A8740
Ultra Small Mobile Phone Xenon Photoflash
Capacitor Charger with IGBT Driver
Charging Waveforms
Output Capacitor Charging at Various Battery Voltages
Test conditions: VIN = 3.6 V, COUT = 100 μF / 330 V UCC, transformer = T-16-024A (LPRIMARY =12.8 μH, N = 10.25), at room temperature
Oscilloscope settings: Ch1 = ¯D¯¯O¯¯N¯¯E¯ (5 V / div), Ch2 = Battery Voltage (1 V / div), Ch3 = Output Voltage (50 V / div), Ch4 = Input Current (200 mA V / div),
Time scale = 1 sec / div
VOUT
VBAT = 2.5 V
C2,C3,C4
C1
VBAT = 3.7 V
C2,C3,C4
C1
VBAT = 5.0 V
VBAT
IIN
VDONE
t
VOUT
VBAT
IIN
VDONE
t
VOUT
VBAT
C2,C3,C4
C1
IIN
VDONE
t
Allegro MicroSystems, Inc.
9
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com