UC3842

SMPS Controller

Description TheUC3842/UC3843/UC3844/UC3845arefixedfrequencycurrent-modePWMcontroller.TheyarespeciallydesignedforOff-LineandDCtoDCconverterapplicationswithminimumexternalcomponents.Theseintegratedcircuitsfeatureatrimmedoscillatorforprecisedutycyclecontrol,atempe

UC3842

HIGH PERFORMANCE CURRENT MODE PWM CONTROLLER

DESCRIPTION TheUC384xAfamilyofcontrolICsprovidesthenecessaryfeaturestoimplementoff-lineorDCtoDCfixedfrequencycurrentmodecontrolschemeswithaminimalexternalpartscount.InternallyimplementedcircuitsincludeatrimmedoscillatorforpreciseDUTYCYCLECONTROLundervoltage

UC3842

CURRENTMODE PWM CONTROLLER

DESCRIPTION TheUC3842/3/4/5familyofcontrolICsprovidesthenecessaryfeaturestoimplementoff-lineorDCtoDCfixedfrequencycurrentmodecontrolschemeswithaminimalexternalpartscount. ■OPTIMIZEDFOROFF-LINEANDDCTODC CONVERTERS ■LOWSTART-UPCURRENT(

UC3842

HIGH PERFORMANCE CURRENT MODE PWM CONTROLLER

DESCRIPTION TheUC384xBfamilyofcontrolICsprovidesthenecessaryfeaturestoimplementoff-lineorDCtoDCfixedfrequencycurrentmodecontrolschemeswithaminimalexternalpartscount.InternallyimplementedcircuitsincludeatrimmedoscillatorforpreciseDUTYCYCLECONTROLundervolta

UC3842

Low Start-Up and Operating Current

Description The3842/43/44/45arefixedfrequencycurrentmodePWMcontroller.TheyarespeciallydesignedforOFF?LineandDCto DCconverterapplicationswithaminimalexternalcomponents.Internallyimplementedcircuitsincludeatrimmedoscillatorforprecise dutycyclecontrol,atemperat

UC3842

Low Start-Up and Operating Current

Description The3842/43/44/45arefixedfrequencycurrentmodePWMcontroller.TheyarespeciallydesignedforOFF?LineandDCto DCconverterapplicationswithaminimalexternalcomponents.Internallyimplementedcircuitsincludeatrimmedoscillatorforprecise dutycyclecontrol,atemperat

UC3842

CURRENT MODE PWM CONTROLLER

■Features ●LowStartupCurrent ●MaximumDutyClamp ●UVLOWithHysteresis ●OperatingFrequencyupto500KHz

UC3842

具有 16V/10V UVLO 和 100% 占空比、溫度范圍為 0°C 至 70°C 的單端 500KHz 電流模式 PWM 控制器; ? Optimized for off-line and DC-to-DC converters\n? Low start-up current (;

The UCx84x series of control integrated circuits provide the features that are necessary to implement off-line or DC-to-DC fixed-frequency current-mode control schemes, with a minimum number of external components. The internally implemented circuits include an undervoltage lockout (UVLO), featuring a start-up current of less than 1 mA, and a precision reference trimmed for accuracy at the error amplifier input. Other internal circuits include logic to ensure latched operation, a pulse-width modulation (PWM) comparator that also provides current-limit control, and a totem-pole output stage that is designed to source or sink high-peak current. The output stage, suitable for driving N-channel MOSFETs, is low when it is in the off state.\n\nThe UCx84x family offers a variety of package options, temperature range options, choice of maximum duty cycle, and choice of turnon and turnoff thresholds and hysteresis ranges. Devices with higher turnon or turnoff hysteresis are ideal choices for off-line power supplies, while the devices with a narrower hysteresis range are suited for DC-DC applications. The UC184x devices are specified for operation from –55°C to 125°C, the UC284x series is specified for operation from –40°C to 85°C, and the UC384x series is specified for operation from 0°C to 70°C.

UC3842

Current-mode PWM controller; ? Low start-up current (≤1mA)\n? Automatic feed-forward compensation\n? Pulse-by-pulse current limiting\n? Enhanced load response characteristics\n? Undervoltage lock-out with hysteresis\n? Double pulse suppression\n? High current totem-pole output\n? Internally-trimmed bandgap reference\n? 400kHz operation, guaranteed min;

DESCRIPTION\nThe UC3842 is available in an 8-Pin mini-DIP the necessary features to implement off-line, fixed-frequency current-mode control schemes with a minimal external parts count. This technique results in improved line regulation, enhanced load response characteristics, and a simpler, easier to design control loop. Topological advantages include inherent pulse-by-pulse current limiting.\nProtection circuitry includes built-in undervoltage lock-out and current limiting. Other features include fully-latched operation, a 1% trimmed bandgap reference, and start-up current less than 1mA. These devices feature a totem-pole output designed to source and sink high peak current from a capacitive load, such as the gate of a power MOSFET. Consistent with N-channel power devices, the output is low in the OFF-state.FEATURES\n? Low start-up current (≤1mA)\n? Automatic feed-forward compensation\n? Pulse-by-pulse current limiting\n? Enhanced load response characteristics\n? Undervoltage lock-out with hysteresis\n? Double pulse suppression\n? High current totem-pole output\n? Internally-trimmed bandgap reference\n? 400kHz operation, guaranteed minAPPLICATIONS\n? Off-line switched mode power supplies\n? DC-to-DC converters UC3842

恩XP

UC3842

Current-mode PWM controller

PHI