UCC28720 Datasheet, PDF (1/29 Pages) Texas Instruments – Constant-Voltage, Constant-Current Controller With Primary-Side Regulation

UCC28720
www.ti.com
SLUSBE8 – MAY 2013
Constant-Voltage, Constant-Current Controller With Primary-Side Regulation
Check for Samples: UCC28720
FEATURES
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• < 10-mW No-Load Power
• Primary-Side Regulation (PSR) Eliminates
Opto-Coupler
• ±5% Voltage and Current Regulation Across
Line and Load
• 700-V Start-Up Switch
• 80-kHz Maximum Switching Frequency
Enables High-Power Density Charger Designs
• Quasi-Resonant Valley-Switching Operation
for Highest Overall Efficiency
• Wide VDD Range Allows Small Bias Capacitor
• Dynamic BJT Drive
• Overvoltage, Low-Line, and Overcurrent
Protection Functions
• Programmable Cable Compensation
• SOIC-7 Package
SIMPLIFIED APPLICATION
V_AC
V_AUX
UCC28720
VDD HV
DRV
VS
CBC CS
GND
V_OUT
UDG-13090
APPLICATIONS
• USB-Compliant Adapters and Chargers for
Consumer Electronics
– Smart phones
– Tablet computers
– Cameras
• Standby Supply for TV and Desktop
• White Goods
DESCRIPTION
The UCC28720 flyback power supply controller
provides isolated-output Constant-Voltage (CV) and
Constant-Current (CC) output regulation without the
use of an optical coupler. The devices process
information from the primary power switch and an
auxiliary flyback winding for precise control of output
voltage and current.
An internal 700-V start-up switch, dynamically-
controlled operating states and a tailored modulation
profile support ultra-low standby power without
sacrificing start-up time or output transient response.
Control algorithms in the UCC28720 allow operating
efficiencies to meet or exceed applicable standards.
The output drive interfaces to a bipolar transistor
power switch. Discontinuous conduction mode (DCM)
with valley switching reduces switching losses.
Modulation of switching frequency and primary
current peak amplitude (FM and AM) keeps the
conversion efficiency high across the entire load and
line ranges.
The controller has a maximum switching frequency of
80 kHz and always maintains control of the peak-
primary current in the transformer. Protection features
help keep primary and secondary component
stresses in check. The UCC28720 allows
compensation for voltage drop in the cable to be
programmed with an external resistor.
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Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2013, Texas Instruments Incorporated