| 摘要 |
<p>PCT No. PCT/DE96/02011 Sec. 371 Date Jun. 18, 1998 Sec. 102(e) Date Jun. 18, 1998 PCT Filed Oct. 23, 1996 PCT Pub. No. WO97/15976 PCT Pub. Date May 1, 1997A back-up device includes at least one back-up battery, in particular a rechargeable battery which can be charged via the power supply, and a control unit. The control unit connects the back-up battery when the actual value of the DC voltage is less than a predefined minimum value, generates a predefined back-up time period and disconnects the back-up battery again, cyclically, after this time period has elapsed. The device has the advantage that the return of the output DC voltage of the power supply can be identified effectively without major complexity. The loads continue to be supplied both in the event of a failure of the supplying input voltage and in the event of a failure of the power supply, since the output DC voltage, which is essential for the loads, of the power supply is monitored. The device can be connected additively downstream of a power supply, without any intervention in its design being necessary. The device has the further advantage that it automatically connects the battery as a back-up, even in the event of dips in the output DC voltage caused by short-circuits, as soon as the load voltage falls below the minimum value. Thus, the device allows a virtually continuous transfer and back-up of the output DC voltage in a multiplicity of fault situations.</p> |
