Datasheet

f -SwitchingFrequency-kHz
s
0
20
40
60
80
100
120
140
160
180
220 720 1220 1720 2220 2720 3220 3720 4220
C -pF
f
R =748
f
W
f -SwitchingFrequency-kHz
s
50
70
90
110
130
150
170
190
210
200 300 400 500 600 700 800 900 1000 1100 1200
R -
f
W
C =1000pF
f
bq2000
www.ti.com SLUS138D –JANUARY 2008–REVISED DECEMBER 2009
voltage and/or inductor value or decreasing C
HYS
and/or the R
f
× C
f
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 R
f
and C
f
. This data was taken with an input voltage of 12V, inductor value of 220 µH, R
SNS
value of
50 mΩ, and C
HYS
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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