学习了

WuJin_eOakJ 发表于 2018-4-25 17:56
$ E! |& D9 E, \学习了

8 J% f# z/ z2 b' P/ [2 E# z。。。。。。。学习了哥

学习了

AD9_PCB 发表于 2018-4-24 14:08
感觉没啥区别

$ [( Z' \% T$ D+ w  `2 V3 H从仿真角度看区别还挺大

学习了

感觉没啥区别

czxjuren 发表于 2018-4-24 09:13
) I7 ~$ l: ?4 f" r+ D; t老外分析的很好

+ \- Z( \! F2 f# y3 ]# T; j$ I我感觉不是同一个电路，老外分析的是current mirror。我这个是限流电路

老外分析的很好

超級狗 发表于 2018-4-24 08:50
3 H& d/ F6 ^, ^3 x" C# r4 U2 s洋人的分析！

3 ?) n- Z; S4 l# }The Basic Current Mirror with PNP Transistors

! Y9 A# r' O! _老外的分析是从哪儿能找到呢？求教！
另外 从谷歌找到的网站来看，似乎我帖子里的电路和老外的current mirror还不一样呀。
& O# P* `$ O5 Y8 n8 \* Zcurrent mirror：http://www.play-hookey.com/analog/current_mirrors/current_mirror_pnp.html

洋人的分析！
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/ B+ p" s# n' N) \( ]1 n. JThe Basic Current Mirror with PNP Transistors
6 D: O4 g1 a/ W) a6 \0 D$ [A basic current mirror using PNP transistors. All of the current mirror circuits presented in previous pages in this group have used NPN transistors. This is by no means necessary; as shown to the left, we can easily use PNP transistors to build current mirrors. Every mirror configuration that can be built with NPN transistors can also be built with PNP transistors, and the general behavior, advantages, and disadvantages of each configuration will be the same.
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There are only two differences in using PNP rather than NPN transistors in current mirrors. The first is the obvious fact that the applied voltage polarity must be reversed. The emitters are connected to +V, while the collectors are referenced to a more negative voltage. This can be ground as shown here, or any voltage more negative than +V. In many practical circuits, both positive and negative power supplies are used to maintain balanced voltages, and in such circuits the PNP collector circuits are commonly referenced to -V rather than to ground.

The second factor to be considered is that in an IC, while it is always possible to manufacture both NPN and PNP transistors on the same die, it is not possible to make them the same way or to match their parameters. NPN transistors are made vertically, so the width of the base region can be closely controlled to enable high values of current gain. PNP transistors must be constructed horizontally (known as "lateral PNP transistors"), which means the base region must be wider, so the current gain is necessarily more limited. This does not preclude their use, but it does mean that their lower current gain must be accounted for, and in many cases compensated in some way.
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附上仿真电路
' b' @0 A  T! Q( y/ Z  k9 `. G* y3 C使用Tina V9搭建。