Isolated Transformer Driver

for PCMCIA Applications

______________________________________________________________________________________

15

Table 2. Rectifier Topology Trade-Offs

TOPOLOGY

ADVANTAGE

DISADVANTAGE

2-Diode

Push/Pull

(Figure 11a)

• Only 3 external

components

• Low output ripple

• Single diode drop

• More turns on

transformer

4-Diode

Bridge

(Figure 11b)

• Simpler transformer

winding requirements

• Low output ripple

• 5 external

components

• Higher cost

• 2 diode drops

Voltage

Doubler

(Figure 11c)

• Fewest turns on

transformer

• 4 external

components

• Higher output

ripple

• 2 diode drops

___________________Chip Topography

GND2

FS

0.085"

(2.159mm)

0.058"

(1.4732mm)

SD

D1

D2

GND1

SUPPLIER

CAPACITOR

Low-ESR 267 Series

Matsuo

USA Phone: (714) 969-2491

FAX: (714) 960-6492

Ceramic

Murata Erie

USA Phone: (800) 831-9172

FAX: (404) 436-3030

Very Low-ESR 595D/293D

Series

Sprague Electric Co.

USA Phone: (603) 224-1961

FAX: (603) 224-1430

Table 3. Suggested Capacitor Suppliers

TRANSISTOR COUNT: 31