www.irf.com

10

RD-0608

0

50

100

150

200

250

300

350

400

0

1020

30

4050

Capacitance (uF)

40V

100V

160V

Fig. 13 Iout = 350mA, Vout = 16.8V, L = 470uH

The addition of the COUT is essentially increasing the amount of energy that can be stored in the output stage,

which also means it can supply current for an increased period of time. Therefore by slowing down the di/dt

transients in the load, the frequency is effectively decreased.

With the COUT capacitor added to the circuit the inductor current is no longer identical to that seen in the load. The

inductor current has a triangular shape, where as the load will see the same basic trend in the current, but all sharp

corners become rounded with peaks significantly reduced, as can be seen in Fig. 14 and 13.

Fig. 14 Iout = 350mA, Vin = 100V, Vout = 16.85V, L = 470uH, COUT = 33uF