General Texas Instruments High Voltage Evaluation (TI HV EMV) User Safety Guidelines
Always follow TI's set-up and application instructions, including use of all interface components within their
recommended electrical rated voltage and power limits. Always use electrical safety precautions to help
ensure your personal safety and those working around you. Contact TI's Product Information Center
http://ti.com/customer support for further information.
Save all warnings and instructions for future reference.
WARNING
Failure to follow warnings and instructions may 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 suitable qualified, you should immediately stop from further
use of the HV EVM.
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1. Work Area Safety:
a. Keep work area clean and orderly.
b. Qualified observer(s) must be present anytime circuits are energized.
c. Effective barriers and signage must be present in the area where the TI HV EVM and its interface
electronics are energized, indicating operation of accessible high voltages may 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 non-conductive 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 good engineering practice to assume that the entire EVM
may have fully accessible and active high voltages.
a. De-energize the TI HV EVM and all its 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 hook-ups and other application needs, while still assuming the
EVM circuit and measuring instruments are electrically live.
c. Once EVM readiness is complete, energize the EVM as intended.
EVMs are not to be used as all or part of a production unit.
WARNING
While the EVM is energized, never touch the EVM or its electrical
circuits, as they could be at high voltages capable of causing
electrical shock hazard.
a. Wear personal protective equipment e.g. latex gloves or safety glasses with side shields or protect
EVM in an adequate lucent plastic box with interlocks from accidental touch.
The purpose of the UCC25640EVM-020 (EVM) is to aid in evaluation of the UCC256403 and UCC256404
LLC resonant controller. The EVM is a stand-alone LLC resonant half-bridge DC-DC power converter
designed to operate with DC input from 365 VDC to 410 VDC, AC input from 85 to 265 V
and a nominal output of 12 VDC up to 180-W. The EVM is delivered using a diode rectifier at the output.
The user has the option to evaluate this converter with a synchronous rectifier (SR) by populating the
UCC24624 and SR FETs. This user’s guide provides basic evaluation instruction from a viewpoint of
system operation of the stand-alone LLC resonant power converter.
2.5Using the EVM with UCC24624 Synchronous Rectifier Controller
UCC25640EVM-020 is delivered using the diode rectifier at the output. The option to evaluate the
converter with synchronous rectification (SR) is available to the user. SR is often used to increase
efficiency by replacing the freewheeling diode with a lower loss FET.
DC Voltage Source: Capable of 365 VDC to 410 VDC, adjustable, with minimum power rating 500 W, or
current rating not less than 1 A, with current limit function. The DC voltage source to be used should meet
IEC 60950 reinforced insulation requirement.
AC Voltage Source: Capable of single-phase output AC voltage 85 to 265 VAC, 47 to 63 Hz, adjustable,
with minimum power rating 100 W and current limit function. The AC voltage source to be used should
meet IEC 60950 reinforced insulation requirement.
DC Digital Multimeter: One unit capable of 0-VDC to 450-VDC input range, four digit display preferred;
and one unit capable of 0-VDC to 20-VDC input range, four digit display preferred.
Output Load: : DC load capable of receiving 0 VDC to 20 VDC, 0 A to 15 A, and 0 W to 300 W or
greater, with the capability to display information such as load current and load power.
Oscilloscope: Capable of 500-MHz full bandwidth, digital or analog: if digital, 5 Gsps, or better.
Fan: 200 to 400 LFM forced air cooling is recommended, but not required.
Recommended Wire Gauge: Capable of 25 A, or better than #14 AWG, with the total length of wire less
High voltages that may cause injury exist on this evaluation
module (EVM). Please ensure all safety procedures are followed
whenworkingonthisEVM.NeverleaveapoweredEVM
unattended.
5.3Power Factor Correction (PFC) Boost Front End Setup
UCC25640EVM-020 is typical for a two stage AC/DC power supply with a PFC boost converter in front of
it. The following steps and schematic describe how to connect the UCC28056EVM-296 or
UCC28064EVM-004, Transition-Mode (TM) PFC Controllers, to this EVM.
1. Remove D8 and D9 from UCC25640EVM-020.
2. Connect the anode of D8 to AC Line and the anode of D9 to AC Neutral on UCC28056EVM-296 or
UCC28064EVM-004.
3. Connect both the cathodes of D8 and D9 to TP14 on UCC25640EVM-020.
4. Connect TP15 (RVCC) on UCC25640EVM-020 to TP9 (VCC) on UCC28056EVM-296 or J1-1 (VCC)
on UCC28064EVM-004.
Figure 6 is a diagram of the PFC LLC setup used for testing.
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Figure 6. UCC28056EVM-296/UCC28064EVM-004 PFC to UCC25640EVM-020 LLC Test Setup