JAJSIR5C October 2019 – October 2023 TPS65313-Q1
PRODUCTION DATA
The minimum output capacitance for the BOOST converter is 25 µF and the maximum output capacitance is 100 µF. X7R-type, low-ESR ceramic capacitors are recommended. The capacitance value specified in this example is the effective capacitance value after considering all the tolerances, voltage derating, and aging effects. Select the output capacitor value to be 1.5 times the minimum required capacitance value. In this example, two 22-µF, 10-V rating, X7R-type capacitors (GCM31CR71A226KE02 from Murata) are used.
Use Equation 8 to calculate the peak-to-peak output voltage ripple.
where
where
The ESR of the output capacitors has an impact on the output voltage ripple. Use Equation 10 to calculate output voltage ripple as a result of ESR.
where
where
Use Equation 12 to calculate the total peak-to-peak output ripple.
For this example, the calculated BOOST output voltage ripple is approximately 6 mVPP for a typical 44-µF output capacitor with 3-mΩ effective ESR, 5-V BOOST output voltage (VBOOST), 3.3-V BOOST input voltage, 0.6-A maximum load current, and 1.5-µH inductor.