Features: · Ideal for Active Clamp/Reset Forward, Flyback Converters
· Provides Complementary Auxiliary Driver with Programmable Deadtime (Turn-On Delay) between AUX and MAIN Switches
· Peak Current-Mode Control with Cycle-by-Cycle Current Limiting
· 110-V Input Startup Regulator on UCC2891/3
· TrueDrive 2-A Sink, 2-A Source Outputs
· Accurate Line UV and Line OV Threshold
· Programmable Slope Compensation
· 1.0-MHz Synchronizable Oscillator
· Precise Programmable Maximum Duty Cycle
· Programmable Soft Start
Application· 150-W to 700-W SMPS
· High-Efficiency, Low EMI/RFI Off-Line or DC/DC Converters
· Server, 48-V Telecom, Datacom
· High Power Adapter, LCD-TV and PDP-TV
Pinout
Specifications
| |
|
UNIT |
| Line input voltage range, VIN |
|
120 |
V |
| Supply voltage range, VDD |
(IDD < 10 mA) |
15 |
V |
| Analog inputs |
FB, CS |
−0.3 to (VREF + 0.3)
not to exceed 6 |
V |
| Output source current (peak), IO_SOURCE |
OUT, AUX |
2.5 |
A |
| Output sink current (peak), IO_SINK |
−2.5 |
| Operating junction temperature range, TJ |
−55 to 150 |
|
| |
−65 to 150 |
| ESD rating |
Human body model, (HBM) |
1500 |
V |
| Change device model (CDM) |
1500 |
| Lead temperature, Tsol, 1,6 mm (1/16 inch) from case for 10 seconds |
300 |
|
(1) Stresses beyond those listed under "absolute maximum ratings" may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under "recommended operating conditions" is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. All voltages are with respect to GND. Currents are positive into and negative out of, the specified terminal.
DescriptionThe UCC2891/2/3/4 family of PWM controllers is designed to simplify implementation of the various active clamp/reset switching power topologies.
The UCC289x is a peak current-mode, fixedfrequency, high-performance pulse width modulator.
It includes the logic and the drive capability for the auxiliary switch with a simple method of programming the critical delays for proper active clamp operation.
The UCC2891/3 includes a 110-V start-up regulator for initial start-up and to provide keep-alive power during stand-by.
Additional features of UCC2891/3 include an internal programmable slope compensation circuit, precise DMAX limit, and a single resistor programmable synchronizable oscillator. An accurate line monitoring function also programs the converter's ON and OFF transitions with regard to the bulk input voltage. Along with the UCC2897, this UCC289x family allows the power supply designer to eliminate many of the external components, reducing the size and complexity of the design.
UCC2891PW_1180110 Data Sheet
