LP3972 datasheet(51/59 Pages) NSC

51 / 59 page

LP3972 Controls (Continued)

THERMAL MANAGEMENT

Application: There is a mode wherein all 6 comparators

(flags) can be turned on via the “enallflags” control register

bit. This mode allows the user to interrogate the device or

system temperature under the set operating conditions.

Thus, the rate of temperature change can also be estimated.

The system may then negotiate for speed and power trade

off, or deploy cooling maneuvers to optimize system perfor-

mance. The “enallflags” bit needs enabled only when the

“bct<2:0> bits are read to conserve power.

Note: The thermal management flags have been verified

functional. Presently these registers are accessible by fac-

tory only. If there is a demand for this function, the relevant

bank; the temperature range and resolution of these flags,

might also be refined/redefined.

THERMAL WARNING

2 of 6 low power comparators, each consumes less than 1

µA, are always enabled to operate the “T=125˚C warning

flag with hysteresis. This allows continuous monitoring of a

thermal-warning flag feature with very low power consump-

tion.

LP3972 THERMAL FLAGS FUNCTIONAL DIAGRAM,

DATA FROM INITIAL SILICON

The following functions are extra features from the thermal

shutdown circuit:

20207646

LP3972 数据表(PDF) 51 Page - National Semiconductor (TI)