A circuit is provided for detecting peaks of a sinusoidal input signal includes circuitry for generating first and second sinusoidal output signals that are out of phase with one another and with the sinusoidal input signal. A comparator block compares the sinusoidal output signals to determine instances where the amplitudes of the first and second sinusoidal output signals cross over each other. The sinusoidal output signals may lead the sinusoidal input signal somewhat so that, after taking into account processing delay, the indicated crossover instances substantially coincide with peaks in the sinusoidal input signal such that a trigger signal generated by the circuit accurately indicates the timing of the peaks.