Datasheet.kr   

A8435 데이터시트 PDF




Allegro MicroSystems에서 제조한 전자 부품 A8435은 전자 산업 및 응용 분야에서
광범위하게 사용되는 반도체 소자입니다.


PDF 형식의 A8435 자료 제공

부품번호 A8435 기능
기능 High Efficiency Charge Pump White LED Driver
제조업체 Allegro MicroSystems
로고 Allegro MicroSystems 로고


A8435 데이터시트 를 다운로드하여 반도체의 전기적 특성과 매개변수에 대해 알아보세요.




전체 9 페이지수

미리보기를 사용할 수 없습니다

A8435 데이터시트, 핀배열, 회로
www.DataSheet4U.com
A8435
High Efficiency Charge Pump White LED Driver
Features and Benefits
Proprietary adaptive control scheme (1×, 1.5×)
Maximum efficiency, over 92%
0.5% LED current matching
1 MHz operating frequency
Flexible dimming control:
Serial 11-level dimming, down to 5%
PWM
2-bit parallel
Drives up to 4 white LEDs
30 mA per LED
120 mA total continuous output
Low input ripple and EMI
Soft-start limits inrush current
Short circuit protection
Overvoltage protection
Thermal shutdown protection
Space-saving MLP-16 package: 3 × 3 mm footprint
Very thin 0.75 mm nominal height package
Package: 16 pin QFN/MLP (suffix ES)
Approximate Scale
Description
The A8435 high efficiency charge pump IC offers a simple,
low-cost white LED driver solution for portable electronics
display applications. Using a proprietary control scheme (1×,
1.5×), the A8435 can output well-matched currents for up to
4 LEDs, while maintaining the highest efficiency over most
of the Li-ion battery lifetime.
The A8435 accepts an input range of 2.7 to 5.5 V and delivers
up to 30 mA for each of the four regulated current sources. The
A8435 can deliver a total continuous output current of 120 mA,
meeting the requirements of most Li-ion battery-powered white
LED backlight applications. Outputs can also be tied together
for WLED flash/torch applications.
The A8435 offers flexible options for LED current driving.
The LED current can be set by any of the following methods:
(a) choosing an appropriate value for RSET, (b) 2-bit
parallel control with 3 levels, (c) PWM control, or (d) serial
programming
TheA8435 is available in a very thin profile 0.75 mm (nominal
height) 3 × 3 mm QFN/MLP-16 package (ES), fitting the needs
of space-conscious applications.
Applications include:
White LED backlights for cellular phones, PDAs
Digital cameras, camcorders
Portable audio devices
Other portable device white LED backlighting
120 mA WLED flash/torch
Typical Applications
CIN
1 µF
VBATT
2.7 to 5.5 V
C1
1 µF
C2
1 µF
VIN
C1+
C1–
C2+
C2–
EN1
EN2
On/Off and
NC CTRL
Dimming Control
VOUT
LED1
A8435 LED2
LED3
GND
LED4
ISET
COUT
1 µF
RSET
Figure 1. Typical Circuit. Dual wire control configuration: 2-bit
parallel or PWM dimming.
VBATT
2.7 to 5.5 V
CIN
1 µF
C1
1 µF
C2
1 µF
Single-Wire On/Off and
Dimming Control
VIN
C1+
C1-
C2+
C2-
EN1
EN2
CTRL
VOUT
LED1
A8435 LED2
LED3
GND
LED4
ISET
COUT
1 µF
RSET
Figure 2. Typical Circuit. Single wire control configuration.
A8435-DS, Rev. 1




