參數(shù)資料
型號: E-L6917BD
廠商: STMICROELECTRONICS
元件分類: 穩(wěn)壓器
英文描述: SWITCHING CONTROLLER, 600 kHz SWITCHING FREQ-MAX, PDSO28
封裝: ROHS COMPLIANT, SO-28
文件頁數(shù): 3/33頁
文件大小: 465K
代理商: E-L6917BD
11/33
L6917B
which the low-side mosfet is on (OFF Time). During this time, the reaction keeps the pin ISENx and PGNDSx
at the same voltage while during the time in which the reading circuitry is off, an internal clamp keeps these two
pins at the same voltage sinking from the ISENx pin the necessary current.
The proprietary current reading circuit allows a very precise and high bandwidth reading for both positive and
negative current. This circuit reproduces the current flowing through the sensing element using a high speed
Track & Hold transconductance amplifier. In particular, it reads the current during the second half of the OFF
time reducing noise injection into the device due to the mosfet turn-on (See fig. 4). Track time must be at least
200ns to make proper reading of the delivered current.
Figure 4. Current Reading Timing (Left) and Circuit (Right)
This circuit sources a constant 50
A current from the PGNDSx pin and keeps the pins ISENx and PGNDSx at
the same voltage. Referring to figure 4, the current that flows in the ISENx pin is then given by the following
equation:
Where RSENSE is an external sense resistor or the rds,on of the low side mosfet and Rg is the transconductance
resistor used between ISENx and PGNDSx pins toward the reading points; IPHASE is the current carried by each
phase and, in particular, the current measured in the middle of the oscillator period
The current information reproduced internally is represented by the second term of the previous equation as
follow:
Since the current is read in differential mode, also negative current information is kept; this allow the device to
check for dangerous returning current between the two phases assuring the complete equalization between the
phase’s currents.
From the current information of each phase, information about the total current delivered (IFB =IINFO1 +IINFO2)
and the average current for each phase (IAVG =(IINFO1 +IINFO2)/2 ) is taken. IINFOX is then compared to IAVG
to give the correction to the PWM output in order to equalize the current carried by the two phases.
The transconductance resistor Rg has to be designed in order to have current information of 25
A per phase
at full nominal load; the over current intervention threshold is set at 140% of the nominal (IINFOx = 35
A).
According to the above relationship, the limiting current (ILIM) for each phase, which has to be placed at one half
of the total delivered maximum current, results:
An over current is detected when the current flowing into the sense element is greater than 140% of the nominal
R
SENSE
Rg
50
A
IISENx
I
PHASE
Rg
LGATEX
ISENX
PGNDSX
ILS1
ILS2
Track & Hold
Total current
information
I
ISENx
50
A
R
SENSE IPHASE
R
g
----------------------------------------------
+
50
AI
INF Ox
+
==
I
INF O x
R
SENSE IPH ASE
R
g
----------------------------------------------
=
I
LIM
35
ARg
R
SENSE
---------------------------
=
Rg
I
LIM
R
SE N S E
35
A
-------------------------------------
=
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E-L6917BDTR 功能描述:DC/DC 開關(guān)控制器 Prog Dual-Phase Cont 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
E-L6919E 功能描述:電流型 PWM 控制器 5-Bit Dual Ph Contlr RoHS:否 制造商:Texas Instruments 開關(guān)頻率:27 KHz 上升時間: 下降時間: 工作電源電壓:6 V to 15 V 工作電源電流:1.5 mA 輸出端數(shù)量:1 最大工作溫度:+ 105 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:TSSOP-14
E-L6919ETR 功能描述:電流型 PWM 控制器 5-Bit Dual Ph Contlr RoHS:否 制造商:Texas Instruments 開關(guān)頻率:27 KHz 上升時間: 下降時間: 工作電源電壓:6 V to 15 V 工作電源電流:1.5 mA 輸出端數(shù)量:1 最大工作溫度:+ 105 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:TSSOP-14
E-L6920D 功能描述:直流/直流開關(guān)轉(zhuǎn)換器 0.6 to 5.5V Step-Up RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開關(guān)頻率:1.5 MHz 輸出電壓:4.6 V 輸出電流:250 mA 輸出端數(shù)量:2 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT
E-L6920DTR 功能描述:直流/直流開關(guān)轉(zhuǎn)換器 0.6 to 5.5V Step-Up RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開關(guān)頻率:1.5 MHz 輸出電壓:4.6 V 輸出電流:250 mA 輸出端數(shù)量:2 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT