illustrate

The PWM controllers UCC2891/2/3/4 series are designed to simplify the implementation of a wide range of active clamping/reset switching power supply topologies.

The UCC289x is a peak current mode, fixed frequency, high-performance pulse width modulator. It includes logic and the ability to drive a critical delay auxiliary switch for a simple way to operate with the correct programming active clamping.

The initial start-up includes a 110-V start-up regulator at UCC2891/3 and provides keep-alive power on standby.

Other features include an internal programmable slope compensation circuit, precise D-maximum limit, and a resistor-programmable synchronized oscillator. The conversion function of the accurate online monitoring scheme is also on\x92s and OFF conversion about the large capacity input voltage.

characteristic

• Low output jitter
• Soft stop shutdown primary and auxiliary
• Active clamping/reset forward, ideal for flyback converters
• Supplemental auxiliary drivers are available with programmable dead time (on-delay) between the AUX and the main switch
• The peak current mode controls the periodic current limit
• 110-V input starts the regulator pair UCC2891/3
• TrueDrive™2 sinks, 2 A source outputs
• Accurate line UV and OV threshold lines
• Programmable slope compensation
• 1.0 - MHz synchronized oscillator
• Precisely programmable maximum duty cycle
• Programmable soft start
• apply
  • 150 watt to 700 watt switching power supply
  • High efficiency, low EMI/RFI off-line or DC/DC converter
  • Server, 48 V telecommunications, data communications
  • High power converter, LCD TV and plasma TV