- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄361035 > LM9061N (NATIONAL SEMICONDUCTOR CORP) Power MOSFET Driver with Lossless Protection PDF資料下載
參數(shù)資料
| 型號(hào)： | LM9061N |
| 廠商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分類： | MOSFETs |
| 英文描述： | Power MOSFET Driver with Lossless Protection |
| 中文描述： | BUF OR INV BASED MOSFET DRIVER, PDIP8 |
| 封裝： | DIP-8 |
| 文件頁數(shù)： | 8/14頁 |
| 文件大?。?/td> | 234K |
| 代理商： | LM9061N |
Application Hints
(Continued)
To protect the MOSFET from exceeding its maximum junc-
tion temperature rating, the power dissipation needs to be
limited. The maximum power dissipation allowed (derated
for temperature) and the maximum drain to source ON re-
sistance, R
DS(ON)
, with both at the maximum operating am-
bient temperature, needs to be determined. When switched
ON the power dissipation in the MOSFET will be:
P
DISS
e
V
DS2
R
DS(ON)
The V
DS
voltage to limit the maximum power dissipation is
therefore:
V
DS (MAX)
e
P
D (MAX)
c
R
DS(ON) (MAX)
With this restriction the actual load current and power dissi-
pation obtained will be a direct function of the actual
R
DS(ON)
of the MOSFET at any particular ambient tempera-
ture but the junction temperature of the power device will
never exceed its rated maximum.
To limit the maximum load current requires an estimate of
the minimum R
DS(ON)
of the MOSFET (the minimum
R
DS(ON)
of discrete MOSFETs is rarely specified) over the
required operating temperature range.
The maximum current to the load will be:
I
LOAD (MAX)
e
V
DS
R
DS(ON) (MIN)
The maximum junction temperature of the MOSFET and/or
the maximum current to the load can be limited by monitor-
ing and setting a maximum operational value for the drain to
source voltage drop, V
DS
. In addition, in the event that the
load is inadvertently shorted to ground, the power device
will automatically be turned-OFF.
In all cases, should the MOSFET be switched OFF by the
built in protection comparator, the output sink current is
switched to only 10
m
A to gradually turn OFF the power
device.
Figure 3 illustrates how the threshold voltage for the internal
protection comparator is established.
Two resistors connect the drain and source of the MOSFET
to the LM9061. The Sense input, pin 1, monitors the source
voltage while the Threshold input, pin 2, is connected to the
drain, which is also connected to the constant load power
supply. Both of these inputs are the two inputs to the protec-
tion comparator. Should the voltage at the sense input ever
drop below the voltage at the threshold input, the protection
comparator output goes high and initiates an automatic
latch-OFF function to protect the power device. Therefore
the switching threshold voltage of the comparator directly
controls the maximum V
DS
allowed across the MOSFET
while conducting load current.
The threshold voltage is set by the voltage drop across re-
sistor R
THRESHOLD
. A reference current is fixed by a resis-
tor to ground at I
REF
, pin 6. To precisely regulate the refer-
ence current over temperature, a stable band gap reference
voltage is provided to bias a constant current sink. The ref-
erence current is set by:
I
REF
e
V
REF
R
REF
The reference current sink output is internally connected to
the threshold pin. I
REF
then flows from the load supply
through R
THRESHOLD
. The fixed voltage drop across
R
THRESHOLD
is approximately equal to the maximum value
of V
DS
across the MOSFET before the protection compara-
tor trips.
It is important to note that the programmed reference cur-
rent serves a multiple purpose as it is used internally for
biasing and also has a direct effect on the internal charge
pump switching frequency. The design of the LM9061 is
optimized for a reference current of approximately 80
m
A,
set with a 15.4 k
X
g
1% resistor for R
REF
. To obtain the
guaranteed performance characteristics it is recommended
that a 15.4 k
X
resistor be used for R
REF
.
The protection comparator is configured such that during
normal operation, when the output of the comparator is low,
the differential input stage of the comparator is switched in
TL/H/12317–11
FIGURE 3. Protection Comparator Biasing
8
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| LM9070 | Low-Dropout System Voltage Regulator with Keep-Alive ON/OFF Control |
| LM9070M | Low-Dropout System Voltage Regulator with Keep-Alive ON/OFF Control |
| LM9070S | Low-Dropout System Voltage Regulator with Keep-Alive ON/OFF Control |
| LM9070T | Low-Dropout System Voltage Regulator with Keep-Alive ON/OFF Control |
| LM9071 | Low-Dropout System Voltage Regulator with Delayed Reset |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LM9070 | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:Low-Dropout System Voltage Regulator with Keep-Alive ON/OFF Control |
| LM9070M | 制造商:Rochester Electronics LLC 功能描述:5V LDO REG W/ KEEP ALIVE - Bulk |
| LM9070S | 功能描述:低壓差穩(wěn)壓器 - LDO RoHS:否 制造商:Texas Instruments 最大輸入電壓:36 V 輸出電壓:1.4 V to 20.5 V 回動(dòng)電壓（最大值）:307 mV 輸出電流:1 A 負(fù)載調(diào)節(jié):0.3 % 輸出端數(shù)量: 輸出類型:Fixed 最大工作溫度:+ 125 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VQFN-20 |
| LM9070S/NOPB | 功能描述:低壓差穩(wěn)壓器 - LDO RoHS:否 制造商:Texas Instruments 最大輸入電壓:36 V 輸出電壓:1.4 V to 20.5 V 回動(dòng)電壓（最大值）:307 mV 輸出電流:1 A 負(fù)載調(diào)節(jié):0.3 % 輸出端數(shù)量: 輸出類型:Fixed 最大工作溫度:+ 125 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VQFN-20 |
| LM9070SX | 功能描述:低壓差穩(wěn)壓器 - LDO RoHS:否 制造商:Texas Instruments 最大輸入電壓:36 V 輸出電壓:1.4 V to 20.5 V 回動(dòng)電壓（最大值）:307 mV 輸出電流:1 A 負(fù)載調(diào)節(jié):0.3 % 輸出端數(shù)量: 輸出類型:Fixed 最大工作溫度:+ 125 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VQFN-20 |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。