A7985A datasheet(25/44 Pages) STMICROELECTRONICS

Numer części	A7985A

Szczegółowy opis	2 A step-down switching regulator for automotive applications

PDF	44 Pages

Scroll/Zoom	100%

Producent	STMICROELECTRONICS [STMicroelectronics]

Strona internetowa	http://www.st.com

Logo

25 / 44 page

DocID023128 Rev 5

25/44

A7985A

Application information

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 not-negligible ESR (> 30 m

), so with

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

the stabilizing of the loop.

In Figure 13 the Type II network is shown.

Figure 13. Type II compensation network

The singularities of the network are:

Equation 30

fZ1

 R

4 C4



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

fP0 0

fP1

 R

C4 C5



C4 C5

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



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



A7985A Arkusz danych(PDF) 25 Page - STMicroelectronics