The market of TWS wireless bluetooth headsets continues to be hot, and headset charging compartments for storage and charging are essential. Apple added a wireless charging function to the Airpods' second-generation headset charging compartment to realize the "true wireless" function of wireless Bluetooth + wireless charging, and the user experience is better. It is considered to be the ultimate form of TWS headphones.
Although the TWS Bluetooth headset charging box is a headset accessory, its role is crucial. Due to the relatively refined design and small size of the headset box, the battery capacity is not high, requiring long-distance logistics and silent shelving, so ultra-low self-discharge is a Hard indicators. In addition, the high integration, safety, and cost-effectiveness of the headphone box power chip are also important directions for engineers.
The sports wireless headset manufacturer gives you a comprehensive analysis of how to design the internal structure of the TWS headset wireless charging box
In today's technology, the charging method of TWS true wireless Bluetooth headset is basically charged by the headset charging box. On the one hand, because the headset's compact interior cannot accommodate a larger battery, on the other hand, the charging socket and other components will occupy More space.
The power supply PCBA in the TWS earphone charging box has two main purposes. It is not only responsible for charging the internal battery of the charging box, but also responsible for charging the earphone with the internal battery boost output of the charging box. In addition, it is also responsible for safety protection to prevent the built-in lithium battery from overcharging, overdischarging, short circuit, overcurrent and other protection functions.
First, control the external power supply to charge the TWS earphone battery box, and charge the external charger into the lithium ion battery. The external charger here is mainly a 5V charger, such as a common mobile phone adapter, the interface is MicroUSB or USB-C, and then the buck is converted to the 4.2V voltage required by the lithium-ion battery for charging, in addition to 4.3V or 4.35 V multiple specifications. There are two types of charging chips: linear and switch. Among them, high charging efficiency and low heat generation are the mainstream charging methods.
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Secondly, the TWS headset battery box power supply PCBA also needs to externally power the TWS Bluetooth headset. At this time, the lithium ion battery is boosted to 5V and then output to the headset. The headset completes the charging of the built-in battery through the internal charging circuit. In this way, when the TWS headset needs electricity, it can be put back into the charging box to automatically recharge the battery.
The booster chip of the charging box is also divided into synchronous and non-synchronous. Among them, the efficiency of the synchronous architecture is high, the heat generation is low, and the efficiency of the non-synchronous rectification is lower. The reason is the same as that of the mobile power supply.
To realize the wireless charging function, you need a power management + wireless receiving two-in-one module, or a GND directly external independent wireless receiving based on the existing TWS headphone box PCBA.