Class D amplifier reference designs from Zetex

Based around the ZXCD Series of Class D modulator IC’s, the ZXCDSUBEV closed loop designs have proved capable of producing a damping factor as high as 285 and a total harmonic distortion plus noise (THD+N) figure better than 0.05% with a flat frequency response set ideally for subwoofer applications.
By taking its feedback signal from the filtered amplifier output, these high gain circuit designs compensate for any bridge mismatches and filter non-linearities to attain a guaranteed reduction in distortion across the entire power band.
The feedback also ensures an excellent power supply rejection ratio, allowing the subwoofer amplifier circuits to operate well with unregulated linear power supplies. In addition, the circuits are very tolerant of high off-load voltages.
90% efficiency and power levels up to 500W and beyond provides the ZXCDSUBEV series with the necessary headroom to maximise the impact of the dynamics of many movie sound tracks.
Subwoofer manufacturers have a choice of single-ended and bridge tied load architectures with initial options producing output power levels of 150W, 250W and 500W into 4Ω. In addition, the scalability of the design means that higher powers are easily produced from this single cost effective platform.