TDK Lambda LS Series Single Output Power Supplies
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The document introduces the TDK Lambda LS series of single output power supplies with ratings from 25W to 150W. It summarizes the key features of the LS series including their small size, wide input voltage range, safety certifications, high efficiency ratings, and improved design over previous models such as enhanced cooling and terminal block support. Testing results are also presented showing the LS series performs better than competing products in areas like EMI emissions, vibration tolerance, temperature rise, and lifetime.
TDK Lambda LS Series Single Output Power Supplies
- 1. TDK Lambda LS Series Single Output Power Supplies Source: Suppliers
- 2. Introduction Purpose To introduce the TDK Lambda LS series power supplies and their key features. Outline LS series overview Key features High performance design Content 17 pages
- 3. Lambda LS Series Overview 25W, 35W, 50W, 75W, 100W & 150W ratings 3.3V to 48V outputs 88 - 264VAC input (88-132/176-264VAC for LS150) Small package size Three year warranty
- 4. Key Points Convection cooled Needs no external airflow or fan Small size and low profile Safety Certification IEC60950-1 (UL & EN) For information technology equipment Operation to 300VAC for 5 seconds Ideal for India, China, Brazil (where AC often wildly varies)
- 5. Harmonic currents & power factor specifications EN61000-3-2 is the specification to meet There are several ways to meet that specification Using “active" power factor correction Extra electronic circuit "boost circuit" – possibly excessive Or “passive" power factor correction Uses extra passive components to meet EN 61000-3-2 Chosen for the LS150 models Careful circuit design of bulk capacitor & transformer Chosen for the LS25-100 models Meets specification, but cuts costs dramatically
- 6. Harmonic Currents & Power Factor Specs Results of SWS150 (active correction) and LS150 (passive correction).
- 7. The LS150 has Manual Input Selection The LS150 range has a user selectable input switch User accessible from the side Keeping costs low On the old design the switch is hard to access LS150 units are preset at 230VAC from the factory Safe mode, unlike applying 230VAC when set for 115VAC
- 8. High Performance High efficient – up to 4% Model LS 50W 12V 84% 50W 24V 86% 75W 3.3V 75% 75W 12V 84% Higher calculated lifetime figures (MTBF) Model LS 50W 712k 75W 648k 100W 545k 150W 505k (Stated in hours to MIL-HDBK-217F)
- 9. Better Cooling Area 14.5mm 2 Area 21.1mm 2 Top surface 203 x 21.1 = 4,283mm 2 Top surface 251.5 x 14.5 = 3,647mm 2 17% additional space to aid cooling Old cover - circular LS series' cover - hex
- 10. High Performance cont’d Higher efficiency, better cover design = cooler LS series Old series
- 11. Support Flange Design Improved terminal block support! Other series No PCB support during connection Flexing can cause damage to underside surface mount parts LS Series has a support flange
- 12. Less Severe De-rating Others
- 13. Testing the Competitor’s models Evaluation Item Result Remarks Harmonic Current Fail 100W and 150W exceed limiting level EMI (CE) Fail 50W and 75W failed without shielding plate Vibration Fail Components dropped off at 5g Temperature rise Fail Temperature of magnetic components and electrolytic capacitors exceed their rating E-cap life Fail 150W : Less than 3 years at 8 hours per day Area of Safe Operation Fail 100W : Failed -25 o C turn-on test Fail Output hiccup at cold start up
- 14. Testing the competitor’s models Transformer Saturation (Bad) Switching current waveform (XX-100-5)
- 15. Testing the competitor’s models -25 o C turn on testing (XX100) Multiple attempts to start DC Output AC Input
- 16. Lambda LS series part numbering LS50 - 24 Output Power LS25 LS35 LS50 LS75 LS100 LS150 Output Voltage (Nominal) 3.3V 5V 12V 15V 24V 36V 48V
- 17. Additional Resource For ordering LS series power supplies, please click the part list or Call our sales hotline For more product information go to http://www.lambdapower.com/products/ls-series.htm Visit Element 14 to post your question www.element-14.com For additional inquires contact our technical service hotline or use our “Live Technical Chat” online facility Newark Farnell
Editor's Notes
- #2: Welcome to the training module on LS Series Single Output Power Supplies.
