www.德州仪器.com
PTH12050W
Trac k
地
PTV12010W
Trac k
地
+
+
+
+
U1
U2
12 v
0 v
Q1
BSS138
V
I
V
O
V
O
1 = 3.3 v
V
O
V
I
C1
0.1
F
R1
100 k
地 调整
R2
2 k
V
O
2 = 2 v
R3
8.06 k
调整
开关 控制
1 = 电源 向下
0 = 电源 向上
C1
C1
C3
C3
C2
C2
vo1 (1 v/div)
vo2 (1 v/div)
开关 控制
(5 v/div)
horiz 规模: 10 ms/div
vo1 (1 v/div)
vo2 (1 v/div)
开关 控制
(5 v/div)
horiz 规模: 10 ms/div
prebiasstart-upcapability
PTV12010L
PTV12010W
SLTS234–DECEMBER2004
4.themoduledoesnotfollowavoltageatitstrackcontrolinputuntilithascompleteditssoft-开始
initialization.thistakesabout10msfromthetimethatthemodulehassensedthatavalidvoltagehasbeen
appliedtoitsinput.duringthisperiod,itisrecommendedthatthetrackpinbeheldatgroundpotential.
5.themoduleiscapableofbothsinkingandsourcingcurrentwhenfollowingavoltageatitstrackpin.
因此,startupintoanoutputprebiascannotbesupportedwhenamoduleisunderauto-trackcontrol.
便条:
Aprebiasholdoffisnotnecessarywhenallsupplyvoltagesrisesimultaneouslyunderthecontrolof
自动-追踪.
6.theauto-trackfunctioncanbedisabledbyconnectingthetrackpintotheinputvoltage(v
I
).当
自动-trackisdisabled,theoutputvoltagerisesataquickerandmorelinearrateafterinputpowerisapplied.
figure16.sequencedpowerupandpowerdownusingauto-追踪
figure17.simultaneouspowerupwithauto-trackfigure18.simultaneouspowerdownwithauto-追踪
ControlControl
aprebiasstart-upconditionoccursasaresultofanexternalvoltagebeingpresentattheoutputofapower
modulepriortoitsoutputbecomingactive.thisoftenoccursincomplexdigitalsystemswhencurrentfrom
anotherpowersourceisbackfedthroughadual-supplylogiccomponent,suchasanfpgaorasic.另一
pathmightbeviaclampdiodes,sometimesusedaspartofadual-supplypower-upsequencingarrangement.一个
16
: 点此下载
