A8740EEETR-T Allegro Microsystems Inc, A8740EEETR-T Datasheet - Page 5

• Manufacturer Part Number: A8740EEETR-T
• Description: Photoflash Capacitor Charger
• Manufacturer: Allegro Microsystems Inc
• Series: -r

Specifications of A8740EEETR-T

• Constant Current: -
• Constant Voltage: -
• Topology: Flyback
• Number Of Outputs: 1
• Internal Driver: No
• Type - Primary: Flash/Torch
• Type - Secondary: -
• Frequency: -
• Voltage - Supply: 1.5 V ~ 5.5 V
• Voltage - Output: -
• Mounting Type: *
• Package / Case: *
• Operating Temperature: -40°C ~ 85°C
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

A8740
CHARGE
DONE
GATE
VBAT
V
TRIG
OUT
SW
V
IN
Target V
UVLO
Explanation of Events
A: Start charging by pulling CHARGE to high, provided that V
B: Charging stops when V
C: Start a new charging process with a low-to-
D: Pull CHARGE to low to put the controller in low-power standby mode.
E: Charging does not start, because V
F: After V
start the charging.
T1, T2, T3 (Trigger instances): IGBT driver output pulled high whenever the TRIG pin is at logic
high. It is recommended to avoid applying any trigger pulses during charging.
OUT
GATE
A
TRIG
IN
T1
goes above UVLO, another low-to-high transition at the CHARGE pin is required to
Ultra Small Mobile Phone Xenon Photoflash
IGBT Drive Timing Definition
Operation Timing Diagram
B
50%
t
10%
Dr
OUT
T2
reaches the target voltage .
t
r
Capacitor Charger with IGBT Driver
C
90%
IN
is below UVLO level when CHARGE goes high.
50%
high transition at the CHARGE pin.
90%
t
Df
D
10%
T3
t
f
IN
E
is above UVLO level.
F
115 Northeast Cutoff
1.508.853.5000; www.allegromicro.com
Allegro MicroSystems, Inc.
Worcester, Massachusetts 01615-0036 U.S.A.
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