AMSCO AS3683

a u s t ri a m i c r o s y s t e m s
AS3683
1A Backlight and Camera LED Power Charge Pump
1 General Description
The AS3683 is a low-noise, high-current 1A charge
pump designed for camera flash LEDs and LCD backlighting applications. The current sinks are capable of
driving up to 960mA of load current.
P ro du c t B ri e f
2 Key Features
!
High-Power 1A Charge Pump
- 1:1, 1:1.5, and 1:2 Intelligent Adaptive Mode Setting (IAMS)
- Efficiency up to 95%
- Soft Start to Reduce Inrush Current
- Low-Noise Constant-Frequency Operation
!
Current Sinks
- 400mA Continuous Current (@VIN = 3.2 to 5V,
VOUT = 5V)
- Up to 960mA Pulsed Flash Current
- Programmable: 0 to 160mA, 0.625mA Resolution
!
Flexible Brightness Control
- Three 0 to 160mA LEDs
- Individually Addressable via I2C Interface
!
2 Operating Modes
- Softflash Mode (I2C Interface)
- Hardflash Mode (Dedicated Control Pins)
!
2 General Purpose Inputs/Outputs in Softflash Mode
- Digital Input, Output, and Tristate
- Programmable Pull-Up and Pull-Down
- Strobe Pin can be used for Camera Flash Control
In Softflash Mode the device is controlled by an I2C
interface. In these modes the LED brightness, flash
duration, GPIOs and various charge pump states are
controlled by internal register settings. The GPIO pins
can act as programmable input or output pins and can
also be set to trigger preview and flash light directly by a
camera module.
!
LED Disconnect in Shutdown
!
Open LED Detection
!
Low Stand-By Current (6µA), Interface Fully
Operating
!
Low Shut-Down Current (0.2µA)
In Hardflash mode the LED brightness is controlled by
the Enable pins. These programming pins can be used
as simple enable pins, or as PWM input, again offering
ample flexibility for setting the LED brightness.
!
Wide Battery Supply Range: 3.0 to 5.5V
!
Thermal Protection
!
24-Pin, Small Form-Factor QFN Package
- 4 x 4 x 0.85mm, 0.5mm Pitch
- Enhanced Thermal Characteristics
The AS3683 integrates two independent current source
blocks for driving a single flash LED (CURR11 to
CURR13) with up to 480mA, and general purpose LEDs
(CURR2 to CURR4) with up to 160mA/LED. The general
purpose LEDs are controlled individually and can be
used for backlighting, but also in support of an RGB funlight or a movie indicator lamp. To meet high-flash current requirements (up to 960mA), both current source
blocks can be connected together (CURR11 to CURR13
and CURR2 to CURR4).
The AS3683 utilizes austriamicrosystems's patent-pending Intelligent Adaptive Mode Setting (IAMS) to switch
between 1:1, 1:1.5, and 1: 2 modes. In combination with
very-low-drop-out current sinks, the device achieves
high efficiency over the full single-cell Li+ battery voltage
range. The charge pump operates at a fixed frequency
of 1MHz allowing for tiny external components and its
design ensures low EMI and low input-ripple.
The ultra-flexible brightness control scheme allows for
simple adaptation of the device to different system architectures.
3 Application
Lighting management for cameras, mobile telephones,
PDAs, and other 1-cell Li+ or 3-cell NiMH powered
devices.
© 1997-2005, austriamicrosystems AG, 8141 Unterpremstaetten, Austria-Europe. All Rights Reserved.
www.austriamicrosystems.com
Revision 1.0
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austriam i c r o systems
AS3683
Product Bri ef
4 Block Diagram
Figure 1. AS3683 Block Diagram
V2_5
22
AS3683
2
Digital
Supply
RBIAS
23
Bandgap
and
Current
Reference
Charge Pump
1:1, 1:1.5, 1:2
VBAT1
6
VBAT2
5
C2_P
7
C2_N
3
C1_P
C1_N
ADR
1
24
VDD_GPIO
12
4
CP_OUT
CLK/P2
8
13
CURR11
14
CURR12
15
CURR13
19
CURR2
20
CURR3
21
CURR4
DATA/P1
9
Digital
Part
Mode
Selector
Serial
Interface
Current Source
STROBE/F2
11
GPIO0/P0
10
SFL/F1
16
T1/F0
17
HFL
18
Current Source
GND
Exposed Pad
© 1997-2005, austriamicrosystems AG, 8141 Unterpremstaetten, Austria-Europe. All Rights Reserved.
