- Fri Sep 03, 2010 5:07 pm
#108837
Hi all -
I've been working on this project for a bit, and I'd appreciate some feedback on my design from some more knowledgeable minds. I built a prototype board, and have had a few issues so a new perspective would be helpful.
I've built a data logger on a bare-bones Arduino set-up. The data logger includes an ADXL345 accelerometer and a micro-SD card (both run on 3.3V). I would like to power the Atmega chip with 5V so that I can use the 16 MHz crystal. I would like to supply power to this set-up with a LiPo battery and include a circuit to charge the battery through a mini-USB.
I've chosen Microchip's MCP73833 (http://ww1.microchip.com/downloads/en/D ... 22005b.pdf) to charge the battery. To boost the battery voltage to 5V I selected the LT1302 (http://cds.linear.com/docs/Datasheet/lt1302.pdf). I then used a LDO regulator (http://ww1.microchip.com/downloads/en/D ... 22008d.pdf) to drop the 5V to 3.3V. I'm not sure if this is the most efficient design, so any tips in that area would be appreciated. I also added a switch so that I can charge the battery without supplying power to the other components. The goal of this would be to prevent data-logging while charging the board.
I've attached the schematic. Thanks for taking the time to look at it.
I've been working on this project for a bit, and I'd appreciate some feedback on my design from some more knowledgeable minds. I built a prototype board, and have had a few issues so a new perspective would be helpful.
I've built a data logger on a bare-bones Arduino set-up. The data logger includes an ADXL345 accelerometer and a micro-SD card (both run on 3.3V). I would like to power the Atmega chip with 5V so that I can use the 16 MHz crystal. I would like to supply power to this set-up with a LiPo battery and include a circuit to charge the battery through a mini-USB.
I've chosen Microchip's MCP73833 (http://ww1.microchip.com/downloads/en/D ... 22005b.pdf) to charge the battery. To boost the battery voltage to 5V I selected the LT1302 (http://cds.linear.com/docs/Datasheet/lt1302.pdf). I then used a LDO regulator (http://ww1.microchip.com/downloads/en/D ... 22008d.pdf) to drop the 5V to 3.3V. I'm not sure if this is the most efficient design, so any tips in that area would be appreciated. I also added a switch so that I can charge the battery without supplying power to the other components. The goal of this would be to prevent data-logging while charging the board.
I've attached the schematic. Thanks for taking the time to look at it.
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