How to Choose a DC Regulated Power Supply? Everything You Need to Know

18 septembre 2025

In the electronics field, a DC regulated power supply is a crucial piece of equipment. Choosing the right one ensures smooth subsequent work, while a wrong choice can lead to constant troubles. Let's discuss how to select a DC regulated power supply.

First, Clarify Core Parameters

Voltage and Current Range

First, determine the maximum voltage and current required by the equipment. When selecting a power supply, it should cover the maximum demand and also reserve a 10-30% margin to cope with transient requirements or future expansions. For example, if the equipment operates at 12V, choose a power supply with a maximum output of 15V or 18V; if the operating current is 1A, select one with a maximum output of 1.5A or 2A. Additionally, some equipment has high peak currents during startup or operation, so it is necessary to check whether the power supply can provide sufficient instantaneous current without triggering protection.

Power

Power is calculated as the product of the maximum voltage and maximum current. The rated power of the power supply must be greater than the calculated maximum power demand. Similarly, it is recommended to reserve a 20% power margin to avoid reduced power supply lifespan and increased failure risks due to long-term full-load operation.

Accuracy and Stability Cannot Be Ignored

Setting and Reading Accuracy

There are errors between the set values and actual output values of voltage and current, as well as between the display values on the meter and the actual values. Examples of such error ranges include ±0.1% + 10mV and ±0.1% + 20mV.

Regulation Rate

Load regulation rate refers to the rate of change in output voltage when the load current changes from no-load to full-load. Line regulation rate is the rate of change in output voltage when the AC input voltage varies within a specified range. The smaller these two rates, the better; for instance, 0.01% is an excellent value.

Ripple and Noise

These are AC components superimposed on the DC output. Digital circuits, high-precision analog circuits (operational amplifiers, ADC/DAC), and RF circuits are sensitive to ripple and noise, thus requiring a low-ripple and low-noise power supply (e.g., <5mVpp or <1mVrms).

Choose Channels and Output Modes Based on Needs

Number of Channels

If you need to power multiple devices or multiple voltage points simultaneously, a multi-channel power supply is convenient but comes with a higher cost.

Channel Relationship

The channels of a multi-channel power supply can be independent, series-connected, parallel-connected, or rail-to-rail. Independent isolated channels are particularly useful, such as for separately powering analog and digital components.

Output Modes

Most power supplies are constant voltage (CV) sources, and some also support constant current (CC) mode (e.g., for charging, driving LEDs). Advanced power supplies can also operate in constant power (CP) mode or battery simulation mode.

Interfaces and Control Should Be User-Friendly

Front-Panel Control

Control methods include knobs, buttons, numeric keypads, and encoders. Usability is crucial—displays should be clear and operations simple.

Remote Control Interfaces

Analog: 0-5V/0-10V voltage control or 4-20mA current control for setting output.

Digital communication: Interfaces such as USB, RS232, GPIB (IEEE-488), LAN (Ethernet), and CAN. These are key for remote control, automated test equipment (ATE) integration, and data acquisition. Select interfaces supported by your test system (e.g., LabVIEW).

Display

LED/LCD/VFD screens should be clear and easy to read, capable of displaying set values, actual values, status information, etc., simultaneously.

Protection Functions Ensure Safety

Over-Voltage Protection (OVP): Automatically cuts off or clamps the output when the output voltage exceeds the preset safe value, protecting the device under test.

Over-Current Protection (OCP): Automatically limits current or cuts off the output when the output current exceeds the preset safe value, protecting both the power supply and the device under test.

Over-Temperature Protection (OTP): Automatically reduces power or shuts down when the internal temperature of the power supply is too high.

Reverse Polarity Protection: Prevents damage caused by reversed positive and negative output connections (available on some models).

Reliable protection functions are essential for the safety of experiments and production.

Special Requirements

Low noise/low ripple: Essential for critical applications.

Battery simulation function: Can simulate battery internal resistance and charge-discharge curves.

High-speed modulation capability: Suitable for applications requiring the power supply to change output quickly, such as power dynamic response testing.

List/timing function: Can automatically change output voltage/current values according to a preset program.

Readback accuracy: Important when data collection via interfaces is needed.

Physical factors: Consider size and weight (desktop or rack-mounted, standard 1U/2U) and input voltage (AC 100V/120V/220V/240V, etc.) to ensure compatibility with the local region.

Balance Brand, Quality, and Budget

Choose brands with a good reputation and strong technical capabilities. Their products undergo thorough verification and use reliable designs and materials. Also, pay attention to heat dissipation design, fan noise level (temperature-controlled fans are an advantage), warranty period, and technical support/service capabilities. Check user reviews and professional evaluations.

Typically, the higher the functionality, accuracy, power, and brand reputation, the higher the price. Seek the best cost-effectiveness while meeting core needs.

Summary of Selection Steps

Clarify core needs: Determine the most demanding requirements of the device/system to be powered, such as maximum voltage, current, power, ripple requirements, accuracy, and necessary functions like programmability.

Screen specification parameters: Preliminarily screen power supply models that meet the parameter requirements based on core needs.

Select type and grade: Decide whether to choose a basic, high-performance, economical, or programmable model, and whether multi-channels or special interfaces are needed.

Compare brands and models: Among models that meet core specifications, compare functionality richness, usability, interface types, protection functions, size, noise, brand reputation, and user reviews.

Consider budget and services: After comprehensive comparison, make the final choice within the budget and pay attention to warranty and support services.

Review manuals in detail: Before the final selection, be sure to read the user manual and technical specifications carefully to confirm that all details (e.g., protection threshold setting methods, ripple test conditions) meet expectations.

Key point: Do not only focus on maximum specification values. Pay special attention to indicators reflecting power supply output quality and adaptability to different loads, such as accuracy, ripple noise, and regulation rate. For R&D and testing, accuracy and stability are often more core requirements.

By systematically evaluating the above aspects, you can select the most suitable DC regulated power supply for your specific application.

If you're looking for a DC regulated power supply brand with a wide range of models, functions, and parameters to choose from, KUAIQU is a great option.