SmartVID Debug Checklist and Voltage Regulator Guidelines

ID 757318
Date 4/01/2024

1.5. Steps to Obtain the Voltage Output Information from the Voltage Regulator Data Sheet

In this example, the ISL68137 voltage regulator is used.

To obtain the voltage output information from the voltage regulator data sheet, follow these steps:

  1. Gather the available voltage output information from the supported PMBus command details from page 29 of 54 of the ISL68137 data sheet as shown in the following figure.
    Figure 8. Gathering the Available Voltage Output Format Information
  2. Calculate the coefficient for the direct data format.
    Figure 9. Direct Format Equation
    1. The equation shows how to convert the direct format value where:
      • X, is the calculated, real value in mV;
      • m, is the slope coefficient, a 2-byte two's complement integer;
      • Y, is the 2-byte two's complement integer received from the PMBus device;
      • b, is the offset, a 2-byte two's complement integer;
      • R, is the exponent, a 1-byte two's complement integer
    2. By using this equation, with X = 900 and Y = 0x0384h, the value for coefficient m, b, and R can be calculated, where m = 1, b = 0, and R = 0. For this calculation, note that Y must be converted from hexadecimal format (0x0384h) to decimal format (0x900d).