A8435 pdf, 반도체, 판매, 대치품
A8435
High Efficiency Charge Pump White LED Driver
ELECTRICAL CHARACTERISTICS1
VIN = VEN1 = VEN2 = 3.6 V, C1 = C2 = 1 μF, TA = –40 to 85°C, typical values at TA = 25°C (unless otherwise noted)
Characteristics
Symbol
Test Conditions
Min. Typ. Max.
Units
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
VIN
VUVLO VIN falling, VUVLOHYS = 35 mV
VUVLOHYS
IQ
Switching, TA = 25°C
EN1 = EN2 = GND, TA = 25°C
tSS
VISETBIAS
VISETLKG
IISET
ILEDx / IISET
IISET = 60 μA,
CTRL = open or HIGH
EN1 = EN2 = VIN
EN1 = VIN, EN2 = GND
EN1 = GND, EN2 = VIN
IISET = 60 μA,
CTRL = LOW
Full brightness
2.7
2.25
0.56
40
190
105
51
2.45
35
2.8
0.1
2
0.6
0.01
219
121
60
200
5.5
2.60
4
1
0.64
1
140
245
137
69
V
V
mV
mA
μA
ms
V
μA
μA
A/A
A/A
A/A
A/A
ILED Accuracy
LED Current Matching2
Regulation Voltage at LEDx (1.5×)
Open Loop Output Resistance3
1× to 1.5× Mode Transition Voltage at LEDx
Transition to Dropout Voltage Difference4
LED Leakage in Shutdown
Oscillator Frequency
Output Overvoltage Protection5
EILED
ΔILED
VLED
ROUT
VTrans
ΔVdr
VLEDLKG
fosc
VOVP
EN1 = EN2 = VIN, RSET = 4.3 kΩ
VIN =3.6 V, ILED = 30 mA per LED
EN1 = EN2 = VIN
1× mode: [(VIN – VOUT) / IOUT]
1.5× mode: [(1.5 × VIN – VOUT) / IOUT]
VLEDx Falling
Measured as VTrans – VDropout
EN1 = EN2 = GND, VIN = 5.5 V, TA = 25°C
Open circuit at any LED that is programmed to be
in the ON state
±0.9
±0.5
150
1.1
3.6
100
60
0.01
1
5.74
–%
–%
– mV
Ω
Ω
– mV
– mV
1 μA
– MHz
–V
CTRL, EN1, EN2 Input High Logic Threshold6
VIH
1.6 –
–V
CTRL, EN1, EN2 Input Low Logic Threshold6
VIL
– – 0.4 V
Input High Current
IIH VIH = VIN
––
1 μA
Input Low Current
IIL VIL = GND
––
1 μA
EN1 Pulse Low Time7
tLO
0.5 – 500 μs
EN1 Pulse High Time7
tHI
0.5 –
μs
Initial EN1 Pulse High Time7
tHI(Init) First EN1 pulse after shutdown
100 –
μs
Shutdown Delay7
tSHDN Falling edge of EN1 pulse
–2
3 ms
Thermal-Shutdown Threshold
TSHDN 20°C hysteresis
– 165 – °C
1Specifications guaranteed by design over operating temperature range, –40°C to 85°C.
2LED current matching is defined as (ILEDX – ILED(AVG)) / ILED(AVG) .
3The Open Loop Output Resistance for 1.5× mode is measured with one of the LEDx pins tied to ground or open (thus its voltage is always less
than 80 mV).
4Dropout Voltage, VDropout, is defined as the LEDx-to-GND voltage at which ILEDx drops 10% below the value of ILEDX at VLEDX = 200 mV.
5Guaranteed by design.
6EN2 is not used when CTRL is tied to ground.
7Applies only when CTRL is tied to ground. See figure 3 in Application Information section.
Allegro MicroSystems, Inc.
4
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
www.allegromicro.com

4페이지










A8435 전자부품, 판매, 대치품
A8435
High Efficiency Charge Pump White LED Driver
Application Information
Setting LED Current
The LED current level, ILEDX, is set by the value chosen for the
external resistor, RSET, which is connected to the ISET terminal.
The full current (100%) level for ILEDX can be calculated using
the following formulas:
Setting
CTRL = Open or HIGH
CTRL = LOW
Formula
RSET (Ω) = 0.6 V × 219 / ILEDX
RSET (Ω) = 0.6 V × 200 / ILEDX
Dimming
The A8435 offers serial, 2-bit parallel, and PWM dimming
control. When the CTRL pin is pulled LOW, the EN1 pin accepts
one-wire serial pulse input both to enable the part, and to select
one of the 11 dimming levels, from 100% down to 5% (see
table 1).
With EN2 low, when EN1 is pulled high, the IC turns on. The
initial LED current defaults to 100% after softstart is complete.
The tLO must be < 500 ms to avoid shutdown. With EN2 high,
the operation of EN1 is the same as when EN2 is low, except
shutdown is disabled (TLO = ).
Table 1. CTRL, EN1, and EN2 Pin States
CTRL
EN1 EN2 Brightness
Open or HIGH LOW LOW Shutdown
LED Current, ILED
0
Open or HIGH
Open or HIGH
Open or HIGH
LOW HIGH 27% Brightness
HIGH LOW 55% Brightness
HIGH HIGH Full Brightness
60 × IISET
121 × IISET
219 × IISET
LOW
Pulse
input
No
effect
Adjustable; 11 levels of dimming from
100% to 5% (see figure 3; 100% cor-
responds to 200 × IISET)
LOW
LOW
> 2 ms
LOW
Shutdown
Allegro MicroSystems, Inc.
7
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
www.allegromicro.com

7페이지


구       성 총 9 페이지수
다운로드[ A8435.PDF 데이터시트 ]

당사 플랫폼은 키워드, 제품 이름 또는 부품 번호를 사용하여 검색할 수 있는

포괄적인 데이터시트를 제공합니다.


구매 문의
일반 IC 문의 : 샘플 및 소량 구매
-----------------------------------------------------------------------

IGBT, TR 모듈, SCR 및 다이오드 모듈을 포함한
광범위한 전력 반도체를 판매합니다.

전력 반도체 전문업체

상호 : 아이지 인터내셔날

사이트 방문 :     [ 홈페이지 ]     [ 블로그 1 ]     [ 블로그 2 ]



관련 데이터시트

부품번호상세설명 및 기능제조사
A8430

White LED Driver Constant Current Step-up Converter

Allegro MicroSystems
Allegro MicroSystems
A8431

White LED Driver Constant Current Step-up Converter

Allegro MicroSystems
Allegro MicroSystems

DataSheet.kr       |      2020   |     연락처      |     링크모음      |      검색     |      사이트맵