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參數(shù)資料
| 型號： | SM8120 |
| 廠商： | Seiko NPC Corporation |
| 元件分類： | LED驅(qū)動器 |
| 英文描述： | White LED Driver IC |
| 中文描述： | 白光LED驅(qū)動IC |
| 文件頁數(shù)： | 4/14頁 |
| 文件大?。?/td> | 201K |
| 代理商： | SM8120 |
SM8120A
NIPPON PRECISION CIRCUITS INC.—4
OPERATION OVERVIEW
The SM8120A basic structure is a step-up DC/DC converter. The booster control employs Pulse Frequency
Modulation (PFM) which controls the frequency (500kHz max.) at constant SW-Tr ON time (1.2
LED current is set by a current-setting resistor R1 connected between pins FB (with stable voltage of 0.5V
typ.) and VSS.
μ
s typ.). The
When the switching transistor SW-Tr is ON, energy is stored in the inductor L. When SW-Tr is rapidly
switched OFF, the energy stored in the inductor generates a voltage across the terminals of the inductor. The
induced voltage, after being added to the input voltage, turns ON the Schottky barrier diode SBD and the
stored energy is transferred to the output capacitor. This sequence of events continues repeatedly, boosting the
output voltage.
The SM8120A features a built-in soft-start function. The soft-start time is approximately 500μs from after the
chip enable input CE rising edge. During this interval, the maximum SW-Tr ON time is restricted to 0.6
μ
s.
Selecting the Current-setting Resistor (R1)
The SM8120A control stabilizes the voltage on pin FB (0.5V typ.). Hence, the current-setting resistor R1 con-
nected between FB and VSS sets the LED current I
LED
equation.
, where the resistance R1 is given by the following
R1
=
0.5 / I
LED
SW
FB
COMP
Buff
Q
S
R
VREF
SOFT
START
OSC
C
OUT
1.0
μ
F
ZD
VSS
SBD
L
22
μ
H
C
IN
4.7
μ
F
V
IN
3.0 to 4.5V
CE
VDD
LED
R1
Enable
Disable
I
LED
=0.5/R1
FB
V
FB
=0.5V
R1=0.5/
I
LED
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| SM8120A | White LED Driver IC |
| SM8120AH | White LED Driver IC |
| SM8143 | EL Sheet Driver |
| SM8143A | EL Sheet Driver |
| SM8143AV | EL Sheet Driver |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| SM8120A | 制造商:NPC 制造商全稱:Nippon Precision Circuits Inc 功能描述:White LED Driver IC |
| SM8120AH | 制造商:NPC 制造商全稱:Nippon Precision Circuits Inc 功能描述:White LED Driver IC |
| SM8121A | 制造商:NPC 制造商全稱:Nippon Precision Circuits Inc 功能描述:White LED Driver IC |
| SM8121AD | 制造商:NPC 制造商全稱:Nippon Precision Circuits Inc 功能描述:White LED Driver IC |
| SM8121AH | 制造商:NPC 制造商全稱:Nippon Precision Circuits Inc 功能描述:White LED Driver IC |
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