Intro

Step-Up converter module using TPS61040, ideal to boost a single li-ion cell (typically 2.5V - 4.2V) or a USB power supply (5V) to up to 28V, to power any device that does not need lots of current, but requires a very low quiescent current to ensure the battery is not drained, when there is no load.

Specs of the IC

• 1.8V - 6V input
• 1.8V - 28V adj. output Voltage
• 0.4A output current
• 28uA quiescent current

Specs of the PCB (measured)

• 2.2V - 6V input
• 2.2V - 28V adj. output
• 0.4A output
• 60 uA quiescent current

Power Consumption

Power consumed by the board alone with no load (quiescent current)

• 61 uA @ 6.0V in (6V out)
• 59 uA @ 5.0V in (6V out)
• 60 uA @ 4.2V in (6V out)
• 63 uA @ 3.3V in (6V out)
• 65 uA @ 3.0V in (6V out)
• 73 uA @ 2.2V in (6V out)

Power Output

output range 2.93V - 13.87V
output power @ 3.0V in
V out without load -> V out with load after @

• 13.87V loadless -> 13.8V @ 100mA
• 12.00V loadless -> 11.8V @ 100 mA
• 9.00V loadless -> 8.8V @ 100 mA
• 6.0V loadless -> 5.8V @ 100mA
• 5.0V loadless -> 4.7V @ 100mA
• 3.3V loadless -> 3.0V @ 100mA

BOM

• C_FF: 0603 22pF
• C_IN: 0603 4.7uF
• C_O: 0603 1nF
• D1: any Schottky between SS14 & SS54
• EN_J: short, if board should be always on -> EN becomes redundant
• L1: CD43 10uH
• R1: 0603 up to 1MOhm, use if VR1 is unnecessary and needed resstance is known
• R2: 0603 100kOhm
• U1: SOT23-5 TPS61040
• VR1: 3x3 trimpot 1MOhm, sets output voltage by adjusting its resistance

PCB

Schematic