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參數資料
| 型號： | R1218N021A |
| 廠商： | Ricoh Co., Ltd. |
| 英文描述： | Step-up DC/DC converter for White LED Backlight |
| 中文描述： | 升壓直流/直流轉換器的白光LED背光 |
| 文件頁數： | 1/21頁 |
| 文件大小： | 679K |
| 代理商： | R1218N021A |
R1218x S ERIES
Step-up DC/DC converter for White LED Backlight
NO.EA-166-070905
OUTLINE
1
The R1218x Series are PWM control type step-up DC/DC converter ICs with low supply current.
The R1218x is fully dedicated to drive White LED with constant current. Each of these ICs consists of an
NMOS FET, an oscillator, a PWM comparator, a voltage reference unit, an error amplifier, an under voltage
lockout circuit (UVLO), an over-voltage protection circuit (OVP), and so on.
The R1218x can drive white LEDs with high efficiency with low supply current. A diode is built-in the
R1218xxx1A, therefore it is possible to drive up to 4LEDs without an external diode. The R1218xxx2A, an
external diode is necessary, however, up to 6 serial LEDs can be driven with the R1218xxx2A.
Constant current can be set with an external resistance value. Dimming control is possible by PWM signal for
CE pin. Feedback voltage is 0.2V, therefore power loss by current setting resistance is small and efficiency is
good. Maximum duty cycle is internally fixed, Typ. 91%. LEDs can be driven from low voltage. Protection circuits
are the current limit of Lx peak current, the over voltage limit of output, and the under voltage lockout function.
Packages are standard SOT-23-6 and very tiny PLP1820-6.
FEATURES
Operating voltage..........................................1.8V to 5.5V
Built-in 400mA, 1.5
, 20V Nch MOSFET (R1218xxx1A)
Built-in 400mA, 1.5
, 29V Nch MOSFET (R1218xxx2A)
Oscillator Frequency (PWM control).............1.2MHz
Maximum Duty Cycle....................................Typ. 91%
Feedback Voltage .........................................Typ. 0.2V
UVLO Threshold Voltage ..............................Typ. 1.6V (Hysteresis Typ. 0.1V)
Lx Current limit Protection.............................Typ. 700mA
Over Voltage Protection (OVP) Threshold....Typ. 9.5V (R1218x021A)
Typ. 14.0V (R1218x031A)
Typ. 18.5V (R1218x041A)
Typ. 23.0V (R1218x052A)
Typ. 27.5V (R1218x062A)
LED dimming control.....................................by external PWM signal (Frequency 200Hz to 5kHz) to CE pin
by feedback voltage and filtered PWM signal (high frequency)
Packages ......................................................SOT-23-6 or PLP1820-6
APPLICATION
White LED Backlight for portable equipment
相關PDF資料 |
PDF描述 |
|---|---|
| R1218N022A | Step-up DC/DC converter for White LED Backlight |
| R1218N031A | Step-up DC/DC converter for White LED Backlight |
| R1218N032A | Step-up DC/DC converter for White LED Backlight |
| R1218N041A | Step-up DC/DC converter for White LED Backlight |
| R1218N052A | Step-up DC/DC converter for White LED Backlight |
相關代理商/技術參數 |
參數描述 |
|---|---|
| R1218N022A | 制造商:RICOH 制造商全稱:RICOH electronics devices division 功能描述:Step-up DC/DC converter for White LED Backlight |
| R1218N031A | 制造商:RICOH 制造商全稱:RICOH electronics devices division 功能描述:Step-up DC/DC converter for White LED Backlight |
| R1218N032A | 制造商:RICOH 制造商全稱:RICOH electronics devices division 功能描述:Step-up DC/DC converter for White LED Backlight |
| R1218N041A | 制造商:RICOH 制造商全稱:RICOH electronics devices division 功能描述:Step-up DC/DC converter for White LED Backlight |
| R1218N042A | 制造商:RICOH 制造商全稱:RICOH electronics devices division 功能描述:Step-up DC/DC converter for White LED Backlight |
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