AS3643
Datasheet, Confidential - D e t a i l e d D e s c r i p t i o n
Flash Current Reductions
TXMASK
Usually the flash current is defined by the register led_current . If the TXMASK/TORCH input is used and (configured
by ext_torch_on =01), the flash current is reduced to flash_txmask_current if TXMASK/TORCH=1.
Current Reduction by VIN measurements in Flash Mode
Due to the high load of the flash driver and the ESR of the battery (especially critical at low temperatures), the voltage
on the battery drops. If the voltage drops below the reset threshold of the system would reset. To prevent this condition
the AS3643 monitors the battery voltage and keeps it above vin_low_v_run as follows:
Before a flash is started the voltage on VIN is measured. If the voltage is below the setting of vin_low_v the fault_uvlo
(see page 25) is set and the flash is disabled (driver stays in shutdown) if vin_low_v_shutdown =1. The flash current is
reduced to flash_txmask_current if vin_low_v_shutdown =0.
During flash, if the voltage on VIN drops below the threshold defined by vin_low_v_run , the flash current is reduced (or
ramping of the current is stopped during flash current startup) and fault_uvlo is set. The timing for the reduction of the
current is 8μs/LSB current change.
During the flash pulse the actual used current can be readout by the register led_current_actual .
After the flash pulse the minimum current can be readout by the register led_current_min - this allows to adjust the
camera sensitivity (gain or iso-settings) for the subsequent flash pulse (e.g. when using a pre-flash and a main flash
pulse).
The internal circuit for low voltage current reductions are shown in Figure 20 :
Figure 20. Low Voltage current Reduction Internal Circuit
     
 
( .
    
    
  
      
      
         
! "      ! #$  
%"&       ' 
 
   (  
 
       
           
 )         
 
