UC3844D8TR ,Current-Mode PWM ControllerTable of Contents8.4 Device Functional Modes.... 201
UC3844D8TRG4 ,Current-Mode PWM Controller 8-SOIC 0 to 70 SLUS223E–APRIL 1997–REVISED JANUARY 20175 Device Comparison TableUVLOTURNON AT 16 V TURNON AT 8.4 ..
UC3844DR2 ,High Performance Current Mode Controllerblock diagram. Once the topology and operating mode areset, designing the power transformer is the ..
UC3844DR2G , High Performance Current Mode Controllers
UC3844DTR ,Current-Mode PWM ControllerFeatures... 19 Application and Implementation...... 212 Applications..... 19.1 Application Informat ..
UC3844DTRG4 ,Current-Mode PWM Controller 14-SOIC 0 to 70FeaturesThe UCx84x family offers a variety of package• Optimized for Off-Line and DC-to-DC Converte ..
UN2123 ,Composite DeviceFeatures• Costs can be reduced through downsizing of the equipment andreduction of the number of pa ..
UN2124 ,Composite DeviceAbsolute Maximum Ratings T = 25°CaR1CParameter Symbol Rating UnitBCollector-base voltage (Emitter ..
UN212X ,Composite DeviceAbsolute Maximum Ratings T = 25°CaR1CParameter Symbol Rating UnitBCollector-base voltage (Emitter ..
UN212Y ,Composite DeviceTransistors with built-in ResistorUNR212x Series (UN212x Series)Silicon PNP epitaxial planar typeUn ..
UN2154 ,Composite DeviceElectrical Characteristics T = 25°C ± 3°CaParameter Symbol Conditions Min Typ Max UnitCollector-ba ..
UN2210 ,Composite DeviceElectrical Characteristics T = 25°C ± 3°CaParameter Symbol Conditions Min Typ Max UnitCollector-ba ..
UC3844D8-UC3844D8G4-UC3844D8TR-UC3844D8TRG4-UC3844DTR-UC3844DTRG4-UC3844NG4
Current-Mode PWM Controller
VIN
VCC
VREF
RT/CT
GROUND
VFB
ISENSE
OUTPUT
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UC1842, UC2842, UC3842, UC1843, UC2843, UC3843
UC1844, UC2844, UC3844, UC1845, UC2845, UC3845SLUS223E –APRIL 1997–REVISED JANUARY
UCx84x Current-Mode PWM Controllers Features Optimized for Off-Line and DC-to-DC Converters Low Start-Up Current(<1 mA) Automatic Feedforward Compensation Pulse-by-Pulse Current Limiting Enhanced Load-Response Characteristics Undervoltage Lockout With Hysteresis Double-Pulse Suppression High-Current Totem-Pole Output Internally Trimmed Bandgap Reference Upto 500-kHz Operation Error Amplifier With Low Output Resistance
Applications Switching Regulatorsof Any Polarity Transformer-Coupled DC-DC Converters
DescriptionThe UCx84x series of control integrated circuits
provide the features that are necessaryto implement
off-line or DC-to-DC fixed-frequency current-mode
control schemes, witha minimum numberof external
components. The internally implemented circuits
include an undervoltage lockout (UVLO), featuringa
start-up currentof less than1 mA, anda precision
reference trimmed for accuracyat the error amplifier
input. Other internal circuits include logicto ensure
latched operation,a pulse-width modulation (PWM)
comparator that also provides current-limit control,
anda totem-pole output stage thatis designedto
sourceor sink high-peak current. The output stage,
suitable for driving N-channel MOSFETs,is low whenisin theoff state.
The UCx84x family offersa variety of package
options, temperature range options, choice
maximum duty cycle, and choiceof turnon and turnoff
thresholds and hysteresis ranges. Devices
higher turnonor turnoff hysteresis are ideal choices
for off-line power supplies, while the devices with
narrower hysteresis range are suited for DC-DC
applications. The UC184x devices are specified
operation from –55°Cto 125°C, the UC284x series
specified for operation from –40°Cto 85°C, and
UC384x seriesis specified for operation from 0°C
70°C.
Device Information(1)(1) Forall available packages, see the orderable addendum
the endofthe datasheet.
Simplified Application
