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Problem with Jaycar XC-4514

December 2015

For a recent project there was a requirement to obtain 12Vdc from 5Vdc. I bought the Jaycar XC-4514 module.

From the Jaycar page, the module is titled as: "Arduino Compatible Adjustable Voltage Regulator Module"

Described as: "This module accepts any voltage from 3-34VDC, and outputs any higher voltage from 4-35VDC. Output is adjusted via a multi-turn potentiometer. Use it to run higher voltages from your lower supply. (ie. run 12V devices from a 5V supply) • Input voltage 3-34VDC • Output voltage continuously adjustable 4-35VDC • Maximum output current 2.5A • Dimensions: 49(L) x 26(W) x 12(H)mm.

The page is linked below and the description above was still showing on 27 November, 2015.

Link to Jaycar XC-4514 page

The problem

The board is nicely made and looks the part. I powered it up with 5V, but only got 3.3V out and it wasn't adjustable with the potentiometer. XC4514 pic At an input of 10V, the board could be adjusted from 3.2V to 9.3V out. At no stage could I make it produce any higher dc output than was present at the input.

I checked the board for obvious faults and found no problem. Noting the chip used was the Texas Instruments LM2596S-ADJ, I enquired of Jaycar as to whether they had known of problems with this part. I did receive a prompt response from a nice chap who wanted to know if I had operated the module with a load connected (yes) and advised me that there was plenty of data on the web about the LM2596 chip. I responded that I had used a load on the output and suggested that they power one up from stock to check behaviour for themselves. Alas, there were to be no more responses from Jaycar on the subject.

What was found

Well, it didn't take me long. Looking up the LM2596S datasheet, the manufacturer states it is a "LM2596 SIMPLE SWITCHER® Power Converter 150 kHz 3A Step-Down Voltage Regulator". The immediate clue is "Step-down" but on reading the complete data sheet, it is quite clear the unit is not a boost converter and therefore cannot, under any circumstances produce a higher dc voltage out than is applied to the input.

It appears Jaycar is confused as to what this module does and has unintentionally given it an incorrect product application and description. It would be appreciated if they were to acknowledge the mistake but that isn't the way of modern business. Of course I received no offer to replace or refund, but I will keep the unit. It is actually a small, efficient step-down converter.

Comments

(1) From: Axino

Update: Jaycar have now (noted on 14 Jan 2016) updated the product description.

(2) From: Brian Date: 7 May 2016
Message: Jaycar new Zealand are still selling the module, with its incorrect description. I brought one and found the same, aweful truth. It is indeed a step down module. I needed 20 volts from 5 volts to run the anodes of a vacuum flourescent display, without it I require two power supplies. Thanks Jaycar!

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