Medical device with fail-safe power supply

A medical device comprising:

• a power supply for connecting to an AC power grid, the power supply having:
• a bridge rectifier;
• a smoothing capacitor for smoothing a DC voltage to be supplied by the power supply;
• a discharge resistor for discharging the smoothing capacitor;
• and
• a circuit that is electrically connected to the discharge resistor and the smoothing capacitor and configured to detect a switched-on state of the medical device, with an AC input voltage present at its power supply, across an entire input voltage range, and to only connect the discharge resistor in parallel to the smoothing capacitor if the circuit does not detect a switched-on state of the medical device, the circuit having:
• a first transistor for connecting the discharge resistor in parallel to the smoothing capacitor that is arranged and dimensioned to connect and cause the smoothing capacitor to discharge if a control capacitor connected to a base or a gate of the first transistor is sufficiently charged, the control capacitor being connected to a control transistor that is arranged and dimensioned to regularly connect and discharge the control capacitor as long as the power supply receives a mains voltage;
• a first resistor;
• a second resistor;
• and
• a circuit capacitor, the first resistor, the second resistor, and the circuit capacitor being connected in series between an input of the bridge rectifier and a negative output of the bridge rectifier, a junction between the second resistor and the circuit capacitor being connected to a base of the control transistor.