L6717ATR datasheet(33/57 Pages) STMICROELECTRONICS

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L6717A

Power manager I2C

6.2

Dynamic phase management (DPM)

Dynamic phase management allows to adjust the number of working phases according to

the delivered current still maintaining the benefits of the multiphase regulation.

Phase number is reduced by monitoring the voltage level across ILIM pin: L6717A reduces

the number of working phase according to the strategy defined by the PSI_A flag when the

voltage across ILIM pin is lower than V

DPM

. In the same way, phase number is restored to

the original value when the voltage across ILIM pin exceeds V

DPM

threshold is selected through the DPMTH command. See

Section 6.1.

The current at which the transition happens (I

DPM

) can be estimated as:

DPM

thresholds are defined as a percentage of the voltage on ILIM pin corresponding to

the thermal design current of the application.

1.8 V on ILIM pin corresponds to 100% of the load and DPM threshold are defined as a

percentage of 1.8 V (see

Table 18 for details).

An hysteresis (5 % typ) is provided for each threshold in order to avoid multiple DPM actions

triggering in steady load conditions.

DPM is enabled by default; to disable it proper command must be sent through the power

manager I

C bus. Once enabled, L6717A starts monitoring the ILIM voltage for phase

Table 17. Power management flags

Data Stream bit

Flag

Description

[1:3]

n/a

000b.

[4:5]

DPMTH

DPM threshold. Allow to define 4 different values for V

DPM

See

Section 6.2 for code/thresholds correspondence.

[6]

PSI_A

0b (default): IC working in single phase when PSI_L asserted.

1b:IC working in two phase when PSI_L asserted.

[7]

PSI_EN

0b (default): PSI_L flag in SVI ignored.

1b: PSI_L flag in SVI monitored and phase dropping enabled

according to PSI_A.

[8]

DPM_ON

0b: DPM disabled.

1b (default): DPM enabled.

Table 18. VDPM thresholds (ILIM rising - 5% hyst)

CODE

1/2 phase transition

2/3 phase transition

3/4 phase transition

00 (default)

15%

25%

40%

20%

30%

45%

25%

35%

50%

30%

40%

55%

DP M

DPM

ILIM

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

DC R

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

⋅

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