收藏本站
24-Output PWM LED Drivers
for Message Boards
(PWM) value. Each output current driver in the R, G,
and B ports has a unique 12-bit (MAX6974) or 14-bit
(MAX6975) PWM control value providing fine resolution
adjustment of average current output. Each bit time of
the PWM corresponds to one period of CLKI (T CLKI ).
The PWM setting determines the amount of time, out of
the total period, that the output is on. The subframes
have PWM off-zones at the start (t SPWM ) and end
(t EPWM ) of the PWM period (see Figure 3). The sub-
frame period and PWM off zones are shown in Table 2
for each device.
The MAX6974 subdivides each subframe by 4096
(12-bit) PWM steps and has 16 cycle off zones, leaving
an active PWM region of 4064 PWM steps ranging from
Table 2. Subframe and PWM Timing
16 to 4079. The MAX6975 subdivides each subframe
by 16,384 (14-bit) PWM steps and has 32 cycle off
zones, leaving an active PWM region of 16,320 PWM
steps ranging from 32 to 16,351. The PWM phase for
outputs R0, R2, R4, R6, G0, G2, G4, G6, B0, B2, B4,
and B6 use phasing with the outputs on first and off
second. Inverse phasing is used for outputs R1, R3,
R5, R7, G1, G3, G5, G7, B1, B3, B5, and B7 as shown
in Figure 3 to balance the timing of loads on the LED
anode power supply.
In multiplexed operation, the subframes are shared
between MUX0 and MUX1 active times, effectively
reducing the number of subframes by 2.
LED-Intensity Control Example
The three levels of intensity control are shown in Figure 2
PART
MAX6974
MAX6975
SUBFRAME
(T CLKI )
4096
16,384
t SPWM
(T CLKI )
16
32
t EPWM
(T CLKI )
16
32
t EMUX
(T CLKI )
16
32
for one LED output driver in a MAX6974 in nonmulti-
plexed mode. As an example, the CALDAC is set to
169 DEC, setting the port output current level to 21.8mA.
The global-intensity PDM value is set to 96 DEC , producing
an even distribution of ON subframes out of the 128
MULTIPLEXED
SUBFRAME (n), MUX0
SUBFRAME (n), MUX1
t EMUX
MUX0
t EMUX
MUX1
R0, R2, R4, R6
t SPWM
t SPWM
G0, G2, G4, G6
B0, B2, B4, B6
50%
75%
R1, R3, R5, R7
G1, G3, G5, G7
B1, B3, B5, B7
ON/OFF PHASING
OFF/ON PHASING
NONMULTIPLEXED
25%
t SPWM
100%
t EPWM
R0, R2, R4, R6
t SPWM
SUBFRAME (n)
t EPWM
SUBFRAME (n + 1)
G0, G2, G4, G6
75%
75%
B0, B2, B4, B6
ON/OFF PHASING
R1, R3, R5, R7
G1, G3, G5, G7
75%
75%
B1, B3, B5, B7
OFF/ON PHASING
Figure 3. Multiplexed and Nonmultiplexed Output Driver Phasing and Example PWM Values
10
______________________________________________________________________________________
发布紧急采购，3分钟左右您将得到回复。

采购需求

(若只采购一条型号，填写一行即可)

发布成功！您可以继续发布采购。也可以进入我的后台，查看报价

发布成功！您可以继续发布采购。也可以进入我的后台，查看报价

*型号 *数量 厂商 批号 封装
添加更多采购

我的联系方式

*
*
*
相关PDF资料
MAX6977AAE+ IC LED DRIVER LINEAR 16-SSOP
MAX6978AUE+ IC LED DVR CONST-CURR 16TSSOP
MAX6979AUG+ IC LED DRIVER LINEAR 24-TSSOP
MAX6983AUG+T IC LED DRIVER LINEAR 24-TSSOP
MAX71020AEUI+ IC ENERGY METER 1PH 28TSSOP
MAX7302ATE+ IC LED DRIVER LINEAR 16-TQFN
MAX7307AUB+T IC LED DRIVER LINEAR 10-UMAX
MAX831EVKIT-SO EVAL KIT FOR MAX831
相关代理商/技术参数
MAX6974ATL+T 功能描述:LED照明驱动器 24-Output PWM LED Driver 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
MAX6974ATL-T 制造商:Maxim Integrated Products 功能描述:24-OUTPUT PWM LED DRIVERS FOR MESSA - Tape and Reel
MAX6974EVKIT 功能描述:LED 照明开发工具 MAX6974 Evaluation Kit RoHS:否 制造商:Fairchild Semiconductor 产品:Evaluation Kits 用于:FL7732 核心: 电源电压:120V 系列: 封装:
MAX6974EVKIT+ 功能描述:LED 照明开发工具 MAX6974 Evaluation Kit RoHS:否 制造商:Fairchild Semiconductor 产品:Evaluation Kits 用于:FL7732 核心: 电源电压:120V 系列: 封装:
MAX6975ATL 功能描述:LED显示驱动器 RoHS:否 制造商:Micrel 数位数量:5 片段数量: 安装风格:SMD/SMT 封装 / 箱体:PLCC-44 工作电源电压:4.75 V to 11 V 最大电源电流:10 mA 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装:Tube
MAX6975ATL+ 功能描述:LED照明驱动器 24-Output PWM LED Driver 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
MAX6975ATL+T 功能描述:LED照明驱动器 24-Output PWM LED Driver 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
MAX6975ATL-T 功能描述:LED显示驱动器 RoHS:否 制造商:Micrel 数位数量:5 片段数量: 安装风格:SMD/SMT 封装 / 箱体:PLCC-44 工作电源电压:4.75 V to 11 V 最大电源电流:10 mA 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装:Tube