Design Review Challenge 2015 -- Answers!

Design Reviews
#1

So, the Design Review Challenge we’ve been hosting is complete. A link to the working schematic can be found Here.

Answers:

3 Schematic Errors:

  1. CEn is tied to VCC_BAT. Should be tied to GND to enable charging.
  2. EN2 is tied to GND. Should should be tied to VCC_5V_USB to allow the input current limit to be set by R8.
  3. R9 is set to 72K. Should be 37.4K to set the fast charge safety timer to 5 hours.

4th bonus error on layout:
4. The dot on the silkscreens for D1 and D3 are on the wrong side. As a result, the LEDs will be installed backwards during manufacturing and they won’t turn on. The industry standard is to have the dot on the side of the cathode

Special shoutouts to the people who forked our broken design and fixed it!

1 Like
#2

Hi all,

Schematic Error 2:
Why is EN2 connected to VCC_5V_USB and not to VCC_Sys (as you see in the datasheets typical application circuit)?

Thomas