- 您现在的位置：买卖IC网 > Sheet目录335 > ISL97635AIRZ (Intersil)IC LED DRVR WHT/RGB BCKLGT 24QFN
ISL97635A
BRTDC can be programmed from 0 to 255 in decimal and
defaults to 255 (0xFF). If left at the default value, LED
current will be fixed at I LEDmax . BRTDC can be adjusted
dynamically on the fly during operation. BRTDC = 0
disconnects all channels and ILED is guaranteed to be
<10μA at this state.
The SMBus controlled PWM frequency is adjusted by a
capacitor at the FPWM pin, which will be described in “PWM
Dimming Frequency Adjustment” on page 13.
Method 2 (External Mode)
The average LED current of each channel can also be
controlled by an external PWMI signal, as shown in Equation 7:
For example, if the maximum required LED current (I LEDmax )
is 20mA, rearranging Equation 1 yields Equation 3:
I LED ( ave ) = I LED × PWMI
(EQ. 7)
R SET = 733 ? 0.02 = 36.6k Ω
If BRTDC is set to 200, then:
I LED = 2.87 ? 200 ? 36600 = 15.7mA
(EQ. 3)
(EQ. 4)
The PWM dimming frequency can be for example 20kHz but
there are a minimum on and off time requirements such that
the dimming will be in the range of 10% to 99.5%. If the
dimming frequency is below 5kHz, the dimming range can
be 1% to 99.5%.
PWM CONTROL
The ISL97635A provides four different PWM dimming
methods, as described in the following. Each of these
methods results in PWM chopping of the current in the LEDs
for all 6 channels to provide an average LED current. During
the on-periods, the LED current will be defined by the value
of R SET and BRTDC, as described in Equations 1 and 2. The
source of the PWM signal can be described as follows:
1. Internally generated 256 step duty cycle programmed
The PWM dimming off time cannot be longer than 28ms or
else the driver will enter shutdown.
To use PWMI only brightness control, users need to set
Register 0x01 to 0x03.
Method 3 (DPST Mode)
The average LED current of each channel can also be
controlled by the product of the SMBus controlled PWM and
the external PWMI signals as follows:
through the SMBus.
2. External signal from PWMI.
3. DPST mode. Internally generated signal with a duty cycle
defined by the product of the external PWMI and SMBus
programmed PWM at the internal setting frequency.
4. DC-to-PWM control.
The default PWM dimming is in DPST mode. In all four
methods, the average LED current of each channel is
controlled by I LED and the PWM duty cycle in percent as
I LED ( ave ) = I LED xPWM DPST
Where:
PWM DPST = BRT ? 255 × PWMI
Therefore:
I LED ( ave ) = I LED × BRT ? 255 × PWMI
(EQ. 8)
(EQ. 9)
(EQ. 10)
shown in Equation 5:
Where BRT is the value held in register 0x00 (default setting
I LED ( ave ) = I LED × PWM
(EQ. 5)
0xFF) controlled by SMBus and PWMI is the duty cycle of
the incoming PWMI signal. In this way, the users can change
Method 1 (Internal Mode, SMBus controlled PWM)
The average LED current of each channel is controlled by the
internally generated PWM signal as shown in Equation 6:
the PWM current in ratiometric manner to achieve DPST
compliance backlight dimming.
To use the DPST mode, users need to set register 0x01 to
0x01 with the external PWM signal.
I LED ( ave ) = I LED × ( BRT ? 255 )
(EQ. 6)
The DPST mode PWM frequency is adjusted by a capacitor
at the FPWM pin. Also, a C PWMO capacitor is also needed,
where BRT is the PWM brightness level programmed in the
register 0x00. BRT ranges from 0 to 255 in decimal and
defaults to 255 (0xFF). BRT = 0 disconnects all channels
and I LED is guaranteed to be <10μA in this state.
To use only the SMBus controlled PWM brightness control,
users need to set Register 0x01 to 0x05 with EN/PWMI in
logic high.
12
which will be described in “PWM Dimming Frequency
Adjustment” on page 13.
For example, if the SMBus controlled PWM duty is 80%
dimming at 200Hz (see C FPWM in Equation 10) and the
external PWMI duty cycle is 60% dimming at 1kHz, the
resultant PWM duty cycle is 48% dimming at 200Hz.
