Patent ID: 6150874
Filing Date: 2000-11-21
Classification: G05F

Abstract:
Circuit layout for generating a supply DC voltage (U.sub.Z) at an output in a dependent relationship to a non-constant input DC voltage (U.sub.Batt) applied at the input end,i1) where in a first voltage interval (I.sub.1) the input DC voltage (U.sub.Batt), reduced by a constant first value (.DELTA.U.sub.1), is transmitted, andi2) where in a following second voltage interval (I.sub.2) the supply DC voltage (U.sub.Z) will be maintained at a constant level (U.sub.nenn), andi3) where, if the input DC voltage (U.sub.Batt) exceeds this second voltage interval (I.sub.2), the supply DC voltage (U.sub.Z) at the output end, reduced by a second constant value (.DELTA.U.sub.2), follows the input DC voltage (U.sub.Batt),wherein(a) starting from the input DC voltage (U.sub.Batt), in a first current path, there are a number (n) of serially connected diodes (D.sub.1 . . . D.sub.n) whose connections are made in pass direction, which, on the one hand, are connected to ground via a first resistor (R.sub.1), and which, on the other hand, are connected to the output of the supply DC voltage (U.sub.Z) via a second high impedance resistor (R.sub.2).(b) there is, in parallel to the first current path, a second current path which is connected from the input DC voltage (U.sub.Batt), via a first Zener diode arrangement (Z.sub.1), to the output, and(c) the output of the supply DC voltage (U.sub.Z) is connected to ground via a third resistor (R.sub.3) and, in a series connection, via a second Zener diode arrangement (Z.sub.2).