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R =748

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bq2000

www.ti.com

SLUS138D – JANUARY 2008 – REVISED DECEMBER 2009

voltage and/or inductor value or decreasing CHYS and/or the Rf × Cf filter corner frequency will increase the

switching frequency. Figure 10 and Figure 11 show empirical data on the variation in switching frequency based

on adjusting Rf and Cf. This data was taken with an input voltage of 12V, inductor value of 220 µH, RSNS value of

50 m

Ω, and CHYS value of 4.7 pF. Typical switching frequencies for the bq2000 are between 100 and 200 kHz,

though it is possible to achieve switching frequencies in excess of 300kHz.

Figure 10. Switching Frequency vs Capacitance

Figure 11. Switching Frequency vs Resistance

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