Demand is growing for AC/DC power supplies in the medical and industrial equipment markets. OEM designers not only require power supplies that have safety approvals and can operate in harsh environments, but they also need to provide higher power density and efficiency. In addition, cooling, size, and easy installation matter in these applications. Many of the latest AC/DC power supply designs address one or more of these challenges.
In many cases, requirements for AC/DC power supplies in medical and industrial applications overlap, allowing them to be used in both applications. A good example is XP Power’s UCH600 series of convection-cooled, 600-W AC/DC power supplies. These power supplies deliver full-load power under a range of conditions without the need for additional cooling. The ultra-compact power supply measures 8.0 × 5.0 × 1.57 inches, delivering a power density of 9.5 W/in.3 and easy installation thanks to its U-channel construction and low profile.
XP Power’s UCH600 power supplies (Source: XP Power)
These power supplies can be used in medical devices, as well as those requiring body-floating (BF) patient protection that need to operate silently. They can also be used in ITE or industrial electronics applications in environments where dirt ingress would be worsened by forced air cooling or where audible noise and fan reliability issues make forced air cooling impractical, said XP Power.
The power supplies offer high efficiency up to 95%, which ensures that the devices can deliver their full rated power of 600 W at ambient temperatures up to 50°C, even at low line input. At 70°C, a full 300 W of power is available, which does not require any forced air cooling, said XP Power. A 12-V/0.6-A auxiliary fan supply is available for equipment designs that use some forced air cooling.
The UCH600 series carries worldwide safety approvals for ITE/industrial and health-care applications, including IEC60950-1, IEC/EN/UL62368-1, and IEC/EN60601-1 3rd Edition.
Also offering high-density solutions for industrial and medical applications is Bel Power Solutions, a Bel group company. Bel’s ACC750 (industrial) and MCC750 (medical) AC/DC convection-cooled (without a fan) power supplies are suited for environments sensitive to acoustical noise.
The ACC/MCC750 Series provides up to 750 W (900 W peak for <10 s) of regulated output power over a wide input voltage range of 85–305 VAC in a single output of 24 VDC or 48 VDC. The ACC750 Series comes in two U-shaped 1.6-inch–high packages, with and without a protective cover, offering 12- and 5-VSB standby outputs and protection features. These power supplies can be used in video wall display and entertainment lighting, LED lighting engines, industrial control systems, and industrial laser applications.
The MCC750 Series is designed and approved to medical standards (EN/IEC 60601-1) for medical equipment that requires 2 × MOPP protection grade and displays the CE mark for the European Low Voltage Directive. These medical power supplies are suited for laboratory and analysis equipment, X-ray and CT scanners, dental equipment, and medical devices and applications.
In addition, the ACC750/MCC750 Series supports digital power management over the Power Management Bus communications protocol. Multiple units can be connected in parallel for N+1 redundancy and/or higher power, enabled with the internal OR’ing and current-sharing functions.
Another double-duty, as well as tiny, power supply is Recom’s RACM40-K series of 40-W AC/DC power supplies, housed in a 1.6 × 3-inch footprint for open-frame versions and a 1.8 × 3.2-inch footprint for potted versions. The RACM40-K series typically achieves 90% efficiency across a wide line and load range and, despite the ultra-compact size, operates up to 60°C at full load and to 85°C with airflow or derating, according to the company. Full load is also available across the line range of 90–264 VAC.
Single outputs available are 5 V, 12 V, 15 V, 18 V, 24 V, 36 V, and 48 V, with full protection against short-circuit, overload, and overvoltage. No-load consumption is below 0.1 W at 240 VAC.
The RACM40-K series provides 2 × MOPP medical certification up to a 4,000-meter altitude and is suitable for B and BF applications. Other certifications include IEC/EN 62368-1 for audio-visual/IT, IEC 61558-1 for industrial, IEC/EN 61010 for test and measurement, and IEC/EN 60335 for household appliances. Built-in EMC filtering achieves “Class B” compliance with a good margin, said Recom, and meets the requirements of medical EMC standard IEC/EN 60601-1-2 4th edition.
