Matching between power supply and application
By understanding engineering parameters such as efficiency, input surge current, ripple and noise, and startup overvoltage, we are able to test and validate commercial solutions to ensure they meet the power requirements of industrial PID controllers and provide good regulation performance with longer mean time between failures (MTBF).

However, it is easier said than done to match commercial solutions with the product specifications of the application, as at that time, the solutions provided by each supplier were often limited to a few models. In addition, due to our budget constraints, the available models have become even fewer. This usually means specifying a power source that can work properly, which usually represents making some kind of compromise.

For example, sometimes we end up using a commercial power supply that can fully meet the controller's current and voltage requirements, but typically operates outside its most efficient output range, especially at low loads. As a result, it resulted in additional power consumption and thermal management challenges that we could have avoided.

Expand the scope
The field of modular power supply has undergone decades of rapid changes, and compared to my original design, it has already achieved a leap forward. Now, the range of options for commercial spot solutions is amazing and completely unrestricted by budget constraints.

Taking TRACO Power's industrial AC/DC power supply series as an example. The company has added four new power stages to its already extensive TXN series. These power supplies now come in 35 W, 200 W, 350 W, or 800 W output power versions, and can specify 12 V, 15 V, 24 V, or 48 V output voltages for each power level. For the 35W version, 3.3 V and 5 V options are also available. This series of products also includes the following models: TXN 35-124 (35 W, 24 W AC/DC power supply), TXN 200-124 (200 W, 24 V), TXN 350-115 (350 W, 15 V) (Figure 1), and TXN 800-148 (800 W, 48 V).

Figure 1: The TXN 350-115 350 W power supply provides a 15 V DC output voltage at 90 V to 260 V AC input. (Image source: TRACO Power)

This series of power supplies adopts a frame type metal shell and is equipped with threaded terminal block connectors, making it the most cost-effective enclosed AC/DC power supply product of the company. Its features include: 3000 VAC enhanced I/O isolation, built-in EN55032 Class B filter (for reducing conducted and radiated emissions), active power factor correction (PFC) of over 100 W, IEC/EN/UL 62368-1 safety certification, and compliance with EN 61000-3-2 electromagnetic compatibility (EMC) standards. These power supplies are even equipped with internal fans for forced cooling.

Affordable price and excellent performance
However, the TRACO Power TXN series power supply not only achieves high cost-effectiveness, but also maintains the expected performance. For example, the input voltage range of TXN 350-115 is 90 V to 260 VAC, and the operating temperature range is -30 ° C to 70 ° C. This power supply offers an adjustable nominal output voltage (Vout (nom)) ranging from 13.5 V to 15.5 V, with a maximum output current (Iout (max)) of 22 A and a maximum output power of 330 W.

At 230 V input, the active PFC is 0.95. The voltage setting accuracy is ± 1%. Within the load variation range of 10% to 90%, the regulation rate changes by 1%, and the maximum output voltage ripple is 150 mV peak to peak (mVpp) (Figure 2). This power supply has an output current limit of 110% to 160% Iout (max) and overvoltage protection of 110% to 140% Vout (nom). MTBF is 230600 hours.