ObsidianVault/PCB Design/Music Player/Process.md

#pcb/musicplayer #pcb

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TPS63020

Choosing an Inductor

The equations needed to find the peak current in steady state operation are Duty cycle boost: D=\frac{{V_{OUT} - V_{IN}}}{V_{OUT}} and peak current: I_{PEAK} = \frac{I_{out}}{\eta * (1 - D)} + \frac{{V_{IN} * D}}{2 * f * L} where

• D = duty cycle in boost mode
• f = converter switching frequency
• L = inductor value
• \eta = estimated converter efficiency (This is taken from section 8.2.2.2 of the datasheet)

First, to calculate the duty cycle boost we can plug in the output voltage (3.3V) and the "minimum input voltage in boost mode" which for the BQ25985 is listed as 2.304V

D = \frac{{3.3 - 2.304}}{3.3} = 0.302