LTC2978C View Datasheet(PDF) - Linear Technology
Part Name
Description
MFG CO.
'LTC2978C' PDF : 64 Pages View PDF
LTC2978
PMBus Command Description
STATUS_WORD:
The STATUS_WORD command returns two bytes of information with a summary of the unit’s fault condition. Based on
the information in these bytes, the host can get more information by reading the appropriate detailed status register.
The low byte of the STATUS_WORD is the same register as the STATUS_BYTE command.
STATUS_WORD Data Contents
BIT(S) SYMBOL
b[15] Status_word_vout
b[14] Status_word_iout
b[13] Status_word_input
b[12] Status_word_mfr
b[11] Status_word_power_not_good
b[10] Status_word_fans
b[9] Status_word_other
b[8] Status_word_unknown
b[7] Status_word_busy
b[6] Status_word_off
b[5] Status_word_vout_ov
b[4] Status_word_iout_oc
b[3] Status_word_vin_uv
b[2] Status_word_temp
b[1] Status_word_cml
b[0] Status_word_high_byte
OPERATION
An output voltage fault or warning has occurred. See STATUS_VOUT.
Not supported. Always returns 0.
An input voltage fault or warning has occurred. See STATUS_INPUT.
A manufacturer specific fault has occurred. See STATUS_MFR_SPECIFIC.
The PWRGD pin, if enabled is negated. Power is not good.
Not supported. Always returns 0.
Not supported. Always returns 0.
Not supported. Always returns 0.
Device busy when PMBus command received. See OPERATION: Processing Commands.
This bit is asserted if the unit is not providing power to the output, regardless of the reason, including
simply not being enabled. The off bit is clear if unit is allowed to provide power to the output.
An output overvoltage fault has occurred.
Not supported. Always returns 0.
A VIN undervoltage fault has occurred.
A temperature fault or warning has occurred. See STATUS_TEMPERATURE.
A communication, memory or logic fault has occurred. See STATUS_CML.
A fault/warning not listed in b[7:1] has occurred.
STATUS_VOUT
The STATUS_VOUT command returns the summary of the output voltage faults or warnings which have occurred, as
shown in the following table:
STATUS_VOUT Data Contents
BIT(S) SYMBOL
b[7] Status_vout_ov_fault
b[6] Status_vout_ov_warn
b[5] Status_vout_uv_warn
b[4] Status_vout_uv_fault
b[3] Status_vout_max_fault
b[2] Status_vout_ton_max_fault
b[1] Status_vout_toff_max_warn
b[0] Status_vout_tracking_error
OPERATION
Overvoltage fault.
Overvoltage warning.
Undervoltage warning
Undervoltage fault.
VOUT_MAX fault. An attempt has been made to set the output voltage to a value higher than allowed by the
VOUT_MAX command. After being cleared, Status_vout_max_fault will not report additional faults until a
channel state transition (off-then-on) has been performed or a valid output voltage, lower than allowed by
VOUT_MAX, has been set.
TON_MAX_FAULT sequencing fault.
Not supported. Always returns 0.
Not supported. Always returns 0.
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