UCC28720_15 Datasheet, PDF (1/33 Pages) Texas Instruments – UCC28720 Constant-Voltage, Constant-Current Controller With Primary-Side Regulation

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UCC28720
SLUSBE8B – MAY 2013 – REVISED SEPTEMBER 2015
UCC28720 Constant-Voltage, Constant-Current Controller With Primary-Side Regulation
1 Features
•1 < 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
2 Applications
• USB-Compliant Adapters and Chargers for
Consumer Electronics
– Smart phones
– Tablet computers
– Cameras
• Standby Supply for TV and Desktop
• White Goods
3 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.
Device Information⁽¹⁾
PART NUMBER
PACKAGE
BODY SIZE (NOM)
UCC28720
SOIC (7)
3.91 mm × 4.90 mm
(1) For all available packages, see the orderable addendum at
the end of the data sheet.
Typical Application
+
V_AC –
V_AUX
UCC28720
VDD HV
DRV
VS
CBC CS
GND
V_OUT
UDG-13090
1
An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,
intellectual property matters and other important disclaimers. PRODUCTION DATA.