Catch here


the output voltage ranges between -1200 volts (NHV0512N) and 1200 volts (NHV0512) at 83 microamperes (µA), to -100 volts (NHV0501N) and 100 volts (NHV0501) at 1 mA. The series employs a high impedance programming input (100 kilohms (kΩ)) to make the devices easy to install and eliminate the need for a low-impedance adjustable power source voltage. The output voltage is independent of the input voltage and is instead proportional to the programming voltage to ensure robust linearity.


Wide input range


Like the nHV series, XP Power’s DTJ15 and DTJ20 series of 15 watt and 20 watt DC/DC converters are also miniaturized for easy installation and power-effi cient operation, but with a twist: they can be installed to a chassis or DIN rail and connected via screw terminals (Figure 4).


Protection features portfolio Power system designs for railway, industrial, and transportation applications demand fast settling times to transient step loads. Other transient events such as oscillations in the input and output voltage make the self-protection features critical for the safe and reliable operation of DC/ DC converters.


In current limiting, also referred to as power limiting, as soon as the output current increases to approximately 130% of its rated value, the DC/DC converter will go into a current-limiting mode. As a result, the output voltage will start decreasing proportionately to maintain somewhat constant power dissipation.


If environmental conditions cause the temperature of the DC/DC converter to rise above its designed operating temperature, a precision temperature sensor will power down the unit. Once the internal temperature decreases below the threshold of the temperature sensor, the DC/ DC converter will self-start.


Figure 4: The DTJ15 and DTJ20 series DC/DC converters are optimized for small size, can be easily installed using a DIN rail, and feature a wide input voltage range. (Image source: XP Power)


Besides easy installation, what’s important about these power converters is their ability to cover a wide DC voltage input range, spanning from 9 volts to 36 volts, and 18 volts to 75 volts. A variety of input sources, including multiple nominal battery voltages and vehicle supplies, allow these converters to serve a broad range of industrial, commercial, and communication applications.


Together, the DTJ15 and DTJ20 series DC/DC controllers offer a total of 14 variants with single- output devices providing voltages of 3.3 volts, 5.0 volts, 12.0 volts and 15.0 volts, and dual-output devices providing ±5.0 volts, ±12.0 volts, and ±15.0 volts, respectively.


A remote ON/OFF function allows the DC/DC converters to be controlled by software, which helps control overall power consumption, allowing remote installations to operate efficiently.


Another important feature of the DTJ15 and DTJ20 series DC/DC converters is the soft start that ramps the output voltage by modulating the internal error amplifi er reference. This causes the output voltage to approximate a piecewise linear ramp, which fi nishes when the voltage reaches the nominal output voltage. Other protection features offered by the DTJ15 and DTJ20 series controllers include short-circuit protection and input reverse polarity protection.


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Murata’s IRE-Q12 Series of isolated DC/ DC converters feature self-protection features to ensure that there are no adverse effects from higher capacitive loads (Figure 6). For example, the IRE-12/10-Q12PF-C incorporates all relevant self-protection features while meeting the EN50155 requirements for facilitating nominal battery voltages during brownout and transient conditions.


Figure 6: The DC-ZVS topology enables DCM2322 converters to achieve up to 93% effi ciency. (Image source: Vicor)


Figure 5: The IRE-Q12 series converters go through extensive testing to ensure that they can withstand the harsh environmental conditions typically found in railway and industrial applications. (Image source: Murata)


The IRE-Q12 Series converters provide a single 120 watt isolated output from an input voltage range of 9 volts to 36 volts in a standard eighth- brick package and footprint. It also provides two baseplate options, one for minimal board space consumption, the other a slotted fl ange for mechanical fi xing to a heatsink.


The output of these DC/DC converters can be trimmed +/-10% to ensure fast settling times to transient step loads. Furthermore, all of the converters are tested and specifi ed for input refl ected ripple current, input terminal ripple current, and output noise.


Standalone and array power modes Vicor’s DCM2322 is an isolated DC/DC converter series that operates from unregulated DC inputs


The DC/DC converter module (DCM) units, such as the DCM2322T50T3160T60, leverage the thermal and density benefi ts of Vicor’s ChiP packaging technology that distributes the internally generated heat evenly across the sur- face of the package. The ChiP technology also enables the DCM converters to offer fl exible thermal management options with very low top and bottom side thermal impedances. The effi cient thermal distribution allows the DCM units to feature connectivity from a variety of unregulated power sources to the point-of-load. They provide both input and output overvoltage fault protection and other fault handling mechanisms that shut down the converters when a fault is detected (Figure 7). These features allow the DCM converters to provide a regulated output voltage around defi ned nominal load line and temperature coeffi cients. If the internal temperature of the converter exceeds its limit, a temperature fault is registered, and the powertrain immediately


ranging from 9 volts to 50 volts to generate an isolated 28 volt output (Figure 6). It’s based on the company’s double-clamped zero-voltage switching (DC-ZVS) topology that helps it deliver a high effi ciency of 93% across the full input voltage range.


stops switching. The converter waits for the internal temperature to return to the given threshold and then restarts.


Moreover, these DC/DC converters provide integrated EMI fi ltering, tight output voltage regulation, and a secondary referenced control interface while retaining the fundamental design benefi ts of the conventional brick architecture. In applications that call for more power than a single DC/DC converter can deliver, such as data centers and telecommunication gear, multiple devices can be used in parallel. Multiple DCM converters can be paralleled in array mode for higher power capacity via load sharing, even when they are operating off different input voltage supplies. Vicor has qualifi ed arrays of up to eight DC/DC converters for 480 watt capacity.


Conclusion


For designers of power supplies to support electronic systems for industrial, medical, transportation, and instrumentation applications, the complexities and associated costs are many, from the need for wide input voltage ranges to thermal management and load sharing. However, as shown, DC/DC converters have evolved into ever-smaller, easy-to-install, self- contained power supplies that eliminate many of those complexities.


Still, for designers looking for better performance, additional components can be added. Also, where more fl exibility is required, remote and programmable features are increasingly available to carry out impedance compensation and facilitate a variety of protection features to avoid burnouts, respond to transient conditions, and reduce overall system power consumption. digikey.co.uk


Power


Figure 7: The DCM converters facilitate fault monitoring handling capabilities, as well as safety features that include current limiting and soft-start control. (Image source: Vicor)


Components in Electronics November 2020 27


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