A8437ECGLT View Datasheet(PDF) - Allegro MicroSystems
Part Name
Description
MFG CO.
'A8437ECGLT' PDF : 22 Pages View PDF
A8437
Mobile Phone Xenon Photoflash Capacitor Charger
with IGBT Driver
Timing and IGBT Interlock Function
The two TRIGGER signals are internally ANDed together. As
shown in the timing diagram, below, triggering is prohibited dur-
ing the initial charging process. This prevents premature firing
of the flash before the output capacitor has been charged to its
target voltage. Refer to the section IGBT Gate Driver Interlock
for details.
VIN
CHARGE
SW
VOUT
DONE
A
B
TRIGGER
IGBTDRV
C
D
Case
A
B
C
D
Description
TRIGGER pulse arrives before first charging process is finished (CHARGE and
¯D¯¯O¯¯N¯¯E¯ pins are both high). IGBTDRV is disabled in this case.
Arrives during regulation mode, while not refreshing. IGBTDRV is enabled.
Charging resumes once TRIGGER is low again.
Arrives during regulation mode, while refreshing. Charging is stopped after
present cycle. IGBTDRV is enabled. Charging resumes after TRIGGER is low
again.
Arrives while IC is in low-power Standby mode (CHARGE pin is low).
IGBTDRV is always enabled in this case.
IGBT Drive Timing Definition
TRIGGER
GSOURCE,
GSINK,
or GATE
50%
50%
tDr tr
tDf
tf
10%
90%
90%
10%
Allegro MicroSystems, Inc.
6
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
Share Link: 
