Recently, EPC, Efficient Power Conversion Corporation, announced the launch of the EPC9192 reference design. The reference design enables a high performance, compact, and high efficiency Class D audio amplifier, which is widely used in digital amplifier equipment for home audio, professional audio, car audio, etc. The EPC9192 adopts the high current digital amplifier inductor CPD2315FA-100M, which is independently researched and designed by codaca Electronics, to help realise the high fidelity, low distortion, and low noise of digital amplifier equipment.

1 - Programme design and application

The EPC9192 features a ground-referenced, split dual-supply single-ended (SE) design that delivers up to 700 W of output power per channel at 4 Ω loads. 200 V, EPC2307, eGaN® FETs from EPC are used in a half-bridge topology. two channels can also be configured in bridge-to-load (BTL) mode for up to 1400 W / 8 Ω.

The EPC9192 has a modular design for high flexibility and expandability. It includes one EPC9192 main board, two EPC9558L PWM modulator daughter boards, and two EPC9558P power stage daughter boards. Enables dual-channel digital power amplifier with auxiliary power management and protection functions. Users are able to implement custom circuits for PWM modulator and power stage. Different modulation techniques can be achieved by customising the PWM modulator, and the switching frequency can also be changed. The power stage board can also be customised so that different devices can be evaluated and compared.

The reference design board is shown in Figure 1, and the EPC9192 solution board schematic and the EPC9558P power stage daughter board schematic are shown in Figure 2 and Figure 3, respectively.

Figure 1: EPC9192 programme board

Figure 2: Schematic diagram of the EPC9192 programme board

Figure 3: EPC9558P Power Stage Sub-Board Schematic Diagram (Source: EPC website)

1.1 Main characteristics

◦ 700 W per channel @ 2-4Ω / 350 W @ 8Ω

◦ BTL capable (1400 W @ 4-8Ω, > 100 VRMS)

◦ < 0.005% THD+N, > 120 dB SNR

◦ Frequency response: 5 Hz - 20 kHz +/- 0.5 dB

◦ Overcurrent, overheat, undervoltage and overvoltage protection functions

1.2 Performance testing

The audio was measured using an audio analyser and the efficiency was tested at different supply voltages and output powers under 8Ω load conditions.

Figure 4 shows the efficiency of the GaN transistor-based Class D audio amplifier as a function of output power in the low power range (a) and high power range (b) at 48V, 70V and 82V supply voltages. Tests show that the EPC9192 evaluation board has an efficiency of approximately 96% at 350 W/8Ω load.

Fig. 4a: Efficiency at Low Power

Fig. 4b: Efficiency at High Power

Figure 5 : THD+N vs. Output Power Level, 4Ω Load

Figure 6: THD+N vs. Frequency 1 W (solid line), 10 W (dashed line), 100 W (dotted line), 4 Ω load

2 - Digital Amplifier Sensor Product Features

The EPC9192 reference design power stage daughter board adopts Codaca's high-current digital amplifier inductor CPD2315FA-100M With an inductance value of 10μH and a saturation current of 45.50A, the product has a size of 23x23x15mm, and an operating temperature of -40°C to +125°C. The inductor is designed with a wide temperature and low power consumption material and flat coil winding design. The inductors are designed with wide temperature and low power consumption materials and flat coil winding, featuring low resistance, low temperature rise, low loss, excellent current stability and signal transmission performance, and compact package size design, suitable for a variety of small-size solution design.

2.1 Electrical characteristics

CPD2315FA-100M saturation current curve:

CPD2315FA-100M temperature rise current curve:

The CPD2315FA series is currently available in three models with inductance range of 10 to 22μH, saturation current of 45.5 to 23.5A, and temperature rise current of 14A, which can meet the needs of different solution designs.

As a global leading supplier of magnetic components technology, Cortaca Electronics has been focusing on power inductor development for 23 years. In order to meet the design requirements of small size, high power, low radiation and low distortion of digital amplifier, Cortarge has developed several series of digital amplifier inductors independently. Such as: CPD, CSD, CPE, CSAD, VSAD, VSD and many other series. Among them, CPD series has been written into the reference design many times by Infineon and other world famous IC solution providers for its advantages of high current, low loss, high efficiency and strong anti-interference ability.

2.2 Features of Codaca CPD series products

◦ CPD series digital amplifier inductors have the following features:

◦ Compact design, saving PCB mounting area.

◦ Magnetic shielding structure for high EMI resistance.

◦ Flat coil winding, low resistance and low temperature rise.

◦ Wide temperature and low power consumption materials, low core loss.

2.3 Application environment

Operating temperature: -40℃～+125℃ (including coil heat).

2.4 Environmental standards

Comply with RoHS, REACH, halogen-free and other environmental requirements.

2.5 Production

Batch production, delivery time 4-6 weeks, samples can be requested.

For more information or to request samples, please visit Codaca official website.