Parts - Voltage Converter modules

Specifications

• Buck and Boost DC-DC voltage regulator
• 1.8 - 5.0V input
• 3.3V output
• 100mA continuous, 150mA burst
• 0.65mA no-load current
• 11mm x 7.62mm x 4.5mm (excludes pins)
• Ideal for LiPo battery input (3.0 - 4.2v)

Specifications

• 3.3v DC-DC Boost convertor
• 0.8 - 3.3V input
• 3.3V output
• 11mm x 10.5mm x 7.5mm (excludes pins)
• Ideal for AA/AAA battery operation

Specifications

• HT7333-A
• 3.3v LDO Linear Regulator
• Upto 12v input
• 250mA max current
• 4µA quiescent current (power used when off)
• Dropout voltage: 90 mV
• Ideal for battery powered circuits with low power sleep mode
•  Data Sheet

Specifications

• 5v DC-DC Boost convertor
• Input: 2 - 5v
• Current: 1A typ, max 1.2A
• Output: 5v USB-A connector

This is the kind of circuit you find in those phone charger battery packs, use it to provide a USB style power connection supplied from LiPo or AA batteries.

Pair this with a TP4056 Battery Charger and a Lithium battery to make your own rechargable battery pack.