參數(shù)資料
型號(hào)： MAX1739
廠商： Maxim Integrated Products, Inc.
英文描述： Wide Brightness Range CCFL Backlight Controllers
中文描述： 寬亮度范圍CCFL背光控制器
文件頁(yè)數(shù)： 15/26頁(yè)
文件大?。?/td> 444K
代理商： MAX1739
M
Wide Brightness Range
CCFL Backlight Controllers
______________________________________________________________________________________
15
See
Digital Interface
for instructions on using the
SMBus interface.
Synchronizing the DPWM Frequency
MODE has two functions: one is to select the interface
mode as described in
Interface Selection
, and the other
is to synchronize the DPWM
“
chopping
”
frequency to
an external signal to prevent unwanted effects in the
display screen.
To synchronize the DPWM frequency, connect MODE
to VL, REF, or GND through a 10k
resistor. Then con-
nect a 500pF capacitor from an AC signal source to
MODE as shown in Figure 6. The synchronization range
is from 32kHz to 100kHz, which corresponds to a
DPWM frequency range of 250Hz to 781Hz (128 MODE
pulses per DPWM cycle). High DPWM frequencies limit
the dimming range. See
Loop Compensation
for more
information concerning high DPWM frequencies.
Royer Oscillator MOSFET Drivers
The MAX1739/MAX1839 directly drive the two external
MOSFETs used in the Royer oscillator. This has many
advantages over the traditional method that uses bipo-
lar switching and an extra winding on the transformer.
Directly driving the MOSFET eliminates the need for an
extra winding on the transformer, which reduces cost
and minimizes the size of the transformer. Also, driving
the switches directly improves commutation efficiency
and commutation timing. Using MOSFETs for the
switches typically improves overall inverter efficiency
due to lower switch drops.
The Royer topology works as a zero voltage crossing
(ZVC) detector and switches currents between the two
sections of the transformer primary windings. The two
windings work alternately, each generating a half wave
that is transferred to the secondary to produce the full-
wave sinusoidal lamp voltage and current. The
MAX1739/MAX1839 detect the zero crossing through
the SYNC pin; the threshold is set at 500mV referred to
CS and has a typical delay of 50ns. The active switch-
ing forces commutation very close to the ZVC point and
has better performance than the traditional winding-
based ZVC switchover. Commutation can be further
BRIGHTNESS
POSITIVE-
SCALE ADC
NEGATIVE-
SCALE ADC
SMBus
DAC
OUTPUT
DPWM DUTY
CYCLE
(%)
COMBINED
POWER
LEVEL (%)
Maximum
Brightness
MODE = GND,
V
CTL/SCL
=
V
CRF/SDA
MODE = REF,
V
CTL/SCL
= 0
Bright [4:0] =
ob11111
Full-scale
DAC OUTPUT =
195.83mV
100
100
Minimum
Brightness
MODE = GND,
V
CTL/SCL
= 0,
V
MINDAC
=
VREF / 3
MODE = REF,
V
CTL/SCL
= V
CRF/SDA
,
V
MINDAC
= VREF / 3
Bright [4:0] =
ob00000,
V
MINDAC
=
VREF / 3
Zero-scale
DAC OUTPUT =
V
MINDAC
/ 10
9
3
Table 3. Brightness Adjustment Ranges (for 33:1 Dimming)
Note:
The current-level range is solely determined by the MINDAC-to-REF ratio and is externally set.
B
31
30
29
3
2
1
0
1
33
2
33
3
33
4
33
V
CTL
V
CRF
(MODE = GND)
V
CTL
V
CRF
(MODE = REF)
30
33
31
33
32
33
1
32
33
31
33
30
33
29
33
3
33
2
33
1
33
0
1
Figure 5. Brightness Code
相關(guān)PDF資料
PDF描述
MAX1739-MAX1839 Wide Brightness Range CCFL Backlight Controllers
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MAX1839 Wide Brightness Range CCFL Backlight Controllers
MAX1839EEP Wide Brightness Range CCFL Backlight Controllers
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
MAX1739EEP 功能描述:顯示驅(qū)動(dòng)器和控制器 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
MAX1739EEP+ 功能描述:顯示驅(qū)動(dòng)器和控制器 CCFL Backlight 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
MAX1739EEP+T 功能描述:顯示驅(qū)動(dòng)器和控制器 CCFL Backlight 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
MAX1739EEP-T 功能描述:顯示驅(qū)動(dòng)器和控制器 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
MAX1739EVKIT 功能描述:電源管理IC開(kāi)發(fā)工具 MAX1739 Eval Kit RoHS:否 制造商:Maxim Integrated 產(chǎn)品:Evaluation Kits 類(lèi)型:Battery Management 工具用于評(píng)估:MAX17710GB 輸入電壓: 輸出電壓:1.8 V
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