參數(shù)資料
型號(hào)： L6924U
廠商： STMICROELECTRONICS
元件分類： 電源管理
英文描述： POWER SUPPLY SUPPORT CKT, QCC16
封裝： 3 X 3 MM, ROHS COMPLIANT, VFQFP-16
文件頁(yè)數(shù)： 27/38頁(yè)
文件大?。?/td> 598K
代理商： L6924U
L6924U
Application idea: dual input management with AC priority
33/38
10
Application idea: dual input management with AC
priority
In some applications both AC adapter and USB power source may be available.
shows a possible schematic which provides the possibility to manage two power
sources (AC/USB) and gives the priority to AC adapter in case both sources are available at
the same time.
For simplicity, only the relevant parts of L6924U for this application have been indicated.
If only the AC adapter is available, since the gates of Q1 and Q2 are connected to AC, both
MOSFETs are off. The AC adapter voltage is provided to the pin VIN through the diode D1.
The voltage of the pin VIN is:
A correct choice of this diode is important to limit Vdiode and keeping VIN as close as
possible to AC.
In this condition the pin MODE is low. This sets the L6924U in AC mode and the battery is
charged with the current programmed by RAC.
When only the USB power source is available, both Q1 and Q2 switch on and the pin VIN is
connected to USB.
The pin MODE is connected to the drains of Q1 and Q2 and is high. Therefore USB mode
for L6924U is selected and the battery is charged with a current in accordance with the
resistor connected to the pin IUSB (RUSB).
The voltage of the pin VIN is given by:
The voltage drop across the MOSFETs must be kept as low as possible to avoid reducing
too much the voltage of the pin VIN.
When both sources are present, this circuit gives the priority to the AC adapter. In fact, for
VAC ≥ 5 V, surely both Q1 and Q2 are off and VIN is connected to the AC adapter through
D1. The pin MODE is kept low and L6924U is set to AC mode.
The use of two P-channel MOSFETs connected as shown in Figure 1 is particularly useful
in this case because they remove any path between the two power sources.
diode
AC
IN
V
=
(
)
USB
2
Q
_
DSon
1
Q
_
DSon
USB
IN
I
R
V
+
=
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
L6924U013TR 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:USB compatible battery charger system with integrated power switch for Li-Ion/Li-Polymer
L6924UTR 功能描述:電池管理 Battery Charger USB Compatible RoHS:否 制造商:Texas Instruments 電池類型:Li-Ion 輸出電壓:5 V 輸出電流:4.5 A 工作電源電壓:3.9 V to 17 V 最大工作溫度:+ 85 C 最小工作溫度:- 40 C 封裝 / 箱體:VQFN-24 封裝:Reel
L6925 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:HIGH EFFICIENCY MONOLITHIC SYNCHRONOUS STEP DOWN REGULATOR
L6925013TR 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:HIGH EFFICIENCY MONOLITHIC SYNCHRONOUS STEP DOWN REGULATOR
L6925D 功能描述:直流/直流開關(guān)調(diào)節(jié)器 Synchronous Step-Dwn RoHS:否 制造商:International Rectifier 最大輸入電壓:21 V 開關(guān)頻率:1.5 MHz 輸出電壓:0.5 V to 0.86 V 輸出電流:4 A 輸出端數(shù)量: 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:PQFN 4 x 5
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