Description
Unitrode / Texas Instruments UC3844D8, PWM Current Mode Controller, 1 A, 500 kHz 8-Pin SOIC
SMD SOIC-8
FEATURES· Optimized For Off-line And To DC Converters Low Start Up Current (<1mA) Automatic Feed Forward Compensation Pulse-by-pulse Current Limiting Enhanced Load Response Characteristics Under-voltage Lockout With Hysteresis Double Pulse Suppression High Current Totem Pole Output Internally Trimmed Bandgap Reference 500khz Operation Low RO Error Amp DESCRIPTION The UC1842/3/4/5 family of control ICs provides the necessary features to implement off-line to DC fixed frequency current mode control schemes with a minimal external parts count. Internally implemented circuits include under-voltage lockout featuring start up current less than 1mA, a precision reference trimmed for accuracy at the error amp input, logic to insure latched operation, a PWM comparator which also provides current limit control, and a totem pole output stage designed to source or sink high peak current. The output stage, suitable for driving N Channel MOSFETs, is low in the off state. Differences between members of this family are the under-voltage lockout thresholds and maximum duty cycle ranges. The UC1842 and UC1844 have UVLO thresholds of 16V (on) and 10V (off), ideally suited to off-line applications. The corresponding thresholds for the UC1843 and UC1845 are 8.4V and 7.6V. The UC1842 and UC1843 can operate to duty cycles approaching 100%. A range of zero 50% is obtained by the UC1844 and UC1845 by the addition of an internal toggle flip flop which blanks the output off every other clock cycle. Flyback Controller, Current Control, UC18/UC28/UC38 Series, Texas Instruments
The isolated-flyback power supply controller provides Constant-Voltage (CV) and Constant-Current (CC) output regulation to improve transient response to large load steps. Primary-Side Regulation (PSR) eliminates the need for an Optocoupler.
Manufacturer Part Number: UC3844D8
Manufacturer: Texas Instruments
