Seiko NPC moved into mass production stage for the SM6803AB: class D speaker amplifier of low standby current consumption with dynamic range compression.
The selectable dynamic range compression function of the greatest feature operates in real time without having a feedback loop, the gain for small input signals are increased while large input signals are converted using a curve that performs soft-clipping. This increases the average sound pressure level emitted from the speaker during playback, when usually reproducing, higher sound pressure level can be obtained in the case with a small speaker. Additionally, total harmonic distortion plus noise(THD+N) has been greatly improved 0.2% compared to our conventional 0.8% by optimizing the driver circuit. Furthermore, the standby current consumption was reduced to 0.2µA, we succeeded to reduce the standby power consumption.
The output stage is BTL (Balanced Transformer Less) output, and an output waveform that reverses only the modulated components enables direct driving of dynamic speakers without use of an LC filter. Additionally, the slim dielectric speakers can be driven by simply connecting a series resistor to the output. The miniaturization of the amplifier circuit is due largely to the peripheral circuitry, which can consist of only a chip capacitor.
By using this product, the miniaturization and slim down of the speaker, and the miniaturization of the battery by low standby power consumption and the miniaturization of the amplifier circuit are realized and it contributes to the total miniaturization and slim down.
We look forward to releasing new products in the future which will use these technologies.