© 2011 Fairchild Semiconductor Corporation
15
FEBFSQ500L_H257v1 • Rev. 1.0.1
4.14.
Maximum Duty Ratio
4.14.1.
Test Condition
Set the output at maximum loading. Decrease the input voltage with 5VAC step. Verify
the FB voltage is under overload state (between 2.7~4V). Measure the maximum duty
and waveform.
Figure 35.
50V
AC
/ 60Hz at Max. Load (Ch 1: V
O
, Ch 2: V
FB
, Ch 3: V
CC
, Ch 4: I
DRAIN
)
4.15.
Power Off
4.15.1.
Test Condition
Set the output at the maximum load. Remove power.
Figure 36. 120V
AC
/ 60Hz at Max. Load
(Ch 1: V
O
, Ch 2: V
CC
, Ch 3: V
FB
, Ch 4:V
DS
)
Figure 37. 240V
AC
/ 50Hz at Max. Load
(Ch 1: V
O
, Ch 2: V
CC
, Ch 3: V
FB
, Ch 4:V
DS
)
4.16.
Over-Temperature Protection (OTP)
4.16.1.
Test Condition
Set the output at maximum loading. Heat the IC with a heatgun, measure the waveform to
enable the OTP, and disable the OTP.
Ch2
Ch3
Ch4
Ch3
Ch2
Ch3
Ch2
Ch4
Ch4
Ch1
Ch1
Ch1
