REFERENCE DESIGNS

General camera photoflash charger

Specification

275V

Efficiency =

71%

Charging time =

4 seconds

ZXSC440

SEMICO NDUC TORS

ISSUE 1 - JANUARY 2005

10

Circuit diagram

Ref

Value

Package

Part number

Manufacturer

Notes

U1

MSOP8

ZXSC440

Zetex

Q1

SOT23

ZXMN6A07F

Zetex

60V N-channel MOSFET

D1

(2)

200V

SOT23

BAS21

Philips

x2 200V fast rectifier diodes

connected in series

Tx1

Pulse

See note

(1)

R1

22m

0805

RL1210

Cyntec

R2

10M /400V

Axial

Generic

Generic

Output voltage across resistor

R3

10k

0805

Generic

Generic

R4

100k

0805

Generic

Generic

C1

100uF/10V

0805

Generic

Murata

C2

10pF/500V

1206

Generic

Generic

Output voltage seen across capacitor

C3

10nF/6V3

1206

Generic

Generic

C4

120uF/330V

Radial

FW Series

Rubycon

Photoflash capacitor

Bill of materials

NOTES:

(1) Transformer specification: Primary inductance: 24uH, Core: Pulse PAO367, Turns ratio: 1:12

(2) Two BAS21 200V rectifier diodes are connected in series and used in place of a 400V rectifier diode to provide faster switching speeds and

higher efficiency.