| 摘要 |
<p>The protection circuit for a power supply unit of the present invention includes a switching stage (T1), at which at least two output voltages (U1 - U4) to be monitored are connected, these voltages being separated from one another by means of resistors (R4 -R7). Arranged here in the connection path of the output voltages is a diode (D2 - D4), which turns on and thereby triggers the switching stage (T1) in the event of a fault, when there is a drop in one of the output voltages. In this way, the switching stage provides information which acts on a control loop of the power supply unit, so that the power supply unit switches off. <??>The protection circuit also includes a passive network with a resistor (R1) and a capacitor (C1), which prescribes a time constant, after which the protection circuit permits renewed starting of the power supply unit. <??>Applications of the protection circuit arise in particular for television sets and video recorders, the power supply units of which provide a considerable number of output voltages for operating the unit concerned. <IMAGE></p> |
