DCDC Buck Converter USB Charger
author: fisher0251
2 layer board of 2.15 x 1.60 inches (54.6 x 40.6 mm)
Uploaded:
June 07, 2015
Shared:
June 08, 2015
Total Price:
$17.20
I designed this as a universal USB charger for phones and tablets. Vin = +8-12V, Vout = +5V @ 1A. I’m using one or two 8-AA battery packs for Vin depending on how much current is required at the output.
It uses the LM2675-ADJ from TI as U1. By choosing the appropriate inductor L1, input and output capacitors C1 and C2, and feedback resistors R1 and R2, this can be configured for other output voltages. R3 to R6 set voltages on the D- and D+ USB lines to allow for Apple device charging up to 1A (as discussed by Adafruit’s Lady Ada here).
Components: LM2675-ADJ, PDIP-8 package L1 = 33uH, CoilCraft DO3316P-333 C1 = 150uF, low-ESR aluminum electrolytic cap, Panasonic EEE-FP1V151AP C2 = 100uF, low-ESR aluminum electrolytic cap, Panasonic EEE-FP1V101AP C3 = 0.01uF, 0805 ceramic cap D1 = 20V 3A Schottky diode, DO214AC package R1 through R6 all 0805, 1%: R1 = 1k, R2 = 3.16k, R3 = 43k, R4 = R6 = 49.9k, R5 = 75k R7 = 220ohm, 0805, 5%
Vin is designed for a 5.5mm DC barrel jack like this one.
The USB jack is a common USB-A female through-hole plug.
This board has been tested at +5V, 1A output. The LED polarity has been reversed from what is indicated on the silkscreen.
I designed this as a universal USB charger for phones and tablets. Vin = +8-12V, Vout = +5V @ 1A. I’m using one or two 8-AA battery packs for Vin depending on how much current is required at the output.
It uses the LM2675-ADJ from TI as U1. By choosing the appropriate inductor L1, input and output capacitors C1 and C2, and feedback resistors R1 and R2, this can be configured for other output voltages. R3 to R6 set voltages on the D- and D+ USB lines to allow for Apple device charging up to 1A (as discussed by Adafruit’s Lady Ada here).
Components: LM2675-ADJ, PDIP-8 package L1 = 33uH, CoilCraft DO3316P-333 C1 = 150uF, low-ESR aluminum electrolytic cap, Panasonic EEE-FP1V151AP C2 = 100uF, low-ESR aluminum electrolytic cap, Panasonic EEE-FP1V101AP C3 = 0.01uF, 0805 ceramic cap D1 = 20V 3A Schottky diode, DO214AC package R1 through R6 all 0805, 1%: R1 = 1k, R2 = 3.16k, R3 = 43k, R4 = R6 = 49.9k, R5 = 75k R7 = 220ohm, 0805, 5%
Vin is designed for a 5.5mm DC barrel jack like this one.
The USB jack is a common USB-A female through-hole plug.
This board has been tested at +5V, 1A output. The LED polarity has been reversed from what is indicated on the silkscreen.
