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**Edit: the answers are below. This design has been fixed. 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 FUNCTIONAL SPEC * The functional purpose of this design is to charge a battery from the USB connector that is connected to a 1.5A wall charger. This board also provides power to a load connected to VCC_SYS. Status is indicated by the LEDs. The battery is a standard LiPo with max voltage = 4.2V. A limit of 1.3A (+/- 20%) is imposed on the current drawn from the USB connector. A fast charge current of 800mA (+/- 10%) is imposed on the battery. CHALLENGE DETAILS * There are 3 errors in this schematic that will result in the board not working as specified above. * Fork the design, open it in the editor, find the errors, and fix them on the schematic. * Prizes: $25 Amazon Gift if you correctly fix all 3 schematic errors. Upped to $30 if you also make corresponding fixes to the layout and clear all Design Rule violations. Upped to $35 if you also find and fix the 4th bonus error on the layout (ie. the board will not fully function as specified if manufactured and assembled with the current layout. Hint: this error is obscure and you have to be a sharp HW design reviewer to spot it!) HOW TO SUBMIT Tweet us your Upverter username using this message: Hey @upverter, I'm and I completed your Schematic Review challenge. Now gimme my $25 Amazon gift card! * Submissions will be accepted until Feb 26, 2015!
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Component (10)

R10, R9, R6, R8

Generic Resistor (1.13K)


USB Micro B, SMT


Generic Capacitor (1uF)


Generic Capacitor (4.7uF)

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