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부품번호 | FAN5610 기능 |
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기능 | LED Driver for White/ Blue or any Color LED | ||
제조업체 | Fairchild Semiconductor | ||
로고 | |||
전체 10 페이지수
www.fairchildsemi.com
FAN5610
LED Driver for White, Blue or any Color LED
Features
• LED Driver for 4 Parallel-connected LEDs
• Low Voltage Drop (<350mV) to Support Direct Li-ion
Applications with Low VF LEDs
• Independent Control Loop for Each LED
• Regulated, Matched Constant Current in LEDs
• No External Components
• No EMI, No Switching Noise
• Built-in DAC for Digital and PWM Brightness Control
• Up to 91% Maximum Efficiency
• Up to 84mA (21mA/LED) Bias Current
• 2.7V to 5.5V Input Voltage Range
• ICC < 1µA in Shutdown Mode
• 3mmX3mm MLP-8 Package
Applications
• Cell Phones
• Handheld Computers
• PDA, DSC, MP3 Players
• LCD Display Modules
• Keyboard Backlight
• LED Displays
Description
The FAN5610 generates matched current source drives for a
maximum of four LEDs. Since each LED current source has
its own self-regulating loop, precise current matching is
maintained even if there is a substantial forward voltage
spread among the LEDs. LED pre-selection therefore is not
required. In order to minimize voltage drop, and maximize
efficiency, the value of the internal current sense resistors
connected in series with the LEDs is very low (10Ω). This is
an important consideration for direct DC-driven white LEDs
in battery-powered systems.
The LEDs’ current can be set to 0mA (OFF Mode), 7mA,
14mA, and 21mA with a built-in two-bit digital-to-analog
converter. Customized current settings can also be used.
When the control bits are set to zero, the internal circuitry is
disabled and the quiescent current drops below 1µA.
Both digital input lines (A, B) can be pulse-width-modulated
(PWM). Using PWM, any value of average LED current can
be obtained within the 1 to 20 mA range. The FAN5610 is
available in an 8-lead 3X3 MLP package.
Typical Application
VIN
VIN D4
D3
D2
D IN A
A
C IN B
FAN5610
GND
D1
REV. 1.0.2 10/28/03
FAN5610
Block Diagram
VIN
D1
Bandgap
Reference
2-bit
DAC
IN A
IN B
+
Error Ampl.
-
10Ω
+
Error Ampl.
-
10Ω
PRODUCT SPECIFICATION
D2
+
Error Ampl.
-
10Ω
+
Error Ampl.
-
10Ω
GND
D3
D4
4 REV. 1.0.2 10/28/03
4페이지 PRODUCT SPECIFICATION
Digital Control with PWM (Continued)
A and B are PWM. ILED (Average) = δ x 21mA where δ is Duty Cycle. (Note 6)
FAN5610
A Input (PWM)
B Input (PWM)
30%
Duty Cycle
1KHz
30%
Duty Cycle
ss
70%
Duty Cycle
1KHz
ss
70%
Duty Cycle
ILED
0mA
ILED (Average) = 0.3 x 21mA = 6.3mA
ss
ILED (Average) = 0.7 x 21mA = 14.7mA
OFF
Note:
6. Proportionally select the duty cycle to achieve the desired value of typical LED current between 1mA to 20mA.
Application Information
As seen in the block diagram, the FAN5610 includes four
independent current regulators able to maintain a program-
mable constant current through LEDs, regardless of their for-
ward voltage. This is true over a wide range of input
voltage starting from VF_max + 0.35V, where VF_max is the
highest forward voltage among the LEDs driven by
FAN5610. The independence of current (LED current
changes less than 1%) with change in VIN and VF for
VIN > VF (MAX) + 0.35V, is shown in the graph below.
Current Regulation Performance
25
VF1 = 3.3 V
20
VIN > V F ( MA X) + 0.3 5V
15
10 VF2 =3 .6V
5
0
2.5 3.0 3.5 4.0 4.5 5.0 5.5
Input Voltage (V)
Program the LED’s brightness by applying a continuous
voltage level or a PWM signal at the inputs of the built-in
digital to analog converter (DAC). When a PWM signal is
utilized to drive the DAC inputs, the current through the
LEDs is switched between two levels with the PWM signal
frequency. Consequently, the average current changes with
the duty cycle. The LED current waveform tracks the PWM
signal, so the LEDs brightness depends on the duty cycle.
For white LEDs the spectral composition is optimal at a
current level specified by the manufacturer. The DAC inputs
should be programmed to set the current required to achieve
white LED spectrum and PWM used for dimming. To main-
tain the "purest" white, the current through the LEDs should
be switched between zero and a specified current level
(usually around 20mA) corresponding to the white light
chromaticity coordinate.
Conversion errors are minimized and the best LED to LED
matching is achieved over the entire range of average current
settings, when PWM brightness control is used to modulate
the LED current between zero and the maximum value
(A=1, B=1).
REV. 1.0.2 10/28/03
7
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다운로드 | [ FAN5610.PDF 데이터시트 ] |
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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 ] |
부품번호 | 상세설명 및 기능 | 제조사 |
FAN5610 | LED Driver for White/ Blue or any Color LED | Fairchild Semiconductor |
FAN5610MPX | LED Driver for White/ Blue or any Color LED | Fairchild Semiconductor |
DataSheet.kr | 2020 | 연락처 | 링크모음 | 검색 | 사이트맵 |