Targeting Class I and II medical and industrial applications is the TDK-Lambda brand CUS400M AC/DC power supply series from TDK Corporation. Rated at 400 W with forced air, the series can continuously deliver 250 W, with peaks of up to 400 W for 30 minutes when convection- or conduction-cooled. TDK said this is considerably longer than many products on the market.
TDK’s TDK-Lambda CUS400M power supplies (Source: TDK Corp.)
These power supplies are well-suited for applications with occasional peak demands, including hospital beds, dental chairs, and other motor-driven products. Applications range from home health care, medical, and dental to test and measurement, broadcast, and industrial equipment.
The CUS400M meets curve B conducted and radiated EMI in either a Class I or Class II (double-insulated) construction, without the need for external filtering or shielding. The power supplies accept an 85- to 264-VAC input and are available with 12-V, 15-V, 19-V, 24-V, 28-V, 36-V, and 48-V outputs. The operating ambient temperature is –20°C (–30°C startup) to 70°C, derating linearly above 50°C to 50% load.
The CUS400M offers an input-to-output isolation of 4,000 VAC (2 × MOPP), an input-to-ground isolation of 1,500 VAC (1 × MOPP), and an output-to-ground isolation of 1,500 VAC (1 × MOPP) for suitability in B- and BF-rated medical equipment. The leakage current is <250 µA and touch current is <100 µA. The maximum operating, transportation, and storage altitude is 5,000 meters.
Safety certifications include IEC/EN/ES 60601-1, IEC/EN/UL 62368-1, and IEC/EN/UL 60950-1, with CE marking for the Low Voltage, EMC, and RoHS Directives. The units also comply with EN 55011-B and EN 55032-B conducted and radiated emissions (Class I and II) and meet the EN 61000-3-2 harmonics, IEC60601-1-2 Edition 4, and IEC 61000-4 immunity standards.
These power supplies are housed in an industry-standard 3 × 5-inch footprint. They are available with multiple mechanical configurations.
Power modules
For space-constrained industrial and medical applications that also require high efficiency and safety compliance, several power supply manufacturers are offering modules. One of the most recent introductions is TT Electronics’ compact PAA/PAAM series of AC/DC encapsulated power modules. The PAA series is suitable for industrial applications including automation equipment, EV charging systems, and parcel locker stations, while the PAAM series is suited for portable medical devices, mobile clinical workstations, and other medical equipment.
Available in power ratings ranging from 5 to 150 W, the PAA encapsulated modules are PCB-mountable in a compact footprint starting at 1.1 × 1.5 inches (8.05 W/in.³). These small modules offer conversion efficiencies of up to 89% and are free-air convection-cooled.
Other features include 4-kVAC input-to-output isolation, which provides safety when interfacing with downstream SELV networks, and approval to IEC 62368-1 and IEC 60335-1 that makes the PAA series suited for industrial and smart appliances for the home environment.
With footprint sizes starting at 1.1 × 2.1 inches (9.7 W/in.³), the IEC 60601-1–approved medical-grade PAAM encapsulated power modules are available in 15- to 150-W options. Power densities in some models exceed 11 W/in.³ and maintain conversion efficiencies as high as 93.5%. This includes what the company claims is the industry-first 150-W (PAAM150) encapsulated power module.
The PAA/PAAM series offer standard output voltages from 3.3 VDC to 48 VDC and operate across a wide range of ambient temperatures. They are fully certified to all applicable safety and EMC standards. Some PAA and PAAM module options are available in chassis-mount package styles.
Another space-saver is XP Power’s 75-W AC/DC power supply modules, targeting harsh environments, including industrial, ITE, and IoT. The ASB75 series offers a range of low-profile, half-brick AC/DC power supply modules that require no external circuitry for operation or EMC compliance.
