L7986 datasheet(24/43 Pages) STMICROELECTRONICS

部件名	L7986

功能描述	3 A step-down switching regulator

PDF	43 Pages

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制造商	STMICROELECTRONICS [STMicroelectronics]

网页	http://www.st.com

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24 / 43 page

Application information

L7986

24/43

DocID022450 Rev 6

6.4.2

Type II compensation network

If the equivalent series resistance (ESR) of the output capacitor introduces a zero with

a frequency lower than the desired bandwidth (that is: 2

ESR COUT > 1 / BW), this zero

helps stabilize the loop. Electrolytic capacitors show non-negligible ESR (> 30 m

), so with

this kind of output capacitor the type II network combined with the zero of the ESR allows to

stabilize the loop.

In Figure 13 the type II network is shown.

Figure 13. Type II compensation network

The singularities of the network are:

Equation 28

fZ1

 R

4 C4



------------------------------

fP0 0

fP1

 R

C4 C5



C4 C5

--------------------



--------------------------------------------



L7986 数据表(PDF) 24 Page - STMicroelectronics