 (       *
 (       +
   
   
    ,-  
 )     
 -   -
 )     
 &
AS3643
be read back through the I C interface from register led_current_min (see page 26) and used for the setting for the
A mobile phone camera flash system can trigger a diagnostic flash and a main-flash:
The diagnostic flash is initiated by the processor. After this diagnostic flash, the determined maximum flash current can
2
main flash. Therefore the current in the main-flash is constant and additionally the camera system can use this current
for picture quality adjustments - the waveforms for this concept are shown in Figure 21 :
www.austriamicrosystems.com/AS3643
1.5-4
15 - 33
相关PDF资料
AS3647-ZWLT IC LED DVR 1600MA FLASH 13WLCSP
AS3648-ZWLT-500 IC WHITE LED FLASH DVR 13WLCSP
AS3665-ZWLT IC LED DRIVER SMARTLIGHT 25WLCSP
AS3685B-T IC DVR PHOTOFLASH 1A 10-DFN
AS3685C-T IC DVR PHOTOFLASH 1A 10-DFN
AS3691B-ZMFT IC LED DVR 400MA RGB/WHT 64-MLF
AS3691B-ZTSP IC LED DVR 400MA RGB/WH 20ETSSOP
AS3693A-ZQFT IC LED DVR 16CH W/PWM 48-QFN
相关代理商/技术参数
AS3643-ZWLT-500 功能描述:IC WHITE LED FLASH DVR 13WLCSP RoHS:是 类别:集成电路 (IC) >> PMIC - LED 驱动器 系列:- 特色产品:LM3445 TRIAC Dimmable LED Driver 标准包装:55 系列:PowerWise® 恒定电流:是 恒定电压:- 拓扑:PWM,降压(降压) 输出数:1 内部驱动器:无 类型 - 主要:- 类型 - 次要:高亮度 LED(HBLED) 频率:30kHz ~ 1MHz 电源电压:8 V ~ 12 V 输出电压:- 安装类型:表面贴装 封装/外壳:14-SOIC(0.154",3.90mm 宽) 供应商设备封装:14-SOICN 包装:管件 工作温度:-40°C ~ 125°C 产品目录页面:1285 (CN2011-ZH PDF) 其它名称:LM3445M
AS3644-ZWLT 功能描述:LED 驱动器 IC 1 输出 DC DC 稳压器 升压(升压) I2C 调光 320mA(闪存) 6-WLCSP(1.5x1.1) 制造商:ams 系列:- 包装:带卷(TR) 零件状态:有效 类型:DC DC 稳压器 拓扑:升压(升压) 内部开关:是 输出数:1 电压 - 供电(最低):2.5V 电压 -?供电(最高):5V 电压 - 输出:- 电流 - 输出/通道:320mA(闪存) 频率:4MHz 调光:I2C 应用:照相机闪光灯 工作温度:-30°C ~ 85°C(TA) 安装类型:表面贴装 封装/外壳:6-UFBGA,WLCSP 供应商器件封装:6-WLCSP(1.5x1.1) 标准包装:12,000
AS3645A-ZWLT 制造商:ams 功能描述:IC PHOTOFLASH DRIVER 12WLCSP 制造商:ams 功能描述:T&R / WL-CSP12 (2.0x1.5x0.5)
AS3645-ZWLT 功能描述:IC PHOTOFLASH DRIVER 12WLCSP RoHS:是 类别:集成电路 (IC) >> PMIC - LED 驱动器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:- 恒定电流:- 恒定电压:- 拓扑:升压(升压),切换式电容器(充电泵) 输出数:1 内部驱动器:是 类型 - 主要:背光 类型 - 次要:白色 LED 频率:625kHz ~ 875kHz 电源电压:2.7 V ~ 5.3 V 输出电压:5V 安装类型:表面贴装 封装/外壳:10-TFSOP,10-MSOP(0.118",3.00mm 宽) 供应商设备封装:10-µMAX 包装:带卷 (TR) 工作温度:-40°C ~ 85°C
AS3646-ZWLT 功能描述:IC LED DRIVER REGULATOR 12WLCSP 制造商:ams 系列:* 零件状态:有效 标准包装:500
AS3647B-ZWLT 功能描述:LED 驱动器 IC 2 输出 DC DC 稳压器 升压(升压) I2C 调光 800mA(闪存) 15-WLCSP 制造商:ams 系列:- 包装:带卷(TR) 零件状态:有效 类型:DC DC 稳压器 拓扑:升压(升压) 内部开关:是 输出数:2 电压 - 供电(最低):2.7V 电压 -?供电(最高):4.4V 电压 - 输出:2.8 V ~ 5.5 V 电流 - 输出/通道:800mA(闪存) 频率:4MHz 调光:I2C 应用:照相机闪光灯 工作温度:-30°C ~ 85°C(TA) 安装类型:表面贴装 封装/外壳:15-UFBGA,WLCSP 供应商器件封装:15-WLCSP 标准包装:10,000
AS3647B-ZWLT-500 功能描述:LED 驱动器 IC 2 输出 DC DC 稳压器 升压(升压) I2C 调光 800mA(闪存) 15-WLCSP 制造商:ams 系列:- 包装:带卷(TR) 零件状态:有效 类型:DC DC 稳压器 拓扑:升压(升压) 内部开关:是 输出数:2 电压 - 供电(最低):2.7V 电压 -?供电(最高):4.4V 电压 - 输出:2.8 V ~ 5.5 V 电流 - 输出/通道:800mA(闪存) 频率:4MHz 调光:I2C 应用:照相机闪光灯 工作温度:-30°C ~ 85°C(TA) 安装类型:表面贴装 封装/外壳:15-UFBGA,WLCSP 供应商器件封装:15-WLCSP 标准包装:500
AS3647-ZWLM 功能描述:LED 驱动器 IC 2 输出 DC DC 稳压器 升压(升压) I2C 调光 800mA(闪存) 13-WLCSP(2.25x1.5) 制造商:ams 系列:- 包装:带卷(TR) 零件状态:有效 类型:DC DC 稳压器 拓扑:升压(升压) 内部开关:是 输出数:2 电压 - 供电(最低):2.7V 电压 -?供电(最高):4.4V 电压 - 输出:2.8 V ~ 5.5 V 电流 - 输出/通道:800mA(闪存) 频率:4MHz 调光:I2C 应用:照相机闪光灯 工作温度:-30°C ~ 85°C(TA) 安装类型:表面贴装 封装/外壳:13-UFBGA,WLCSP 供应商器件封装:13-WLCSP(2.25x1.5) 标准包装:500