TDK Corporation has introduced the TDK-Lambda brand SFL series of programmable electronic DC loads. The series comprises 300W and 1,000W power levels and either a 120V or 500V maximum rating. The SFL incorporates high-speed current feedback control to eliminate load current overshoot and oscillation to generate a stable and predictable load waveform during turn-on or dynamic operation. The unit is capable of operating in seven different load modes and four operating modes. This flexibility allows the user to perform up to seventeen different types of load tests on DC power supplies, fuel cells, solar cells, batteries and components to characterise their performance fully.
The loads can be programmed for multiple load types, including constant current, constant resistance, constant power, external control, short circuit, and constant voltage with a current limit. The operating modes are normal, pulsed load (dynamic time and frequency), complex waveform generation and “sweep” to test and determine a product’s voltage-current characteristics, overcurrent or power limit performance. The SFL also offers high-speed current control, eliminating load current overshoot and oscillation, low voltage operation, no turn-on delay and linear operation from 0V.
In addition, the SFL load current rise and fall times (slew rate) can be controlled up to 30A/µs, and the internal memory can store and recall eight different load settings. The isolated trigger output signal is used for pulsed load waveform capture on a storage oscilloscope or test equipment synchronisation.
Up to 10 units may be paralleled in a master-slave arrangement for higher power load requirements using a unit-to-unit RJ45 Ethernet cable. Multiple SFL loads can also be connected to separate devices using that cable for synchronised load control and dynamic operation.
Standard control methods include an 89mm colour LCD front panel display, a remote analogue EXT interface and a remote digital USB (2.0) interface. An optional rear panel IEEE (488.1) interface (with a built-in DIDO Interface for PLC interfacing) is available, plus an output ripple and noise measurement interface allowing measurements without the need for an oscilloscope.
A wide range 85 to 264Vac input enables global use. The loads have built-in protection features and indicator signals, including overcurrent, power limit, overtemperature, overvoltage protection and reverse connection. The operating ambient temperature is 0°C to +40°C. The 300W models measure 215 x 420 x 128.6 (3U) W x D x H and the 1,000W 430 x 450 x 128.6 (3U). The product weights are 6.5kg and 13kg, respectively and can be carried using the side-mounted handle. Both front and rear load connections are available, and accessories can be purchased for 19″ rack mounting.
The SFL series carries a two-year warranty and is compliant to IEC/EN 61010-1 for safety and to EN61326-1: 2013 (Class A) for EMC. The products are also CE and UKCA marked.