Guide to Output Voltage Trimming

Output voltage trimming is an advanced engineering technique that delivers several valuable benefits to power supplies. This approach can help meet performance and customization demands across industries.

At Astrodyne TDI, we use output voltage trimming in our high-quality power supplies. We deliver reliable, durable solutions and can customize components according to your unique needs. We help solve product design and manufacturing time issues through processes like output voltage trimming.

What Is Voltage Trimming?

Systems engineers usually identify the voltages they need to run their circuits, often as nominal values like 5V. 12V or 24V. Their circuits can work with a certain range of input voltage, so they don’t usually like to create any special voltages. But not all circuits are the same. There are always some unique circuits that need a very specific voltage to perform best. Examples are RF amplifiers which deliver their best performance at only one input DC voltage. Another common example of an unusual voltage system is the common laptop power supply where a non-standard voltage like 19V is specified. 

In early development, the system designer determines the ‘sweet spot’ by iterating between a few voltages. This is when having the ability to TRIM the output voltage of the power supply helps immensely. Once a sweet spot is known, the systems engineer may specify a value to be set in production, so that they receive all units with the exact same voltage to start with. Once they have a reference, they can always fine-tune the exact voltage by one of the methods discussed below.
 

Common Voltage Trimming Methods

There are a few methods of voltage trimming

• The preset trim resistor on the power supply’s control board is the most common but does not allow the end-user to trim it themselves
• A trimpot, or potentiometer provided on the power supply with an access hole for the end-user to trim using a fine screwdriver blade is quite common. A single-turn trimpot is an economical type, but a multi-turn trimpot gives the user ability to adjust in fine steps. 
• Trimming with an external resistor or trimpot allows the end-user full control within the limits defined by the power supply manufacturer
• Analog control voltage trimming (Vtrim) requires the user to apply a specified voltage to achieve a target output voltage. The user can vary the Vtrim to tweak the voltage precisely. 
• Digital control with a digital word that represents the power supply and a control value is common. This will enable the user to set the target voltage on a GUI which is then translated to a control voltage and sent to the power supply via a communication interface. Interfaces like RS-232/RS-485 are commonly used as local control means. Remote control from a network like the internet may need more sophisticated interfaces like PM Bus, ModBUS, CANBUS, or Ethernet. In specific industrial markets like semiconductor manufacturing, EtherCAT is widely used. 

The objective of all the above methods is to TRIM the power supply voltage either just once or dynamically during use. Most power systems offer a trim range of +/-5% with some application-specific types offering a wider range of +/-10%.

Different end uses have different types of trim requirements, both in value and speed. At Astrodyne TDI we recognize the value of unlimited flexibility to the systems engineers and launched power systems with ultra-wide trim range, sometimes from zero volts to as high as 500V. This feature is available in our high-power product line in Mercury Flex, LiquaBlade, and other derivative power systems. 

To enable the user with unlimited flexibility in the method of control we offer multiple types of trimming by presetting in our production line or letting the user set their target value with digital control over one or more communication bus standards.  We even offer a communication platform called the e-Link which can support multiple communication bus standards. 

Voltage Trimming Benefits

Voltage trimming techniques serve various purposes, offering several benefits.

• Performance: System performance can be optimized with the precise setting of its operating voltage. 
• Reduced stock requirements Allow procurement of one power system and use it widely in their organization minimizing thus minimizing variety and streamlining the supply chain. 
• Flexibility: Voltage trimming can standardize the device's output voltage for almost any application to meet custom or non-standard needs.

Below are some fine examples of systems performance-optimized and supply chain simplified using trimmable power supplies from Astrodyne TDI.

1. Large corporations with several product lines purchased a Mercury Flex power supply with a 0-56V trim range and used the same part effectively in different uses by setting it to 24V to run motors, 18V to run electronics, and 48V to run other electromechanical parts
2. A laser tattoo removal machine used to break up colored ink under the skin with lasers needs to vary the laser drive voltage between 22 and 28V depending on the intensity of the patch. The system normally uses a 24V but occasionally, it may need 28V to generate higher laser power. The best way to get there is to trim a power supply to using local analog trim.  The system designer can hit a single button to change the output voltage from 24V to 28V and back again.
3. Radar needs to adjust its performance according to different battle scenarios and weather conditions. Engineers vary the voltage to the RF amplifier during development and determine different voltages needed for the different conditions.  To get there, they can trim the power supply.
4. Company A is developing a line of new battery chargers to accommodate multiple battery types, such as lead-acid and lithium. These batteries need different charge voltages, which a trimmable power supply can offer through a switch-selectable battery type setting.
5. A company might be developing a system to seal beverage cups of different sizes. Smaller cups have correspondingly smaller lids and need less power to seal. The larger cups use more power and voltage to seal. A voltage trimmable power supply can make it simple to ramp the voltage up or down for the different cup sizes.

Tethered drones and ROV manufacturers need a specific voltage at the end of a long tethering feed cable, which can vary. Depending on a site, they can select different voltages to feed to the tether to achieve a set value at the end of the tether feed cable. An extra-wide trim power system enables them to install one power supply and use it for all their sites and tether feed lengths.

Astrodyne TDI's Voltage Trimming Capabilities

Astrodyne TDI offers an array of products that can support voltage trimming, along with custom solutions when an off-the-shelf product doesn’t match your exact requirements. Using advanced tools and modern technology, we design made-to-order power supplies and EMI filters to support your operations.
Some of our voltage trimming solutions include the following.

• HermesFlex: HermesFlex is the ideal solution for applications that need a digitally controlled industrial or medical power supply with a universal 90-264VAC, 50/60Hz single-phase input, and wide-range DC output. These modules support outputs from 28 to 500V. Hermes Flex is a medical-grade IEC60601 certified with 2 MOPP isolation and BF leakage current.
• LiquaBlade: This 16.5kW water-cooled power supply offers efficiency, reliability, and easy maintenance for high-powered DC systems in industrial and military settings. Output options range from 0 to 500V.
• MercuryFlex: The MercuryFlex lineup is well-suited to a range of applications, thanks to programmable fixed or variable outputs from 0 to 450V. It offers strong reliability through 100% HASS testing and a highly maintainable hot-swap design, with analog or digital and local or remote control options.

At Astrodyne TDI, we provide state-of-the-art engineering, with ISO 9001 and ISO 13485-certified facilities in New Jersey, California, and China. With 60 years of experience, we have earned a reputation for our ability to manufacture high-quality products for some of the most demanding industries and markets. If you have challenging power conversion requirements, our team is ready to discuss power and filtering solutions designed to meet your specific needs.
Contact Astrodyne TDI online to learn more about how we can work together or call a representative at 908-850-5088 for additional support.