Instruction Manual

MAX15303 PMBus Command Set User’s Guide
Page 19 of 52
Fault-Related Commands
CLEAR_FAULTS
Reference:
Standard Command
Lockable:
Yes
Command Code:
0x03
Format:
N/A
Data Bytes:
0
Units:
N/A
Transfer:
Send Byte
Factory Value:
N/A
Description/Notes:
See Section 15.1 of the PMBus Specification Part II.
If the MAX15303 has latched off for a fault condition, sending the CLEAR_FAULTS command will cause
a restart.
VOUT_OV_FAULT_LIMIT
Reference:
Standard Command
Lockable:
Yes
Command Code:
0x40
Format:
Unsigned integer mantissa
Data Bytes:
2
Units:
V
Transfer:
Read/Write Word
Factory Value:
0x170A (1.440V)
Description/Notes:
See Section 15.2 of the PMBus Specification Part II.
VOUT_OV_FAULT_LIMIT mantissa data sent to and from the MAX15303 must be divided by 4096 to
determine the actual voltage value, according to the fixed value of VOUT_MODE
.
In the MAX15303, there are seven possible output voltage ranges based on seven corresponding
internal feedback divider taps. The MAX15303 hardware has 8-bit resolution for the overvoltage fault
limit within each of these seven ranges.
The desired value of VOUT_OV
_FAULT_LIMIT is retained in memory, regardless of limitations
imposed by the feedback divider range and the 8-bit fault limit resolution, but the read-back value is
based on actual hardware register settings.
The factory value of 0x170A (1.440V) will
be overridden during initialization to
VOUT_COMMAND x 1.15, unless a specific value has been written to the User Store.
VOUT_OV_FAULT_RESPONSE
Reference:
Standard Command
Lockable:
Yes
Command Code:
0x41
Format:
Bit field
Data Bytes:
1
Units:
N/A
Transfer:
Read/Write Byte
Factory Value:
0x80 (Stop regulating and remain off)
Description/Notes:
See Sections 10.5.1 and 15.3 of the PMBus Specification Part II.
Note that the MAX15303 does not support finite, non-zero restart-attempt counts. (Continuous
restart attempts are supported.)
The VOUT_OV_FAULT_RESPONSE command data comprises three bit-fields:
Bits [7:6] determine the basic fault-response mode. The MAX15303 supports the following modes:
00 Ignore the fault condition.
01 Continue operating and wait for the fault to abate for time specified in bits [2:0]. If the