A detection circuit is provided for a power supply for an electrostatic chuck generating a trapezoidal waveform with approximately flat tops and minimal dead-time between phase reversals. The detection circuit includes an amplifying circuit which receives inputs from a secondary winding of a transformer of the power supply and produces an amplified buffered signal. A chucking detect circuit receives the signal from the amplifying circuit and is configured to produce a first signal indicative of a substrate on the electrostatic chuck and a second signal indicative of an electrostatic chuck without a substrate. A chucking quality circuit receives the signal from the amplifying circuit and produces a signal indicative of a quality of the chucking of the substrate. A movement detection circuit receives the signal from the amplifying circuit and produces a signal indicative of movement of the substrate on the electrostatic chuck.