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Electronics => Beginners => Topic started by: tomoram on June 19, 2022, 04:05:12 pm

Title: Trying to work out how a DD1718PA works
Post by: tomoram on June 19, 2022, 04:05:12 pm

I'm trying to understand how the DD1718PA boost converter works. It outputs an increased, dual-rail voltage from a lower voltage.

https://www.amazon.co.uk/Precise-Converter-DD1718PA-Operational-Amplifier-Turn-plus-minus-9V/dp/B09K6HDDFJ (https://www.amazon.co.uk/Precise-Converter-DD1718PA-Operational-Amplifier-Turn-plus-minus-9V/dp/B09K6HDDFJ)

It uses the XL6007E1 boost IC, but the configuration seems to be different to any schematic I can find. I've tried to reverse engineer the schematic from the pictures online I can't see enough detail.

Some things I've noticed that confuse me:

1. It looks like it's a single inductor - most dual-rail schematics use a transformer
2. The input GND and output GND is the same - which suggests that it's not simply outputting double the voltage and dividing it to create a + and - voltage around the centre.

Does anyone have any ideas on what this schematic might look like?

Title: Re: Trying to work out how a DD1718PA works
Post by: ledtester on June 20, 2022, 04:38:26 am

Have a look at this thread:

https://www.eevblog.com/forum/projects/challenge-a-buck-converter-providing-split-rail/ (https://www.eevblog.com/forum/projects/challenge-a-buck-converter-providing-split-rail/)

where they discuss a similar design problem.

Title: Re: Trying to work out how a DD1718PA works
Post by: ledtester on June 20, 2022, 07:59:17 pm

fwiw, the industry uses the acronym "SIMO" for "single inductor, multiple output" regulators. TI and Maxim seem to be the main players in this area.

Some resources:

A Maxim white paper on SIMO:

https://www.maximintegrated.com/en/design/partners-and-technology/design-technology/single-inductor-multiple-output.html (https://www.maximintegrated.com/en/design/partners-and-technology/design-technology/single-inductor-multiple-output.html)

The technical discussion in this UK patent *might* be easy to follow:

UK Patent GB2441358A: https://patentimages.storage.googleapis.com/cf/c2/09/43fd6e12faa0d2/GB2441358A.pdf (https://patentimages.storage.googleapis.com/cf/c2/09/43fd6e12faa0d2/GB2441358A.pdf)

Title: Re: Trying to work out how a DD1718PA works
Post by: tomoram on June 22, 2022, 06:03:42 am

Thanks ledtester. I had seen the thread you linked but it still left some questions. The SIMO acronym is really useful to know, thanks!

Title: Re: Trying to work out how a DD1718PA works
Post by: Jeanious2011 on May 07, 2023, 05:46:16 pm

Thats the same chip as XL6007E1. I ordered the same unit and it came with that chip.