1. 图腾柱:
图腾柱由上拉和下拉晶体管以及二极管电阻组成。图腾柱以高速运行。使用的两个晶体管驱动一个高输出,另一个在集成电路中将其拉低。
2. 集电极开路:
在集电极开路的情况下,我们只有下拉晶体管并且它以低速运行。集电极开路就像一个开关,在集成电路中它要么连接要么断开。
图腾柱和开放式收藏家的区别:
Totem Pole | Open Collector |
---|---|
Output stage of totem pole circuit consists of pull-up transistor, diode resistor and a pull down transistor. | Output stage of Open collector consists of only pull down transistor. |
Outputs of the two gates cannot be tied up together | output of two gates can be tied together using a wired AND method. |
Operating speed of totem pole circuit is high as compared to open collector | Operating speed is low for open collector |
External pull up resistor is not required in case of totem pole | External pull up resistor is required for proper operation of gate in open collectors |
Due to the presence of pull up transistor, power dissipation is low in totem pole circuits | In cae of open collector, power dissipation is high due to the current flowing trough the extra resistors. |