An electronic load complements a power supply when it comes to electronic testing. While a power supply tests electronic circuits under different sourcing conditions, an electronic load tests energy sources with static or dynamic loading.

Electronic loads are categorised into DC, AC, Regenerative DC, and Regenerative AC.

What is a DC Electronic Load?

A wide range of DC power sources, from DC power supplies and batteries to fuel cells and solar cells can be tested and characterised using DC electronic loads. Operating under various modes such as constant current (CC), constant voltage (CV), constant power (CW), and constant resistance (CR), DC electronic loads simulate power consumption under different load conditions, helping in the assessment of device energy efficiency under various operating scenarios.

DC power supplies such as battery chargers, converters, fuel cells, batteries, telecommunications rectifiers, etc must be tested for hundreds or thousands of cycles to determine factors like quality, longevity, durability, reliability, and expected lifetime.

Operating Modes

DC Electronic Loads work in many operating modes.

Constant Current (CC) mode

Here, the load’s power supply is a current source. At a constant current in the output terminals, the output voltage is varied with current load conditions.

Constant Resistance (CR) mode

Here, at a set resistance value, the load draws the current inversely to compensate for any change in the testing voltage.

Constant Voltage (CV) mode

At a fixed voltage. the electronic load sinks the current needed to keep the voltage constant.

Constant Power (CP) mode

For a constant wattage level during the test, the load draws the current proportionate to voltage change.

A well-designed DC programmable electronic load always controls the current, irrespective of the mode, allowing users to set a current level that the DC load will draw, regardless of any changes in voltage.

Regenerative DC Loads

Regenerative DC loads can simulate a wide range of load characteristics while also feeding energy back to the grid, providing an efficient and sustainable solution that reduces test environment temperatures, HVAC power consumption, and power conversion electricity costs.

Chroma 63700 Series Regenerative DC Electronic Loads

The Chroma 63700 Series Regenerative DC Electronic Loads are suitable for product reliability testing in a wide range of applications, such as Electric Vehicle Test Solutions, EV battery discharge, fuel cell discharge, high-power power supply aging, DC EV supply equipment (EVSE), unidirectional on-board chargers (OBC), fuel cell systems, energy storage systems (ESS), AC/DC and DC/DC power supply burn-in tests, and various power electronics applications.

The 63700 Series offers high power density within a compact 3U form factor, with a power rating of up to 18kW per unit and currents of up to 540A. A maximum of 10 units in parallel provides a maximum power and current of 180kW and 1200A respectively. Voltage can be set at 100V, 600V, 1200V, or 1800V.

What’s more, the master/slave control enables parallel operation of identical 63700 units for synchronised dynamic loading to store up to 256 programmable sequences, thereby reducing test duration and increasing throughput during automated testing.

The external signal control functionality allows the simulation of real current waveforms. The 63700 Series performs precise voltage and current measurements in real-time. Operation and setup are convenient with the TFT touch display and rotary knob on the front panel, with the capability to control via LAN, USB, GPIB, or CAN.

The 63700 Series is an ideal solution for design verification and integration into automated test systems with its over-current, over-power, and over-temperature protection functions, as well as an over-voltage alarm mechanism, ensuring product reliability during testing.

Photonic Integrated Circuit (PIC) solutions are being adopted by manufacturers to address the reduced size and complexity challenges while also addressing heat management issues experienced in today’s data centres. Frantic development of smaller, faster, cheaper and greener transceivers/active components and passive components is driving the development of high-speed networks and 5G, Photonic Integrated Circuits (PICs).

Passive optical components used in optical systems operate without external power or active control. They use processes such as transmission, reflection, polarisation, coupling, splitting, filtering, and attenuation to alter light signals.

Need for Testing

A PIC is composed of many optical components such as optical couplers, fibre-optic switches, splitters, attenuators, wavelength-division multiplexers, and transceivers.

Testing of any PIC-based device is needed in all life cycle stages — from design and development, and qualification to validation of production.

