a8530 Allegro MicroSystems, Inc., a8530 Datasheet

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a8530

Manufacturer Part Number
a8530
Description
Ultracompact 6-channel Backlight And Flash/torch White Led Driver
Manufacturer
Allegro MicroSystems, Inc.
Datasheet
Features and Benefits
▪ Proprietary adaptive control scheme (1×, 1.5×, 2×)
▪ 0.5% typical LED current matching
▪ 2 separate serial interfaces for dimming control
▪ Drives up to 6 white LEDs (4 display backlight, 2 flash/torch)
▪ 30 mA per LED channel for display backlight
▪ 100 mA per LED channel for flash/torch backlight
▪ 320 mA total output current capability
▪ Low EMI design and soft-start function
▪ Short circuit, overvoltage, thermal shutdown protection
▪ 0.75 mm very thin profile, 3 mm × 3 mm package
Package: 16 pin QFN/MLP (suffix ES)
8530-DS, Rev. 1
Approximate Scale 1:1
Figure 1. 4 × 30 mA backlight with 2 × 100 mA flash
4.7 µF
4.7 µF
RSET
RSET
On/Off and
CIN
CIN
Dimming
On/Off and
Control
V BATT
2.7 to 5.5 V
V BATT
2.7 to 5.5 V
Dimming
Control
1 µF
1 µF
1 µF
1 µF
C1
C2
C2
C1
Figure 3. 320 mA flash
VIN
C1+
C1–
C2+
C2–
ISET
ENM
ENF
VIN
C1+
C1–
C2+
C2–
ISET
ENM
ENF
A8530
A8530
GND
GND
VOUT
VOUT
LED1
LED2
LED3
LED4
LED5
LED6
LED1
LED2
LED3
LED4
LED5
LED6
D1-D4 Backlight; D5-D6 Flash
D1
D2
D3
D4
D5
D6
D1
4.7 µF
4.7 µF
COUT
COUT
Typical Applications
and Flash/Torch White LED Driver
Ultracompact 6-Channel Backlight
Description
The A8530 high efficiency charge pump ICs offer a simple,
low-cost white LED driver solution for driving four display
backlight and two flash/torch/video mode white LEDs. Using
a proprietary control scheme (1×, 1.5×, and 2×), the A8530
can deliver well-matched LED current while maintaining the
highest efficiency and low EMI. The LED current is regulated
over the entire range of Li+ battery voltage to provide uniform
intensity.
LED brightness and on/off can be controlled for 4 display
backlight LEDs and 2 flash/torch LEDs through 2 single-wire
serial interface pins.
The A8530 is available in a very thin profile (0.75 mm nominal
height) 3 mm× 3 mm QFN/MLP 16 pin package. Applications
include:
White LED backlights for cellular phones, PDAs
Digital cameras, camcorders
Other portable device white LED backlighting
320 mA WLED flash/torch
4.7 µF
RSET
RSET
CIN
1 μF
On/Off and
CIN
On/Off and
Dimming
V BATT
2.7 to 5.5 V
Control
Dimming
V BATT
Figure 4. High efficiency current sink
Control
1 µF
1 µF
C1
C2
Figure 2. 3 × 100 mA flash
VIN
C1+
C1–
C2+
C2–
ISET
ENM
ENF
VIN
C1+
C1–
C2+
C2–
ISET
ENM
ENF
A8530
A8530
GND
GND
VOUT
LED1
LED2
LED3
LED4
LED5
LED6
VOUT
V
D1-D4 Backlight; D5-D6 Flash
LED1
LED2
LED3
LED4
LED5
LED6
IN
>V
f
(max)+0.2 V, V
D1-D4 Main; D5-D6 Flash
D1
D5
D6
D1
D2
D3
D4
D5
D6
f
= LED forward drop
A8530
4.7 µF
COUT

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a8530 Summary of contents

Page 1

... LED brightness and on/off can be controlled for 4 display backlight LEDs and 2 flash/torch LEDs through 2 single-wire serial interface pins. The A8530 is available in a very thin profile (0.75 mm nominal height) 3 mm× QFN/MLP 16 pin package. Applications include: ▪ White LED backlights for cellular phones, PDAs ▪ ...

