In today's era of pursuing high-quality audio experiences, how to achieve powerful dual-channel boost functions at a relatively low cost has become the focus of attention for many electronic device designers. Today, let's delve into how to achieve a cost-effective 2x10W dual-channel boost solution using two ChipSourceTek-CST8337. This innovative design not only excels in performance but also demonstrates significant advantages in cost control and space utilization, providing new ideas for the development of various audio devices.

Overview of the Plan

    ChipSourceTek-CST8337, as an outstanding audio power amplifier chip, features a unique design and powerful functions, making it an ideal choice for building a cost-effective dual-channel boost system. By ingeniously combining two ChipSourceTek-CST8337, the boost output of one is directly used to power the other, successfully eliminating the need for a set of peripheral boost supporting circuits. This design concept greatly optimizes the overall structure of the solution, reduces the number of components, lowers production costs, and at the same time can stably provide dual-channel built-in boost 2X10W power output, meeting the market demand for high-power stereo sound.

Advantages of packaging and board occupation

    The ChipSourceTek-CST8337 adopts the ESSOP-10 small volume package form. This feature makes the area occupied by two ChipSourceTek-CST8337 chips on the PCB board relatively small. Under the trend of increasing miniaturization of electronic devices, compact package size is of great significance. It not only helps save precious circuit board space, but also enables designers to layout other components more flexibly, enhancing the integration of the entire system. For instance, in the design of portable Bluetooth speakers or smart speakers, a smaller board area means that more functional modules such as batteries, microphones, and Bluetooth modules can be accommodated within a limited internal space, thus creating products that are more feature-rich and lighter in size.

Optimization of peripheral devices

    In this solution, the two ChipSourceTek-CST8337 only require one set of peripheral boost devices, including inductors and Schottky diodes. This is a major breakthrough in the traditional design scheme. In the past, each channel required an independent boost circuit, resulting in a large number of peripheral components and increasing the complexity and cost of the circuit. Nowadays, by sharing a set of boost devices, the circuit structure has been greatly simplified, the number of components and soldering points have been reduced, and production efficiency and reliability have been improved. At the same time, it also reduces the risk of performance inconsistency caused by component differences, ensuring the balance and stability between the two channels. From a practical production perspective, fewer components mean lower material procurement costs, simpler assembly processes, and higher yield rates, which are crucial for mass-produced electronic products.

AB/D class switchable function

    Products on the market with larger power (2X10W) dual channels and built-in boost often lack support for Class AB operation modes, while ChipSourceTek-CST8337 makes up for this deficiency. It features AB/D class switchable functions, allowing users to select the appropriate amplification mode based on different application scenarios and audio quality requirements. Class AB amplifiers are renowned for their low distortion and high fidelity, capable of providing a warmer and more natural tone. They are suitable for music playback scenarios with high requirements for sound quality. Class D amplifiers are known for their high efficiency. Under the premise of ensuring a certain level of sound quality, they can effectively reduce power consumption and heat generation, making them suitable for devices that operate continuously for long periods. This flexible ability to switch working modes provides users with more choices, enabling them to enjoy the best auditory experience in different usage environments.

Strong boost current capacity

    ChipSourceTek-CST8337 has a strong boost current capability, with an instantaneous input current of up to 8A. This feature fully meets the power requirements of dual-channel systems, ensuring a stable voltage supply even when driving high-impedance loads and avoiding clipping distortion of audio signals caused by insufficient current. Whether playing passionate symphonies or stunning movie sound effects, it can ensure sufficient dynamic range and dynamic sense, allowing users to experience an immersive musical feast. Moreover, the powerful current capacity also provides a strong guarantee for the rapid start-up and response of the device, reducing waiting time and enhancing the user experience.

Advantages of stereo performance

    Another highlight of this solution is that the left and right channels are separated from each other. This design effectively suppresses crosstalk between channels, making the signal transmission of each channel purer and more independent. During the actual listening process, users can clearly feel that the positioning of different instruments and sound elements in the space is more accurate and the sense of layering is more distinct. The excellent power distortion index further ensures the authenticity and fidelity of the sound, better meeting customers' high requirements for stereoscopic sound quality. Whether it is enjoying the delicate melodies in classical music or experiencing the dynamic rhythm of pop music, one can achieve an outstanding auditory effect.

Detailed explanation of application circuits

    To better understand this application solution, let's take a look at the combined implementation circuits of the two CST8337 circuits #1 and #2 shown in Fig.2. In this circuit, there are several key connection points that need attention:

1. VCTRL pin connection：The VCTRL (Pin3) of #1 and #2 need to be connected together as the enable control pins of the entire system. This pin can not only control the switching between AB and D classes, but also it should be noted that when performing mode switching, the enable should be turned off for at least 100mS. This is because during the switching process, a series of configuration adjustments need to be made inside the chip. Sufficient delay time can ensure the stability and reliability of the switching process and prevent abnormal situations from occurring.

