Showing posts with label power card. Show all posts
Showing posts with label power card. Show all posts

Thursday, November 23, 2006

Soldering the Power Card


The power card is soldered and seen on top of the sensor board. The critical components in the card is the two TPS60130 step-up converters, the ceramic input capacitors, the ceramic output capacitors and the ceramic flying capacitors which are not seen on the picture since they are on the bottom side. There is also one SMD red LED (near the bottom right corner) to show the condition of the battery. The red cable is used to connect Vin to the ENABLE pin of TPS60130 which makes the power card always ON. This configuration is temporary and for testing purposes only. There will be a PIC 10F202 microcontroller that will take input from LOW BATTERY output of TPS60130 and from power button of the Kobot. In this way Kobot can be turned on and turned off by the user. Also when the battery is low, the microcontroller sends a signal to the microcontroller on the main card to take precautions before the system is shutdown. The power system includes also a fuse mounted on the bottom side of the sensor board.

Power Card

We started building the Kobot from the power card. The power card is the main power source of Kobot's. It is 30X20mm in size and has two TPS60130 step-up converter chips from TI. The input to the power card is either from one-cell Li-Poly battery having a nominal voltage of 3.7V or from 3-cell AAA-size NiMH batteries having a nominal voltage of 3.6V. The output is a constant, almost ripple free 5V.