Site icon Pallav Aggarwal

My experiment with 76V / 100V Input DC DC Converter

I work on various custom embedded product development for companies and I come across requirements where different dc input voltage range is required.

Sometimes, it is low voltage like 5V but very low IQ but some times it is wide range like 10V to 85V DC Input.

Recently, I did a custom Fork Lift Vehicle Body Control Unit Project for a Canadian company where the requirements were like that, 10 to 85V DC input to power the hardware.

And another company, I give consultancy to, also had similar requirement where they needed same dc dc power supply design to be able to work for various needs like it should work for 12/24/48V battery inputs which internally powers the whole hardware.

Considering above requirements in mind I started exploring various available options and came across these DC DC Converter ICs which I finally tested.

DC DC Converter Rohm BD9G341AEFJ-E2

This was the setup for my testing. 60V DC Power Supply, Electronic DC Load and Nano Ranger for precision current measurement, Fluke Temperature Gun for temperature measurement.

Please ignore reading in the DC power supply, the current sensing in the power supply has gone bad.

No Load Current tested at 60V DC Input was 5.83mA, from the datasheet it was not clear what will be the Quiescent Current. I feel this is way too high, i will check again why it is so high. We can also optimize (increase) feedback resistor values to reduce IQ, currently I am using 22.1K and 2K.

Efficiency and Thermal testing of DC DC Converter at load

I would say with such a large input, output voltage difference this efficiency is quite good.

For much better efficiency and uA IQ for high voltage input requirement you can look for Analog Devices Converters.

Temperature of the Diode/Converter IC and Inductor was at 66-70 Degree C @ 12W output. One must make better thermal arrangements ( like adding a heatsink/PCB Copper area/PCB layer thickness 70um) for output power greater than 7-8W.

DC DC Converter Silergy SY8501

No Load / Quiescent Current of SY8512


DC DC Converter Silergy SY8512

No Load / Quiescent Current of SY8512


DC DC Converter Silergy SY8503

No Load / Quiescent Current of SY8513


I hope you found this post interesting and learned something new today.

Have you also used some of the DC DC Converter ICs which has wide input range, please do share, would love to know how was the performance and your observations.

Please do share your feedback in the comments below, can’t wait to hear from you.

You can read my other interesting blogs & articles on embedded system design here.

I help embedded engineers and companies build reliable and successful embedded products. If you need any help please let me know here.

Happy Learning to you!

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