Texas Instruments UCC38500EVM User manual

SLUU068C
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User’s Guide

-2
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User’s Guide
February 2005 Power Management Products
SLUU068C

IMPORTANT NOTICE
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TI warrants performance of its hardware products to the specifications applicable at the time of sale in
accordance with TI’s standard warranty. Testing and other quality control techniques are used to the extent TI
deems necessary to support this warranty. Except where mandated by government requirements, testing of all
parameters of each product is not necessarily performed.
TI assumes no liability for applications assistance or customer product design. Customers are responsible for
their products and applications using TI components. To minimize the risks associated with customer products
and applications, customers should provide adequate design and operating safeguards.
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copyright, mask work right, or other TI intellectual property right relating to any combination, machine, or process
in which TI products or services are used. Information published by TI regarding third−party products or services
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Mailing Address:
Texas Instruments
Post Office Box 655303
Dallas, Texas 75265
Copyright 2001, Texas Instruments Incorporated

EVM IMPORTANT NOTICE
Texas Instruments (TI) provides the enclosed product(s) under the following conditions:
This evaluation kit being sold by TI is intended for use for ENGINEERING DEVELOPMENT OR EVALUATION
PURPOSES ONLY and is not considered by TI to be fit for commercial use. As such, the goods being provided
may not be complete in terms of required design-, marketing-, and/or manufacturing-related protective
considerations, including product safety measures typically found in the end product incorporating the goods.
As a prototype, this product does not fall within the scope of the European Union directive on electromagnetic
compatibility and therefore may not meet the technical requirements of the directive.
Should this evaluation kit not meet the specifications indicated in the EVM User’s Guide, the kit may be returned
within 30 days from the date of delivery for a full refund. THE FOREGOING WARRANTY IS THE EXCLUSIVE
WARRANTY MADE BY SELLER TO BUYER AND IS IN LIEU OF ALL OTHER WARRANTIES, EXPRESSED,
IMPLIED, OR STATUTORY, INCLUDING ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR ANY
PARTICULAR PURPOSE.
The user assumes all responsibility and liability for proper and safe handling of the goods. Further, the user
indemnifies TI from all claims arising from the handling or use of the goods. Please be aware that the products
received may not be regulatory compliant or agency certified (FCC, UL, CE, etc.). Due to the open construction
of the product, it is the user’s responsibility to take any and all appropriate precautions with regard to electrostatic
discharge.
EXCEPT TO THE EXTENT OF THE INDEMNITY SET FORTH ABOVE, NEITHER PARTY SHALL BE LIABLE
TO THE OTHER FOR ANY INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES.
TI currently deals with a variety of customers for products, and therefore our arrangement with the user is not
exclusive.
TI assumes no liability for applications assistance, customer product design, software performance, or
infringement of patents or services described herein.
Please read the EVM User’s Guide and, specifically, the EVM Warnings and Restrictions notice in the EVM
User’s Guide prior to handling the product. This notice contains important safety information about temperatures
and voltages. For further safety concerns, please contact the TI application engineer.
Persons handling the product must have electronics training and observe good laboratory practice standards.
No license is granted under any patent right or other intellectual property right of TI covering or relating to any
machine, process, or combination in which such TI products or services might be or are used.
Mailing Address:
Texas Instruments
Post Office Box 655303
Dallas, Texas 75265
Copyright 2001, Texas Instruments Incorporated

EVM WARNINGS AND RESTRICTIONS
It is important to operate this EVM within the input voltage range of 85 V to 265 V and the output
voltage of 12 V +/− 5%.
Exceeding the specified input range may cause unexpected operation and/or irreversible
damage to the EVM. If there are questions concerning the input range, please contact a TI
field representative prior to connecting the input power.
Applying loads outside of the specified output range may result in unintended operation and/or
possible permanent damage to the EVM. Please consult the EVM User’s Guide prior to
connecting any load to the EVM output. If there is uncertainty as to the load specification,
please contact a TI field representative.
During normal operation, some circuit components may have case temperatures greater than
50°C. The EVM is designed to operate properly with certain components above 50°C as long
as the input and output ranges are maintained. These components include but are not limited
to linear regulators, switching transistors, pass transistors, and current sense resistors. These
types of devices can be identified using the EVM schematic located in the EVM User’s Guide.
When placing measurement probes near these devices during operation, please be aware
that these devices may be very warm to the touch.
Mailing Address:
Texas Instruments
Post Office Box 655303
Dallas, Texas 75265
Copyright 2001, Texas Instruments Incorporated

Contents
Contents
1 General Information 1-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.1 Features 1-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.2 Description 1-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.3 Operating Guidelines 1-3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.3.1 Step 1. Load Connections 1-3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.3.2 Step 2. Applying Input Power 1-3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.3.3 Step 3. Evaluating the Demonstration’s Boards Performance. 1-3. . . . . . . . . . . . .
1.3.4 Additional Information 1-3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.4 DM38500 EVM Performance 1-5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2 Reference 2-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.1 DM38500 EVM Part Descriptions 2-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.2 DM38500 Board Layouts 2-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Figures
1−1. DM38500 Evaluation Module Application Schematic 1-4. . . . . . . . . . . . . . . . . . . . . . . . . . . .
1−2. DM38500 EVM Response, VCC = +15 V 1-5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1−3. DM38500 Response, VCC = +15 V 1-5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1−4. DM38500 Response, VCC = +15 V 1-6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2−1. DM38500 EVM PC Board: Top Assembly 2-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1-1
General Information
General
Information
This chapter details the Texas Instruments (TI) DM38500 PFC/PWM
Combination Controller 100W Power Factor Correction Preregulator
Evaluation Module (EVM) SLUU068. It includes a list of EVM features, a brief
description of the module illustrated with a pictorial, schematic diagrams, and
EVM specifications.
Topic Page
1.1 Features 1−2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.2 Description 1−2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.3 Operating Guidelines 1−3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.4 DM38500 EVM Performance 1−5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Chapter 1

