Patent ID: 9214934
Filing Date: 2015-12-15
Classification: H03K

Abstract:
1. A desaturation detection circuit for use between a desaturation detection input of an optocoupler and an output of a power switching device, the desaturation detection circuit comprising: a threshold setting element having an input and an output, the input for connection to the output of a power switching device via one or more diode(s), the threshold setting element being arranged to set a threshold voltage at the input at which the threshold setting element will provide an output at the output of the threshold setting element when an input voltage is exceeded, the threshold setting element including a first switching element arranged to be in an on state during desaturation operation of the power switching device until the output of the power switching device reaches the threshold voltage, and a detector having an input connected to the output of the threshold setting element and an output connectable to a desaturation detection input of an optocoupler, the detector being arranged to detect an output at the output of the threshold setting element and in response to provide a control signal at the output of the detector for the desaturation detection input to trigger a desaturation routine in the optocoupler, the detector including a second switching element arranged to be in an off state when the threshold setting element provides an output and arranged to provide the control signal when an output from the threshold setting element is provided.