Two key points of the new design of TWS wireless earbuds air 4 wireless earbuds

In recent years, TWS wireless earbuds have entered the electronics market. Now, users can ditch their streaming devices without having to worry about a stuck headphone cable snapping back. True wireless earbuds are Bluetooth®-based wireless earbuds with left and right channels separated into separate housings. Although this innovative design eliminates the need for users to connect their phones with wires, it creates a new set of design challenges for earbud makers. www.bjbjaudio.com

To maximize battery life and battery runtime, it is imperative to ensure that earbuds properly placed in the charging case charge efficiently. Magnetic sensors help ensure proper placement of the earbuds because the earbuds use magnets to detect movement of delicate objects. In general, using current sense amplifiers for earbud charging and Hall-effect switches for wireless charging cases maximizes battery charging and battery life for these applications. www.bjbjaudio.com

Designing with Current Sense Amplifiers
Batteries for TWS wireless earbuds are typically below 100-mAh. Therefore, in order to protect and accurately charge these small capacity batteries, better current measurement is required. Traditional battery chargers and fuel gauges are excellent at monitoring current in larger batteries (such as those in a charging case), but are often mediocre at monitoring lower currents. Dedicated current sense amplifiers are more accurate when measuring small currents. If you already have a microcontroller (MCU) or power management integrated circuit (PMIC) in your design, you can use the output of these amplifiers to monitor and measure battery usage and battery life based on algorithms written into the MCU or PMIC. www.bjbjaudio.com

Designing with Hall Effect Sensors
New features of the TWS wireless earbuds are their matching charging case lid and charging detection inside the case. The charging case must be able to detect the position of the lid and be able to detect the presence of earbuds in the charging case that need to be charged. Other sensor technologies may not be able or have the sensitivity to correctly identify these things cost-effectively, so choosing the right sensor is critical. www.bjbjaudio.com 

Hall-effect sensors work well for detecting charging case lids and earbud charging. Given that magnets are already used to close the lid of the charging case, using a magnetic sensing solution in the form of a Hall-effect switch to detect the lid is an obvious solution that requires no additional parts. In addition, placing magnets in the earbuds is an effective way to detect the presence of earbuds in the charging case. Knowing if the earbuds are in the charging case allows automatic Bluetooth connection when the earbuds are removed, or charging detection when the earbuds are in the charging case. www.bjbjaudio.com

Choosing the right digital Hall-effect sensor is very important, and features like low frequency and low power consumption make the DRV5032 the obvious choice. For the application of Hall-effect sensors in earplugs, it is completely possible to provide magnet detection information 5 times per second. This frequency allows you to use the low-power option of the DRV5032, which consumes only about 0.5µA and does not seriously drain the device's battery. www.bjbjaudio.com