| 摘要 |
<p>A battery charger (10) is provided with a power supply (26) which is energized by a main winding (22) and a bias winding (24) on the secondary side (18) of an input transformer (14). The charger switches a main voltage level provided at a main voltage output (28) according to a pulse width modulation scheme, and has an output section (36) for filtering the switched voltage. A power switch (38) is coupled between the output section and the main voltage output, and is driven by a bias switch (48) coupled between the control terminal (50) of the power switch, and a bias voltage output (30), which provides a bias voltage level that is higher than the main voltage level by a minimum delta.</p> |
