SLVUAW9C September 2016 – February 2020 UCD90320
This command, described in Sections 8.1 and 8.2 of the PMBus specification, indicates the data format used for all commands related to output voltage (all LINEAR16 commands). The command includes a 3-bit Mode field and a 5-bit Parameter field. In UCD90320, the Mode field is a read-only and is fixed to 000b(linear data format, described in Section 2.1). The Parameter field is the exponent value and can be modified.
NOTE
This exponent field must be updated before modifying any value that is affected by this setting (all LINEAR16 commands).
Table 4 shows the influence that the exponent value has on the voltage range that can be monitored and the monitoring resolution. For example, to monitor a voltage that is 8 V when enabled, set the exponent to –11.
Exponent | Range
(V) |
Resolution
(mV) |
|
---|---|---|---|
–7 | 0 | 255.99219 | 7.81250 |
–8 | 0 | 127.99609 | 3.90625 |
–9 | 0 | 63.99805 | 1.95313 |
–10 | 0 | 31.99902 | 0.97656 |
–11 | 0 | 15.99951 | 0.48828 |
–12 | 0 | 7.99976 | 0.24414 |
–13 | 0 | 3.99988 | 0.12207 |
–14 | 0 | 1.99994 | 0.06104 |
–15 | 0 | 0.99997 | 0.03052 |
Given that the actual nominal voltage on the monitor pin will be 1.875 volts (this allows for a 25% overhead). Table 5 shows examples of VOUT_MODE and VOUT_SCALE_MONITOR settings for various monitoring ranges. The voltage in the table is the nominal value for the monitored voltage before being modified with a resistor-divider circuit to fit below the voltage monitoring limit of 2.5 V.
Exponent | High | Low | ||
---|---|---|---|---|
Voltage | Scale | Voltage | Scale | |
–7 | 192 | 0.009766 | 96 | 0.019531 |
–8 | 96 | 0.019531 | 48 | 0.039063 |
–9 | 48 | 0.039063 | 24 | 0.078125 |
–10 | 24 | 0.078125 | 12 | 0.15625 |
–11 | 12 | 0.15625 | 6 | 0.3125 |
–12 | 6 | 0.3125 | 3 | 0.625 |
–13 | 3 | 0.625 | 1.5 | 1.25 |
–14 | 1.5 | 1.25 | 0.75 | 2.5 |
–15 | 0.75 | 2.5 | 0.375 | 5 |