LTC3722-2_15 Datasheet, PDF (8/28 Pages) Linear Technology – Synchronous Dual Mode Phase Modulated Full Bridge Controllers

LTC3722-1/LTC3722-2
PIN FUNCTIONS (LTC3722-1/LTC3722-2)
OUTC (Pin 19/Pin 19): 50mA Driver for High Side of the
Full Bridge Active Leg.
OUTB (Pin 20/Pin 20): 50mA Driver for Low Side of the
Full Bridge Passive Leg.
OUTA (Pin 21/Pin 21): 50mA Driver for High Side of the
Full Bridge Passive Leg.
PGND (Pin 22/Pin 22): Power Ground for the LTC3722.
The output drivers of the LTC3722 are referenced to
PGND. Connect the ceramic V_CC bypass capacitor di-
rectly to PGND.
GND (Pin 23/Pin 23): All circuits other than the output
drivers in the LTC3722 are referenced to GND. Use of a
ground plane is recommended but not absolutely neces-
sary.
C_T (Pin 24/Pin 24): Timing Capacitor for the Oscillator.
Use a ±5% or better low ESR ceramic capacitor for best
results.
BLOCK DIAGRAM
LTC3722-1 Current Mode SYNC Phase-Shift PWM
V_CC
UVLO
18
12
V_REF
14
C_T
SYNC SPRG DPRG SBUS
24
1
13
2
10
V_CC UVLO
10.25V = ON
6V = OFF
FB
–
+
6
+
1.2V
ERROR
–
5V
COMP
AMPLIFIER _R1
50k
4
5V
REF AND LDO
1.2V
REF GOOD
SYSTEM
UVLO
V_CC
GOOD
–
+
650mV
–
R2
14.9k
+
PHASE
MODULATOR
M1
QB R
20Ω
V_REF
QS
SS
12µA
7
SHUTDOWN
CURRENT
LIMIT
+
FAULT
LOGIC
650mV –
M2
CS
3
BLANK
+
SLOPE
COMPENSATION
C_T/R
5
R_LEB
300mV –
PULSE BY PULSE
CURRENT LIMIT
OSC
1 = ENABLE
0 = DISABLE
Q
T
QB
R QB
S
23
GND
PASSIVE
DELAY
SYNC
RECTIFIER
DRIVE
LOGIC
ACTIVE
DELAY
8
For more information www.linear.com/LTC3722
PDLY
9
OUTA
21
OUTB
20
OUTE
16
OUTF
15
OUTC
19
OUTD
17
ADLY
11
PGND
22
372212 BD01
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