SLUU077C – September 2000 – Revised November 2002
5
UCC3817 BiCMOS Power Factor Preregulator
2.1
Step 1. Load Connections
A resistive or electronic load should be applied to the output connections of V
O
and GND.
NOTE: For safety reasons the load should be connected before power is supplied to the evaluation
board.
2.2
Step 2. Applying Input Power
A 50- or 60-Hz ac power source not exceeding 265 V
RMS
needs be applied across terminals AC1 and AC2 for
proper operation.
2.3
Step 3. Measuring the Evaluation Board’s Performance
With the ac source set between 85 V
RMS
and 265 V
RMS
, 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 in the 90–95% range. At lighter loads, there may be some
distortion in the line current due to DCM operation. Please refer to Figure 3 and Figure 4 for typical evaluation
board performance.
3
Evaluation Board Layouts
R16
R10
R9
R11
C9
C8
C10
C11
R21
R13
C2
C3
U1
R5
R4
R3
R19
R2
R1
R20
SYNC
VCC
R22
C1
C4
D4
C5
R6
R7
C14
C7
C15
C6
D5 D6
R8
R12
FA1
UCC3817 EVALUATION BOARD
D3
AC1
XC12
AC2
C13
D8
L1
XL1
D7
R18
R15
D2
D1
V0
Q1
HS1
GND
C12
GND
R17
R14
HIGH TEMPERATURE
SEE EVM WARNINGS
AND RESTRICTIONS
HIGH VOLTAGE
SEE EVM WARNINGS
AND RESTRICTIONS
HIGH VOLTAGE
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.
Figure 2. UCC3817 Evaluation Board Layout Assembly