Application Note
32 of 63
V 1.2
2018-12-12
5 Output PMIC Controller/ IRPS5401
User guide with DB295 and DB296 demo boards
8.1
Description of Excel PI Calculator Tool
An Excel tool has been created to help determine the Ki and Kp values that should be used in the config file
based on the application L, C and switching frequency. Contact your local FAE to receive a copy.
The Calculator is divided into 2 worksheets, the ‘Power Section’ tab and the “Compensator” tab
In the Power Section tab, the user describes their application: VIN, VOUT, FSW, Inductor and Capacitor…etc.
The tool will use the design inputs to calculate the minimum L and C.
Shown is a 1 V output at 800 kHz. The calculated L for 33% ripple is 0.87
µ
H. A standard value of 1
µ
H has been
used.
A ‘minimum’ bulk capacitor is shown based on the max voltage overshoot and undershoot. This cap value is
usually augmented as a safety factor to guarantee meeting the spec.
The Capacitor section shows different banks of capacitors so you can put in different ESR and ESL values. The
capacitor value in the worksheet should be the de-rated value after DC and AC coefficients are taken into
account. This is typically 55% to 60% of the MFR specified value.
Figure 41
Design Tool
