LTC3815_15 Datasheet, PDF (37/42 Pages) Linear Technology – 6A Monolithic Synchronous DC/DC Step-Down Converter with Digital Power System Management

LTC3815
PMBus Command Details
All of the following telemetry registers are initialized to
0x8000 when cycling power, cycling RUN_MSTR pin or
sending a MFS_RESET command. The register will remain
at this value until its first conversion is complete—typically
within 50ms of the initialization event.
READ_V_IN
The READ_V_IN command returns the measured input
voltage, in volts, at the V_IN pin.
This read-only command has two data bytes and is for-
matted as a 16-bit 2’s complement value scaled 4mV/bit.
READ_VOUT
The READ_VOUT command returns the measured output
voltage, in volts as specified by the VOUT_MODE command.
The output voltage is sensed at the VCC_SEN and VSS_SEN
pins.
This read-only command has two data bytes and is format-
ted as a 16-bit 2’s complement value scaled 0.5mV/bit.
READ_IIN
The READ_IIN command returns the input current in
Amperes. The input current is derived from READ_IOUT
current and the measured duty cycle with an offset term
added to account for quiescent current and driver current.
For accurate values at light load currents the part must be
in continuous conduction mode.
This register is reset to 0x8000 is standby mode when
the drivers are off.
This read-only command has two data bytes and is format-
ted as a 16-bit 2’s complement value scaled 10mA/bit.
READ_IOUT
The READ_IOUT command returns the average output
current in amperes. The LTC3815 senses and measures
the currents through its top and bottom power switches
to derive I_OUT current. For accurate values at light load
currents the part must be in continuous conduction mode.
This register is reset to 0x8000 is standby mode when
the drivers are off.
This read-only command has two data bytes and is format-
ted as a 16-bit 2’s complement value scaled 10mA/bit.
READ_TEMPERATURE_1
The READ_TEMPERATURE_1 command returns the inter-
nal die temperature, in degrees Celsius, of the LTC3815.
This read-only command has two data bytes and is for-
matted as a 16-bit 2’s complement value scaled 1°C/bit.
MFR_VOUT_PEAK
The MFR_VOUT_PEAK command reports the highest
voltage, in volts, reported by the READ_VOUT measure-
ment.
To clear the peak value and restart the peak monitor,
use the MFS_CLEAR_PEAKS command or write to the
MFR_VOUT_PEAK. When writing to MFR_VOUT_PEAK,
zero, one or two data bytes are accepted but the data is
ignored.
This read-only command has two data bytes and is format-
ted as a 16-bit 2’s complement value scaled 0.5mV/bit.
MFR_V_IN_PEAK
The MFR_V_IN_PEAK command reports the highest voltage,
in volts, reported by the READ_V_IN measurement.
To clear the peak value and restart the peak monitor,
use the MFS_CLEAR_PEAKS command or write to the
MFR_V_IN_PEAK. When writing to MFR_V_IN_PEAK zero,
one or two data bytes are accepted but the data is ignored.
This read-only command has two data bytes and is for-
matted as a 16-bit 2’s complement value scaled 4mV/bit.
MFR_TEMPERATURE_1_PEAK
The MFR_TEMPERATURE_1_PEAK command reports the
highest temperature, in degrees Celsius, reported by the
READ_TEMPERATURE_1 measurement.
To clear the peak value and restart the peak monitor,
use the MFS_CLEAR_PEAKS command or write to the
MFR_TEMPERATURE_1_PEAK. When writing to MFR_
TEMPERATURE_1__PEAK zero, one or two data bytes
are accepted but the data is ignored.
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