欢迎访问ic37.com |
会员登录 免费注册
发布采购

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 ]
 浏览型号AAT2846_08的Datasheet PDF文件第6页浏览型号AAT2846_08的Datasheet PDF文件第7页浏览型号AAT2846_08的Datasheet PDF文件第8页浏览型号AAT2846_08的Datasheet PDF文件第9页浏览型号AAT2846_08的Datasheet PDF文件第11页浏览型号AAT2846_08的Datasheet PDF文件第12页浏览型号AAT2846_08的Datasheet PDF文件第13页浏览型号AAT2846_08的Datasheet PDF文件第14页  
PRODUCT DATASHEET  
AAT2846  
ChargePumpTM High Current Charge Pump with Dual LDO for Backlight and Flash Applications  
AS2Cwire Serial Interface  
The backlight and flash LED current levels are dynami-  
cally controllable by the AS2Cwire single-wire interface.  
The AAT2846 is dynamically programmable by the  
The backlight section has multiple current level scales  
AS2Cwire single-wire interface. AS2Cwire records rising  
and the maximum current level is fixed at 20mA or  
edges detected at the ENS pin to address and load the  
30mA, depending on the scale chosen through program-  
data registers. AS2Cwire latches data or address after the  
ming. The flash section maximum current level is user  
ENS input has been held high for time TLAT (500µs).  
programmable by an external set resistor. The maximum  
Address or data is differentiated by the number of ENS  
flash current that can be supported by the device is  
rising edges. Since the data registers are 4 bits each, the  
300mA/channel, or 600mA total. This corresponds to a  
differentiating number of pulses is 24 or 16, so that  
280K set resistor value.  
Address 0 is identified by 17 rising edges, Address 1 by  
For maximum LED current lower than 300mA, use a  
programming resistor greater than 280kup to 1M.  
Calculate the flash programming resistor value using the  
equation:  
18 rising edges, Address 2 by 19 rising edges, etc. Data  
is set to any number of rising edges between 1 and 16. A  
typical write protocol is a burst of ENS rising edges iden-  
tifying a particular address, followed by a pause with ENS  
held high for the TLAT timeout period, then a burst of rising  
edges signifying data, and another TLAT timeout after the  
data has been sent. Once an address is set, multiple  
writes to that address are allowed since the address is not  
reset after each write. Address edges are needed when  
changing the address, or writing to an address other than  
the default after shutdown. Address 0 is the default  
address after shutdown. If the part is enabled with only  
data edges and no address, then Address 0 will be pro-  
grammed and backlight channels BL1-BL6 will turn-on  
according to the number of data edges applied.  
280k · 300mA  
RFSET  
=
IFMAX  
where IFMAX is the maximum flash LED current in mA.  
If any one of the backlight or flash current sinks is not  
used, connect that current sink to OUT. The current con-  
troller monitors the sink voltage and, if it is connected to  
OUT, then the controller determines that the current sink  
is not used or that the LED is shorted. In either case, the  
controller turns off the affected current sink.  
When ENS is held low for a time greater than TOFF  
(500µs), the AAT2846 enters shutdown mode and draws  
less than 1µA of current from IN. At shutdown, the data  
and address registers are reset to 0.  
Address  
Data  
THI  
TLAT  
TLO  
TLAT  
EN/SET  
1
2
17  
0
18  
1
2 . . .  
n 16  
Address  
Data Reg 1  
Data Reg 2  
1
0
0
n
Figure 1: AS2Cwire Serial Interface Timing.  
w w w . a n a l o g i c t e c h . c o m  
10  
2846.2008.03.1.1