参数资料
| 型号： | MAX8722CEEG+ |
| 厂商： | Maxim Integrated |
| 文件页数： | 16/21页 |
| 文件大小： | 0K |
| 描述： | IC CCFL BACKLIGHT CTRL 24-QSOP |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 50 |
| 类型： | CCFL 控制器 |
| 频率： | 30 ~ 80 kHz |
| 电流 - 电源： | 1mA |
| 电流 - 输出： | 300mA |
| 电源电压： | 4.6 V ~ 28 V |
| 工作温度： | -40°C ~ 85°C |
| 封装/外壳： | 24-SSOP（0.154"，3.90mm 宽） |
| 供应商设备封装： | 24-QSOP |
| 包装： | 管件 |
Low-Cost CCFL Backlight Controller
DPWM Frequency Setting
There are three ways to set the DPWM frequency.
1) The DPWM frequency can be set with an external
resistor. Connect SYNC to GND and connect a
resistor between FREQ and GND. The DPWM fre-
quency is given by the following equation:
f DPWM = 210 Hz × 169 k Ω / R FREQ
The adjustable range of the DPWM frequency is
between 100Hz and 350Hz (R FREQ is between
353k Ω and 101k Ω ). CNTL controls the DPWM duty
cycle.
2) The DPWM frequency can be clocked by an exter-
nal high-frequency signal. Connect FREQ to V CC
and connect SYNC to the external high-frequency
signal. The DPWM frequency is 1/128 of the fre-
quency of the external signal:
The frequency range of the external signal is between
100Hz and 350Hz. In this mode, the brightness control
input CNTL is disabled, and the brightness is propor-
tional to the duty cycle of the external signal.
Table 3 summarizes the three ways of setting the
DPWM frequency.
UVLO
The MAX8722C includes an undervoltage-lockout
(UVLO) circuit. The UVLO circuit monitors the V CC volt-
age. When V CC is below V UVLO (typ), the MAX8722C
disables both high-side and low-side MOSFET drivers
and resets the fault latch.
Low-Power Shutdown
When the MAX8722C is placed in shutdown, all func-
tions of the IC are turned off except for the 5.4V linear
regulator. In shutdown, the linear-regulator output volt-
age drops to about 4.6V and the supply current is 6μA
(typ). While in shutdown, the fault latch is reset. The
device can be placed into shutdown by pulling SHDN
f DPWM = EXT
f
1 / 128
to its logic-low level.
Lamp-Out Protection
For safety, the MAX8722C monitors the lamp-current
where f EXT is the frequency of the external signal.
The frequency range of the external signal should
be between 26kHz and 90kHz, resulting in a DPWM
frequency range between 100Hz and 350Hz. CNTL
controls the DPWM duty cycle.
3) The DPWM frequency can be synchronized to an
external low-frequency signal. To enable this mode,
connect SYNC to V CC , connect FREQ to GND
through a 100k Ω resistor, and connect DPWM to
the external low-frequency signal. The DPWM fre-
quency and duty cycle are equal to those of the
external signal.
Table 3. DPWM Frequency Setting
feedback (IFB) to detect faulty or open CCFL tubes and
secondary short circuits in the lamp and IFB sense
resistor. As described in the Lamp-Current Regulation
section, the voltage on IFB is internally full-wave recti-
fied. If the rectified IFB voltage is below 600mV, the
MAX8722C charges the TFLT capacitor with 1μA. The
MAX8722C latches off if the voltage on TFLT exceeds
4.1V. Unlike the normal shutdown mode, the linear-reg-
ulator output (V CC ) remains at 5.4V. Toggling SHDN or
cycling the input power reactivates the device.
FREQ
Connect FREQ to GND
through an external resistor.
Connect FREQ to V CC .
Connect FREQ to GND
through a 100k resistor.
SYNC
Connect SYNC to GND.
Connect SYNC to an
external high-frequency
signal.
Connect SYNC to V CC .
DPWM
DPWM is used as the DPWM
signal output.
DPWM is used as the DPWM
signal output.
Connect DPWM to an external
low-frequency signal.
DIGITAL PWM
FREQUENCY/DUTY CYCLE
The resistor value sets the frequency.
CNTL controls the duty cycle.
The frequency is 1/128 of the
frequency of the external signal. CNTL
controls the duty cycle.
The frequency and duty cycle are
equal to those of the external signal.
16
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相关代理商/技术参数 |
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| MAX8722CEEG+ | 功能描述:显示驱动器和控制器 CCFL Backlight Controller RoHS:否 制造商:Panasonic Electronic Components 工作电源电压:2.7 V to 5.5 V 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:QFN-44 封装:Reel |
| MAX8722CEEG+T | 功能描述:显示驱动器和控制器 CCFL Backlight Controller RoHS:否 制造商:Panasonic Electronic Components 工作电源电压:2.7 V to 5.5 V 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:QFN-44 封装:Reel |
| MAX8722EEG | 功能描述:显示驱动器和控制器 RoHS:否 制造商:Panasonic Electronic Components 工作电源电压:2.7 V to 5.5 V 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:QFN-44 封装:Reel |
| MAX8722EEG+ | 功能描述:显示驱动器和控制器 CCFL Backlight Controller RoHS:否 制造商:Panasonic Electronic Components 工作电源电压:2.7 V to 5.5 V 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:QFN-44 封装:Reel |
| MAX8722EEG+T | 功能描述:显示驱动器和控制器 CCFL Backlight Controller RoHS:否 制造商:Panasonic Electronic Components 工作电源电压:2.7 V to 5.5 V 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:QFN-44 封装:Reel |
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