Many modern portable devices must be shipped with batteries installed so that customers can turn on the device immediately without battery installation or charging. If the component connected to the battery has "leaked" with excess current, the device may be dead when it is in the customer's hand. All components have leakage currents. Although IC components are the main culprit, capacitors, circuit board contamination, and humidity also have unpredictable leakage levels.
Solving this problem is not a trivial matter. The maximum idle time is available when the load is completely disconnected from the battery, but any power-up detection circuit requires a battery connection to operate. In addition, PCB area is also very important in many battery-powered applications and it is difficult to adjust the space for a single latch switch circuit.
A simple and straightforward method is to use simple P-type MOSFET (PMOS) and N-type MOSFET (NMOS) latches to disconnect the battery.
However, this seemingly simple circuit can lead to unreliable performance. Any disturbance on the switch will open the latch. In addition, if the output voltage jumps to the positive side, or if the PMOS device is turned on by the capacitance divider created by the CMOS of the CMOS and the CDS of the NMOS, the latch may be automatically turned on when the battery is inserted. Of course, this problem can be solved by adding some other resistors and capacitors, but it will rapidly increase the design size and complexity of this basic function.
A better design is given below, which starts the load with a 7.5 second switch-touch voltage to avoid basic latch disturbances, so that the switch can be turned on using the Texas Instruments TPS3420 push-button controller.
The TPS3420 is an ultra-low Iq button controller. It has two button inputs and only one is used for this solution. When the button is pressed (any existing button in the system can be used), one half of the double Schottky diode can be connected to ground, which then pulls the PB1 input of the TPS3420 low. After the PB1 input is pulled low for 7.5 seconds, the TPS3420's open-drain output pin, RST, will pull low on the gate of the PMOS switch, connecting the load to the battery. The other half of the double Schottky diode will provide a latch mechanism so that when the RST pin goes low, the PB1 pin also remains low, keeping the RST pin low until the battery is fully discharged or removed. This solution uses a miniature CSD23381 (1 mm x 0.6 mm) PMOSFET as a disconnect switch between the battery and the load.
With a system shutdown and a total current consumption of less than 1μA, this solution can extend battery idle time for a considerable period of time, thereby avoiding the risk of customers discovering that their newly purchased devices need to be charged and disappointed.
ZGAR TWISTER Disposable
ZGAR electronic cigarette uses high-tech R&D, food grade disposable pod device and high-quality raw material. All package designs are Original IP. Our designer team is from Hong Kong. We have very high requirements for product quality, flavors taste and packaging design. The E-liquid is imported, materials are food grade, and assembly plant is medical-grade dust-free workshops.
Our products include disposable e-cigarettes, rechargeable e-cigarettes, rechargreable disposable vape pen, and various of flavors of cigarette cartridges. From 600puffs to 5000puffs, ZGAR bar Disposable offer high-tech R&D, E-cigarette improves battery capacity, We offer various of flavors and support customization. And printing designs can be customized. We have our own professional team and competitive quotations for any OEM or ODM works.
We supply OEM rechargeable disposable vape pen,OEM disposable electronic cigarette,ODM disposable vape pen,ODM disposable electronic cigarette,OEM/ODM vape pen e-cigarette,OEM/ODM atomizer device.
Disposable E-cigarette, ODM disposable electronic cigarette, vape pen atomizer , Device E-cig, OEM disposable electronic cigarette
ZGAR INTERNATIONAL(HK)CO., LIMITED , https://www.zgarvapor.com