www.德州仪器.com
DP1
DM1
DP2
DM2
DP3
DM3
DP4
PWRON1
OVRCUR1
PWRON2
OVRCUR2
DM4
DP0
DM0
V
CC
XTAL1
XTAL2
OCSOFF
SN75240
d +
d −
5 v
地
d +
d −
5 v
d +
d −
5 v
d +
d −
5 v
48-mhz
结晶
Downstream
端口
TUSB2040
hub 控制
Tuning
电路
一个
B
C
D
33
µ
F
†
SN75240
一个
B
C
D
地
地
地
33
µ
F
†
33
µ
F
†
33
µ
F
†
d +
d −
Upstream
端口
TPS2041B
SN75240
一个
B
5 v
地
C
D
1
µ
F
在
地
ferrite beads
ferrite beads
ferrite beads
ferrite beads
BUSPWR
GANGED
Tie 至 tps2041 en输入
OC EN
输出
5-v 电源
供应
在
地
3.3 v
4.7
µ
F
0.1
µ
F
4.7
µ
F
EN1
在
OC1
OUT1
TPS2062
EN2
OC2
OUT2
0.1
µ
F
地
†
usb rev 1.1 需要 120
µ
f 每 hub.
TPS76333
generichot-plugapplications
tps2061,tps2062,tps2063
tps2065,tps2066,tps2067
SLVS490B–DECEMBER2003–REVISEDDECEMBER2004
applicationinformation(持续)
figure29.hybridself/总线-poweredhubimplementation
inmanyapplicationsitmaybenecessarytoremovemodulesorpcboardswhilethemainunitisstilloperating.
theseareconsideredhot-plugapplications.suchimplementationsrequirethecontrolofcurrentsurgesseenby
themainpowersupplyandthecardbeinginserted.themosteffectivewaytocontrolthesesurgesistolimitand
slowlyrampthecurrentandvoltagebeingappliedtothecard,similartothewayinwhichapowersupply
normallyturnson.duetothecontrolledrisetimesandfalltimesofthetps206x,thesedevicescanbeusedto
provideasofterstart-uptodevicesbeinghot-pluggedintoapoweredsystem.theuvlofeatureofthetps206x
alsoensuresthattheswitchisoffafterthecardhasbeenremoved,andthattheswitchisoffduringthenext
嵌入.theuvlofeatureinsuresasoftstartwithacontrolledrisetimeforeveryinsertionofthecardor
单元.
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