Texas Instruments UCC28750EVM-071 User manual

EVM User's Guide: UCC28750EVM-071 UCC287502
Using the UCC28750EVM-071 60-W AC to DC Converter
Description
The UCC28750EVM-071 is a 60-W evaluation module
(EVM) for evaluating an off-line power AC to
DC flyback converter. The UCC28750EVM-071 is
intended for evaluation purposes and is not intended
to be an end product. The UCC28750EVM-071
converters 85-VRMS to 265-VRMS input voltage down
to 24-VDC, capable of delivering 60 W of output
power. This evaluation module uses the UCC287502
Constant-Voltage Flyback Controller Using Opto-
Coupled Feed-Back in a 60 W converter to provide
2.5 A of constant charge current. The input accepts
a voltge range of 85 VAC to 265 VAC. Depending
upon the operating conditions, the control law
algorithm modulates the switching frequency or the
peak primary current to satisfy the power transfer
requirements. The programmable slope compensation
enables both CCM and DCM operation. Power-boost
mode provides additional power for momentary peak
demand.
Get Started
1. Read and study this user's guide completely
before evaluating
2. Order the UCC28750EVM-071 for evaluation if
step 1 and 2 is met
3. Setup and test the UCC28750EVM-071 per user's
guide instructions
Features
• Regulated 24 V ,+/-5%, 60 W Ouput
• Wide Input Range 85 to 265-V RMS
• Max Load Efficency > 90%
Applications
• Isolated offline AC/DC power supply
•Industrial AC/DC for grid infrastructure, appliances
• Audio, printer, TV, set-top box offline AC/DC
•Battery charger
•Merchant DIN rail power supply, Server PSU
•Electricity meter
•String inverter, Micro inverter
•Small home appliances, Major appliances, AC
indoor/outdoor unit
UCC28750EVM-071
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1 Evaluation Module Overview
1.1 Introduction
The UCC28750EVM-071 has frequency foldback and burst mode enable higher efficiency and standby
performance at light load. Opto-coupled feed-back maintains a tightly regulated output with fast dynamic
response to load transients. The controller further enhances the efficient operation with valley switching. The
UCC287502 also includes a omprehensive protection features including UVLO/OVLO, OTP, OPP, OVP, OCP,
brown-out detection, and options to latch and auto-restart. The UCC287502 also uses dithering of the gate drive
helps to ease EMI compliance. This user’s guide provides the schematic, component list, assembly drawing, art
work, and test set up necessary to evaluate the UCC287502 in a typical off-line converter application.
1.2 Kit Contents
• An Evaluation Module (EVM) TI part number UCC28750EVM-071
• EVM Disclaimer and Read Me material
1.3 Specifications
Table 1-1. UCC28750EVM-071 Electrical Performance Specifications
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
INPUT CHARACTERISTICS
VIN Input voltage (RMS) 85 115/230 265 V
fLINE Line frequency 47 50/60 63 Hz
PSTBY No load input power VIN = 115 V / 230 V RMS, IOUT = 0 A 750 mW
OUTPUT CHARACTERISTICS
VOUT Output voltage VIN = 85 - 265 V AC, IOUT = 0 A-2.5 A 22.8 24 25.2 V
VOUT Output ripple voltage VIN = nom, IOUT = 0-2.5A, 500 mVpp
IOUT Output current VIN = min to max 0.0 2.5 A
SYSTEMS CHARACTERISTICS
Average
efficiency
25%, 50%, 75%, 100% load
average at nominal input
voltages
115-V / 230-V RMS input 89%
Operating temperature range VIN = min to max, IOUT = min to max 25 °C
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2 Hardware
2.1 Test Points
Table 2-1. Test Point Functions
TEST POINTS DESCRIPTION
TP1 AC LINE
TP2 AC Neutral
TP3 Capacitor Voltage C9..C12
TP4 Output Supply
TP5 Secondary Switch Node
TP6 Output Return
TP7 AC Neutral
TP8 Primary Switch Node
TP9 Output Return
TP10 UCC287502 Supply Voltage
TP11 Feedback Test Point
TP12 UCC287502 DRV Pin
TP13 Q1 Gate
TP14 Feedback Test Point
TP15 UCC287502 CS Pin
TP16 UCC287502 FB Pin
TP17 UCC287502 OPP Pin
TP18 Primary Ground
2.2 Test Setup
2.2.1 Test Setup Requirements
Safety: This evaluation module is not encapsulated and there are voltages that are much greater than 50 VDC.
