bd9202efs ROHM Co. Ltd., bd9202efs Datasheet - Page 10

• Manufacturer Part Number: bd9202efs
• Description: White Backlight Led Drivers For Medium To Large Lcd Panels Swreg Type
• Manufacturer: ROHM Co. Ltd.

○ Register setting example of LED illuminations
○ The method connected control wire when plural IC is used
Connected method of the control wire when plural BD9202EFS is controlled with one CPU is shown.
You connect CPUCLK and CPUDI in parallel (note the ability of respective drive), CPUCS wires in each BD9202EFS.
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BD9202EFS
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※
※ COUNT [9:0 ] =1 with Illumination timing of each channel becomes being identical.
※ When setting of pwm modulated light is modified, it is reflected being at the point where COUNT [ 9:0 ] is reset to 0
※ After writing ' 1 ' in PWMEN, the delay of 0 ～maximum of 1 clocks occurs until LED lights up.
PWMCLK(=FBCT)
(600kHz)
PWMEN
(resister)
COUNT [9:0]
(internal)
PWMLED1 [9:0] = 300d = 12Ch
LED1ON
(internal)
PWMLED2 [9:0] = 6d = 006h
LED2ON
(internal)
・ When illuminates LED3 and LED8 regular (100% illumination)
・ When it does PWM modulated light with 40% to LED3, and 80% to LED8,
value that is set by PWM pulse, LEDON will become Low and the light goes out.
(It is not immediately reflection with register entry)
When count [ 9:0 ] becomes 1, LEDON will become High and then LED lights up. When COUNT [ 9:0 ] reaches to the
① (ADDR,DATA)＝(01h､84h)
1024×40%=409 , 1024×80%=819
Because (409)DEC=(199)HEX , (819)DEC=(333)HEX
① (ADDR,DATA)＝(06h､99h)
② (ADDR,DATA)＝(10h､33h)
③ (ADDR,DATA)＝(00h､01h)
(ADDR,DATA)＝(07h､01h)
(ADDR,DATA)＝(11h､03h)
CPU
0
DATA
CLK
CS1
CS2
CS3
1
2
3
4
5
6
BD9202 No.2
BD9202 No.3
BD9202 No.1
CPUCLK
CPUCS
CPUDI
CPUCS
CPUDI
CPUCLK
CPUCS
CPUDI
CPUCLK
PWM Setting example
→ Operation of regular illumination
PWM設定例
10/19
→Setting LED3 to 40%
→Setting LED8 to 80%
→Operation of modulated light
300
1.71ms（586Hz）
Technical Note
2009.04 - Rev.A
1021 1022 1023
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