The UCC28704 Off-line flyback controller is a highly integrated, 6-pin primary-side
regulated PWM controller for designing high efficiency AC-to-DC power supplies with low standby
power consumption to comply with global efficiency standards. The controller has ultra-low current
consumption at start-up to enable designs with <30-mW no-load input power and save standby mode
energy consumption. Intelligent primary-side sensing and control enables 5% output voltage and
current control without using an opto coupler or secondary-side feedback circuits.
UCC28704 incorporates an enhanced load transient response technique which helps minimize
the output capacitor, reducing the overall system size and cost. The controller also eliminates the
need for loop compensation components which simplify the design and debugging process for power
supply designers. The converter output voltage and current is regulated to prevent overstress
conditions that may damage the load or connectors. Similarly, the CCUV shutdown feature monitors
for an output under voltage fault to protect connectors from over heat or burn out from soft
shorts, which greatly enhance overall system reliability. Board or component over temperature
protection is facilitated with an NTC interface pin.
UCC28704 can be readily used with TI secondary-side synchronous rectifier (SR)
controllers at 2-A or higher output current levels for higher conversion efficiency or more compact
For all available packages, see the orderable addendum at the
end of the datasheet.
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