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9

RD-0608

The output capacitor can be used simultaneously to reduce the frequency and improve current control accuracy. Fig.

11 shows how the capacitance reduces the frequency over a range of input voltage. A capacitance of 4.7uF has a

large effect on reducing the frequency. Fig. 12 shows how the current regulation is also improved with the output

capacitance. There is a point at which continuing to add capacitance no longer has a significant effect on the

operating frequency or current regulation, as can be seen in Fig. 12 and Fig. 13.

10

100

1000

30

50

70

90

110

130

150

170

Vin (V)

0uF

4.7uF

10uF

22uF

33uF

47uF

Fig. 11 Iout = 350mA, Vout = 16.8V, L = 470uH

330

340

350

360

370

380

390

30

80

130

180

Vin (V)

0uF

4.7uF

10uF

22uF

33uF

47uF

Fig. 12 Iout = 350mA, Vout = 16.8V, L = 470uH