ISL1903 Datasheet, PDF (2/19 Pages) Intersil Corporation – Dimmable Buck LED Driver - AC Mains or DC Input LED Driver

Functional Block Diagram - ISL1903
VREF
VDD
GND
UVLO
+
-
OTP
BG
SHUTDOWN
150°C TO 170°C
BIAS AND
REFERENCE
GENERATOR
BIAS/UVLO/OTP
DUTY CYCLE TO
VOLTAGE CONVERTER
LOW PASS FILTER
REFERENCE OUT
MASTER
OSCILLATOR
CLK
TRIANGLE WAVE
GENERATOR
CLK
DIMMING PWM
-
+
AC
OFFREF
IOUT
CS+
DELADJ
OC
RAMP
PEAK REF
DETECTOR
AC DETECTION -
+
AC-PRESENT
+
-
ISENSE
PRIMARY CURRENT
SENSE PROCESSOR
IOUT
MINIMUM DIMMING LEVEL
CONTROL
+
-
INHIBIT
REFINBUFF
+
+
_
REFERENCE
SS BUFFER
-
+
CRCM
DETECTOR
QUASI-ZVS
DELAY
FMAX
CLAMP
FMIN
CLAMP
LEADING
EDGE
BLANKING
+
600mV -
PRIMARY OC
200mV
VERR/5
SS/5
+
-
-
PWM
COMPARATOR
1/5
1/5
EA1
+
-
SQ
RQ
PWM LATCH
PWM
SS
REFINBUFF
VERR
CRCM OSCILLATOR/PWM/ERROR AMPLIFIERS
VERR
FB1
INHIBIT
REFERENCE SS
VERR CLAMP
-
+
SOFT-START/POR/OVP
DHC
PWMOUT
OUT
+
- 1.50V
SS
ENABLE
300ms
SOFT-START
OVP
SS LOW +
-
0.25V
FAULT LATCH
SQ
RQ