Testing — The Requirements

Automation, repeatability, scalability and parallelisation of the testing processes are needed for the huge volume of circuits and ports, to be able to meet the profitability of economies of scale. Photonics labs must evolve with the optical test requirements of passive (guiding light) optical components.

The fast-maturing PIC die manufacturing has given rise to photonic wafers containing thousands of components made available by foundries through Process Design Kits (PDKs). Reliable testing is needed to optimise the different parameters of a given optical component.

Testing — The Challenges

Accuracy/repeatability: Obtaining traceable results for tight acceptance thresholds and greater yield of known good dies.

Dynamic range: Seeing full optical spectral contrast in a single measurement.

Speed: Keeping alignment and measurement time to a minimum, but also accelerating the ease of the test and analysis iterative flow.

From data to insight: Generating and managing structured data that is ready for artificial intelligence and business intelligence.

Flexible/Scalable: Leveraging test station modularity and third-party compatibility of software to improve test throughput and complexity over time or swap equipment as needed.

Automation: Automating chip and wafer advanced navigation to control any instrument and execute data analysis in user-defined test routines to test massive circuits with minimal cost of ownership.

Testing PIC-based passive components is challenging due to the high port count of some components like Arrayed Waveguide Grating (AWG) and the huge number of components to test on a single die. A component test platform operates in conjunction with a continuously tunable laser to measure optical insertion loss, return loss and polarisation-dependent loss across the laser’s spectral range. The optical spectrum must be realised quickly and with a high wavelength resolution, typically to the order of a picometer.

Testing — The Process

The PIC devices are usually tested at the wafer level prior to dicing to detect defects as early as possible and to avoid packaging defective dies.

Using a PIC wafer probe station, light is coupled into the wafer to enable measurement of the optical characteristics of the DUT.

Testing Solutions for Photonics from MELSS

MELSS brings you Test and Measurement (T&M) hardware and software solutions from market leaders EXFO, which are automated, scalable, fast, accurate and cost-optimised. These T&M solutions range from those for Passive and Active components as well as automated probe stations for wafer and single-die testing.

The OPAL series of probe stations deliver industry-leading performance for testing wafers, multiple as well as single dies, enabling accurate, repeatable and fast measurement. The PILOT software suite offers automation capabilities that support the full test flow (preparation through measurement to results analysis), using EXFOs or third-party T&M instruments.

EXFOs comprehensive range of optical testing solutions includes component test platforms, optical testing solutions, light sources, benchtop tunable lasers, passive component testers, optical spectrum analysers, tunable filters with adjustable bandwidth, variable attenuators, switches and power meters.

EXFO has developed automated, scalable, fast, accurate and cost-effective Test and Measurement (T&M) hardware and software solutions. Ranging from simple optical testing to spectral optical characterisation or traffic analysis, EXFO offers an extensive selection of probe stations for wafer, bar, multi-die or single-die configurations, and a powerful automation software suite.

The CTP10 from EXFO specifically addresses key PIC measurement challenges. measuring optical components quickly, reliably and accurately.

The CTP10 is a modular component test platform that operates together with the T200S or T500S continuously tunable lasers. The CTP10 characterises the spectral properties of high port count devices in one single scan with

High spectral resolution

70-dB dynamic range, even at a sweep speed of 200 nm/s

Operation from 1240 to 1680 nm

Coverage of a wide range of applications, including telecom, sensing and LIDAR.

Both optical and photocurrent measurements with analog output for PIC first-light search and coupling optimisation

Fast data transfer

Remote control using SCPI commands is possible

Increased PIC testing throughput

Reduced test time

High sampling resolution of 20 fm

Accurate measurement of narrow spectral features

The CT440 is a compact variant of the CTP10, with the same performance — ideal for the characterisation of PIC components with limited outputs.

In addition to the above range of products, EXFO produces other advanced products such as the T200S, T500S, CTP10, CT440, OSICS T100, FTBx-2850 and OSA20.