These power supply modules offer fanless power with baseplate cooling for harsh or rugged applications. The baseplate cooling enables operation in sealed metal enclosures using passive cold wall cooling to transfer any heat to the outside of the equipment, said the company. An optional heat sink is also available pre-mounted or separately, allowing designers to use conventional convection or forced air cooling where preferred.
The AC/DC power supplies deliver up to 75 W of power from a universal (90- to 264-VAC) input and feature an integral AC fuse, EMC filter, and holdup capacitor that simplify integration while reducing space required for the solution. The five models available in the series offer single-output voltages of 12 V, 15 V, 24 V, 36 V, or 48 V.
The efficiency levels as high as 90% minimize heat generation and contribute to a high power density of 20 W/in.³ in an industry-standard half-brick package, measuring 2.28 × 2.40 × 0.67 inches (57.9 × 61.0 × 17.0 mm). With a no-load current draw of less than 150 mW of power, the ASB75 models significantly reduce the standby power needs of end equipment, enabling them to meet current efficiency standards, said the company.
The AC/DC power supply modules provide EMC compliance with no external components required to meet EN55032 Level B for conducted and radiated emissions. They also provide immunity to meet EN61000-4 and are compliant to safety standard UL/EN/IEC62368-1.
The encapsulated devices provide built-in protection for overtemperature, overcurrent, overvoltage, and output short-circuit, which protects the device as well as any load that it is powering, said XP Power.
Industrial power supplies
For industrial applications that require protection against harsh environments, including shock and vibration and demanding weather conditions, Calex Manufacturing Company Inc. offers the 250-W weatherproof AC/DC power supply. The LHC Series is suited for severe environmental conditions thanks to its ruggedized, weatherproof enclosure and thermal design.
The LHC series is housed in an air-cooled, ruggedized IP67-rated enclosure that can operate in an ambient temperature range of –20°C to 50°C. The enclosure is fabricated from an extruded aluminum case that is sealed using a thermally conductive material. The sealed enclosure allows the power supplies to operate in environments where there is fluid, chemicals, dust, and sand. Applications include outdoor signs, automated assembly lines, and manufacturing applications.
The LHC series is offered in fixed single-output voltages of 12 VDC, 24 VDC, and 48 VDC with constant-current overload protection. The power supply design includes a universal AC input with an active PFC, enabling the supply to reach a peak efficiency of 95%, said the company.
The LHC series power supplies measure 6.29 × 3.90 × 2.24 inches, with a weight of 3.46 pounds, and are designed with an EMI filter that meets Class B CISPR and FCC standards. The power supplies are RoHS-compliant and IEC 60950-1–certified.
CUI Inc., a Bel group company, recently added three new lines to its VGS family of chassis-mount, single-output AC/DC power supplies housed in a compact metal case. The rugged VGS-C, VGS-D, and VGS-W series offer power ratings from 35 to 350 W, depending on the series, and an operating temperature range of –25°C to 70°C, with most series offering an operating temperature range of –30°C to 70°C. All three series are 62368-1 safety-certified with low, no-load power consumption for reducing standby power usage in industrial applications, said CUI.
CUI’s VGS series of power supplies (Source: CUI Inc.)
For budget-constrained applications, the VGS-C series offers power ratings from 35 to 350 W and carries single-output voltages of 5 VDC, 12 VDC, 15 VDC, 24 VDC, 36 VDC, and 48 VDC. The VGS-D series offers power ratings from 75 to 320 W; carries voltages from 5 VDC, 12 VDC, 15 VDC, 24 VDC, and 48 VDC; and features active power-factor correction and overtemperature protection. The VGS-W series is rated from 35 to 150 W and carries 5 VDC, 12 VDC, 15 VDC, 24 VDC, 36 VDC, and 48 VDC. The VGS-D and VGS-W series have a wide input range of 305 VAC, and models across all three series are output-adjustable.
