Method for measuring currents, involves causing drain-source-voltage of switching transistor to correspond to drain source voltage of decoupling transistor by using operational amplifier

摘要

The method involves decoupling current to be measured as transformed current over a current mirror, which has a switching transistor (16) and a decoupling transistor (18). The transformed current is led through a measuring resistor (42), where an operational amplifier (22) is provided, which causes drain-source-voltage of the switching transistor to correspond to the drain source voltage of the decoupling transistor. The operational amplifier is separated form switching transistor during an opening time of the switching transistor. The transformed voltage is guided over another current mirror. An independent claim is included for a circuit arrangement for the measurement of currents.