ltc2978 Linear Technology Corporation, ltc2978 Datasheet - Page 28

• Manufacturer Part Number: ltc2978
• Description: Octal Pmbus Power Supply Monitor And Controller With Eeprom
• Manufacturer: Linear Technology Corporation

Fault Response for Voltages Measured by the High
Speed Supervisor
VOUT_OV_FAULT_RESPONSE and VOUT_UV_FAULT_
RESPONSE
The fault response documented here is for voltages that
are measured by the high speed supervisor. These voltages
are measured over a short period of time and may require
a de-glitch period. Note that in addition to the response
described by these commands, the LTC2978 will also:
Data Contents
LTC2978
operaTion

BIT(S) SYMBOL
b[7:6] Vout_ov_fault_response_action,
b[5:3] Vout_ov_fault_response_retry,
b[2:0] Vout_ov_fault_response_delay,
Vout_uv_fault_response_action
Vout_uv_fault_response_retry
Vout_uv_fault_response_delay
OPERATION
Response action.
2’b00: The unit continues operation without interruption.
2’b01: The unit continues operating for the delay time specified by bits[2:0] in increments of Ts_vs.
If the fault is still present at the end of the delay time, the unit responds as programmed in the retry
setting (bits [5:3]).
2’b1X: The device shuts down and responds according to the retry setting in bits [5:3].
Response action:
3’b000: A zero value for the retry setting means that the unit does not attempt to restart. The output remains
disabled until the fault is cleared.
3’b001-111: The PMBus device attempts to restart continuously, without limitation, using Mfr_retry_delay,
until it is commanded OFF (by the CONTROL pin or OPERATION command or both), bias power is removed,
or another fault condition causes the unit to shut down.
This sample count determines the amount of time a unit is to ignore a fault after it is first detected. Use this
delay to de-glitch fast faults.
3’b000: The unit turns off immediately.
3’b001 – 3’b111: The unit turns off after b[2:0] samples at the sampling period of Ts_vs (12.2µs typical).
• Set the appropriate bit(s) in the STATUS_BYTE
• Set the appropriate bit(s) in the STATUS_WORD
• Set the appropriate bit in the corresponding STATUS_
• Notify the host by pulling the ALERTB pin low.
Note: Odd numbered channels configured for high resolu-
tion ADC measurements will not respond to OV/UV faults
or warnings.
VOUT register, and
2978fa