| 摘要 |
<p>The invention relates to a switching power supply with a battery branch circuit provided for an emergency power supply, which can, similar to the primary circuit, be switched on in case of an emergency, by a switching transistor (13, 43). The battery branch circuit is connected in parallel with the secondary winding (7, 37) of transformer (4) and poled unidirectional with the current pulses which are induced in the secondary winding (7, 37) from the primary side during mains operation. The second switching transistor (13, 43) is switched on during the respective on-phase of the primary-side switching transistor (6), but, relative to this, is switched on later and switched off earlier.</p> |
