USB Charged UPS
Created: Jun 17, 2015
No description available.
This design is a simple USB charged UPS that can switch between adapter and battery. The device specifically uses the TE Connectivity’s splash proof 2108877-1 micro USB connector recognized for their reliability, robustness and versatility in meeting USB applications. The staggered contact provides improved signal separation as well as enhanced mechanical stability. Its metal reinforcement plate prevents damage to the plastic tab containing the contacts inside the connector and helps prevent potential electrical short circuits.
The device works when the USB power (or adapter) is not present, the VUSB_IN line gets pulled to 0V by R4. This brings the gate of the PMOS (G on the symbol) to ground and turns it on allowing the battery to power the circuit. The schottky (marked A and K) stops the battery raising the VUSB_IN line and turning the PMOS off again. When the adapter is plugged in, the gate is pulled to +5V and the PMOS turns off, leaving only the adapter voltage powering the circuit and letting the battery charge.
This USB charged UPS is one of the various applications of TE connectivity’s micro USB connectors. In addition, this may be used as USB charger or connectors for mobile phones, tablets, MP3 players, GPS units and other home electronic devices.