IR1155S
www.irf.com
8
?2011 International Rectifier
Block Diagram
VREF
VFB
COMP
V
COMP
Discharge
VOVP
VOLP
Q
S
R1
ISNS
V
m
OSCILLATOR
COM
VCC
GATE
RESET
OVP
V BIAS
V BIAS
V BIAS
V BIAS
V BIAS
VBIAS
MAX
DUTY CYCLE
LIMIT
Blanking
Pulse at Ton
V BIAS
V BIAS
VCC
Q
R
Q
S1
250mV
VISNS(PK)
OVP
VSLEEP
Enable
Comparator
(SLEEP MODE)
VBIAS
FREQ
RAMP
+
-
VSUMMER
V BIAS
UVLO
VOVP = 106% V
REF
VREF
VOLP = 19%V
REF
Internal Rail
&
Precision
Reference
250mV
VSLEEP
VOUV = 50% V
REF
80% VREF
OVP
VCC OK
PWM OFF
GATE OFF
GATE OFF
RESET
SET
MAX
DUTY
OCP
OSC
BLANK
0
VCOMP
Open Loop
Comparator
(Stand-By Mode)
SLEEP
(POWER
OFF)
UVLO/SLEEP
STNDBY
VCOMP Discharge
Threshold
Comparator
Overvoltage
Comparator
Peak
Overcurrent
Comparator
SLEEP