Selecting the right power supply for your product can seem complicated at first, but once you understand the key criteria, the process becomes much easier. This post will help you navigate the most important factors when selecting a power supply for your device.
1. Understanding Input Voltage
The first step in choosing a power supply is identifying the input voltage, which refers to the power source that will feed your device. Power supplies are designed to work with specific ranges of input voltages, and it’s critical to select one that matches your environment.
AC Input Voltage: For most people, their power source will be AC (alternating current) power, typically from the power grid and into their building where the device needing to powered will be in operation. In some instances, it may be from a generator providing AC Power. Common AC voltages vary by region: 110V in North America, and 220V in Europe and Asia. Another factor is the frequency of the input voltage, which for a majority of users will be either 60 or 50 Hz depending on the location. An exception will be generators or aviation applications, which can be 400 to even 800 Hz, but for most applications it is safe to use a power supply designed to handle a range of AC voltages (90V to 264V, 50~60 Hz) to accommodate global use.
DC Input Voltage: Typically for products running on battery power, automotive systems, or are part of a larger power distribution system, you’ll need a DC/DC converter. Common DC inputs include 5V, 12V, 24 or 48V, but can be as high as 110V and as low as 3.3V. These would need to be converted to a different output voltage depending on your device’s needs. ETA-USA’s line of DC/DC power supplies operate on a wide range of 2:1, 4:1 and even an 8:1 input voltage like the ODC150 series, which can accept any input voltage between 8~75 VDC.
Ensure the power supply matches the input voltage of the region or powering device where your product will be used. If you expect it to be deployed globally, a power supply that accepts both 110V and 220V should be considered.
2. Determining the Right Output Voltage
Next, consider the output voltage—the voltage that your device needs to operate. This is a critical parameter since supplying the wrong voltage can cause malfunctions or damage.
Match the device’s voltage requirement. For example, if your device requires 12V, ensure your power supply outputs exactly 12V. Over-voltage can damage your product, while under-voltage can cause improper function. All of ETA-USA’s power supplies provided a regulated (continuous and consistent) output voltage to keep your device functioning.
Look for adjustable outputs if needed. Some power supplies, including ETA’s, offer flexibility by allowing you to adjust the output voltage (often referred to as “voltage trim” or “voltage adjustment” , which can be beneficial if your product requires different voltages for various applications.
Always verify your device’s required voltage before choosing the power supply.
3. Sizing the Output Current (Amps)
After determining the output voltage, the next important factor is output current. This is the amount of current (in amps) the power supply can deliver to your device.
Determine the device’s current draw. Your product’s technical specifications will list the current it requires, such as 2A at 12V.
Select a power supply with a higher current rating, but not too high. For a device that needs 2A, select a power supply that can provide at least 2A, ideally with some margin (e.g., a 3A supply). This ensures your power supply can handle surges and operate efficiently without overheating or activating its overcurrent safety circuitry.
Never undersize the current rating of the power supply, as this can lead to overheating and damage. While over-sizing is safe, oversizing the supply will affect the size of the supply, and affect the nominal efficiency of the power supply, which we will cover in another post.
4. Understanding Power Factor Correction (PFC)
Power Factor Correction (PFC) is a crucial consideration for products that draw significant power, particularly for those exceeding 75 watts. But what exactly is PFC, and why does it matter?
What is Power Factor?
Power factor measures how effectively your power supply uses the electricity from the grid. A power factor of 1 (or unity) is ideal, meaning that all the power drawn from the source is being used effectively. However, many power supplies, especially lower-cost ones, can have a poor power factor, which leads to wasted energy in the form of heat and higher utility costs.
When to Consider PFC: Power factor correction becomes critical in power supplies with outputs over 75 watts. Below this threshold, the energy savings and efficiency gains may not justify the added cost of PFC. However, for devices with higher power demands, PFC ensures energy efficiency, reduces wasted power, and helps you comply with international energy regulations.
If your product exceeds 75 watts of output power, it’s recommended to choose a power supply with active PFC for optimal energy efficiency and compliance with regulations. ETA-USA’s AC/DC power supplies typically have PFC at 60 watts and above to ensure the efficient delivery of the power profile to your product.
5. Other Considerations
Efficiency: Higher efficiency means less energy is wasted as heat, saving on operating costs and ensuring longer device life. ETA-USA power supplies typically deliver 84% efficiency or higher.
Size and Form Factor: Choose a power supply that fits physically within your product’s design. Compact and slim options are available if space is limited.
Cooling: Some power supplies use fans for cooling, while others rely on passive (fan-less) designs. Fan-less designs are quieter and often more reliable due to fewer moving parts, but may fail from heat fatigue or shut themselves off when operating at elevated temperatures or tightly enclosed systems
Operating Temperature: The ambient temperature of the environment can affect the performance of your power supply. ETA’s line of power supplies can operate as low as -40 °C and as high as 85 °C. However, your electronics will work longer if you maintain an ambient temperature between 10 °C -30 °C (50 °F-86 °F).
Environmental Conditions: If your product is used in harsh environments (e.g., extreme temperatures, humidity, or dust), look for a power supply with appropriate protection ratings like IP65 or higher. ETA-USA offers a line of semi-customizable IP65 rated AC/DC power supplies form 500 Watt to 1,400 watts of output power.
Selecting the right power supply for your product involves understanding key factors like input and output voltage, output current, and operating conditions. At ETA-USA, we specialize in offering power solutions that meet a wide range of specifications, from standard ITE applications to critical medical environments, semi-custom and full custom solutions for non-conventional applications. Contact us today to learn more about how we can help you select the perfect power supply for your product!