Today we’ll be taking a look at the Lenmar PowerPort Universal Laptop Power Pack, it’s a power pack to provide power to your laptop or device, it outputs 16V/19V and 5V at 1amp and an input plug accepts your laptop’s charger to charge the Lipo 11.1V / 5500mAh battery. To use the device, you connect your load and press the button which switches the load on.
A lot of little screws later and we’re in.
We have 6x 3.7V 2865mAh batteries with each pair of batteries wired in parallel to give us a 3 cell battery and there’s some adhesive on the case for the inductor to keep that from moving around. PCB date code is Nov 2011.
There’s quite a lot of components, more than I thought would be in it and I didn’t expect to see an ATmega as the MCU. An 0.01 ohm sense resistor at battery1 ground helps to sense current flow so when the button is pressed, the LEDs turn on for a few seconds and if a voltage drop is detected due to having a load connected then it keeps supplying power otherwise after the LEDs turn off, it switches off power. We have 6x R&C branded 220uF capacitors and a 51 ohm resistor with a small 6 pin chip for each battery, I’m guessing it may be some part charge/discharge controller/balancer.
After the input jack we have a large SS54 schottky for input protection and just before the output jack, we have a SR1045 schottky barrier rectifier with a 9962GH N mosfet which allows us to choose whether the output goes through the inductor or not.
A BM2AA DC-DC converter handles the 5V output.
1. Atmel ATmega 8 bit Microcontroller
ATmega48A
2. Seiko Instruments Battery Protection
This chip protects the battery from overcharging and overcurrent and requires an 2 external mosfet for charging/discharging.
S8254A
3. MPS 2/3-Cell Switching Li-ion Battery Charger
Up to 2 amp charge current
MP26123
4. Feeling Technology Boost Converter
Used to boost the battery voltage to 16V or 19V output
FP5139
5. ST LM324 Op-amp
LM324_ST
