Press Center
 
Home About us Products Support Quality & Certification Career Contact us
• Power Management
    Linear Regulators
    Low Dropout Linear Regulators
    DDR Termination Regulators
    Shunt Reference Regulators
    Step Down Switching Regulators
    Switching Regulator
    Step-Up DC-DC Converter
    PWM Controller
    White LED Driver
    Supervisory Circuit
    Voltage Detection and System R
    USB Power Switch
    Power Factor Control
    Li-Battery Protection or Charg
    FET Bias Controllers
    Combo IC
    Inverting DC-DC Converter
• Amplifier / Comparator
    Audio Amplifiers
    Operational Amplifier
    Voltage Comparator
• Analog Switches
    Video Signal Switch
    Analog Multiplexers, Demultipl
• Hall ICs
• Special Application ICs
    Motor Controller IC
    Interface and Driver Circuit
    Telecommunication Circuit
    Melody IC
    Alarm /Sound Generator IC
    Remote Controller IC
    Television Circuit
    Leakage Current Detector
    Automotive IC
    A-D or D-A Converters
    Miscellaneous
    Radio and Cassette Recorder Ci
    Timer
    Mouse&Keyboard Controller
    Transient Voltage Suppressors
    Sense Monitor
    Video Filter
    ZCB snubber
• Logic
• TRANSISTORs
• MOSFETs
    JFET
    Power Mosfet
• TRIACs
• SCRs
• DIODEs
 
Home > Linear Regulators
UC3849B Datasheet
 LOW COST POWER-SAVING MODE PWM CONTROLLER FOR FLYBACK CONVERTERS

 

 

 

DESCRIPTION

                

The UC3849B is a high performance current mode PWM
controller ideally suited for low standby power. Low VDD startup
current make the power reliable on startup design and a large
value resistor could be used in the startup circuit to minimize the
standby power. At no load condition, the IC operates in
power-saving mode for lower standby power, decreasing frequency
for Higher conversion efficiency at light load condition.
The UC3849B contains protection with automatic recovery
including OLP (over load protection), programming OTP (over
temperature protection), OVP (over voltage protection), UVLO (VDD over voltage clamp and under voltage
lockout).To protect the power MOSFET, Gate-drive output is fixed up to 16V max. The UC3849B contains protection
OCP (cycle-by-cycle current limiting).
The internal slope compensation improves system stability at high PWM duty cycle output. Leading-edge
blanking on current sense input removes the signal glitch, which offering minimal external component count in the
design. Excellent EMI performance is achieved with UTC proprietary frequency hopping technique
(ZL201020615247.1) together with soft driver control. Audio noise is eliminated due to switch frequency more than
20kHz during operation.
The UC3849B has such applications as: battery charger, power adaptor, set-top box power supplies, ink jet
printers, open-frame SMPS.


FEATURES

* UTC proprietary frequency hopping technology for Improved EMI performance.
* Power-saving mode for high light-load and standby efficiency
* Soft Start
* Dynamic peak current limiting for constant output power
* Built-in synchronized slope compensation
* OLP,OVP and VDD clamp for higher security
* Programming OTP for higher security
* Fixed switch frequency 65kHz
* Gate output voltage clamped at 15V
* Low start-up current
* Cycle-by-cycle Current Limiting
* Under voltage lockout (UVLO)
* Few external components required

About us  |  Products  |  Contact us
Copyright 2011 UTC All received