vault backup: 2026-06-24 17:21:18

PCB Design/Music Player/Process.md

@@ -3,6 +3,8 @@
 
 ## TPS63020
 ### Choosing an Inductor
+Neither of the options given in the datasheet are still available so a different inductor will need to be chosen
+
 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: $$I_{PEAK} = \frac{I_{out}}{\eta * (1 - D)} + \frac{{V_{IN} * D}}{2 * f * L}$$
@@ -15,3 +17,11 @@ where
 
 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
 $$D = \frac{{3.3 - 2.304}}{3.3} = 0.302$$
+Now calculating for $I_{PEAK}$ using the values 
+- $D = 0.302$ (calculated previously)
+- $f = 2.5$ (MHz, typical stated in datasheet)
+- $L=1.5$ (uH, value for inductor used)
+- $\eta = 0.9$ (efficiency assumption stated in datasheet)
+$$I_{PEAK} = \frac{3.3}{0.9 * (1 - 0.302)} + \frac{{2.304 * 0.302}}{2 * 2.5 * 1.5} = 5.346$$
+The datasheet states to pick an inductor with a saturation current 20% higher than the calculated value which would mean $$I_{sat} \geq 6.415$$
+The []