Avago Technologies ACPL-224-500E - Manual (Page 66)

AV02-4387EN 63 Avago Technologies
Optical Isolation in a DC/DC Converter
Alternative Avago Parts
1) HCPL-0600 High Speed Optocou-
pler
2) HCPL-2200 High CMR Optocou-
pler
3) 4N25, 4N35, CNY17, HCPL-181,
HCPL-817 Phototransistor Opto-
couplers
Description
The HCPL-0708 high speed opto-
coupler provides very good safety
isolation between primary and sec-
ondary sections of the DC/DC con-
verter as shown in the above figure.
The switching frequency specifica-
tion of the DC/DC converter is met
by the low propagation delay (60 ns
max.) and 15 ns typical pulse width
distortion of HCPL-0708 CMOS com-
patible high speed optocoupler. The
smaller size, better noise immunity
performance, high reliability and
wide operating temperature make
HCPL-0708 ideally suited for such
applications.
Performance of Optocoupler
• HCPL­0708: 60 ns maximum
propagation delay time and 15 ns
typical pulse width distortion
• 10KV/µs minimum CMR @ Vcm =
1KV
• Wide operating temperature:
-40 to 100°C
Benefits
• Accurate monitoring and control
of output voltage
• Low propagation delay
• Small size and high reliability
• CMOS compatible and easy inter-
face
Power Supply Applications
Isolation Boundary
Power Switch
DC Input
Digital Optocoupler
HCPL-0708
PWM Controller
Synchronous
Rectifier/
Output Filter
Load
Isolated
Bias Supply