| 摘要 |
<p>A protection circuit for a power supply unit 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.</p> |
