Electrical circuit arrangement

An electrical circuit arrangement for detecting the switching conditions of individual switching devices, the electrical circuit arrangement comprising:

• a direct voltage source having a positive terminal and a negative terminal;
• first and second switching groups each having a plurality of switching devices connected in parallel between a respective input (e1, e2) and a respective output (a1, a2), each one of the switching devices being switchable on and off;
• a plurality of resistors each connected in series to a respective switching device between the respective inputs (e1, e2) and the respective outputs (a1, a2), wherein each one of the resistors has a selected resistance value for providing a voltage encoded signal output across the respective inputs (e1, e2) and the respective outputs (a1, a2) when the corresponding switching devices are switched on;
• a first pair of diodes (D1, D2);
• evaluation electronics having first and second connections (A1, A2), wherein the inputs (e1, e2) of each one of the first and second switching groups is connected by a respective one of the first pair of diodes (D1, D2) to a respective one of the first and second connections (A1, A2) of the evaluation electronics, wherein the first pair of diodes (D1, D2) are forward biased from the first and second connections (A1, A2) of the evaluation electronics to the inputs (e1, e2) of the first and second switching groups;
• and
• a second pair of diodes (D3, D4), wherein the outputs (a1, a2) of each one of the first and second switching groups is connected by a respective one of the second pair of diodes (D3, D4) to a respective other one of the first and second connections (A1, A2) of the evaluation electronics, wherein the second pair of diodes (D3, D4) are reversed biased from the first and second connections (A1, A2) of the evaluation electronics to the outputs (a1, a2) of the first and second switching groups;
• wherein the evaluation electronics alternately connect at predetermined time intervals the inputs (e1, e2) and outputs (a1, a2) of each of the first and second switching groups to the positive terminal and negative terminal of the direct voltage source to measure the voltage encoded signal for determining which switching devices are switched on.