Detection circuit and detection method

Abstract

A detection circuit () comprises a first and a second contact terminal (P, P) for connecting a microphone (HM) with a defined polarity. Furthermore, a first and a second switch (S, S) are provided and respectively connect the first and the second contact terminal (P, P) to a reference potential terminal (GND). A supply terminal (SUP) for supplying an input signal is either connected to the first contact terminal (P) or to the second contact terminal (P) via a third switch (S). A measuring device (MS) for acquiring a measurement signal in response to the supplied input signal is coupled to a connection between the supply terminal (SUP) and the third switch (S). An evaluation device is designed for setting a first switching configuration, in which the first switch (S) is in an open state, the first contact terminal (P) is connected to the supply terminal (SUP) via the third switch (S), and the second contact terminal (P) is connected to the reference potential terminal (GND) via the second switch (S), in a test phase. The evaluation device (CTRL) is furthermore designed for comparing the measurement signal to a threshold value (I, U) in the test phase and for determining whether the polarity of a connected microphone (HM) is suitable for the first switching configuration based on this comparison.