The ES8018 is based on a new patented 7-level Class-D amplifier technology offering improved efficiency and lower EMI than standard amplifiers. The product uses a voltage-tripling capacitive boost that generates up to three times the battery supply without the use of a bulky and expensive inductor. These advances are coupled with the legendary sound quality of ESS Sabre DACs, and advanced audio processing algorithms from the company's audio experts. As a result of this combination, audio product designers can obtain amazing audio quality from micro speakers while having a small and cost-effective solution.
The ES8018 is a self-contained Smart-Amplifier with integrated DSP that runs a cutting-edge speaker-protection and signal-boost algorithm. The solution has fully proven temperature and excursion protection that adapts to the changes in real time, and is capable of safely delivering 4.5 watts into an 8 ohm speaker, and can be used to drive both micro speakers and receivers in a dedicated low-noise mode.
The ES8018 uses a unique voltage-tripling boost, the solution is based on using the combination of a voltage-doubler and voltage-mirror circuit. This voltage-tripling results in an effective boost-voltage of 13V from a typical phone battery, and can reach 15V from a 5V supply. Both the high and low-side boost are accomplished using captive techniques, eliminating the need for a large and expensive inductor, replacing it with two low-cost and small capacitors, resulting in a solution that requires 40% less board space and has a significantly lower profile. The advanced analog-control loop in the amplifier automatically corrects for any loss of power due to battery discharge preventing impacts to audio quality while simultaneously preventing brown-out due to large currents.
Seven-Point Multi-Level Class-D amplifier topology
The Patented Multi-Level Class-D(MLCD) amplifier in the ES8018 tracks the amplitude of the audio signal and seamlessly switches between seven different switching-patterns on the output. The output effectively floats along with the signal. The result is an amplifier that can deliver peak-output swings of 15V while only ever switching 5V. This gives improvements in efficiency and lowers EMI radiation. Unlike competing amplifiers that rely on a fixed boost circuit, the ES8018 never switches the full 15 volts, avoiding significant EMI and efficiency-loss. This is critical for real-world audio signals with large crest factors. The digital control loop, used in the competitors inductive-boosts, requires a look-ahead approach to charge the converter and wastes power when idle or turned-off, the ES8018’s analog control loop has none of these penalties, providing peak-power instantaneously.
According to Shawn Scarlett, Marketing Director for ESS, “The ES8018 has several distinct advantages over Inductive-boost solutions; By removing the inductor we can make the end systems smaller, while delivering amazing sound quality. We have effectively created a new amplifier class that offers incredible sound and efficiency, opening the way for whole new level of performance and experience.”
The ES8018 amplifier is available now with a full application suite to enable effective speaker modeling and sound-quality tuning. Samples and evaluation boards are available.
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