FSCM0465R Green Mode Fairchild Power Switch (FPS™)
© 2006 Fairchild Semiconductor Corporation www.fairchildsemi.com
FSCM0465R Rev. 1.0.1 13
6. Burst Operation: To minimize power dissipation in
standby mode, the FSCM0465R enters into burst-mode
operation at light load condition. As the load decreases,
the feedback voltage decreases. As shown in Figure 23,
the device automatically enters burst mode when the
feedback voltage drops below V
BURL
(300mV). At this
point, switching stops and the output voltages start to
drop at a rate dependent on standby current load. This
causes the feedback voltage to rise. Once it passes
V
BURH
(500mV), switching resumes. The feedback
voltage then falls and the process repeats. Burst mode
operation alternately enables and disables switching of
the power SenseFET, thereby reducing switching loss in
standby mode.
Figure 23. Waveforms of Burst Operation
V
FB
Vds
0.3V
0.5V
Ids
Vo
Vo
set
time
Switching
disabled
T1
T2 T3
Switching
disabled
T4
FSCM0465R Rev. 00
