参数资料
| 型号： | MAX754ESE+T |
| 厂商： | Maxim Integrated |
| 文件页数： | 4/16页 |
| 文件大小： | 0K |
| 描述： | IC CNTRLR CONTRAST 16-SOIC |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 2,500 |
| 显示器类型： | CCFL - 冷色阴极荧光灯 |
| 电流 - 电源： | 500µA |
| 电源电压： | 4 V ~ 30 V |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 16-SOIC（0.154"，3.90mm 宽） |
| 供应商设备封装： | 16-SOIC |
| 包装： | 带卷 (TR) |
CCFL Backlight and
LCD Contrast Controllers
______________________________________________________________Pin Description
PIN
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
NAME
V DD
LADJ
LON
CON
CADJ
GND
REF
CFB
CC
CS
CDRV
PGND
LDRV
LX
BATT
LFB
FUNCTION
5V Power-Supply Input
Digital Input for LCD Backplane Bias Adjustment. See Table 1.
Digital Input to Control LCD Bias Section. See Table 1.
Digital Input to Control CCFT Section. See Table 1.
Digital Input for CCFT Brightness Adjustment. See Table 1.
Analog Ground
Reference Voltage Output, 1.25V
Inverting Input for the CCFT Error Amplifier
Output of the CCFT Error Amplifier
Connect to V DD
Leave unconnected
Power Ground Connection for LDRV
Gate-Driver Output. Drives LCD backplane N-channel MOSFET.
LCD Backplane Inductor Voltage-Sense Pin. Used to sense inductor voltage for on time determination.
Battery Connection. Used to sense battery voltage for on time determination.
Voltage Feedback for the LCD Backplane Section
_______________Theory of Operation
CCFL Inverter
The MAX753/MAX754’s CCFL inverter is designed to
drive one or two cold-cathode fluorescent lamps
(CCFLs) with power levels from 100mW to 6W. These
lamps commonly provide backlighting for LCD panels
in portable computers.
Drive Requirements for CCFL Tubes
CCFL backlights require a high-voltage, adjustable AC
power source. The MAX753/MAX754 generate this AC
waveform with a self-oscillating, current-fed, parallel
resonant circuit, also known as a Royer-type oscillator.
Figure 1 shows one such circuit. The Royer oscillator is
comprised of T1, C9, the load at the secondary, Q4,
and Q5. The circuit self-oscillates at a frequency deter-
mined by the effective primary inductance and capaci-
tance. Q4 and Q5 are self-driven by the extra winding.
The current source feeding the Royer oscillator is com-
prised of L1, D5, and the MAX758A. When current from
the current source increases, so does the lamp current.
The lamp current is half-wave rectified by D7A and
D7B, and forms a voltage across resistor R8. The
MAX753’s error amplifier compares the average of this
voltage to the output of its internal DAC. Adjusting the
DAC output from zero scale to full scale (digital control)
causes the error amplifier to vary the tube current from
a minimum to a maximum. The DAC’s transfer function
is shown in Figure 2.
On power-up or after a reset, the counter sets the DAC
output to mid scale. Each rising edge of CADJ (with
CON high) decrements the DAC output. When decre-
mented beyond full scale, the counter rolls over and
sets the DAC to the maximum value. In this way, a sin-
gle pulse applied to CADJ decreases the DAC set-
point by one step, and 31 pulses increase the set-point
by one step.
The error amplifier’s output voltage controls the peak
current output of the MAX758A. The peak switch cur-
rent is therefore controlled by the output of the error
amplifier. The lower the error amplifier’s output, the
lower the peak current. Since the current through the
current source is related to the current through the
tube, the lower the error amplifier’s output, the lower the
tube current.
4
_______________________________________________________________________________________
相关PDF资料 |
PDF描述 |
|---|---|
| MAX755CPA | IC REG INV ADJ 0.2A 8DIP |
| MAX756CSA | IC REG BOOST 3.3V/5V 0.3A 8SOIC |
| MAX759EWE | IC REG INV ADJ 0.3A 16SOIC |
| MAX761CSA+T | IC REG BOOST 12V/ADJ 0.15A 8SOIC |
| MAX765CSA | IC REG INV -12V/ADJ 0.12A 8SOIC |
相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX755C/D | 功能描述:直流/直流开关转换器 Adjustable Negative-Output Inverting Current-Mode PWM Reg RoHS:否 制造商:STMicroelectronics 最大输入电压:4.5 V 开关频率:1.5 MHz 输出电压:4.6 V 输出电流:250 mA 输出端数量:2 最大工作温度:+ 85 C 安装风格:SMD/SMT |
| MAX755CPA | 功能描述:直流/直流开关调节器 5V- Inverting DC/DC Converter RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
| MAX755CSA | 功能描述:直流/直流开关调节器 5V- Inverting DC/DC Converter RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
| MAX755CSA+ | 功能描述:直流/直流开关调节器 5V- Inverting DC/DC Converter RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
| MAX755CSA+ | 制造商:Maxim Integrated Products 功能描述:IC INVERTING PWM REGULATOR 8-SOIC 制造商:Maxim Integrated Products 功能描述:IC, INVERTING PWM REGULATOR, 8-SOIC |
发布紧急采购，3分钟左右您将得到回复。