Texas Instruments UCC3817–EVM User Manual

User’s Guide

UCC3817 BiCMOS Power Factor
Preregulator Evaluation Board

User’ s Gu ide

1

SLUU077C – September 2000 – Revised November 2002

UCC3817 BiCMOS Power Factor Preregulator

Evaluation Board

Mike O’Loughlin Power Supply Control Products

Contents

1 Introduction 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1.1 Features 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1.2 Description 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2 Operating Guidelines 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.1 Step 1: Load Connections 4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.2 Step 2: Applying Input Power 4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.3 Step 3: Measuring the Evaluation Board’s Performance 4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3 Evaluation Board Layouts 4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4 Evaluation Board Components 5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5 Typical Performance 6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6 Additional Information 7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2

UCC3817 BiCMOS Power Factor Preregulator

SLUU077C – September 2000 – Revised November 2002

1 Introduction

This user’s guide details the Texas Instruments (TI) UCC3817–EVM BiCMOS Power Factor Preregulator
Evaluation Module (EVM) SLUU077. It includes a list of EVM features, a brief description of the module
illustrated with pictorial and schematic diagrams and EVM specifications.

The UCC3817 evaluation board is designed to illustrate the performance of the controller in a 250 W boost
converter with power factor correction. The board is designed to handle a universal input operating voltage
range (i.e. 85–265 V ac) with a regulated 385 V dc output.

Proper precautions must be taken

when working with the board

CAUTION:

D High voltage levels are present on the evaluation board whenever it is energized.
D The output capacitor has high levels of energy storage and it must be discharged before the load is removed.

Improper handling of the evaluation board could cause serious injury.

D It is important to maintain the ambient temperature around the evaluation board to below 40°C during

operation

1.1 Evaluation Module Features

D

Designed for Compliance with IEC 1000-3-2 (Low Total Harmonic Distortion)

D Worldwide Line Operation 85 V

RMS

to 265 V

RMS

D Regulated 385-V, 250-W(max), dc Output
D Accurate Power Limiting
D Accurate Overvoltage Protection

1.2 Description

The UCCx817 provides all the functions necessary for active power-factor-corrected preregulators. The
controller achieves near-unity power factor by shaping the ac input-line current waveform to correspond to that
of the ac input-line voltage. Average current-mode control maintains stable, low-distortion, sinusoidal line
current.

The controller’s operation is similar to previously designed Unitrode preregulators with an added feature to
reduce the RMS-current in the boost capacitor. The controller uses leading-edge modulation that, when
synchronized properly with a downstream dc-to-dc converter, reduces the RMS current in the boost capacitor.

UCC3817 BiCMOS Power Factor Preregulator

3

SLUU077C – September 2000 – Revised November 2002

V

LINE

85–265

V

RMS

AC2

AC1

IAC

F1

C14

1.5µF
400 V

R21
383

k

R16

Ω

R8 12

Ω

k

D6

100

C13

0.47µF
600 V

R14

0.25Ω5
W

R9

4.02

Ω

k

C8 270 pF

R15

51

Ω

k

R10

4.02

Ω

k

(OPTIONAL)

C9 1.2 nF

C7 150 nF
R7

100

Ω

k

C6 2.2µF

R6 30

C15

3.3µF

Ω

k

SEE EVM WARNINGS

AND RESTRICTIONS

VCC

R13
383

Ω

Ω

k

D3

6 A

600 V

R12

2

Ω

k

R11

10

Ω

k

V

REF

(OPTIONAL)

C10
1µF

D7

D8

L1

1 mH

HIGH VOLTAGE –

1

2

IAC

3

4

5

6

7

8

PKLIMIT

CAOUT

CAI

MOUT

IAC

VAOUT

VFF

D5

C11
1µF

D2

8 A, 600 V

UCC3817

VCC

CT

SS

RT

VSENSE

OVP/EN

VREF

HIGH TEMPERATURE –

SEE EVM WARNINGS

AND RESTRICTIONS

Q1

R17

D4

R3 20

Ω

k

VREF

20

C5 1µF

16GND DRVOUT

15

14

13

12

11

10

9

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.

Figure 1. Evaluation Board Schematic

D1

6 A, 600 V

Ω

VCC

C1 560 pF

C4 0.01µF

R1 12

Ω

k

R2

499

Ω

k

V

C12

220µF

450 V

C3

1µF CER

C2

100µF AI EI

R19
499

Ω

k

R20
274

Ω

k

R5 10

Ω

k

O

V

O

+

V

OUT

385V

DC

GND

HIGH VOLTAGE –

SEE EVM WARNINGS

AND RESTRICTIONS

V

O

R4

249

Ω

k

UDG-01001

2 Operating Guidelines

The operating guidelines for the evaluation board are provided with reference to the schematic in Figure 1.

NOTE: In order for the output voltage to regulate, a load of 10 W must be applied to the evaluation
board’s output. In order to maintain power factor near unity , the voltage loop is designed with a slow
frequency response. Large transient steps in output current can cause the evaluation module to go
out of regulation.

4

UCC3817 BiCMOS Power Factor Preregulator