LTC3725 Datasheet, PDF (7/20 Pages) Linear Technology – Single-Switch Forward Controller and Gate Driver

BLOCK DIAGRA
NDRV 3
0.6V
I_NDRV
+ 8V
–
+
–
0.27mA
+
–_V
SSFLT 2
UVLO 1
1.242V
1.226V
V_FF
0.66
+
–
4.9µA
LTC3725
7.4V/7V
LINEAR
–
REGULATOR
TRICKLE
CHARGE
13.4V/7V
TRICKLE
CHARGER
+
SHUNT REGULATOR
V_CC
+
UVGD
5V
REGULATOR
14.25V –
LINE OFF
TIME
SOFT-START
FAULT
5.3V/4.7V +
–
UVINT
OC
10 IS
300mV
UVVIN
GND 11
(PAD)
FB/IN⁺ 4
FS/IN^– 5
IN⁺
CONDITION IN^–
PWM
RECEIVER
SW
DET
SW
PWM SECONDARY CONTROL
DET
5V
+
PRIMARY
SIDE CONTROL
N/C
400mV
–
PWM
PRIMARY
CONTROL
FREQUENCY
2V
SET
RAMP
V_P-P
V_{P-P OSCILLATOR CLOCK}
0V
OPTO
BIAS
I_OSC
SECONDARY SIDE CONTROL
3.3V
V_CC
RECTIFIER
PGND
DRIVE
LOGIC
1.26V
9 VSLMT
SWITCH
ON
8 V_CC
7 GATE
6 PGND
3725 BD
3725f
7