Features
1-2
1.1 Features
UCC38500 PFC/PWM Combination Controller 100W Power Factor Correc-
tion Preregulator include:
JCombines PFC and 2nd Stage Down Converter Controls
JControls Boost Preregulator to Near-unity Power Factor
JAccurate Power Limiting
JImproved Feedforward Line Regulation
JPeak Current Mode Control in Second Stage
JProgrammable Oscillator
JLeading Edge/Trailing Edge Modulation for Reduced Output Ripple
JLow Startup Supply Current
JSynchronized Second Stage with Programmable Soft-start
JProgrammable Second Stage Shut-down
1.2 Description
The UCC38500 provides all the functions necessary for active power factor
correction and a second stage dc-to-dc converter all in one integrated circuit.
The control IC uses leading edge modulation for the boost stage and trailing
edge modulation for the step down converter to reduce the RMS current in the
boost capacitor. The dc-to-dc controller uses peak current mode control for
easy loop compensation.
The UCC38500 evaluation board is designed to illustrate the performance of
the IC in a complete off-line 100W two-stage power converter using power fac-
tor correction. The demonstration board was designed to operate with a uni-
versal input voltage range (i.e. 85−265 Vac) with a regulated 12V dc output.
Caution
High-voltage levels are present on the evaluation module whenever it is
energized. Proper precautions must be taken when working with the
EVM. The output capacitor has high levels of energy storage and it must
be discharged before the load is removed. Serious injury can occur if
proper safety precautions are not followed.

Description
1-3
General Information
1.3 Operating Guidelines
The operating guidelines for the evaluation board are provided with reference
to the schematic in Figure 1−1 and the component layout in Figure 2−1.
1.3.1 Step 1. Load Connections
A resistive or electronic load can be applied to the output terminals labeled
OUT− and OUT+.
Note: For safety reasons the load should be connected before power is sup-
plied to the demonstration board.
1.3.2 Step 2. Applying Input Power
A 60 Hz AC power source not exceeding 265 VRMS needs be applied across
terminals AC−N and AC−L for proper operation.
1.3.3 Step 3. Evaluating the Demonstration’s Boards Performance.
With the AC source set between 85−265 VRMS the output voltage should be
regulated and the input current should track the input voltage shape with near
unity power factor. The operation of the circuit is verified over the line and load
range and shows efficiency as high as 85%. At lighter loads, there may be
some distortion in the line current due to Discontinuous Conduction Mode
(DCM) operation. Please refer to Figures 1−2, 1−3 and 1−4 for typical EVM
performance.
1.3.4 Additional Information
For more information, pin description and specifications for the UCC38500
PFC/PWM Combination Controller, please refer to the datasheet or contact
the Texas Instruments Semiconductor Product Information Center at
1-800-336-5236 or 1-972-644-5580. Product Information can also be found
on the World Wide Web at www.ti.com.

Description
1-4
Figure 1−1.DM38500 Evaluation Module Application Schematic
UDG−00094
12 10
9 5
2
6
11
13
7
8
4 3
1
16
17
15 18
19 14
20
OVP/ENBL VSENSE VAOUT ISENSE MOUT CAOUT IAC VFF PKLIMIT VREF
GT1 GT2
VCC
CT RT
GND
PWRGND
SS2
VERR
ISENSE2
UCC38500
VREF
Q5
R25
VCC
R7
R6 GT1
GT2
D10
D9
C27
PKLIMIT
C28
R17
C19
C22
R28
C25
R23 R34
R21
R22 R33 R20
C2
R15
R5
L1 D3
D1
GT1
R14 R29
PKLIMIT
R19
C26
VREF
R18
R24
C29 C30
ISENSE2
GT2
R13
R2
C5
PWR
GND
GT2
12 V
100 W
+
−
L2
T1
Q2
Q1
Q3
D11
VAC
85−265VRMS
D6
D4
T2
D8
U4 C7
SGND
SGND
SGND
PGND2
PGND
PGND
PGNDPGND
SGND
PGND
D5
D7
C12 C20
L1
VCC
BIAS
CIRCUIT
VCC
VCCBIAS
CIRCUIT
PGND
C23
PGND2
PGND2
R26
D14
R36 R16
C14 R35 R32
R27
D13
R31 C8
R30
R10
R12 R11
C21
C16
C3
PGND
C24
D2
R1C4
C18
R4
D15
D12
D16
AC−N
AC−L
OUT +
OUT −
VREF
R3 R39
C13
ISENSE2
C17
H11AV1
3
2 1
4 5
6
U3
SGND
C6
C38
HIGH VOLTAGE −
SEE EVM WARNINGS
AND RESTRICTIONS
HIGH
TEMPERATURE−
SEE EVM WARNINGS
AND RESTRICTIONS
HIGH VOLTAGE −
SEE EVM WARNINGS
AND RESTRICTIONS
HIGH
TEMPERATURE−
SEE EVM WARNINGS
AND RESTRICTIONS
Note: High-Voltage component. See EVM Warnings and Restrictions at the back of this document.
Note: High-Temperature component. See EVM Warnings and Restrictions at the back of this document.