L6751B datasheet(53/58 Pages) STMICROELECTRONICS

53 / 58 page

L6751B

PMBus support (preliminary)

Doc ID 024028 Rev 1

53/58

12.3

Input voltage monitoring (READ_VIN)

The dedicated PMBus command allows the user to monitor input voltage. By connecting the

VIN pin to the input voltage with the recommended resistor values, the L6751B returns the

value of the input voltage measured as a voltage (linear format, N=-4).

The divider needs to be programmed to have 1.24 V on the pin when VIN=15.9375 V.

According to this, RUP=118.5 kΩ and RDOWN=10 kΩ.

Errors in defining the divider lead to monitoring errors accordingly.

Filter VIN pin locally to GND to increase stability of the voltage being measured.

12.4

Duty cycle monitoring (READ_DUTY)

The dedicated PMBus command allows the user to monitor duty cycle for multi-phase with

the aim of calculating input current inexpensively (no need for input current-sense resistors).

By connecting the PHASE pin to the phase1 PHASE pin, the L6751B returns the value of

the duty cycle as a percentage (linear format, N=-2).

The divider needs to be programmed to respect absolute maximum ratings for the pin (7

Vmax). According to this, RUP=5.6 kΩ and RDOWN=470 Ω.

Figure 17.

Device initialization: PMBus controlling Vout

VCC5

VDRV

VIN

UVLO

2mSec POR

UVLO

50uSec

SVI BUS

PMBus

V_SinglePhase

ENVTT (Ignored by ON_OFF_Config setting)

SVRRDY

64uSec

ON-OFF_Config

Operation

V_MultiPhase

VRRDY

64uSec

SVI Packet

Command Rejected

Command ACK but not executed

AM14848v1

L6751B Datasheet(PDF) 53 Page - STMicroelectronics

L6751B Datasheet(HTML) 53 Page - STMicroelectronics

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58

Datasheet Download

Link URL