Method 4 (Analog Mode, DC-to-PWM Mode)
By overdriving the PWMO pin with a DC voltage between
0.21V and 1.21V, the average LED current of each channel
FN6564.2
December 22, 2008
发布紧急采购，3分钟左右您将得到回复。
相关PDF资料
ISL97635IRZ
IC LED DRVR WHT/RGB BCKLGT 24QFN
ISL97636AIRZ
IC LED DRIVR WHITE BCKLGT 24-QFN
ISL97636IRZ-TK
IC LED DRIVR WHITE BCKLGT 24-QFN
ISL97671AIRZ
IC LED DVR PWM CTRL 6CH 20QFN
ISL97672AIRZ
IC LED DRVR LOW DIMMING 20QFN
ISL97672BIRZ
IC LED DRVR BACKLIGHT 20QFN
ISL97675IRZ-TK
IC LED DVR PWM CTRL 4CH 20QFN
ISL97677IRZ
IC LED DVR PWM CTRL 8CH 32QFN
相关代理商/技术参数
ISL97635AIRZ-T
功能描述:IC LED DRVR WHT/RGB BCKLGT 24QFN RoHS:是 类别:集成电路 (IC) >> PMIC - LED 驱动器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS
Obsolescence Mitigation Program 标准包装:2,500 系列:- 恒定电流:- 恒定电压:- 拓扑:升压（升压），切换式电容器（充电泵） 输出数:1 内部驱动器:是 类型 - 主要:背光 类型 - 次要:白色 LED 频率:625kHz ~ 875kHz 电源电压:2.7 V ~ 5.3 V 输出电压:5V 安装类型:表面贴装 封装/外壳:10-TFSOP，10-MSOP（0.118"，3.00mm 宽） 供应商设备封装:10-µMAX 包装:带卷 (TR) 工作温度:-40°C ~ 85°C
ISL97635AIRZ-TK
功能描述:IC LED DRVR WHT/RGB BCKLGT 24QFN RoHS:是 类别:集成电路 (IC) >> PMIC - LED 驱动器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS
Obsolescence Mitigation Program 标准包装:2,500 系列:- 恒定电流:- 恒定电压:- 拓扑:升压（升压），切换式电容器（充电泵） 输出数:1 内部驱动器:是 类型 - 主要:背光 类型 - 次要:白色 LED 频率:625kHz ~ 875kHz 电源电压:2.7 V ~ 5.3 V 输出电压:5V 安装类型:表面贴装 封装/外壳:10-TFSOP，10-MSOP（0.118"，3.00mm 宽） 供应商设备封装:10-µMAX 包装:带卷 (TR) 工作温度:-40°C ~ 85°C
ISL97635AIRZ-TKR5306
制造商:Intersil Corporation 功能描述:
ISL97635IRZ
功能描述:IC LED DRVR WHT/RGB BCKLGT 24QFN RoHS:是 类别:集成电路 (IC) >> PMIC - LED 驱动器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS
Obsolescence Mitigation Program 标准包装:2,500 系列:- 恒定电流:- 恒定电压:- 拓扑:升压（升压），切换式电容器（充电泵） 输出数:1 内部驱动器:是 类型 - 主要:背光 类型 - 次要:白色 LED 频率:625kHz ~ 875kHz 电源电压:2.7 V ~ 5.3 V 输出电压:5V 安装类型:表面贴装 封装/外壳:10-TFSOP，10-MSOP（0.118"，3.00mm 宽） 供应商设备封装:10-µMAX 包装:带卷 (TR) 工作温度:-40°C ~ 85°C
ISL97635IRZ-T
功能描述:IC LED DRVR WHT/RGB BCKLGT 24QFN RoHS:是 类别:集成电路 (IC) >> PMIC - LED 驱动器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS
Obsolescence Mitigation Program 标准包装:2,500 系列:- 恒定电流:- 恒定电压:- 拓扑:升压（升压），切换式电容器（充电泵） 输出数:1 内部驱动器:是 类型 - 主要:背光 类型 - 次要:白色 LED 频率:625kHz ~ 875kHz 电源电压:2.7 V ~ 5.3 V 输出电压:5V 安装类型:表面贴装 封装/外壳:10-TFSOP，10-MSOP（0.118"，3.00mm 宽） 供应商设备封装:10-µMAX 包装:带卷 (TR) 工作温度:-40°C ~ 85°C
ISL97635IRZ-TK
功能描述:IC LED DRVR WHT/RGB BCKLGT 24QFN RoHS:是 类别:集成电路 (IC) >> PMIC - LED 驱动器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS
Obsolescence Mitigation Program 标准包装:2,500 系列:- 恒定电流:- 恒定电压:- 拓扑:升压（升压），切换式电容器（充电泵） 输出数:1 内部驱动器:是 类型 - 主要:背光 类型 - 次要:白色 LED 频率:625kHz ~ 875kHz 电源电压:2.7 V ~ 5.3 V 输出电压:5V 安装类型:表面贴装 封装/外壳:10-TFSOP，10-MSOP（0.118"，3.00mm 宽） 供应商设备封装:10-µMAX 包装:带卷 (TR) 工作温度:-40°C ~ 85°C
ISL97636AIRZ
功能描述:LED照明驱动器 6-CH LED DRVR RoHS:否 制造商:STMicroelectronics 输入电压:11.5 V to 23 V 工作频率: 最大电源电流:1.7 mA 输出电流: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:SO-16N
ISL97636AIRZ-T
功能描述:IC LED DRIVR WHITE BCKLGT 24-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - LED 驱动器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS
Obsolescence Mitigation Program 标准包装:2,500 系列:- 恒定电流:- 恒定电压:- 拓扑:升压（升压），切换式电容器（充电泵） 输出数:1 内部驱动器:是 类型 - 主要:背光 类型 - 次要:白色 LED 频率:625kHz ~ 875kHz 电源电压:2.7 V ~ 5.3 V 输出电压:5V 安装类型:表面贴装 封装/外壳:10-TFSOP，10-MSOP（0.118"，3.00mm 宽） 供应商设备封装:10-µMAX 包装:带卷 (TR) 工作温度:-40°C ~ 85°C