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参数资料
| 型号： | ISL97684IRTZ-TK |
| 厂商： | Intersil |
| 文件页数： | 12/17页 |
| 文件大小： | 0K |
| 描述： | IC LED DVR PWM CTRL 4CH 16TQFN |
| 标准包装： | 1 |
| 拓扑： | PWM，升压（升压） |
| 输出数： | 4 |
| 内部驱动器： | 是 |
| 类型 - 主要： | 背光 |
| 频率： | 500kHz ~ 650kHz，900kHz ~ 1.1MHz |
| 电源电压： | 4 V ~ 26.5 V |
| 输出电压： | 45V |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 16-WFQFN 裸露焊盘 |
| 供应商设备封装： | 16-TQFN（3x3） |
| 包装： | 标准包装 |
| 工作温度： | -40°C ~ 85°C |
| 其它名称： | ISL97684IRTZ-TKDKR |
ISL97682, ISL97683, ISL97684
Phase Shift Control
The ISL97682, ISL97683, ISL97684 are capable of delaying the
For example, for a 200Hz input PWM frequency, the minimum
duty cycle is:
phase of each current source. Conventional LED drivers exhibit
the worst load transients to the boost circuit by turning on all
Min DC = 450ns × 200Hz = 0.009%
(EQ. 8)
channels simultaneously as shown in Figures 20 and 21. In
contrast, the ISL97682, ISL97683, ISL97684 phase shifts each
channel by turning them on once during each PWM dimming
period as shown in Figures 23 and 24. At each dimming duty
Table 1 shows the PWM Dimming with Phase Shift and Direct
PWM Dimming configurations.
TABLE 1.
cycle except at 100%, the sum of the phase shifted total current
will be less than a conventional LED drivers’ total current.
For ISL97682, the two channels are separated by 180°. For
ISL97683, the three channels are separated by 90° and not
120°. For ISL97684, the four channels are separated by 90°. If
the channels are combined for higher current application, the
phase shift function must be disabled by running the part in
RFWM/
DIRECTPWM
Connects with
Resistor
Floating
FUNCTION
PWM Dimming with
frequency adjust
DirectPWM without
frequency adjust
PHASE
SHIFT
Yes
No
DIMMING
RESOLUTION
8-bit
N/A
direct PWM mode by floating the RFPWM/DirectPWM and
selecting switching frequency by biasing the FSW pin as
explained in Table 2.
t PWMIN
Switching Frequency and PWM/PFM Mode
When the FSW pin is biased from VDC with a resistor divider
R UPPER and R LOWER , the switching frequency and PFM/PWM
mode will change according to the following FSW levels shown in
PWMI
60%
Table 2 with the recommended R UPPER and R LOWER .
ILED1
t FPWM (t PWMOUT )
t OFF
t ON
60% 40%
FSW
F SW
TABLE 2.
PHASE
SHIFT
Mode
R UPPER
R LOWER
ILED2
ILED3
ILED4
(0 ~ 0.11)*VDC
(0.34~0.44)*VDC
(0.53~0.63)*VDC
(0.86~1) VDC
600kHz
600kHz
1.0MHz
1.0MHz
Yes
Yes
Yes
Yes
PFM
PWM
PWM
PFM
Open
187k Ω
100k Ω
0
0
120k Ω
138k Ω
Open
ILED1
FIGURE 24. ISL97684 4 CHANNELS PHASE SHIFT ILLUSTRATION
PWM Dimming Frequency Adjustment
The dimming frequency is set by an external resistor at the
RFPWM/DirectPWM pin to GND calculated by Equation 6:
The ISL97682, ISL97683, ISL97684 goes into PFM mode at
F SW = 600kHz/1MHz when the FSW pin is biased at 0/VDC volts.
The part will only go into PFM mode depending on the LED output
voltage and loading conditions and can be more efficient than
running the part in PWM mode as shown in Figures 5 and 6. The
dimming frequency can be set or applied up to 30kHz with duty
cycle from 0.4% to 100%. The lower limit of 0.4% is the result of
? F
( 12.4 ) × 10
= --------------------------------- ?
? PWM
7
RFPWM ?
(EQ. 6)
an 8-bit digitizer resolution.
Soft-Start
where FPWM is the desirable PWM dimming frequency and
R FPWM is the setting resistor. Do not bias RFPWM/DirectPWM if
direct PWM dimming is used; see Table 1 for clarification.
The PWM dimming frequency can be set or applied up to 30kHz
with duty cycle from 0.4% to 100%. The lower limit of 0.4% is the
result of 8-bit digitizer resolution.
Direct PWM Dimming
The ISL97682, ISL97683, ISL97684 can also operate in direct
PWM dimming mode such that the output follows the input PWM
signal without phase shifting. The FSW pin can still be used to
select between 600kHz and 1MHz in PWM or PFM mode as
explained in “Pin Descriptions” on page 4. To use Direct PWM
mode, users should float the RFPWM/DirectPWM pin. The input
PWM frequency should be limited to 30kHz and the minimum
duty cycle be calculated by Equation 7:
The in-rush current will flow towards C OUT when V IN is applied
and it is determined by the ramp rate of V IN and the values of
C OUT and L.
Once the part is enabled, the boost regulator will begin to switch
and the current in the inductor will ramp-up. The current in the
boost power switch is monitored and the switching is terminated
in any cycle where the current exceeds the current limit. The
ISL97682, ISL97683, ISL97684 include a soft-start feature
where this current limit starts at a low value (225mA). This is
stepped up to the final 1.8A current limit in 7 further steps of
225mA. These steps will happen over approximately 8ms and
will be extended at a low LED PWM frequency if the LED duty
cycle is low. This allows the output capacitor to be charged to the
required value at a low current limit and prevents high input
current for systems that have only a low to medium output
current requirement.
Min Duty Cycle = 450ns × Input PWM Frequency
12
(EQ. 7)
FN7689.1
May 16, 2012
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相关代理商/技术参数 |
参数描述 |
|---|---|
| ISL97686IBZ | 功能描述:IC LED DRVR BACKLIGHT 28SOIC 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 |
| ISL97686IBZ-T | 功能描述:IC LED DRVR BACKLIGHT 28SOIC 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 |
| ISL97686IRTZ | 功能描述:IC LED DRVR BACKLIGHT 28TQFN 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 |
| ISL97686IRTZ-T | 功能描述:IC LED DRVR BACKLIGHT 28TQFN 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 |
| ISL97687IBZ | 功能描述:IC LED DRVR 4 CHAN PWM 28SOIC 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 |
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