Component high voltage output DC/DC converters have changed the way many manufacturers implement and use high voltage in their products. These standard high voltage DC/DC converter modules are miniaturized, PCB-mounted, encapsulated, low noise assemblies generating a high voltage output that is fully controllable using standard low voltage circuitry.

Providing an approved, single DC-DC power solution which covers all nominal traction voltages from 24VDC through to 110VDC and complies with the latest electromagnetic compatibility and fire protection standards, simplifies system integration across all power platforms that may be encountered in rail applications, negating the need for multiple variants of electronic transportation equipment.

Specifying an AC/DC power supply for systems with peak load requirements that are higher than the normal power requirements for short periods can result in larger, higher power and higher cost product selection.

In these applications the average power required is typically significantly lower than the peak demand and, with care, savings in product size and cost can be realized without compromising system reliability or lifetime. Using a power supply that can support the peak load but with a lower continuous power rating will result in a physically smaller power supply reducing system size, weight and cost. The supply must be electrically rated to safely support the peak demand but can be thermally rated at the lower power level.

The New Safety Standard for ITE and AV Equipment

IEC/EN/UL 62368-1 is the new safety standard with a broad scope that covers ITE, communication technology, audio/video & similar type of equipment. It is a convergence of safety standards to replace IEC 60950 & IEC 60065 as the technologies also converge. The new standard adopts a hazard-based safety engineering (HSBE) approach/standard rather than applying specific safety requirements for specific product types.

HSBE adopts a 3 Block model which, identifies energy sources in the product, classifies the energy and potential to cause injury or damage, identifies the required safeguards for protection from energy sources with the potential to cause injury or damage and qualifies the safeguards as effective.

Power supplies fall into one of three protection classes based on the need, or not, for a protective earth connection:

Class I   - where user protection from electric shock is achieved through a combination of insulation and a protective ground. Class II  - where user protection from electric shock is achieved through two levels of insulation (either double or reinforced). Class III - where the input is connected to a safety extra low voltage (SELV) circuit meaning no further protection is required.

Electrolytic capacitors are an essential ingredient in AC-DC power supplies, providing high Capacitance x Voltage (CV) and low Equivalent Series Resistance (ESR) in low-volume packages that simply cannot be achieved cost-effectively using alternative parts. The service life of these electrolytic capacitors is an increasingly key design parameter in power supplies. 

The new GCU500 series of 500W AC-DC power supplies, with class-leading features, measure just 83.8 x 165.1 x 39.3mm (3.3 x 6.5 x 1.55”), conveniently fitting into 1U systems, if required.

These rugged products are ideal for high reliability, cost-sensitive industrial applications. Dual fusing, low leakage current and input/output isolation of 2 x MOPPs (Means Of Patient Protection) makes the series ideal for use in critical healthcare applications such as ventilators and medical carts in hospital environments. The products meet the latest ‘third edition’ of medical standard IEC 60601-1 including risk management and is rated for safety at high altitudes – 4000m for medical and 5000m for IT.

One of the core immunity tests that electrical & electronic equipment is subjected to is input surge testing. The test method for this is IEC61000-4-5 and the limits are defined by end system requirements.

The basics of the test are to subject the system to voltage spikes on top of the nominal voltage input to the system. These spikes are representative of voltage fluctuations that occur from causes such as large motor drives, nearby lightning strikes, etc. These high voltage deviations can cause a variety of issues when applied to a system not designed to handle them. Testing ensures that the end equipment will give the level of performance needed for the intended application.