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參數(shù)資料
| 型號： | UC2845AD1 |
| 廠商： | 意法半導(dǎo)體 |
| 英文描述： | HIGH PERFORMANCE CURRENT MODE PWM CONTROLLER |
| 中文描述： | 高性能電流模式PWM控制器 |
| 文件頁數(shù)： | 1/15頁 |
| 文件大?。?/td> | 135K |
| 代理商： | UC2845AD1 |
UC2842B/3B/4B/5B
UC3842B/3B/4B/5B
March1999
HIGH PERFORMANCE CURRENT MODE PWM CONTROLLER
.
TRIMMED OSCILLATOR FOR PRECISE FRE-
QUENCY CONTROL
.
OSCILLATOR FREQUENCY GUARANTEED
AT 250kHz
.
CURRENT MODE OPERATION TO 500kHz
.
AUTOMATIC FEED FORWARD COMPENSA-
TION
.
LATCHING PWM FOR CYCLE-BY-CYCLE
CURRENT LIMITING
.
INTERNALLY TRIMMED REFERENCE WITH
UNDERVOLTAGELOCKOUT
.
HIGH CURRENT TOTEM POLEOUTPUT
.
UNDERVOLTAGE LOCKOUT WITH HYSTER-
ESIS
.
LOWSTART-UPANDOPERATINGCURRENT
DESCRIPTION
TheUC384xBfamilyofcontrolICsprovidesthenec-
essary features to implement off-line or DC to DC
fixedfrequencycurrent modecontrolschemeswith
a minimal external parts count. Internally imple-
mentedcircuits includea trimmedoscillatorfor pre-
cise DUTY CYCLE CONTROL under voltagelock-
outfeaturingstart-upcurrentlessthan0.5mA,a pre-
cision reference trimmed for accuracy at the error
ampinput,logicto insurelatchedoperation,a PWM
comparatorwhichalsoprovidescurrentlimitcontrol,
and a totem pole output stage designed to source
orsinkhighpeakcurrent.Theoutputstage,suitable
for driving N-Channel MOSFETs, is low in the off-
state.
Differencesbetweenmembers of this family arethe
under-voltagelockoutthresholdsandmaximum duty
cycle ranges. The UC3842B and UC3844B have
UVLO thresholds of 16V (on) and 10V (off), ideally
suitedoff-lineapplicationsThecorrespondingthresh-
oldsfortheUC3843BandUC3845Bare8.5Vand7.9
V.TheUC3842BandUC3843Bcanoperateto duty
cyclesapproaching100%. A rangeof the zero to <
50 % is obtainedbythe UC3844Band UC3845Bby
theadditionofaninternaltoggleflipflopwhichblanks
theoutputoffeveryotherclockcycle.
BLOCK DIAGRAM
(toggle flip flop used only in UC3844B and UC3845B)
UVLO
S/R
5V
REF
34V
INTERNAL
BIAS
VREF GOOD
LOGIC
2.50V
T
S
R
OSC
R
1V
CURRENT
SENSE
COMPARATOR
2R
+
-
PWM
LATCH
7
5
4
2
1
3
8
6
ERROR AMP.
Vi
GROUND
RT/CT
VFB
COMP
CURRENT
SENSE
VREF
5V 50mA
OUTPUT
D95IN331
Minidip
SO8
UC3842B
1/15
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| UC2845BD1R2G | HIGH PERFORMANCE CURRENT MODE CONTROLLERS |
| UC2845BD1R2 | HIGH PERFORMANCE CURRENT MODE CONTROLLERS |
| UC2845BD1 | HIGH PERFORMANCE CURRENT MODE CONTROLLERS |
| UC3843A | HIGH PERFORMANCE CURRENT MODE PWM CONTROLLER |
| UC3843AD1 | HIGH PERFORMANCE CURRENT MODE PWM CONTROLLER |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| UC2845AD1013TR | 制造商:STMicroelectronics 功能描述: |
| UC2845AD8 | 功能描述:電流型 PWM 控制器 Current Mode RoHS:否 制造商:Texas Instruments 開關(guān)頻率:27 KHz 上升時間: 下降時間: 工作電源電壓:6 V to 15 V 工作電源電流:1.5 mA 輸出端數(shù)量:1 最大工作溫度:+ 105 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:TSSOP-14 |
| UC2845AD8G4 | 功能描述:電流型 PWM 控制器 Current-Mode PWM Controller RoHS:否 制造商:Texas Instruments 開關(guān)頻率:27 KHz 上升時間: 下降時間: 工作電源電壓:6 V to 15 V 工作電源電流:1.5 mA 輸出端數(shù)量:1 最大工作溫度:+ 105 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:TSSOP-14 |
| UC2845AD8TR | 功能描述:電流型 PWM 控制器 Current-Mode PWM Controller RoHS:否 制造商:Texas Instruments 開關(guān)頻率:27 KHz 上升時間: 下降時間: 工作電源電壓:6 V to 15 V 工作電源電流:1.5 mA 輸出端數(shù)量:1 最大工作溫度:+ 105 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:TSSOP-14 |
| UC2845AD8TRG4 | 功能描述:電流型 PWM 控制器 Current-Mode PWM Controller RoHS:否 制造商:Texas Instruments 開關(guān)頻率:27 KHz 上升時間: 下降時間: 工作電源電壓:6 V to 15 V 工作電源電流:1.5 mA 輸出端數(shù)量:1 最大工作溫度:+ 105 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:TSSOP-14 |
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