Circuit operation AN2544
10/17
The above board can be modified to any voltage output from 10 V to 15 V by changing DZ.
To modify the board to 16 or higher, D6 and C4 can be omitted and the jumper wire can be
installed. For 16 V operation or higher, V
dd
and Vf can share the same source without
having the current leak through the Zener and Vf pin path. The output voltage can be
changed by changing DZ from 16 V Zener to a higher value matching the output voltage. If
less current is required, the board can be changed with a VIPer12A-E dip which is pin-for-
pin compatible with the VIPer22ADIP-E.
Also one of the input capacitors, C2, can be reduced to 4.7 µF. Various data and waveforms
from evaluation boards can be seen in the following pages.
The V
dd
cap has to be sized according to the output load and the size of the output
capacitor.
Table 3. Bill of material for VIPer22A-E Buck 12 V at 350 mA
Item Qty Ref. Part V/W Description CAT#
1 1 Cx 0.022 50 V X7R +/-10% GP SM Ceramic
2 2 C1,C2 10 µF 400 V 105 C
UCC
EKMG401ELL100MJ20S
3 1 C3 4.7 µF 25 V X7R +/-10% TDK C3216X7R1E475K
4 1 C4 0.47 µF 25 V X7R +/-10% TDK C2012X7R1E474K
5 1 C6 47 µF 50 V 105 C Low ESR Low ESR
6 1 C7 0.1 µ 1 kV X7R +/-15%
Murata
GRM55DR73A104KW011
7 1 DZ 12 V zener BZT5212FDICT
8 1 DZ1 16 V zener BZT5216FDICT
9 3 D1,D6,D8 S1MDICT SM GP Diode 1 kV 1 A S1MD
10 1 D5 STTH1R06A 600 V 1 A Ultrafast STMicroelectronics
11 2 J1, J2 2 pin Mouser 651-1751099
12 1 L0 470 µH 140 mA JW Miller 5300-33
13 1 L1 1 mH 400 mA
C o m p o s t a r Q 3 27 7 o r
JW Miller RL895-102K
14 1 R0 10 Ω 1 W wire wound ALSR1J-10
15 1 R1 1 kΩ 5% SM 1206 CERAMIC
16 1 U1 VIPer22ADIP-E STMicroelectronics
Table 4. Bill of material for VIPer22A-E Buck 16 V at 350 mA
For 16 V or higher operation.
Omit 1 D8 S1MDICT
SM GP Diode
1 kV 1A
S1MD
Omit 1 C4 0.47 µF 25 V X7R +/-10% TDK C2012X7R1E474K
Add 1 Jumper Wire jumper 24 AWG
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