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AAT2846_08 参数 Datasheet PDF下载

AAT2846_08图片预览
型号: AAT2846_08
PDF下载: 下载PDF文件 查看货源
内容描述: 高电流电荷泵,带有双LDO用于背光和闪光应用 [High Current Charge Pump with Dual LDO for Backlight and Flash Applications]
分类和应用:
文件页数/大小: 22 页 / 1412 K
品牌: ANALOGICTECH [ ADVANCED ANALOGIC TECHNOLOGIES ]
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PRODUCT DATASHEET  
AAT2846  
ChargePumpTM High Current Charge Pump with Dual LDO for Backlight and Flash Applications  
To enable independent channel control mode, write Data  
8 to Address 15. To exit individual mode control, the  
AAT2846 state machine can be reset by strobing ENS low  
and holding ENS low longer than the AS2Cwire’s tOFF latch  
time.  
14% and 100% of the maximum current for both chan-  
nels through Address 4. For lower current applications  
such as torch, flashlight, or movie light, write to Address  
5 to enable only FL1 or only FL2. For higher LED current,  
the flash channels can be connected in parallel to drive  
the sum of the two channel currents into a single LED.  
Data  
Individual Backlight Control  
Data  
BL6  
BL5  
BL4  
BL3  
8
On  
1
2
3
4
5
6
7
8
9
10  
11  
12  
13  
14  
15  
16  
Off  
Off  
Off  
Off  
Off  
Off  
Off  
Off  
On  
On  
On  
On  
On  
On  
On  
On  
Off  
Off  
Off  
Off  
On  
On  
On  
On  
Off  
Off  
Off  
Off  
On  
On  
On  
On  
Off  
Off  
On  
On  
Off  
Off  
On  
On  
Off  
Off  
On  
On  
Off  
Off  
On  
On  
Off  
On  
Off  
On  
Off  
On  
Off  
On  
Off  
On  
Off  
On  
Off  
On  
Off  
On  
Table 7: Data Code for Independent  
Backlight Control, Address 15.  
With independent channel control mode enabled,  
Addresses 2 and 3 are re-mapped according to Tables 8  
and 9. As indicated by the possible settings listed in the  
tables, any combination of backlighting channels can be  
enabled and disabled.  
Because Addresses 2 and 3 are re-mapped when inde-  
pendent channel control mode is enabled, the functions  
originally assigned to Addresses 2 and 3 are no longer  
available.  
It is also important to note that Address 0 is disabled  
when independent channel control mode is enabled.  
Additionally, Address 3 is disabled and the very low cur-  
rent settings cannot be used in this mode. Other  
addresses are unmodified by this mode so that the flash  
features can still be operated and the 30mA backlight  
scale can still be used.  
Table 8: Data Code for BL3-BL6  
On/Off Control, Sub-Address 2.  
Data  
BL2  
BL1  
1
2
3
4
5
6
7
8
9
10  
11  
12  
13  
14  
15  
16  
Off  
Off  
Off  
Off  
Off  
Off  
Off  
Off  
On  
On  
On  
On  
On  
On  
On  
On  
Off  
Off  
Off  
Off  
On  
On  
On  
On  
Off  
Off  
Off  
Off  
On  
On  
On  
On  
The LDO enables are always independent of AS2Cwire  
programming.  
Flash LED Current Control  
The flash LEDs are driven through current sinks FL1 and  
FL2. There are two ways to drive the flash LEDs: either  
through the AS2Cwire serial interface or through the flash  
enable input, FEN. The AAT2846 also includes an adjust-  
able safety timer to turn off the flash in the event of a  
controller fault to prevent overstressing the flash LEDs.  
Flash/Movie Mode Operation  
The flash LED current level is set via the serial interface  
according to a logarithmic scale where each code is  
1.2dB lower than the previous code as a percentage of  
the maximum current set by an external resistor, RFSET  
from FSET to AGND. Flash LED current is set between  
Table 9: Data Code for BL1 and BL2  
On/Off Control, Sub-Address 3.  
w w w . a n a l o g i c t e c h . c o m  
2846.2008.03.1.1  
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