Datasheet

UCC28710, UCC28711
UCC28712, UCC28713
UCC28714, UCC28715
www.ti.com SLUSB86 –NOVEMBER 2012
FUNCTIONAL DESCRIPTION
The UCC28710 family is a flyback power supply controller which provides accurate voltage and constant current
regulation with primary-side feedback, eliminating the need for opto-coupler feedback circuits. The controller
operates in discontinuous conduction mode with valley-switching to minimize switching losses. The modulation
scheme is a combination of frequency and primary peak current modulation to provide high conversion efficiency
across the load range. The control law provides a wide-dynamic operating range of output power which allows
the power designer to achieve the <10-mW stand-by power requirement.
During low-power operating ranges the device has power management features to reduce the device operating
current at operating frequencies below 33 kHz. The UCC28710 family includes features in the modulator to
reduce the EMI peak energy of the fundamental switching frequency and harmonics. Accurate voltage and
constant current regulation, fast dynamic response, and fault protection are achieved with primary-side control. A
complete charger solution can be realized with a straightforward design process, low cost and low component
count.
Primary-Side Voltage Regulation
Figure 13 illustrates a simplified flyback convertor with the main voltage regulation blocks of the device shown.
The power train operation is the same as any DCM flyback circuit but accurate output voltage and current
sensing is the key to primary-side control.
Figure 13. Simplified Flyback Convertor
(with the main voltage regulation blocks)
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Product Folder Links: UCC28710, UCC28711 UCC28712, UCC28713 UCC28714, UCC28715