Page 2

... J(max) Storage Temperature, T ................................................... –55°C to 150°C S Use the following complete part number when ordering: Part Number A8530EESTR-T *Contact Allegro for additional packing options. Ultracompact 6-Channel Backlight and Flash/Torch White LED Driver Functional Block Diagram C1 1 µF C1 – ...

Page 3

... A8530 Terminal List Table Name Number C1– 13 Negative terminal of capacitor C1. Connect capacitor C1 between C1+ and C1–. C1+ 16 Positive terminal of capacitor C1. C2– 15 Negative terminal of capacitor C2 C2+ 1 Positive terminal of capacitor C2. Connect capacitor C2 between C2+ and C2–. ENF 4 Enable and dimming control input for flash/torch. ...

Page 4

... A8530 a ELECTRICAL CHARACTERISTICS T = –40°C to +85°C; typical values are Characteristics Input Voltage Range Undervoltage Lockout Threshold UVLO Hysteresis Window Quiescent Current Soft-start Completion Time ISET Bias Voltage ISET Leakage in Shutdown ISET Current Range ISET to LEDx Current Ratio for LED1 through LED4 ...

Page 5

... A8530 Efficiency versus Supply Voltage for LED1 through LED4, in parallel 2.7 3.1 3.5 3 (V) Logic Level 1.2 1 1.0 0.9 0.8 0.7 0.6 0.5 2.7 3.1 3.5 3 (V) Ultracompact 6-Channel Backlight and Flash/Torch White LED Driver Performance Characteristics Tests performed using application circuit shown in figure 25° ...

Page 6

... A8530 LED5-6 ON, 1.5× mode 200 mA OUT Symbol Parameter Units/Division C3 V Ripple OUT C4 I Ripple IN t time LED5-6 ON, 2× mode 200 mA OUT Symbol Parameter Units/Division C3 V Ripple OUT C4 I Ripple IN t time LED1-4 ON, 1.5× mode mA, V ...

Page 7

... A8530 Turn ON LED1 Mode 280 mA IN OUT Symbol Parameter C1 V and V ENF ENM C2 V OUT C3 I OUT t time Ultracompact 6-Channel Backlight and Flash/Torch White LED Driver Performance Characteristics Tests performed using application circuit shown in figure 25°C ...

Page 8

... Application Information in 1 × mode unless the 150 mV threshold. When V enters 1.5× mode. When the A8530 switches from 1× to 2× mode, it first switches to 1.5× mode for a typical duration before entering 2× mode. When operating in 1.5× mode switches back to 1× mode every 130 ms, and then reenters 1.5× ...

Page 9

... LED6) brightness and on/off can be controlled using digital input at ENF pin. ENF accepts one-wire serial pulse input to enable the A8530 and to set dimming levels, from 100 mA (the default 100% level) down to 5 mA. When the ENF pin is initially pulled up from shutdown, after a ...

Page 10

... Normal operation will be resumed when the fault is removed. LED Disconnection Every LEDx pin has a disable subcircuit, as shown in figure 8. The A8530 compares the voltage on each LED pin, and if the voltage on the pin is greater than either V V – 0.4 V, then the corresponding LED pin is disabled. ...

Page 11

... A8530 17X 0.08 C +0.05 0.25 –0.07 +0.15 0.40 –0. Copyright ©2005-2008, Allegro MicroSystems, Inc. The products described here are manufactured under one or more U.S. patents or U.S. patents pending. Allegro MicroSystems, Inc. reserves the right to make, from time to time, such de par tures from the detail spec tions as may be required to per- mit improvements in the per for mance, reliability, or manufacturability of its products ...

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