Fault detection circuitry and a corresponding method are disclosed. A count value that is indicative of the switching period of a PWM signal is determined and it is determined whether this count value is between a first threshold and a second threshold. An error signal is generated when the switching period is not between the first and the second threshold. A count value that is indicative of the switch-on duration of the PWM signal is determined and compared with a switch-on threshold in order to determine whether the switch-on duration is greater than a maximum switch-on duration. A count value that is indicative of the switch-off duration of the PWM signal is determined and compared with a switch-off threshold in order to determine whether the switch-off duration is greater than a maximum switch-off duration. Error signals can be generated when the durations are greater than the maximum durations.