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參數(shù)資料
| 型號(hào)： | MAX1999EEI |
| 廠商： | MAXIM INTEGRATED PRODUCTS INC |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | High-Efficiency, Quad Output, Main Power- Supply Controllers for Notebook Computers |
| 中文描述： | DUAL SWITCHING CONTROLLER, 500 kHz SWITCHING FREQ-MAX, PDSO28 |
| 封裝： | 0.150 INCH, 0.025 INCH PITCH, QSOP-28 |
| 文件頁數(shù)： | 21/32頁 |
| 文件大?。?/td> | 497K |
| 代理商： | MAX1999EEI |
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M
High-Effic ienc y, Quad Output, Main Power-
S upply Controllers for Notebook Computers
______________________________________________________________________________________
21
A negative current limit prevents excessive reverse
inductor currents when V
OUT
sinks current. The nega-
tive current-limit threshold is set to approximately 120%
of the positive current limit and therefore tracks the
positive current limit when ILIM_ is adjusted.
The current-limit threshold is adjusted with an external
voltage-divider at ILIM_. The current-limit threshold
adjustment range is from 50mV to 300mV. In the
adjustable mode, the current-limit threshold voltage is
precisely 1/10th the voltage at ILIM_. The threshold
defaults to 100mV when ILIM_ is connected to V
CC
.
The logic threshold for switchover to the 100mV default
value is approximately V
CC
- 1V.
Carefully observe the PC board layout guidelines to
ensure that noise and DC errors do not corrupt the cur-
rent-sense signals at CS_. Mount or place the device
close to the synchronous rectifier or sense resistor
(whichever is used) with short, direct traces, making a
Kelvin sense connection to the sense resistor. The cur-
rent-sense accuracy of Figure 8 is degraded if the
Schottky diode conducts during the synchronous recti-
fier on-time. To ensure that all current passes through
the sense resistor, connect the Schottky diode in paral-
lel with only the synchronous recifier (Figure 9) if the
voltage drop across the synchronous rectifier and
sense resistor exceeds the Schottky diode’s forward
voltage. Note that at high temperatures, the on-resis-
tance of the synchronous rectifier increases, and the
forward voltage of the Schottky diode decreases.
MOS FET Gate Drivers (DH_, DL_)
The DH_ and DL_ gate drivers sink 2.0A and 3.3A
respectively of gate drive, ensuring robust gate drive for
high-current applications. The DH_ floating high-side
MOSFET drivers are powered by diode-capacitor charge
pumps at BST_. The DL_ synchronous-rectifier drivers are
powered by LDO5.
The internal pulldown transistors that drive DL_ low
have a 0.6
typical on-resistance. These low on-resis-
tance pulldown transistors prevent DL_ from being
pulled up during the fast rise time of the inductor nodes
due to capacitive coupling from the drain to the gate of
the low-side synchronous-rectifier MOSFETs. However,
for high-current applications, some combinations of
high- and low-side MOSFETS may cause excessive
gate-drain coupling, which leads to poor efficiency and
EMI-producing shoot-through currents. Adding a resis-
tor in series with BST_ increases the turn-on time of the
high-side MOSFETs at the expense of efficiency, without
degrading the turn-off time (Figure 10).
MAX1777
MAX1977
V+
DH_
DL_
CS_
LX_
OUT_
Figure 8. Current Sensing Using Sense Resistor
(MAX1777/MAX1977)
MAX1777
MAX1977
V+
DH_
DL_
CS_
LX_
OUT_
Figure 9. More Accurate Current Sensing with Adjusted
Schottky Connection
MAX1777
MAX1977
MAX1999
5V
V
IN
10
BST
DH
LX
Figure 10. Reducing the Switching-Node Rise Time
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| MAX1999EEI+ | 功能描述:DC/DC 開關(guān)控制器 Quad Out Main Power Supply Controller RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開關(guān)頻率: 輸出電壓:1.215 V to 80 V 輸出電流:3.5 A 輸出端數(shù)量:1 最大工作溫度:+ 125 C 安裝風(fēng)格: 封裝 / 箱體:CPAK |
| MAX1999EEI+T | 功能描述:DC/DC 開關(guān)控制器 Quad Out Main Power Supply Controller RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開關(guān)頻率: 輸出電壓:1.215 V to 80 V 輸出電流:3.5 A 輸出端數(shù)量:1 最大工作溫度:+ 125 C 安裝風(fēng)格: 封裝 / 箱體:CPAK |
| MAX1999EEI-T | 功能描述:DC/DC 開關(guān)控制器 RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開關(guān)頻率: 輸出電壓:1.215 V to 80 V 輸出電流:3.5 A 輸出端數(shù)量:1 最大工作溫度:+ 125 C 安裝風(fēng)格: 封裝 / 箱體:CPAK |
| MAX1999EVKIT | 功能描述:DC/DC 開關(guān)控制器 Evaluation Kit for the MAX1777 MAX1977 MAX1999 RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開關(guān)頻率: 輸出電壓:1.215 V to 80 V 輸出電流:3.5 A 輸出端數(shù)量:1 最大工作溫度:+ 125 C 安裝風(fēng)格: 封裝 / 箱體:CPAK |
| MAX199ACAI | 功能描述:模數(shù)轉(zhuǎn)換器 - ADC RoHS:否 制造商:Texas Instruments 通道數(shù)量:2 結(jié)構(gòu):Sigma-Delta 轉(zhuǎn)換速率:125 SPs to 8 KSPs 分辨率:24 bit 輸入類型:Differential 信噪比:107 dB 接口類型:SPI 工作電源電壓:1.7 V to 3.6 V, 2.7 V to 5.25 V 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VQFN-32 |
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