Disclosed herein is a circuit for determining failure of a movable MEMS mirror. The circuit includes a mirror position sensor associated with the movable MEMS mirror and that generates an analog output as a function of angular position of the movable MEMS mirror. An analog to digital converter converts the analog output from the mirror position sensor to a digital mirror sense signal. Failure detection circuitry calculates a difference between the digital mirror sense signal at a first instant in time and the digital mirror sense signal at a second instant in time, determines whether the difference exceeds a threshold, and indicates failure of the movable MEMS mirror as a function of the difference failing to exceed the threshold.