AAT3151(2004) View Datasheet(PDF) - Analog Technology Inc

Part Name

Description

MFG CO.

AAT3151
(Rev.:2004)

High Efficiency 1X/1.5X/2X Charge Pump For White LED Applications

Analog Technology Inc 

AAT3151

High Efficiency 1X/1.5X/2X Charge Pump

For White LED Applications

AS2Cwire Serial Interface Timing

EN/SET

Address

Address

T HI

T LO

TLAT

1

2

17

18

1

Data

TLAT

1

2 . . . n <= 16

2

Data Reg 1

1

n

Data Reg 2

AS2Cwire Addressing

Five addresses are available to enable all of the

part's functionality. Two 4-bit registers control the

main and sub-channel, giving 16 settings for each.

The main and sub-channel are programmed to the

same constant current level by using Address 1. Use

Addresses 2 and 3 to program the main and sub-

channel independently. Use Address 4 to program

the Max Current register, which sets the Max

Current scale. Lastly, Address 5 programs the Low

Current register. The Low Current register controls

the efficient Low Current mode.

When the Max Current register is programmed to 1,

2, or 3, changing the data for Addresses 1-3 will

result in the corresponding values found in the

Constant Current Programming Levels table. When

the Max Current register is programmed to 4, the

part is programmed to operate in Low Current mode

and the Data for Addresses 1-3 is irrelevant. In Low

Current mode, the Low Current register takes

precedence. See the Low Current Register Settings

table below for the current level settings and main/

sub-configurations that result.

Address

1

2

3

4

5

EN/SET

Edges

17

18

19

20

21

Addressed

Register

1&2: D1-D4

Current

1: D1-D3 Current

2: D4 Current

3: Max Current

4: Low Current

1

Max Current and Low Current Registers

Use the Max Current and Low Current registers to

program constant current settings outside of the

20mA Max scale. By default (without changing the

Max Current register), the AAT3151 operates in the

20mA Max scale (see Constant Current

Programming Levels). For example, to change to the

30mA Max scale, address the Max Current register

with 20 rising edges and pause for TLAT. Program the

Max Current register with 2 rising edges and pause

for TLAT. The part will next operate in the same Data

row, but for the setting found in the 30mA Max col-

umn. Next, to change to a different setting on the

30mA Max scale, address the D1-D4 register with 17

rising edges. Program the new constant current level

with 1-16 rising edges. The part will update to the

new Data setting according to the Constant Current

Programming Levels table.

The AAT3151 has a distinct Low Current mode with

ultra-low quiescent current. For drive currents of

2mA or less, the part operates with significantly

reduced quiescent current. This is particularly use-

ful for applications requiring an "always on" condi-

tion such as transmissive displays. As an example,

to change to Low Current mode, address the Max

Current register with 20 rising edges and pause for

TLAT. Program the Max Current register with 4 ris-

ing edges and pause for TLAT. Address the Low

Current register with 21 rising edges and pause for

TLAT. Program the Low Current register with 1-16

rising edges. The part will update to the new Low

Current mode setting and operate with significant-

ly reduced quiescent current.

8

3151.2004.10.0.6

Share Link: