Importance of a good benchtop power supply

Benchtop power supplies have had to evolve rapidly to provide the features needed to test PCBs integrating complex components.The first instrument which comes to the mind of most engineers when it comes to testing a new board is an oscilloscope. While that will help to assess many aspects of the board’s performance, it’s not the only device that will be needed – a good benchtop power supply is just as important. One reason for this is the range of more advanced components being integrated onto PCBs. While bench power supplies must be capable of providing up to 60V, they also need to be able to supply up to 20A at lower voltages. Meanwhile, voltage rails are changing and there’s not just one supply rail to a PCB any longer.

Benchtop power supplies in the past were predominantly linear devices. However, despite providing low noise and good stability, linear supplies tended to be large and relatively inefficient. According to Edwards, most power supplies rated at more than 100W use switch mode technology. The QPX and CPX ranges use our PowerFlex architecture to provide higher currents as the set voltage is reduced. While PowerFlex uses mixed mode regulation, the PowerFlex+ architecture uses a multiphase conversion technique to eliminate the need for a linear output stage and this provides a wider voltage-current combination. Using this technology, the QPX600D can provide up to 80V or up to 50A within its 600W operating envelope.

Lovell said that, typically, a bench power supply used to offer 0 to 50V and 0 to 10A – a total load of 500W. Today, devices are smarter, with a wider voltage range and a wider current range. That means engineers can use a higher voltage at lower current and vice versa. In this way, one power supply can replace several units that might have been needed in the past. But range is most important. There’s also increasing demand for greater accuracy.