Most models in the three series are convection-cooled, with the exception of the higher-power VGS-350C and VGS-320D, which use forced air cooling with a built-in temperature-controlled fan. All models feature a screw-terminal interface and provide protection for short-circuit, overcurrent, and overvoltage. Terminal cover and conformal coating options are available.
The VGS-C, VGS-D, and VGS-W series meet IEC/EN 61558, IEC/EN 60335, and GB 4943 system requirements. The units also comply with 55032 Class B radiated/conducted emissions and meet 61000-3-2 harmonics and 61000-4-3 immunity.
Medical power supplies
N2Power expanded its medical-grade power supply portfolio with the introduction of the 40-W ML40 and 65-W ML65 power supplies for medical devices. Both series meet the latest UL/EN 60601 medical certifications. They are rated 2 × MOPP, a safety standard that protects patients from shocks by requiring that devices have two redundant means of protection that provide isolation for up to 4,000 VAC, said the company.
Both models offer up to 93.5% power efficiency, which helps prevent heat waste and mitigates the need for cooling fans, making them particularly suited for applications like medical ventilators. They also offer low standby power consumption.
The two series are mechanically compatible with each other as well as with the company’s larger 100-W, 2 × 3-inch ML100 power supply. Like all of N2Power’s medical PSUs, the ML40 and ML65 can be customized to customer specifications without requiring recertification as long as there are no UL critical-safety component changes.
The ML40 and ML60 series measure 6 in.3 and offer power densities of over 6 W/in.3 and over 10 W/in.3, respectively. Thanks to their small size, they can be integrated into space-constrained mobile equipment. They are available in several chassis configurations, including open-frame, U-frame, enclosed, and DIN rail, further simplifying integration, said the company.
Cosel Co., Ltd. recently introduced the 600-W PJMA600F and the 1,000-W PJMA1000F AC/DC power supplies with a universal input range of 85 to 264 VAC. The power supplies are available in four output voltages of 12 VDC, 24 VDC, 36 VDC, and 48 VDC.
Cosel’s PJMA series of power supplies (Source: Cosel Co. Ltd.)
Designed for medical applications, the PJMA series’ input-to-output isolation complies with 2 × MOPP, input-to-ground with 1 × MOPP, and output-to-ground with 1 × MOPP. The units are approved in accordance with ANSI/AAMI ES60601-1 and EN60601-1 3rd Edition.
The PJMA series offers a typical efficiency of 88% at high line and features low power consumption at no load. The power supplies include inrush current-limiting circuitry, overcurrent and overvoltage protection, and thermal protection. The operating temperature range is –20°C to 70°C.
Four single-output voltages are available as standard in each unit. For the PJMA600F, the output voltages are 12 V/50 A, 24 V/25 A, 36 V/16.7 A, and 48 V/12.5 A. Output voltages for the PJMA1000F are 12 V/84 A, 24 V/42 A, 36 V/28 A, and 48 V/21 A. The output voltage can be adjusted by using the built-in potentiometer.
In conducted emissions tests, the PJMA series complies with the FCC-B, CISPR11-B, CISPR32-B, EN55011-B, EN55032-B, and VCCI-B. For applications requiring lower emission levels, an additional filter Cosel-type NAC can be supplied (NAC-16-472 for the PJMA600F and NAC-20-472 for the PJMA1000F). They conform to EU RoHS, REACH, and Low Voltage Directives.
The PJMA series is built in an enclosed, galvanized steel box with fans mounted on the rear side (one for the 600-W and two for the 1,000-W). The PJMA600F measures 120 × 61 × 215 mm (4.72 × 2.40 × 8.46 inches) (W × H × D), with a weight of 2.0 kg max. The PJMA1000F measures 150 × 61 × 240 (5.91 × 2.40 × 9.45 inches) (W × H × D) and weighs 2.8 kg max.