Mouser Electronics Publishes Guide on Power Supply Series and Parallel Connections

Mouser Electronics has published a technical article providing detailed guidance on operating power supply units in both series and parallel configurations. The article was authored by Tassanai Cheangban, Field Application Engineer at Delta Electronics.

Parallel operation is primarily used to increase a system's current output capacity or to provide redundancy for continuous operation. In a 1+1 parallel connection, the total output current can reach up to double the rating of an individual power supply, while also improving load sharing. For N+1 configurations, aimed at enhancing system reliability, the use of external "ORing" diodes, such as Delta's DRR-20N or DRR-40N models, is recommended. In redundant setups, the system's total current demand should not exceed the rating of a single power supply to ensure uninterrupted operation in case of a failure.

Achieving effective load sharing in parallel connections requires that the output voltages of the connected power supplies be closely matched, within a 25mV difference. Voltage adjustments should be performed under a load of at least 50% of the rated current, or above 25% load, ensuring both units are adjusted to the same current level independently.

For redundant operation, "ORing" diodes are installed between the power supplies to maintain a typical output voltage difference of 2%. For a 24V power supply, this translates to approximately 0.48V. If one power supply fails, the other takes over the system load seamlessly. When selecting these "ORing" diodes, it is crucial to ensure they meet the required current and voltage ratings and have adequate heat dissipation capabilities.

Series connection allows for increasing the system's output voltage by connecting power supplies sequentially. It is advised to use power supplies from the same product series and with identical rated output currents for such configurations. If the total output voltage exceeds 60Vdc, it no longer meets SELV (Safety Extra Low Voltage) requirements, necessitating the installation of protective barriers against accidental contact. The total voltage should not exceed 150Vdc.