=5v;channel3(ch3)v
输出
;outputcurrent,i
输出
=0.25a;channel4(ch4)v
BAT
=
3.5v;andi
(pgm-chg)
=1a.thechargerissetforacprioritybutisrunningoffusbuntilacisapplied.whenac
isapplied(1
st
div)andtheusbfetopens(2
nd
div),theacfetcloses(3
rd
div)andtheoutputrecoversfrom
thedppmthreshold(8
th
div).
figure9.applyac–pwrxferfromusbtoac
Figure10illustrateswhenusbisremoved,powertransfersfromusbtoac;psel=l;channel1(ch1)vac=
18