- 您现在的位置：买卖IC网 > PDF目录1774 > A8437ECGLT (Allegro Microsystems Inc)IC PHOTOFLASH CAP CHARGER WLCSP PDF资料下载
参数资料
| 型号： | A8437ECGLT |
| 厂商： | Allegro Microsystems Inc |
| 文件页数： | 12/22页 |
| 文件大小： | 0K |
| 描述： | IC PHOTOFLASH CAP CHARGER WLCSP |
| 标准包装： | 24,000 |
| 应用： | 照相机闪光灯电容器充电器，Xenon |
| 电源电压： | 2.3 V ~ 5.5 V |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 12-UFBGA，WLCSP |
| 供应商设备封装： | 12-WLCSP |
| 包装： | 带卷 (TR) |
A8437
Smart Current Limit (Optional)
Mobile Phone Xenon Photoflash Capacitor Charger
with IGBT Driver
period, 18 μ s, off-time control. One advantage of
With the help of some simple external logic, the
user can change the charging current according to
the battery voltage. For example, assume that I SET is
normally 36 μ A (for I SWlim = 1.0 A). Referring to the
following illustration, when the battery voltage drops
having Timer Mode is that it limits the initial battery
current surge and thus acts as a “soft-start.” A time-
expanded view of a Timer Mode interval is shown in
the following figure.
Timer Mode
BL
RBL
RSET
ISET
V SW
V BAT
below 2.5 V, the signal at BL (battery-low) goes high.
The resistor RBL, connecting BL to the ISET pin,
then injects 10 μ A into RSET. This effectively reduces
ISET current to 26 μ A (for I SWLIM = 0.73 A). A disad-
vantage of the above method is that the 10 μ A current
is always flowing whenever the BL signal goes high.
Timer Mode and Fast Charging Mode
The A8437 achieves fast charging times and high effi-
ciency by operating in discontinuous conduction mode
(DCM) through most of the charging process. The
relationship of Timer Mode and Fast Charging Mode
is shown in the following figure.
V OUT
Timer Mode
V OUT
I SW
V OUT ≤ 14 V; t =2 μ s/div; V BAT =3.6 V; R SET =33.2 k Ω
As soon as a sufficient voltage has built up at the
output capacitor, the IC enters Fast-Charging Mode.
In this mode, the next switching cycle starts after the
secondary side current has stopped flowing, and the
switch voltage has dropped to a minimum value. A
proprietary circuit is used to allow minimum-voltage
switching, even if the SW pin voltage does not drop to
0 V. This enables Fast-Charging Mode to start earlier
than previously possible, thereby reducing the overall
charging time. Minimum-voltage switching is shown
in the following figure.
Fast Charging Mode
V BAT
Minimum Voltage
Switching
I IN
t =200 ms/div; V OUT =50 V/div; V BAT =1 V/div.; I IN =100 mA/div.
V BAT =3.6 V; C OUT =20 μ F/330 V; R SET =46 k Ω (I SWlim ≈ 0.75 A)
The IC operates in Timer Mode when beginning to
charge a completely discharged photoflash capaci-
tor, usually when the output voltage, V OUT , is less
than approximately 15 to 20 V. Timer Mode is a fixed
V SW
V BAT
V OUT
I SW
V OUT ≥ 15 V; t =1 μ s/div; V BAT =3.6 V; R SET =33.2 k Ω
During Fast-Charging Mode, when V OUT is high
enough (over 50 V), true zero-voltage switching
Allegro MicroSystems, Inc.
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
11
相关PDF资料 |
PDF描述 |
|---|---|
| A8438EEJTR-T | IC PHOTOFLASH CHARGER 10-MLP |
| A8439EEJTR-T | IC CHARGER PHOTO FLASH 10-MLP |
| A8447SLJTR-T | IC REG BUCK ADJ 3A 8SOIC |
| A8483EEK-T | IC REG BOOST ADJ 0.35A 5MLP |
| A8498SLJ-T | IC REG BUCK ADJ 3A 8SOIC |
相关代理商/技术参数 |
参数描述 |
|---|---|
| A8437EEJTR-T | 功能描述:IC PHOTOFLASH CAP CHARGER 10TDFN RoHS:是 类别:集成电路 (IC) >> PMIC - 电源管理 - 专用 系列:- 标准包装:1 系列:- 应用:手持/移动设备 电流 - 电源:- 电源电压:3 V ~ 5.5 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:14-WFDFN 裸露焊盘 供应商设备封装:14-LLP-EP（4x4） 包装:Digi-Reel® 配用:LP3905SD-30EV-ND - BOARD EVALUATION LP3905SD-30 其它名称:LP3905SD-30DKR |
| A8438 | 制造商:ALLEGRO 制造商全称:Allegro MicroSystems 功能描述:Photoflash Capacitor Charger with IGBT Driver |
| A8438_06 | 制造商:ALLEGRO 制造商全称:Allegro MicroSystems 功能描述:Photoflash Capacitor Charger with IGBT Driver |
| A8438_13 | 制造商:ALLEGRO 制造商全称:Allegro MicroSystems 功能描述:Photoflash Capacitor Charger with IGBT Driver |
| A8438EEJTR-T | 功能描述:IC PHOTOFLASH CHARGER 10-MLP RoHS:是 类别:集成电路 (IC) >> PMIC - 电源管理 - 专用 系列:- 应用说明:Ultrasound Imaging Systems Application Note 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:37 系列:- 应用:医疗用超声波成像，声纳 电流 - 电源:- 电源电压:2.37 V ~ 6 V 工作温度:0°C ~ 70°C 安装类型:表面贴装 封装/外壳:56-WFQFN 裸露焊盘 供应商设备封装:56-TQFN-EP（8x8） 包装:管件 |
发布紧急采购，3分钟左右您将得到回复。