A8439 ALLEGRO [Allegro MicroSystems], A8439 Datasheet - Page 5

• Manufacturer Part Number: A8439
• Description: Photoflash Capacitor Charger with IGBT Driver and Refresh
• Manufacturer: ALLEGRO [Allegro MicroSystems]

A8439
TRIGGER
IGBTDRV
CHARGE
Explanation of Events:
A.
B.
C. Start a new charging process with a low-to-high transition at the CHARGE pin.
D. Pull CHARGE to low, to put the controller in low-power standby mode.
E.
F.
DONE
V
VIN
SW
OUT
Start charging by pulling CHARGE to high, provided that V
Charging stops when V
completion of the charging process.
Charging does not start, because V
After V
required to start charging.
Target V
Photoflash Capacitor Charger with IGBT Driver and Refresh
V
UVLO
OUT
IN
goes above V
A
Operation Timing Diagram
B
UVLO
OUT
reaches the target voltage. ¯ D ¯ ¯ O ¯ ¯ N ¯ ¯ E ¯ goes low, to signal the
, another low-to-high transition at the CHARGE pin is
IN
C
is below V
UVLO
D
level when CHARGE goes high.
IN
E
is above the V
115 Northeast Cutoff, Box 15036
Allegro MicroSystems, Inc.
Worcester, Massachusetts 01615-0036 [phone]
www.allegromicro.com
F
UVLO
level.
5