WARNING
If you are not trained in the proper safety of handling and testing power electronics please do not
test this evaluation module.
Voltage Source: Isolated AC source or variable AC transformer capable of 265 VAC cable of handling 80 W
Voltmeter: Digital voltage meter
Power Analyzer: Capable of measuring 1 mW to 10 W of input power and capable of handling 265-V RMS input
voltage. Please read the power analyzer’s user manual for proper setup.
Oscilloscope:
• 4 Channel 100 MHz.
• Probes capable of handling 600 V.
Output Load: Resistive or electronic load capable handling 60 W at 24 V.
Recommended Wire Gauge: Insulated 22 AWG.
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2.2.2 Test Setup Diagram
AC Line
AC Neutral
VOUT +
VOUT -
Isolated
Variable AC
Source
Current
Measurement
Voltage
Measurement
Power Analyzer
Load
UCC28750EVM-071
TP1
TP7
TP4
TP9
Volt Meter
Oscilloscope
Scope
Probe
J1 Pin1
J1 Pin3
J2 Pin1
J2 Pin2
Figure 2-1. UCC28750EVM-001 Test Setup Diagram
2.3 Best Practices
CAUTION
!
CAUTION
This EVM has voltages greater than 50 V DC and 50 V AC when power is applied to the input.
Caution must be taken when evaluating the EVM.
CAUTION
This EVM has components that reach tempataures of greater than 55℃. Caution must be taken
when evaluating the EVM.
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2.3.1 General Texas Instruments High Voltage Evaluation (TI HV EVM) User Safety Guidelines
WARNING
Always follow TI’s setup and application instructions, including use of all interface components within the
recommended electrical rated voltage and power limits. Always use electrical safety precautions to help
verify your personal safety and those working around you. Contact TI's Product Information Center http://
support/ti./com for further information.
Save all warnings and instructions for future reference.
WARNING
Failure to follow warnings and instructions can result in personal injury, property damage or death
due to electrical shock and burn hazards.
The term TI HV EVM refers to an electronic device typically provided as an open framed, unenclosed printed
circuit board assembly. It is intended strictly for use in development laboratory environments, solely for qualified
professional users having training, expertise and knowledge of electrical safety risks in development and
application of high voltage electrical circuits. Any other use and/or application are strictly prohibited by Texas
Instruments. If you are not suitably qualified, then immediately stop from further use of the HV EVM.
1. Work Area Safety
a. Keep work area clean and orderly.
b. Qualified observers must be present anytime circuits are energized.
c. Effective barriers and signage must be present in the area where the TI HV EVM and the interface
electronics are energized, indicating operation of accessible high voltages can be present, for the
purpose of protecting inadvertent access.
d. All interface circuits, power supplies, evaluation modules, instruments, meters, scopes and other related
apparatus used in a development environment exceeding 50Vrms/75VDC must be electrically located
within a protected Emergency Power Off EPO protected power strip.
e. Use stable and nonconductive work surface.
f. Use adequately insulated clamps and wires to attach measurement probes and instruments. No
freehand testing whenever possible.
2. Electrical Safety
As a precautionary measure, it is always a good engineering practice to assume that the entire EVM can
have fully accessible and active high voltages.
a. De-energize the TI HV EVM and all the inputs, outputs and electrical loads before performing any
electrical or other diagnostic measurements. Revalidate that TI HV EVM power has been safely de-
energized.
b. With the EVM confirmed de-energized, proceed with required electrical circuit configurations, wiring,
measurement equipment connection, and other application needs, while still assuming the EVM circuit
and measuring instruments are electrically live.
c. After EVM readiness is complete, energize the EVM as intended.
WARNING
While the EVM is energized, never touch the EVM or the electrical circuits, as they can be at
high voltages capable of causing electrical shock hazard.
3. Personal Safety
a. Wear personal protective equipment (for example, latex gloves or safety glasses with side shields) or
protect EVM in an adequate lucent plastic box with interlocks to protect from accidental touch.
Limitation for safe use:
EVMs are not to be used as all or part of a production unit.
