Manual

MAX15301 PMBus Command Set User’s Guide
Rev 1 Page 18 of 53
TON_RISE
Reference:
Standard Command
Lockable:
Yes
Command Code:
0x61
Format:
Linear
Data Bytes:
2
Units:
ms
Transfer:
Read/Write Word
Factory Value:
0xCA80 (see Description)
Description/Notes:
See Section 16.2 of the PMBus Specification Part II.
The TON_RISE command sets the ramp-up time from 0V to regulation at VOUT_COMMAND. The
nominal factory value is 5ms.
The MAX15301 achieves startup dV
OUT
/dt control by incrementing the loop setpoint by one 12-bit
step every time a certain number of ramp-controller clock cycles have elapsed in an 8-bit counter.
This results in a setpoint that increases at a controlled rate, in turn creating a constant dV
OUT
/dt
during startup.
Because the MAX15301 must calculate the ramp control timer setting based upon the value of
VOUT_COMMAND, the possible range and resolution of TON_RISE will vary significantly.
The desired value of TON_RISE is retained in memory, regardless of ramp-timer limitations, but the
read-back value is based on actual hardware register settings.
TOFF_DELAY
Reference:
Standard Command
Lockable:
Yes
Command Code:
0x64
Format:
Linear
Data Bytes:
2
Units:
ms
Transfer:
Read/Write Word
Factory Value:
0xBA00 (see Description)
Description/Notes:
See Section 16.5 of the PMBus Specification Part II.
The TOFF_DELAY command sets the delay time between loss of enable condition and the beginning
of the output ramp-down. The nominal factory value is 1ms.
An 8-bit timer with approximately 570μs resolution allows for delay times from 0ms to ≈145ms.