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Off-line Power Supply Controller
UCC1889 UCC2889 UCC3889
FEATURES
DESCRIPTION
• Transformerless Off-line
The UCC1889 controller is optimized for use as an off-line, low power, low voltage,
Applications
regulated bias supply. The unique circuit topology utilized in this device can be
• Ideal Primary-side Bias Supply visualized as two cascaded flyback converters, each operating in the discontinuous mode, and both driven from a single external power switch. The significant
• Efficient BiCMOS Design
benefit of this approach is the ability to achieve voltage conversion ratios of 400V
• Wide Input Range
to 12V with no transformer and low internal losses.