ABB 5SHY3545L0014 使用外部分流器来产生
几乎所有SCR都表现出一定程度的关断增益。
在阳极电流的正常值下，负栅极电流
不会对内部反馈产生足够的影响
设备的环路，从而导致
阳极电流。然而，它确实在
低阳极电流水平；它可以通过
使用它来修改某些设备参数。明确地
可以减少关断时间，并且可以减少保持电流
增加。减少关闭时间并增加保持时间
电流在逆变器或
全波相位控制电路，其中电感为
目前
当然，负栅极电流可能由
使用外部偏置电源。它也可能由
利用在传导过程中
栅极相对于阴极是正的，并且提供
外部传导路径，如栅极到阴极
电阻器。所有ON半导体SCR，例外
敏感门器件，采用内置
栅极-阴极分流，产生与
负栅极电流。特性的进一步变化
可以通过使用外部分流器来产生。调车
不会产生与
负偏置，因为负栅极电流，甚至
在外部短路的情况下，受到横向短路的限制
基层的电阻。使用外部负极时
偏置电流必须受到限制，并且必须小心
避免将栅极驱动到雪崩区域。
上未显示负栅极电流的影响
设备规格表。图3.13中的曲线
表示对多个SCR进行的测量，以及
因此不应被视为规格限制。他们
然而，确实显示出了明确的趋势。例如，所有
SCR显示关闭时间改善了约
通过使用负偏置直到没有
获得了进一步的显著改善。这个
使用外部分流器增加保持电流
电阻器的范围通常在5%和75%之间，
而在负偏差的情况下，改善的范围
通常在打开闸门值的2−1/2到7倍之间。
请注意，保持电流曲线是标准化的
参考打开的门值。
Almost all SCR’s exhibit some degree of turn−off gain.
At normal values of anode current, negative gate current
will not have sufficient effect upon the internal feedback
loop of the device to cause any significant change in
anode current. However, it does have a marked effect at
low anode current levels; it can be put to advantage by
using it to modify certain device parameters. Specifically,
turn−off time may be reduced and hold current may be
increased. Reduction of turn−off time and increase of hold
current are useful in such circuits as inverters or in
full−wave phase control circuits in which inductance is
present.
Negative gate current may, of course, be produced by
use of an external bias supply. It may also be produced by
taking advantage of the fact that during conduction the
gate is positive with respect to the cathode and providing
an external conduction path such as a gate−to−cathode
resistor. All ON Semiconductor SCR’s, with the exception
of sensitive gate devices, are constructed with a built in
gate−to−cathode shunt, which produces the same effect as
negative gate current. Further change in characteristics
can be produced by use of an external shunt. Shunting
does not produce as much of a change in characteristics as
does negative bias, since the negative gate current, even
with an external short circuit, is limited by the lateral
resistance of the base layer. When using external negative
bias the current must be limited, and care must be taken to
avoid driving the gate into the avalanche region.
The effects of negative gate current are not shown on
the device specification sheets. The curves in Figure 3.13
represent measurements made on a number of SCRs, and
should therefore not be considered as spec limits. They
do, however, show definite trends. For example, all of the
SCRs showed an improvement in turn−off time of about
one−third by using negative bias up to the point where no
further significant improvement was obtained. The
increase in hold current by use of an external shunt
resistor ranged typically between 5 and 75 percent,
whereas with negative bias, the range of improvement ran
typically between 2−1/2 and 7 times the open gate value.
Note that the holding current curves are normalized and are
referred to the open gate value.