2. HPVDD power supply mode：#1 has a complete peripheral circuit, which includes boost matching devices. When #1 is boosted, the HPVDD voltage it outputs will be directly connected to the HPVDD (Pin9) of #2. This ingenious power supply method realizes the effective transmission and sharing of energy, avoiding the waste of resources caused by the repetitive construction of boost circuits.

3. #2. Specific pin processing：#Pins 6, 7 and 8 of #2 are suspended and no external components are required. This design simplifies the circuit layout, reduces unnecessary connections and interference sources, and enhances the simplicity and stability of the system.

4. Current limit setting：The current capacity can be set through the Rlim resistor at the ILIMIT pin of #1. Generally speaking, it is not recommended to exceed 43kΩ. Reasonable current limiting helps protect the chip from overcurrent damage and also ensures stable performance under different load conditions.

5. Key points for capacitor selection：It is recommended that the capacitor connected to ILIMIT be no less than 1uF. This is because a smaller capacitance value may result in a larger starting current, which poses a potential risk of damage to the system. Selecting capacitors of appropriate capacity can effectively smooth out the current impact during the startup process and ensure the reliable operation of the system。

Analysis of Electrical Characteristics of ChipSourceTek-CST8337

    Understanding the electrical characteristics of ChipSourceTek-CST8337 is crucial for fully leveraging its performance. Under the conditions of AV=26dB, TA=25℃, and unless otherwise specified, the following key parameters were tested at VBAT =3.7V:

• High energy conversion efficiency：An efficiency of up to 91% means that most of the electrical energy can be effectively converted into audio output power rather than being lost in the form of heat. This not only reduces energy consumption and extends battery life (which is particularly important for portable devices), but also lowers the difficulty and cost of heat dissipation design. For instance, in the application of Bluetooth speakers, efficient energy utilization enables the speakers to play music for a longer time after a single charge, enhancing the convenience of use for users.

• Fast startup time：Thanks to its advanced circuit design and optimized internal structure, ChipSourceTek-CST8337 features a fast startup characteristic. This enables the device to quickly enter the normal working state the moment it is turned on, without the need for a long waiting process. For users, this means a convenient and ready-to-use experience. For some application scenarios with strict requirements for response speed, such as stage performance equipment, rapid startup performance is even more indispensable.

• Good protective function：It is equipped with built-in protection mechanisms such as OCP (Overcurrent Protection) and UVLO (Undervoltage Lock), providing a solid guarantee for the safe and stable operation of the system. When abnormal conditions such as overcurrent or low voltage occur, the chip can automatically take corresponding protective measures to prevent damage to itself and other related components. This significantly enhances the reliability and durability of the system, reducing maintenance costs and the workload of maintenance.

Practical application cases and prospects

    This scheme has been widely applied in multiple fields. In terms of consumer electronics, such as Bluetooth speakers and smart speakers, it brings users a high-quality stereo experience. In the in-car audio system, its compact design and powerful performance can also meet the complex environment inside the vehicle and the high audio quality standards. Even in some professional audio equipment, this cost-effective solution is gradually being adopted. With the continuous advancement of technology and the growth of market demand, it is believed that this solution will occupy an increasingly important position in the future audio market.

Precautions and debugging skills

    In the actual design and usage process, there are still some details that need attention. For instance, when laying out a PCB, certain rules must be followed to ensure signal integrity and electromagnetic compatibility. As mentioned earlier, the boost inductor and Schottky diode should be placed as close as possible to the LX pin of the ChipSourceTek-CST8337, and the related traces should be short and thick to reduce the influence of parasitic impedance. In addition, when choosing peripheral components, pay attention to whether their quality and specifications meet the requirements, especially the values of inductors and capacitors as well as parameters such as withstand voltage grades. During the debugging stage, tools such as oscilloscopes can be used to monitor the signal waveforms at key nodes and check for any abnormal oscillations or noise issues. If problems are found, the component parameters should be adjusted in time or the circuit layout optimized to solve them.

    The cost-effective 2x10W dual-channel boost solution implemented through two ChipSourceTek-CST8337 is a highly innovative and practical design solution. It has achieved a good balance in terms of performance, cost, volume and other aspects, providing a new idea and method for the development of audio equipment. Whether for professional audio engineers or amateurs, it is worth in-depth study and application.

Seven pieces of materials were referred to：