| 摘要 |
<p>A switched mode power supply (10; 20; 30) for driving a load (11) comprises:
- an inductor (L) in series with the load;
- at least one controllable coil switch (12; M1, M2) in series with the inductor (L);
- a controller (14) for controlling the coil switch. The controller repeatedly opens and closes the coil switch at a substantially constant switching frequency (f S ), so that the coil current (I L ) varies between a minimum value and a maximum value of the same polarity while the load current (I OUT ) is substantially constant with a current ripple. According to the invention, the switching moments of the coil switch are randomized. As a result, the frequency spectrum of the current ripple has a wider and lower peak, and a ripple suppression capacitor can be made smaller or even omitted.</p> |