The shift to Electric Vehicles (EVs) is happening world-wide - and is moving rapidly in India too. The purchasing power of India’s burgeoning middle class is increasing, and more people are investing in vehicles. With the increasing cost of fossil-fuels in India, the need for EVs is acute here. However, the scarcity of lithium reserves made the Indian market dependent on other countries to charge the EVs, especially China which has control over 80% of the world’s lithium reserves. The ‘Atmanirbhar Bharat’ resolve of the government is pushing research on alternate means of charging EVs. The world is moving away from China in the wake of the COVID pandemic and is looking at India as a global manufacturing hub for EVs, riding on the already existing ecosystem of vehicle manufacture here.

Why EVs?

The major advantage of any EV is the ability to regenerate power, which is very useful in any urban environment which involves frequent braking and acceleration. With fewer moving parts EVs need less maintenance and lower operational costs. With no gears, combustion and mechanical drivetrains they are more convenient to operate. Home charging along with government incentives to EV owners such as Income Tax Deduction claim up to INR 150000 make purchasing an EV a wise decision. Besides, zero emission ensures minimal adverse impact on our health. Already, the number of EVs sold has witnessed quantum jumps, year-on-year since 2016.

The Charging Technology

Economic alternatives to the Li-ion charging have been developed and are ready for commercial use, such as Sodium-ion charging or Aluminium-air technology with abundant reserves available in India. With an impressive cost of manufacture in India, many multinational companies have either started or tied up with Indian companies to manufacture this alternative. Many automobile majors in India have already entered into agreements for use of these alternative charging mechanisms.

Incentivising the manufacture of EVs

In a healthy ecosystem, each state in India is wooing investment in the EV sector with various incentives. The world’s largest Electric Scooter manufacturing facility, OLA. is coming up in Tamil Nadu, and another Electric Scooter brand, Ather, has already started manufacturing here. Major heavy vehicle manufacturers (buses and lorries) are betting big with many state governments shifting their public transport to EVs already.

EV manufacturers, Tata Motors and Mahindra have tied up with an Aluminium-air charger manufacturer to power their EVs. The world’s largest manufacturer of Sodium-ion technology, Faradion, has set up base in India and should start production soon to offer an economic alternative to charge EVs. Major vehicle brands in India – Tata Motors, Hyundai, MG and Mahindra are already offering a line of EVs, and other brands will follow suit.  With the expected entirety of vehicle manufacture in India shifting to EVs, the price of EVs will also be attractive as an alternative to fossil-fuelled vehicles. The abundant availability of chargers will make the charging process easy and smooth.

The Infrastructure to Support

The roadmap to EVs as a viable alternative depends on the charging infrastructure available.

“The government is pushing deployment of EV charging stations by providing capital subsidy through Faster Adoption and Manufacturing of Electric Vehicles in India (FAME) India Scheme Phase II and state level initiatives. Further, the government has delicensed the activity of setting up EV charging stations to increase private sector investments and facilitate market adoption” – Bureau of Energy Efficiency, Government of India, Ministry of Power (https://beeindia.gov.in/content/e-mobility).

Under Phase I of FAME India Scheme, 970 charging stations have been installed, and 2877 more EV charging stations across 25 States/UTs have been sanctioned under Phase II. In a big push for the EV sector, the government shared plans to set up at least one EV charging kiosk at each of the 69000 petrol pumps across the country.

No wonder that the Indian Electric Vehicle Market is poised for growth, and many EVs (cars, scooters, 3-wheeled autos, and heavy vehicles such as lorries and buses – many state bus fleets have already completely shifted to EVs) are already on the roads today. Although the sales figures till today leave much scope for growth, the traction the industry is observing today promises phenomenal growth in the coming years.

MELSS provides many electric vehicle test solutions, and has been keeping pace with the fast technology changes in the EV charging space, and brings you an exhaustive range of testing machines from Chroma ATE to test the chargers of EVs. We offer solutions catering to various standards, from AC/DC/CHAdeMO to CCS.