You can set a voltage on this DC-DC converter and the converter itself will determine whether it should reduce or increase the voltage.

Specifications:

• Module type: Non-insulated step-up/down (Buck/Boost)
• Rectification: Non-synchronous rectification
• Input voltage: 5V-32V
• Output voltage: 1.25V-35V
• Maximum input current: 3A
• Maximum output current: 4A (4A requires most likely cooling)
• Conversion Efficiency: 94% (highest)
• Switching frequency: 400KHz
• Output ripple: 50mV (max, factory specification)
• Load regulation: ± 0.5%
• Voltage control: ± 0.5%
• Operating Temperature: -40°C to +85°C
• Short-circuit protection: none
• Dimensions: 48 x 25 x 14 mm

Note: The potentiometer has multiple turns. So it may take a while before you have reached the desired voltage. The potentiometer can rotate about 25x from start to finish.