Are you still worried about choosing a solution for multi-channel power output? Come here and end your worries!

If you do not have professional power supply design experience, especially transformer parameter design, your first choice may be to buy an isolated power supply module. The advantages are small size and ease of use. However, there are very few types of isolated power supply modules on the market that can directly support +/-15V and +5V multi-channel outputs, and the prices are generally high.

Solving your pain has always been ADI's unremitting efforts and pursuit of the goal. To this end, for such applications, ADI provides a variety of simple and easy-to-use reference solutions and standard transformer design indicators to meet customers' different working conditions and different power requirements.

Isolated power topology has been widely used in different industrial products and applications for many years, such as PLC, DCS, etc. In order to achieve better performance, more and more end users require isolation between digital and analog areas, or even physical isolation between channels. The main purposes are as follows:

Safety

reliability

Minimize ground noise

For most amplifiers, multiplexers, and DAC drivers, bipolar supplies are required for proper operation, so an isolated triple-tapped output power supply solution can easily meet most of these requirements.

There are two main types of isolated power solutions on the market: traditional feedback solutions consisting of discrete components and DC to DC modules.

The first type of solution usually requires a lot of design experience. Since a large number of discrete components are used, the PCB size is always a headache.

The advantages of the second type of solution are small size and ease of use, but its efficiency, load regulation and line regulation are far from excellent. Due to the limitation of the transformer, it is difficult for the DC to DC module to provide multiple isolated power outputs, which still requires customers to perform secondary buck/boost regulation themselves.

For general product engineers, designing isolated power supplies from the beginning is a big challenge without rich experience in power supply design, especially in complex transformer design and debugging. To achieve a good isolated power supply design, the following challenges need to be solved:

Smaller PCB size and height

Lower cost X transformer parameter design

Load regulation, line regulation and cross regulation between channels

efficiency

Output Power

LT8301 and ADuM3471 are highly integrated power isolation solutions provided by ADI. They are suitable for isolated multi-tap transformer control in the power range of 2.5 W to 5 W, and different combinations can meet different efficiency, load and power regulation requirements.

To simplify the design workload, several common examples are given below. ADI also provides the key diode product models used and the recommended transformer product models.

Transformer design parameters and specifications

Figure 1. Small package, lower power consumption (ER11.5).

Figure 2. Large package, higher power consumption (EP10).

Figure 3. Solution 1 integrating the LT8301.

Efficiency curve

Figure 4. Solution 2 integrating the ADuM3471.

Efficiency curve

Figure 5. Comparison curve of different transformer efficiencies.

Reference Design

For those who want to evaluate the power supply solution with AD5755-1, ADI will provide the following reference design separately. There are two control methods, one is through PC SDP control, and the other is directly through touch screen control/display.

Figure 6. 4-channel current output design using AD5755-1 (with SDP board).

Figure 7. 4-channel current output design using AD5755-1 (with touch screen control).

In summary, these are ADI's 3 transformers and 6 solutions based on LT8301 and ADuM3471, with applicable conditions ranging from 2.5 W to 5 W to meet different application requirements. In this way, you can easily choose a power supply system for bipolar power supply analog input or analog output. These solutions help to greatly reduce design work, reduce PCB space and bring better efficiency, power supply/load regulation and other performance. I hope everyone can get their own satisfactory isolated power supply design.