TWS is the abbreviation of True Wireless Stereo in English, which means true wireless stereo. TWS technology is also based on the development of Bluetooth chip technology. Apple has to talk about its development process. In 2017, after the iPhone 7 cancelled the 3.5mm jack, the Bluetooth headset market developed rapidly, until Apple first released the world's first TWS Bluetooth headset AirPods. Since then, the Bluetooth headset has launched a new life.
In the circuit structure: GLF73910 does not need external Mosfet, can save 2 Mosfet and 2 resistors, can save more space and cost Package size: only 0.97 * 0.97 WLCSP-4L
Standby power consumption: 0.8ua, shutdown power consumption is only 110na, ultra-low power consumption can increase battery life in the design architecture: the world's exclusive use of positive cut, compared with negative cut, battery negative and system GND are together, can increase System stability, and EMI is easier
GLF solves the pain points of TWS shipping life
In the ultra-small size, a large-capacity battery cannot be placed, especially to export TWS abroad, many manufacturers will choose shipping, long shipping time, sometimes it takes 2-3 months to reach the customer, the customer is in the warehouse Sometimes it will be placed in the hands of consumers for 2-3 months. When the consumers get it, the battery will be too low, or it will not turn on at all, affecting the user experience. Therefore, GLF specially opened a deep sleep GLF76321 to solve Extend the life of TWS under shipping
Lithium battery protection scheme
In order to achieve the best wearing comfort, wireless headphones have strict requirements for weight and volume, and the compactness of the built-in lithium battery pack and circuit in the headset determines the volume and weight of a headset. The internal circuit components are required to be small and the power consumption is low. In response to this demand, GLF has developed an ultra-low lithium battery protection IC, GLF73910, which can be perfectly applied to TWS lithium battery protection.
GLF73910 is a battery full protection IC, including detection and protection of overcharge, overdischarge and overcurrent, so that the battery's standby power consumption is as low as 0.8uA due to overcharge explosion or overdischarge leakage, and the package is WLCSP-4L , Only 0.97 * 0.97mm, the volume is smaller than a 0603 resistor, which can leave more space for the battery pack, improve battery capacity, and increase battery life.
Features:
Ultra-small package 0.97 * 1.47 * WLCSP-6L, does not take up space, ultra-low R (dson): 31mΩ, where the smaller on-resistance will cause less heat loss during power-on, on the one hand, it leads to power efficiency Higher, on the other hand, will reduce the overall temperature rise of the product and reduce the failure rate. Ultra-small power consumption: as low as 7na off current, TWS can basically consume no electricity on the shipping road
Power on: There are two ways, 1. Press the button 1.3S to turn on 2, VBUS power supply trigger
Power Off: There are two ways: 1. Press the button 7S to turn off 2. OFF PIN to trigger a rising edge, turn off after 7S
Application note:
Many TWS now have no buttons. Power on is triggered by Vbus power supply. Power Off is triggered by OFF power supply. GLF76321 is connected behind the lithium battery protection. Before testing the factory, giving a signal to the OFF pin will all the loads behind Vout. Turn off, so as not to consume power. When the user gets the hand, he will put the earbud into the charging compartment, pair the Bluetooth with the mobile phone, and then turn on the GLF76321. After the power is turned on, it is basically fully charged.