- 您现在的位置：买卖IC网 > PDF目录20764 > ISL97677IRZ-TK (Intersil)IC LED DVR PWM CTRL 8CH 32QFN PDF资料下载
参数资料
| 型号： | ISL97677IRZ-TK |
| 厂商： | Intersil |
| 文件页数： | 12/23页 |
| 文件大小： | 0K |
| 描述： | IC LED DVR PWM CTRL 8CH 32QFN |
| 标准包装： | 1,000 |
| 拓扑： | 线性（LDO），PWM，升压（升压） |
| 输出数： | 8 |
| 内部驱动器： | 是 |
| 类型 - 主要： | 背光 |
| 类型 - 次要： | RGB，白色 LED |
| 频率： | 500kHz ~ 1.5MHz |
| 电源电压： | 4.75 V ~ 26 V |
| 输出电压： | 45V |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 32-VFQFN 裸露焊盘 |
| 供应商设备封装： | 32-QFN 裸露焊盘（5x5） |
| 包装： | 带卷 (TR) |
| 工作温度： | -40°C ~ 85°C |
ISL97677
.
The ratio of the OVP capacitors should be the inverse of
the OVP resistors. For example, if R UPPER /R LOWER =
33/1, then C UPPER /C LOWER =1/33 with C UPPER = 100pF
and C LOWER = 3.3nF.
Dimming Controls
The ISL97677 allows two ways of controlling the LED
current, and therefore, the brightness. They are:
+
-
REF
+
-
1. DC current adjustment
2. PWM chopping of the LED current defined in Step 1.
There are various ways to achieve DC or PWM current
I LEDmax = ---------------
R SET
6.66 × 10
f PWM = ------------------------
RSET
+
-
PWM DIMMING
FIGURE 24. SIMPLIFIED CURRENT SOURCE CIRCUIT
Dynamic Headroom Control
The ISL97677 features a proprietary Dynamic Headroom
Control circuit that detects the highest forward voltage
string or effectively the lowest voltage from any of the
CH pins. When this lowest I IN voltage is lower than the
short circuit threshold, V SC , such voltage will be used as
the feedback signal for the boost regulator. The boost
makes the output to the correct level such that the
lowest CH pin is at the target headroom voltage. Since all
LED strings are connected to the same output voltage,
the other CH pins will have a higher voltage, but the
regulated current source circuit on each channel will
ensure that each channel has the same programmed
current. The output voltage will regulate cycle by cycle
and is always referenced to the highest forward voltage
string in the architecture.
OVP and V OUT Requirement
The Overvoltage Protection (OVP) pin has a function of
setting the overvoltage trip level as well as limiting the
V OUT regulation range.
The ISL97677 OVP threshold is set by R UPPER and
R LOWER as shown in Equation 1:
V OUT_OVP = 1.21V × ( R UPPER + R LOWER ) ? R LOWER (EQ. 1)
V OUT can only regulate between 64% and 100% of the
V OUT _ OVP such that:
Allowable V OUT = 64% to 100% of V OUT _ OVP
For example, if 10 LEDs are used with the worst case
V OUT of 35V. If R 1 and R 2 are chosen such that the OVP
level is set at 40V, then the V OUT is allowed to operate
between 25.6V and 40V. If the requirement is changed to
a 6 LEDs 21V V OUT application, then the OVP level must
be reduced and users should follow V OUT = (64%
~100%)OVP requirement. Otherwise, the headroom
control will be disturbed such that the channel voltage
can be much higher than expected and sometimes it can
prevents the driver from operating properly.
12
control, which will be described in the following.
In any dimming controls, the EN pin must be high. EN
is a high voltage pin that can be applied with a digital
signal or tied directly to V IN for enable function.
MAXIMUM DC CURRENT SETTING
The initial brightness should be set by choosing an
appropriate value for R SET . This should be chosen to fix
the maximum possible LED current:
707.9
(EQ. 2)
Alternatively, the R SET can be replaced by digital
potentiometer for adjustable current. On the other
hand, the current accuracy is designed when RSET is
set at 20m to 40mA.
PWM CONTROL
The ISL97677 also provides PWM dimming by PWM
chopping of the current in the LEDs for all 8 channels
to provide an average LED current. During the On
periods, the LED current will be defined by the value of
R SET , as described in Equation 1.
PWM Dimming Frequency Adjustment
The dimming frequencies of all modes are set by an
external resistor at the FPWM pin as shown in
Equation 3:
7
(EQ. 3)
RPWM
where f PWM is the desirable PWM dimming frequency
and R FPWM is the setting resistor.
External PWM Dimming
The ISL97677 can operate as basic PWM dimming LED driver
with or without the need of SMBus/I 2 C interface. To do so,
users need to set EN = high and SMBCLK/SCL = grounded or
floating, SMBDAT/SDA = grounded or floating. The EN is a
high voltage pin that can be applied with a digital I/O signal or
tie to V IN . The PWM output will follow the PWM input and the
dimming frequency will be set by R PWM .
FN6996.1
November 13, 2009
相关PDF资料 |
PDF描述 |
|---|---|
| ISL97677IRZ-T | IC LED DVR PWM CTRL 8CH 32QFN |
| TPMD687K004R0025 | CAP TANT 680UF 4V 10% 2917 |
| TPSD337M006P0045 | CAP TANT 330UF 6.3V 20% 2917 |
| ABC44DRXI | CONN EDGECARD 88POS .100 DIP SLD |
| ABM40DTKN-S288 | CONN EDGECARD EXTEND 80POS .156 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| ISL97678IRZ | 功能描述:IC LED DVR PWM DIMMING 8CH 32QFN RoHS:是 类别:集成电路 (IC) >> PMIC - LED 驱动器 系列:- 标准包装:60 系列:- 恒定电流:- 恒定电压:- 拓扑:线性（LDO），PWM，升压（升压） 输出数:8 内部驱动器:是 类型 - 主要:背光 类型 - 次要:RGB，白色 LED 频率:500kHz ~ 1.5MHz 电源电压:4.75 V ~ 26 V 输出电压:45V 安装类型:* 封装/外壳:* 供应商设备封装:* 包装:* 工作温度:-40°C ~ 85°C |
| ISL97678IRZ-T | 功能描述:IC LED DVR PWM DIMMING 8CH 32QFN 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 |
| ISL97678IRZ-TK | 功能描述:IC LED DVR PWM DIMMING 8CH 32QFN 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 |
| ISL97682IRTZ | 功能描述:IC LED DVR PWM CTRL 2CH 16TQFN 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 |
| ISL97682IRTZEVALZ | 功能描述:EVAL BOARD FOR ISL97682 RoHS:是 类别:编程器，开发系统 >> 评估板 - LED 驱动器 系列:- 标准包装:1 系列:PowerWise® 电流 - 输出 / 通道:20mA 输出及类型:1，非隔离 输出电压:17V 特点:可调光 输入电压:2.7 ~ 5.5 V 已供物品:板 已用 IC / 零件:LM3508 相关产品:LM3508TLX-ND - IC LED DRVR WHT BCKLGT 9USMDLM3508TLDKR-ND - IC LED DRVR WHT BCKLGT 9MICROSMDLM3508TLCT-ND - IC LED DRVR WHT BCKLGT 9MICROSMDLM3508TLTR-ND - IC LED DRVR WHT BCKLGT 9MICROSMD |
发布紧急采购，3分钟左右您将得到回复。