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參數(shù)資料
| 型號(hào)： | DS3994 |
| 廠商： | Maxim Integrated Products, Inc. |
| 英文描述： | 4-Channel Cold-Cathode Fluorescent Lamp Controller |
| 中文描述： | 4通道冷陰極熒光燈控制器 |
| 文件頁數(shù)： | 12/28頁 |
| 文件大?。?/td> | 557K |
| 代理商： | DS3994 |
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D
4-Channel Cold-Cathode
Fluorescent Lamp Controller
12
____________________________________________________________________
When the DPWM signal is provided by an external
source, either from the PSYNC pin of another DS3994 or
from some other user-generated source, it is input into the
PSYNC I/O pin of the DS3994. In this mode, the BRIGHT
and POSC inputs are disabled and should be grounded
(see Figure 4). When multiple DS3994s are used in a
design, DS3994s configured to use externally generated
DPWM signals are referred to as DPWM receivers.
Burst Dimming Stagger (BDS) Functionality
The DS3994 also features burst dimming stagger (BDS)
functionality integrated into the burst dimming con-
troller. BDS is useful to reduce the current ripple on the
DC supply as well as improve the visual motion
response of the LCD panel. This feature allows users to
enter a digital code into each channel independent
register (BDS1/2/3/4) that would delay the start of each
burst period. The 8-bit BDS code can be calculated by
using Table 2 and the following equations.
M, LAMP CYCLE PERIOD MULTIPLICATION FACTOR
POSCR1
(CR2.2)
POSCR0
(CR2.1)
SELECTED PWM
OSCILLATOR RANGE (Hz)
LAMP OSCILLATOR = 40
TO 80kHz (LOFS = 0)
LAMP OSCILLATOR = 20
TO 40kHz (LOFS = 1)
0
0
1
1
0
1
0
1
22.5 to 55
45 to 110
90 to 220
180 to 440
8
4
2
1
8
4
2
1
Table 2. Multiplication Factor M, Based on Lamp Frequency Oscillator and DPWM
Frequency Oscillator
If a BDS_Delay is used that is longer than the burst peri-
od, then the gate drivers, GA and GB, have no output.
For example, assume a lamp frequency of 50kHz and a
burst frequency of 167Hz. The step resolution of the
burst-dimming stagger would be 40μs (2/50,000). To
achieve equal stagger, as shown in Figure 5, the
BDS1/2/3/4 registers would be programmed as
described in Table 3.
BDS_Delay = BDS_Resolution x BDS_8-Bit_Value
BDS_Resolution
f
LF:OSC
=
M
CHANNEL 1
BURST DIMMING CYCLE (167Hz/6ms)
CHANNEL 2
CHANNEL 3
CHANNEL 4
1.5ms
3.0ms
4.5ms
Figure 5. Example Burst Dimming Stagger Cycle
CHANNEL
1
2
3
4
REGISTER
BDS1
BDS2
BDS3
BDS4
DESIRED STAGGER (ms)
0
1.5
3.0
4.5
STEP RESOLUTION (μs)
40
40
40
40
COUNT
0
38
75
113
PROGRAMMED VALUE
00h
26h
48h
71h
Table 3. Example BDS1/2/3/4 Programmed Values
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| DS3994Z+ | 功能描述:顯示驅(qū)動(dòng)器和控制器 4-Ch CCFL Controller RoHS:否 制造商:Panasonic Electronic Components 工作電源電壓:2.7 V to 5.5 V 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:QFN-44 封裝:Reel |
| DS3994Z+T&R | 制造商:Maxim Integrated Products 功能描述:2ND GEN 4CH CCFL CON SOIC-28 T&R LF - Tape and Reel 制造商:Maxim Integrated Products 功能描述:IC CCFL CNTRLR 4CH 28-SOIC |
| DS3994Z+T&R | 功能描述:顯示驅(qū)動(dòng)器和控制器 4-Ch CCFL Controller RoHS:否 制造商:Panasonic Electronic Components 工作電源電壓:2.7 V to 5.5 V 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:QFN-44 封裝:Reel |
| DS3994Z+W | 功能描述:顯示驅(qū)動(dòng)器和控制器 4-Ch CCFL Controller RoHS:否 制造商:Panasonic Electronic Components 工作電源電壓:2.7 V to 5.5 V 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:QFN-44 封裝:Reel |
| DS3CC | 制造商:Thomas & Betts 功能描述:30A,MG,CUP CAP |
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