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3 Implementation Results
3.1 Performance Data and Typical Characteristic Curves
3.1.1 Efficiency
Table 3-1. Efficiency Test Data
VIN RMS VOUT IOUT PIN POUT EFFICIENCY
85 24.2 0.00 0.059 0 NA
85 24.145 0.055 1.573 1.3273 84.38
85 24.143 0.197 5.353 4.763 88.98
85 24.137 0.46 12.278 11.104 90.43
85 24.132 0.696 18.566 16.813 90.55
85 24.13 0.968 25.8 23.357 90.53
85 24.127 1.2119 32.462 29.239 90.07
85 24.125 1.451 39 35 89.74
85 24.122 1.6398 44.17 39.554 89.54
85 24.12 1.887 50.88 45.53 89.48
85 24.113 2.231 60.4 53.83 89.12
85 24.1 2.726 73.9 65 88.97
115 24.21 0.000 0.065 0.000 NA
115 24.145 0.055 1.57 1.328 84.58
115 24.136 0.196 5.35 4.747 88.73
115 24.131 0.46 12.26 11.09 90.45
115 24.126 0.698 18.56 16.85 90.78
115 24.122 0.972 25.76 23.45 91.03
115 24.120 1.211 32.09 29.21 91.02
115 24.115 1.449 38.41 34.96 91.02
115 24.113 1.74] 46.25 42.02 90.85
115 24.112 1.88 49.97 45.35 90.75
115 24.110 2.228 59.2 53.73 90.76
115 24.108 2.72 72.6 65 89.53
230 24.227 0.000 0.102 0.000 NA
230 24.147 0.055 1.6628 1.328 80
230 24.138 0.197 5.512 4.759 86.34
230 24.135 0.46 12.425 11.106 89.38
230 24.135 0.696 18.644 16.812 90.17
230 24.133 0.969 25.7 23.379 90.96
230 24.132 1.2113 32.1 29.219 91.02
230 24.128 1.4512 38.5 35.017 90.95
230 24.123 1.6398 43.418 39.548 91.08
230 24.121 1.8872 49.95 45.51 91.11
230 24.118 2.23 59 53.83 91.23
230 24.115 2.7287 72.33 65.813 90.99
265 24.32 0 0.151 0 NA
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Table 3-1. Efficiency Test Data (continued)
VIN RMS VOUT IOUT PIN POUT EFFICIENCY
265 24.144 0.055 1.7 1.33 78.2
265 24.134 0.197 5.5925 4.7635 85.17
265 24.132 0.46 12.56 11.108 88.43
265 24.13 0.697 18.76 16.83 89.7
265 24.128 0.968 25.903 23.348 90.13
265 24.126 1.211 32.224 29.21 90.64
265 24.125 1.4513 38.53 35.018 90.88
265 24.122 1.64 43.54 39.55 90.83
265 24.12 1.8872 50.06 45.52 90.91
265 24.118 2.231 59.13 53.813 91
265 24.115 2.72 72.09 65.63 91.03
Output Power (W)
Efficiency (%)
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70
0.78
0.8
0.82
0.84
0.86
0.88
0.9
0.92
85 Vrms
115 Vrms
230 Vrms
265 Vrms
Figure 3-1. Efficiency
Note
The inductor L1, which is mounted on the PCB and shown in BOM needs to be removed and shorted
out to get best efficiency results.
Standby Power
AC Input Voltage (Volts) Power (mW)
85 59
115 65
230 102
265 151
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3.1.2 Startup
CH1 =VBULK , CH2 = VCC, CH3 = VGATE, CH4 = VOUT
Figure 3-2. Start-up Waveforms at 85Vac and No
Load
Figure 3-3. Start-up Waveforms at 85Vac and Full
Load
Figure 3-4. Start-up Waveforms at 115Vac and No
Load
Figure 3-5. Start-up Waveforms at 115Vac and Full
Load
Figure 3-6. Start-up Waveforms at 230Vac and No
Load
Figure 3-7. Start-up Waveforms at 230Vac and Full
Load
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Figure 3-8. Start-up Waveforms at 265Vac and No
Load
Figure 3-9. Start-up Waveforms at 265Vac and Full
Load
3.1.3 Load Transients
CH1 = VOUT, CH4 = IOUT
Load = 0.100A to 2 .5A, 1 kHz, 50% Duty Cycle
VIN = 85 VAC
Figure 3-10. Load Transients at 85Vac
VIN = 115 VAC
Figure 3-11. Load Transients at 115Vac
VIN = 230 VAC
Figure 3-12. Load Transients at 230Vac
VIN = 265 VAC
Figure 3-13. Load Transients at 265Vac
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3.1.4 Output Ripple Voltage at Full Load
CH1 = VOUT, CH2 = VAUX, CH3 = VCS
VIN = 85 VAC, RLOAD = 9.6 ohm
Figure 3-14. Voltage Ripple at 85Vac and Full Load
VIN = 265 VAC, RLOAD = 9.6 ohm
Figure 3-15. Voltage Ripple at 265Vac and Full
Load
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