UC2845BD

更新时间： 2024-11-22 22:04:39

品牌	Logo	应用领域
意法半导体 - STMICROELECTRONICS		开关光电二极管控制器
页数	文件大小	规格书
15页	137K
描述
HIGH PERFORMANCE CURRENT MODE PWM CONTROLLER

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中文翻译

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数据手册

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UC2845BD 数据手册

UC2842B/3B/4B/5B

UC3842B/3B/4B/5B

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

Minidip

SO8

LATCHING PWM FOR CYCLE-BY-CYCLE

CURRENT LIMITING

INTERNALLY TRIMMED REFERENCE WITH

UNDERVOLTAGE LOCKOUT

HIGH CURRENT TOTEM POLE OUTPUT

UNDERVOLTAGE LOCKOUT WITH HYSTER-

ESIS

comparatorwhichalsoprovidescurrentlimitcontrol,

and a totem pole output stage designed to source

orsinkhighpeakcurrent.Theoutputstage,suitable

for driving N-Channel MOSFETs, is low in the off-

state.

LOW START-UPAND OPERATINGCURRENT

Differencesbetween members of this family are the

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. The UC3842B and UC3843B can operateto duty

cycles approaching100%. A range of the zero to <

50 % is obtainedby the UC3844Band UC3845Bby

theadditionofan internaltoggleflipflopwhichblanks

theoutputoff everyotherclock cycle.

DESCRIPTION

TheUC384xBfamilyofcontrolICsprovidesthenec-

essary features to implement off-line or DC to DC

fixedfrequencycurrent modecontrol schemes with

a minimal external parts count. Internally imple-

mentedcircuits includea trimmed oscillator for 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

BLOCK DIAGRAM (toggle flip flop used only in UC3844B and UC3845B)

UVLO

34V

REF

VREF

5V 50mA

S/R

GROUND

INTERNAL

BIAS

2.50V

VREF GOOD

LOGIC

OUTPUT

RT/CT

OSC

ERROR AMP.

VFB

PWM

LATCH

COMP

CURRENT

SENSE

UC3842B

CURRENT

SENSE

COMPARATOR

D95IN331

1/15

March 1999

12 3 4 5 6 7...15

中文翻译

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UC2845BD1	STMICROELECTRONICS	获取价格	HIGH PERFORMANCE CURRENT MODE PWM CONTROLLER
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UC2845BD1	MOTOROLA	获取价格	Switching Controller, Current-mode, 1A, 500kHz Switching Freq-Max, BIPolar, PDSO8, PLASTIC
UC2845BD1013TR	STMICROELECTRONICS	获取价格	HIGH PERFORMANCE CURRENT MODE PWM CONTROLLER
UC2845BD1G	ONSEMI	获取价格	High Performance Current Mode PWM Controller, SOIC-8 Narrow Body, 98-TUBE
UC2845BD1R2	ONSEMI	获取价格	HIGH PERFORMANCE CURRENT MODE CONTROLLERS
UC2845BD1R2	MOTOROLA	获取价格	1A SWITCHING CONTROLLER, 500kHz SWITCHING FREQ-MAX, PDSO8, PLASTIC, SO-8
UC2845BD1R2G	ONSEMI	获取价格	HIGH PERFORMANCE CURRENT MODE CONTROLLERS
UC2845BDG	ONSEMI	获取价格	High Performance Current Mode PWM Controller, SOIC-14 NB, 55-TUBE
UC2845BDR2	ONSEMI	获取价格	HIGH PERFORMANCE CURRENT MODE CONTROLLERS