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參數(shù)資料
| 型號： | LP55271TL |
| 廠商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分類： | 顯示驅(qū)動器 |
| 英文描述： | Tiny LED Driver for Camera Flash and 4 LEDs with I2C Programmability, Connectivity Test and Audio Synchronization |
| 中文描述： | LED DISPLAY DRIVER, PBGA30 |
| 封裝： | 2.5 X 3 MM, 0.60 MM HEIGHT, BGA-30 |
| 文件頁數(shù)： | 7/21頁 |
| 文件大小： | 826K |
| 代理商： | LP55271TL |
Magnetic Boost DC/DC Converter
The LP55271 boost DC/DC converter generates a 4.00 –
5.40V output voltage to drive the LEDs from a single Li-Ion
battery (3.0V to 4.5V). The output voltage is controlled with a
4-bit register in 8 steps. The converter is a magnetic switch-
ing PWM mode DC/DC converter with a current limit. The
converter has 2.0 MHz / 1.0 MHz selectable switching fre-
quency operation, when the timing resistor RT is 82 k
.
The LP55271 boost converter uses pulse-skipping elimina-
tion method to stabilize the noise spectrum. Even with light
load or no load a minimum length current pulse is fed to the
inductor. An internal active load is used to remove the ex-
cess charge from the output capacitor when needed.
The topology of the magnetic boost converter is called CPM
control, current programmed mode, where the inductor cur-
rent is measured and controlled with the feedback. The
output voltage control changes the resistor divider in the
feedback loop.
The following figure shows the boost topology with the pro-
tection circuitry. Four different protection schemes are imple-
mented:
1.
Over voltage protection, limits the maximum output volt-
age.
— Keeps the output below breakdown voltage.
— Prevents boost operation if battery voltage is much
higher than desired output.
2.
Over current protection, limits the maximum inductor
current.
— Voltage over switching NMOS is monitored; too high
voltages turn the switch off.
3.
Feedback (FB) protection for no connection.
4.
Duty cycle limiting, done with digital control.
20202477
Boost Converter Topology
L
www.national.com
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相關(guān)PDF資料 |
PDF描述 |
|---|---|
| LP55271TLX | Tiny LED Driver for Camera Flash and 4 LEDs with I2C Programmability, Connectivity Test and Audio Synchronization |
| LP55271 | Tiny LED Driver for Camera Flash and 4 LEDs with I2C Programmability, Connectivity Test and Audio Synchronization |
| LP5527 | Tiny LED Driver for Camera Flash and 4 LEDs with I2C Programmability, Connectivity Test and Audio Synchronization |
| LP5527TL | Tiny LED Driver for Camera Flash and 4 LEDs with I2C Programmability, Connectivity Test and Audio Synchronization |
| LP5527TLX | Tiny LED Driver for Camera Flash and 4 LEDs with I2C Programmability, Connectivity Test and Audio Synchronization |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LP55271TL/NOPB | 功能描述:LED照明驅(qū)動器 RoHS:否 制造商:STMicroelectronics 輸入電壓:11.5 V to 23 V 工作頻率: 最大電源電流:1.7 mA 輸出電流: 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SO-16N |
| LP55271TLX | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:Tiny LED Driver for Camera Flash and 4 LEDs with I2C Programmability, Connectivity Test and Audio Synchronization |
| LP55271TLX/NOPB | 功能描述:LED照明驅(qū)動器 RoHS:否 制造商:STMicroelectronics 輸入電壓:11.5 V to 23 V 工作頻率: 最大電源電流:1.7 mA 輸出電流: 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SO-16N |
| LP5527TL | 制造商:Texas Instruments 功能描述:DRIVER FLASH LED I2C POWERWISE |
| LP5527TL/NOPB | 功能描述:LED照明驅(qū)動器 RoHS:否 制造商:STMicroelectronics 輸入電壓:11.5 V to 23 V 工作頻率: 最大電源電流:1.7 mA 輸出電流: 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SO-16N |
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