I am getting ready to design a circuit using the ME2108A Step-Up voltage converter, but first I wanted to closely examine the CE012 Voltage converter that I recently posted about – HERE. Since Canton Electronic’s CE012 module performed so well I figured that it wouldn’t hurt to examine it closely since their design seemed different from the chip manufacturer’s examples.
Last year, I purchased a ICStation LC100-A High Precision Digital Inductance Capacitance meter on eBay. There are several versions of the LC100 being sold with some physical variation, mostly in pushbutton switch placement, but mine matches the functionality of the user manual for one of the different ones, so I suspect that they are all copies of each other. They are very inexpensive (under $20USD) yet perform admirably with about a 10% tolerance. It does have one fault – the alligator clips are too large and difficult to work with.
I used a hot-air rework station, also a fairly recent purchase, to take apart one of the CE012 Voltage Converter modules. Next, I used the LC100 to measure the inductive and capacitance components. Of particular interest were two totally unmarked SMD capacitors. Once again, the LC100 did its job! I have included photos of the inductor being tested. It is marked “220”. It is listed as a 22uH inductor with a SFOP4521 footprint – but I wanted to measure it to be sure.
The two capacitors measured 12uF and seem similar to Kemet C1210C126K8PACTU. I believe them to be size EIA1210/METRIC3225. The module has one DO-214 packaged 1A Schottky diode, type SS14. Of course it has a ME2108A Step-Up convertor, as described in my previous post. Last, there is the inductor, which is shown in the photos below. So, that’s it – five components plus the PCB.
After tracing out the CE012’s design, which was vastly easier with the components removed, I discovered that it is the same as the chip manufacturer’s first example titled “For use Built-in Transistor”. The apparent difference was just that the CE102 parallels two SMD 12uF capacitors to obtain 24uF. The components vary from the chip manufacturer’s example. The example uses a 47uF capacitor and a 47uH inductor while the CE102 uses a 24uF combined capacitor and a 22uH inductor. BTW, I found that additional filtering capacitance is required on the output, especially with the 5V version, which is rather saw-tooth looking. The 3V output is fairly smooth. I used a 1,000uF electrolytic but a lesser value would probably suffice and a tantalum may be a better choice. The schematic of the CE102 is shown in Figure 1, below.
Okay, the images below show the CE102’s inductor under test with the LC100-A Digital Inductance Capacitance meter. Click on the image to enlarge it.