RT9273 Просмотр технического описания (PDF) - Richtek Technology

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RT9273

High Performance, OLED + LED Driver for Dual Panel Mobile Phone

Richtek Technology 

Preliminary

RT9273

Logic control and application circuit for LED and OLED turning on simultaneously + PWM dimming control for

LED

To achieve LEDs and OLED turning on simultaneously, the following application circuit (Figure 6) provides another

solution by simple logic control (Table 2).

CIN

VIN

2.2uF

R1

4.7k

WLED_ON

EL_ON

L1

4.7uH SS0520

COUT

2.2uF

VCC LX

OVP

CH1

EN

RT9273

SP

CH2

FB2

FB1

GND

R2

1M

R3

300

WLED_ON

R7

R5

R6

100k

16

24k

Dimm

Figure 6. Application circuit for LED and OLED turning on simultaneously

Table 2. Truth table for Figure 6

WLED_ON EL_ON DIMM

M & S turn on simultaneously Normal

H

H

H

M & S turn on simultaneously Dimming

--

Main ONLY Normal

H

--

--

L

H

Main ONLY Dimming

PWM

L

H

Sub ONLY Normal

Sub ONLY Dimming

SHUT DOWN

L

H

H

L

H

L

L

L

Don’t care

Function

VOUT = 16V,

ILED = [VOUT - 3VF(LED)]/R3 mA

--

VOUT = 9.5V, ILED = 18.5 mA

V OUT = 9.5V,

ILED = depends on PWM

VOUT = 13V, ILED = 0 mA

VOUT = 16V, ILED = 0 mA

VOUT = 0V, ILED = 0 mA

DS9273-09 August 2007

www.richtek.com

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