- #3: This training module will introduce the LS series power supplies and their key features.
- #4: The LS series power supplies are available with output voltages ranging from 3.3 volts up to 48 volts DC and power ratings from 25 watts to 150 watts. These units will operate with an AC input of either 115 or 230VAC nominally, and all operate over a wide input range without any user intervention, except the LS150 (AC switch selectable). The LS Series is ideal for the budget sensitive designer who does not want to compromise reliability or performance.
- #5: All the LS models are convection cooled and do not need any external airflow. The height of the units ranges from 1.1" to 1.5" high allowing them to be used in a 1Unit rack. Safety certifications have been obtained from UL and TUV allowing them to be used anywhere in the world. A CB certificate is available upon request. Operation up to 300VAC input is allowed for up to 5 seconds, providing additional reliability for countries where the AC line is not well regulated.
- #6: Although the LS power supply (PSU) does not have active Power Factor Correction (PFC), all the models meet EN 61000-3-2 harmonic correction as mandated by the European Union. Using passive power factor correction (PFC) helps to reduce the price of the LS series.
- #7: EN 61000-3-2 specifies the maximum odd numbered harmonics of the AC input current. You can see on the two graphs the results of an active power corrected unit on the left (TDK-Lambda's SWS150), compared to the LS150. Both are within the limits of EN 61000-3-2 as shown by the curve.
- #8: We mentioned earlier that the LS150 has a switch selectable AC range - like those found on many PC power supplies. A cut out has been added for easy access unlike some of the old models in the market. The LS150 ships with the switch set for 230VAC, to operate with a 115VAC input, simply slide the switch to 115VAC.
- #9: To satisfy today's energy conscious world, the LS efficiencies are higher than most competing models. Operation over time will cost less in electricity than a lower cost model. Field reliability is assured, as can be seen from the calculated MTBF (Mean Time Between Failures) of the TDK-Lambda LS Series.
- #10: Another improvement is the use of a honeycomb hexagonal perforation in the LS Series cover. This allows for more heat to exit the power supply, keeping the internal temperatures lower for better field reliability.
- #11: Using a thermal camera, the better efficiency and superior thermal management of the TDK-Lambda design is evident, again leading to longer field life.
- #12: Many power supplies utilise surface mount components on the underside of the circuit board. TDK-Lambda's clever support flange stops the board from being flexed when cables are attached to the terminal block. Excessive flexing can lead to stress and cracked surface mount components, leading to early field failures.
- #13: Increased efficiency and better thermal design allows the LS models to operate at higher ambient temperatures with less de-rating, allowing more power to be pulled from the supply than lower cost competing models.
- #14: TDK-Lambda products are thoroughly tested during the design stages to ensure performance in line with the published data. On paper, a specification comparison with competing products indicates little or no difference. When electrically tested, however, shortcuts in design margin on those competing products become evident. Usually a customer will only realise these shortcomings during final product testing, possibly resulting in launch delays or customer complaints.
- #15: Analysis of a competitor's power supply shows that the main switching currents are excessively high due to cost cutting in the design of the isolation transformer. These high currents can result in field failures.
- #16: The LS Series is specified to start up at a low -25 º C ambient temperature. The scope plots indicate that a competitor's products tries to start on a few occasions, succeeding only after several attempts. The upper trace is the output voltage, the lower trace is the applied AC input voltage. The expanded view is shown on the lower half of the image. Although choosing a power supply based on price alone is tempting, there are often hidden aspects that may not initially show up. The reputation of the manufacturer is critical for lowest cost of ownership!
- #17: The part numbering sequence for the LS Series is shown above.
- #18: Thank you for taking the time to view this presentation on the “ LS Series Single Output Power Supplies” . If you would like to learn more or go on to purchase some of these devices, you may either click on the part list link, or simply call our sales hotline. For more technical information you may either visit the TDK-Lambda site, or if you would prefer to speak to someone live, please call our hotline number, or even use our ‘live chat’ online facility. You may visit Element 14 e-community to post your questions.