PM6641 datasheet(32/47 Pages) STMICROELECTRONICS

部件名	PM6641

功能描述	Monolithic VR for chipset and DDR2/3 supply for ultra-mobile PC (UMPC) applications

PDF	47 Pages

Scroll/Zoom	100%

制造商	STMICROELECTRONICS [STMicroelectronics]

网页	http://www.st.com

标志

32 / 47 page

Device description

PM6641

32/47

where VREF = 0.9V is the constant voltage forced by CSNS pin, RCSNS [Ω] is the resistor

connected between CSNS and AGND,

α is the coefficient that collects the MOS current

sensing scaling factor and other design parameters and ICL is the peak current limit [A].

The following table resumes values for all the switching regulators.

The following graph is a plot of the switching regulators peak current limit, increasing the

RCSNS resistor:

Figure 33. SW regulators peak current limit

From the previous plot and table it’s clear that the three regulators peak current limits are

scaled; by changing the RCSNS external resistor the three peak current limits all change.

Table 11. Typical SW regulators values

SW regulator

1.8V

333x10e3

1.5V

222x10e3

1.05V

278x10e3

0.00

1.00

2.00

3.00

4.00

5.00

6.00

7.00

100

120

140

160

180

Rcsns [kOhm]

CL_1V8

CL_1V5

CL_1V05