www.austriamicrosystems.com
Revision 1.0
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austriam i c r o systems
AS3683
Product Bri ef
5 Application Diagrams
Figure 2. Softflash Mode Application Diagram
Battery
1µF
240kΩ
V2_5
22
RBIAS
23
C3
VBAT1
6
VBAT2
ADR
VDD_GPIO
1 - 10kΩ
DATA/P1
CLK/P2
Interface
5
C2_P
7
C2_N 1µF
I2C
C1
C4
Flash LEDs
1
12
AS3683
9
8
3
C1_P
24
C1_N
4
1µF
C5
CP_OUT
Flash &
Preview
13
Softflash
Mode
Feature
2.2µF
R1
V2.5 = 41h
GND = 40h
R4
2
Camera 2.2µF
Flash
LED
CURR11
STROBE/F2
11
GPIO0/P0
10
15
CURR13
SFL/F1
16
19
CURR2
T1/F0
17
20
CURR3
HFL
18
21
CURR4
C6
General Purpose
LEDs (CURR2,
CURR3, CURR4)
Current Sinks
3 to 6
Total Current
0 to 960mA
Addressable
Block
Strobe Trigger
Pin STROBE/F2
or software
Strobe Preview
Pin GPIO0/P0
or software
Current Sinks
3
Current per Sink
0 to 160mA
Addressable
Individually
14 CURR12
Note: Connect all 6 current sinks in parallel or use
general purpose current sink for other functions (e.g.,
indicatorlamp).
Battery or
CP_OUT
Exposed Pad
GND
Figure 3. Hardflash Mode Application Diagram
Battery
V2_5
1µF
C3
240kΩ
RBIAS
ADR
R1
VDD_GPIO
22
23
2
VBAT1
6
VBAT2
2.2µF
1
12
5
C2_P
7
C2_N
3
C1_P
24
C1_N
Selectable
DATA/P1
9
MSB Preview
CLK/P2
Preview Control
(Active-Low)
GPIO0/P0
8
10
1µF
1µF
Flash LEDs
C5
CP_OUT
AS3683
Flash &
Preview
13
CURR11
14
CURR12
15
CURR13
19
CURR2
20
CURR3
21
CURR4
Camera 2.2µF
Flash
LED
11
MSB Flash
SFL/F1
16
T1/F0
17
LSB Flash
Battery
HFL
18
GND
Dedicated Control
Pins for Strobe (3x) &
Preview (3x)
Interface
C1
C4
LSB Preview
STROBE/F2
Strobe Control
(Active-Low)
4
Hardflash
Mode
Feature
Current Sinks
6
Total Current
Strobe: 0 to 900mA
Preview: 0 to 480mA
Addressable
Block
Strobe Trigger
By Strobe Control
Pins
Strobe Preview By Preview Control
Pins
C6
General Purpose
LEDs (CURR2,
CURR3, CURR4)
Current Sinks
N/A
Current per
Sink
N/A
Addressable
N/A
Exposed Pad
© 1997-2005, austriamicrosystems AG, 8141 Unterpremstaetten, Austria-Europe. All Rights Reserved.
www.austriamicrosystems.com
Revision 1.0
3-4
austriam i c r o systems
AS3683
Product Bri ef
Copyrights
Copyright © 1997-2005, austriamicrosystems AG, Schloss Premstaetten, 8141 Unterpremstaetten, Austria-Europe.
Trademarks Registered ®. All rights reserved. The material herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner.
All products and companies mentioned are trademarks or registered trademarks of their respective companies.
Disclaimer
Devices sold by austriamicrosystems AG are covered by the warranty and patent indemnification provisions appearing
in its Term of Sale. austriamicrosystems AG makes no warranty, express, statutory, implied, or by description regarding
the information set forth herein or regarding the freedom of the described devices from patent infringement. austriamicrosystems AG reserves the right to change specifications and prices at any time and without notice. Therefore, prior
to designing this product into a system, it is necessary to check with austriamicrosystems AG for current information.
This product is intended for use in normal commercial applications. Applications requiring extended temperature
range, unusual environmental requirements, or high reliability applications, such as military, medical life-support or lifesustaining equipment are specifically not recommended without additional processing by austriamicrosystems AG for
each application.
The information furnished here by austriamicrosystems AG is believed to be correct and accurate. However,
austriamicrosystems AG shall not be liable to recipient or any third party for any damages, including but not limited to
personal injury, property damage, loss of profits, loss of use, interruption of business or indirect, special, incidental or
consequential damages, of any kind, in connection with or arising out of the furnishing, performance or use of the technical data herein. No obligation or liability to recipient or any third party shall arise or flow out of
austriamicrosystems AG rendering of technical or other services.
Contact Information
Headquarters
austriamicrosystems AG
A-8141 Schloss Premstaetten, Austria
Tel: +43 (0) 3136 500 0
Fax: +43 (0) 3136 525 01
e-mail: info@austriamicrosystems.com
For Sales Offices, Distributors and Representatives, please visit:
http://www.austriamicrosystems.com
austriamicrosystems
– a leap ahead in analog
© 1997-2005, austriamicrosystems AG, 8141 Unterpremstaetten, Austria-Europe. All Rights Reserved.
www.austriamicrosystems.com
Revision 1.0
4-4