參數(shù)資料
型號(hào)： TDE1890
廠商： 意法半導(dǎo)體
英文描述： 2A High-Side Driver Industrial Intelligent Power Switch(工業(yè)智能功率開(kāi)關(guān),2A高邊驅(qū)動(dòng)器)
中文描述： 甲高邊驅(qū)動(dòng)器工業(yè)智能功率開(kāi)關(guān)（工業(yè)智能功率開(kāi)關(guān)，甲高邊驅(qū)動(dòng)器）
文件頁(yè)數(shù)： 7/12頁(yè)
文件大?。?/td> 111K
代理商： TDE1890
WORST CONDITION POWER DISSIPATION IN
THE ON-STATE
In IPS applications the maximum average power
dissipation occurs when the device stays for a
long time in the ON state. In such a situation the
internal temperature depends on delivered cur-
rent (and related power), thermal characteristics
of the packageand ambient temperature.
At ambient temperature close to upper limit
(+85
°
C) and in the worst operating conditions,it is
possible that the chip temperature could increase
so much to make the thermal shutdown proce-
dure untimelyintervene.
Our aim is to find the maximum current the IPS
can withstand in the ON state without thermal
shutdown intervention, related to ambient tem-
perature. To this end, we should consider the fol-
lowing points:
1) The ON resistance R
DSON
of the output
NDMOS (the real switch) of the device in-
creases withits temperature.
Experimentalresults show that silicon resistiv-
ity increases with temperature at a constant
rate, rising of 60% from 25
°
C to 125
°
C.
The relationship between R
DSON
and tem-
peratureis therefore:
R
DSON
=
R
DSON0
(
1
+
k
)
(
T
j
25
)
where:
T
j
is the silicon temperature in
°
C
R
DSON0
is R
DSON
at T
j
=25
°
C
k is the constantrate (k
=
4.711
10
3
)
(seefig. 4).
2)
In the ON state the power dissipated in the
deviceis due to three contributes:
a) power lost in the switch:
P
out
=
I
out
rent);
2
R
DSON
(I
out
is the outputcur-
b) power due to quiescentcurrent in the ON
state Iq, sunk by the devicein addition to
I
out
: P
q
=
I
q
V
s
(V
s
is the supply voltage);
c) an external LED could be usedto visualize
the switch state (OUTPUT STATUSpin).
Such a LED is driven by an internalcurrent
source (deliveringI
os
) and therefore,if V
os
is
the voltage drop across the LED, the dissi-
pated power is: P
os
=
I
os
(
V
s
V
os
)
.
Thus the total ON state power consumptionis
given by:
P
on
=
P
out
+
P
q
+
P
os
(1)
In the right sideof equation1, the secondand
the third element are constant, while the first
one increases with temperature because
R
DSON
increasesas well.
3) The chip temperature must not exceed
Θ
Lim
in order do not lose the control of the device.
The heat dissipation path is represented by
the thermal resistance of the system device-
ambient (R
th
). In steady state conditions, this
parameter relates the power dissipated P
on
to
the silicon temperature T
j
and the ambient
temperatureT
amb
:
T
j
T
amb
=
P
on
R
th
(2)
From this relationship, the maximum power
P
on
which can be dissipated without exceed-
ing
Θ
Lim at a given ambient temperature
T
amb
is:
P
on
=Θ
Lim
T
amb
R
th
Replacing the expression (1) in this equation
and solving for I
out
, we can find the maximum
current versus ambient temperature relation-
ship:
I
outx
=
√
Θ
Lim
T
amb
R
th
P
q
P
os
where R
DSON
x is R
DSON
at T
j
=
Θ
Lim. Of
course, I
outx
values are top limited by the
maximum operativecurrent I
outx
(2Anominal).
From the expression (2) we can also find the
maximum ambient temperatureT
amb
at which
a given power P
on
can be dissipated:
T
amb
= Θ
Lim
P
on
R th
=
= Θ
Lim
(
I
out
2
R
DSONx
+
P
q
+
P
os
)
R
th
In particular, this relation is useful to find the
maximum ambient temperature T
ambx
whichI
outx
can be delivered:
at
T
ambx
= Θ
Lim
(
I
outx2
R
DSONx
+
+
P
q
+
P
os
)
R
th
(4)
Referring to application circuit in fig. 6, let us con-
sider the worst case:
- The supply voltage is at maximum value of in-
dustrial bus (30V instead of the 24V nominal
value). This means also that I
outx
rises of 25%
(2.5A insteadof 2A).
TDE1890 - TDE1891
7/12
相關(guān)PDF資料
PDF描述
TDE1891 2A High-Side Driver Industrial Intelligent Power Switch(工業(yè)智能功率開(kāi)關(guān),2A高邊驅(qū)動(dòng)器)
TDE1897C 0.5A High-Side Driver Industrial Intelligent Power Switch(0.5A 高邊驅(qū)動(dòng)工業(yè)智能功率開(kāi)關(guān))
TDE1898C 0.5A High-Side Driver Industrial Intelligent Power Switch(0.5A 高邊驅(qū)動(dòng)工業(yè)智能功率開(kāi)關(guān))
TDE1897RFP 0.5A HIGH-SIDE DRIVER INDUSTRIAL INTELLIGENT POWER SWITCH
TDE1898RDP 0.5A HIGH-SIDE DRIVER INDUSTRIAL INTELLIGENT POWER SWITCH
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
TDE1890D 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:2A HIGH-SIDE DRIVER INDUSTRIAL INTELLIGENT POWER SWITCH
TDE1890V 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:2A HIGH-SIDE DRIVER INDUSTRIAL INTELLIGENT POWER SWITCH
TDE1891 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:2A HIGH-SIDE DRIVER INDUSTRIAL INTELLIGENT POWER SWITCH
TDE1891L 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:2A HIGH-SIDE DRIVER INDUSTRIAL INTELLIGENT POWER SWITCH
TDE1891V 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:2A HIGH-SIDE DRIVER INDUSTRIAL INTELLIGENT POWER SWITCH
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