UCC28704 Datasheet, PDF (1/44 Pages) Texas Instruments – High-Efficiency Off-Line CV

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UCC28704
SLUSCA8A – FEBRUARY 2016 – REVISED FEBRUARY 2016
UCC28704 High-Efficiency Off-Line CV and CC Flyback Controller
with Primary-Side Regulation (PSR)
1 Features
•1 Efficiency Performance Exceeds DoE Level VI
and EU CoC V5 Tier-2 External Power Supply
Standards
• Primary-Side Regulation Eliminates Opto-Coupler
and Secondary Feedback Components
• Compatible with Synchronous Rectifier
• Enables <30-mW No-Load Input Power
• ±5% Output Voltage (CV) and Current (CC)
Regulation
• Enhanced Dynamic Load Response
• Constant Current Output Under-Voltage Protection
(CCUV) with Auto-Restart Response
• Cable Compensation (300 mV at 5-V Full Load)
• 85-kHz Maximum Switching Frequency
• DCM Valley-Switching Operation
• Clamped Gate-Drive Output for MOSFET
• NTC Resistor Interface
• Resistor or External HV Depletion-Mode FET
Start-Up
• Fault Protections: Input Low Line, Output Over-
Voltage, Over-Current, and Short-Circuit
• SOT23-6 Package
2 Applications
• Adapters and Chargers for Phones and Tablets
• USB Type-C AC Adapters for Consumer
Electronics
• Low Power AC to DC SMPS
• Industrial and Medical SMPS
+
VAC
VAUX
NA
Simplified Schematic
VBLK
CB1
T1
D1
NP
NS
RSTR
D2
UCC28704
2 VDD
CDD
RS1
Q1
DRV 3
6 VS
RLC
CS 4
RS2
1 NTC/SU
RCS
RNTC
GND
-t°
5
VREG
COUT
RPL VOUT
3 Description
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 designs.
Device Information ⁽¹⁾
PART NUMBER PACKAGE
BODY SIZE (NOM)
UCC28704
SOT23-6
2.90 mm × 1.60 mm
(1) For all available packages, see the orderable addendum at
the end of the datasheet.
5-V, 2-A Adapter Efficiency Performance
88
85
82
CoC V5 Tier-2 Average
79
76
DOE Level VI Average
73
CoC 10% Load
70
67
0
25
50
Load (%)
115 VAC (with SR)
230 VAC (with SR)
115 VAC (without SR)
230 VAC (without SR)
75
100
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.