| 摘要 |
PURPOSE:To attain proper overload protection even in either the redundant state or the faulty state by providing a means switching a protection threshold value of its own overload protection circuit in terms of binary way depending on a signal from an operating state informing means of other power unit. CONSTITUTION:Each switch drive circuit DR throws a switch SW to the position of a contact (a) in the redundant state and a current I1 (in total 2I1) is supplied from power units I, II to a load LO. If the power unit II is faulty, the switch drive circuit DR receives a signal representing the faulty state from the power unit II to throw the switch SW to the position of contact (b). Thus, a comparator A2 applies overload protection so that a current I1 flowing through a current sensing resistor R1 is not larger than a value corresponding to the 2nd load protecting value VTH2. In this state, a full load current is supplied to the load LO from the power unit I, but it is twice the overload protecting value VTH1 in the redundant state to apply proper overload protecting operation.
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