Catherine Sui
At the beginning of the year 2020, a sudden outbreak of COVID-19 swept the world, causing huge human disasters around the world.
Until the vaccine comes out, the most effective defense we can do is to wear a mask.
Currently, the most effective masks on the market are disposable masks, N95 masks, and electric masks.
Today I would like to introduce the solution for electric mask solutions in the market.
Step 1: The System Charts by TI
About the solution for the electronic mask, TI has a completed solution for reference. The system Charts as below;
JLCPCB$2/5pcs 2Layer & $5/5pcs 4Layer PCBs
Step 2: Lithium Ion Battery Charging Solutions
Electric masks are usually powered by a single string of small lithium-ion batteries, which are charged through a USB port.
For such system configuration, TI provides a high-precision dedicated charging management chip BQ24040, as shown in the typical application block diagram below;
The BQ24040 is a highly integrated high-precision high-current charging management chip designed for portable products in a small space.
An input voltage range of up to 30V allows the battery to be recharged not only via USB but also through a variety of low-cost adapters without damage. The maximum charging current of 1A can satisfy the user to charge quickly. Excellent performance makes BQ24040 widely used in smartwatches, bracelets, Bluetooth headsets, electric masks, and other products.
Step 3: Battery Protection Solution
Improper use of lithium-ion batteries will lead to explosion and other safety risks. The protection of lithium-ion batteries plays a crucial role in the safety performance of products.
For a single low voltage lithium-ion battery, TI launched a BQ2970 low-cost dedicated protection chip. BQ2970 provides protection against lithium-ion/lithium polymer batteries and monitors external power MOSFET to provide protection against the high charge-discharge current, including overcharge protection, over-discharge protection, charge-discharge overcurrent protection, short-circuit detection. The current consumed in normal operation mode is only 4 A, reducing the battery power consumption. The size is the only 1.5mm*1.5mm*0.75mm, which helps reduce the volume of the battery pack.
Step 4: BLDC Fan Motor Drive
The good air permeability of the electric mask comes from its internal circulation fan.
An efficient and silent brushless dc fan motor drive will directly impact the user experience of the product. The DRV10964 is a three-phase sensorless motor driver with internal integrated power MOSFET.
It is designed for high efficiency, low noise, and low peripheral motor drive applications. The proprietary sensorless 180° sinusoidal control scheme provides ultra-quiet motor drive performance.
The DRV10964 includes intelligent lock detection, combined with other internal protection circuits to ensure safe operation. The DRV10964 USES a high thermal efficiency 10-pin USON package with an exposed hot pad.
Step 5: Master Control Solution
The MSP430FR211x series is a powerful 16-bit RISC CPU launched by TI for ultra-low power consumption and low-cost MCU. It provides FRAM of 2KB ~ 4KB and SRAM of 1KB.
The serial interface has UART and IrDA or SPI, integrates 6-bit DAC and 8-channel 10-bit ADC, and has 12 GPIO ports. Its low-power advantages and QFN24(3*3mm) package are ideal for portable devices.
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