18 lines
710 B
Markdown
18 lines
710 B
Markdown
#pcb/musicplayer #pcb
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## TPS63020
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### Choosing an Inductor
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The equations needed to find the peak current in steady state operation are
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Duty cycle boost: $$D=\frac{{V_{OUT} - V_{IN}}}{V_{OUT}}$$
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and peak current: $$I_{PEAK} = \frac{I_{out}}{\eta * (1 - D)} + \frac{{V_{IN} * D}}{2 * f * L}$$
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where
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- $D$ = duty cycle in boost mode
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- $f$ = converter switching frequency
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- $L$ = inductor value
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- $\eta$ = estimated converter efficiency
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(This is taken from section 8.2.2.2 of the datasheet)
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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
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$$D = \frac{{3.3 - 2.304}}{3.3} = 0.302$$
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