I see....thanks TC.... but since my atty is in the mod case I usually dont have room for electrolytic caps...so I have to stay with SMD's.
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I'm using electrolytic 100uf for both caps and it works without problems (3 weeks every day and all day use). i think it is not critical because this cap is behind battery, not some bad psu with lot of trash from high frequency and at 50/60 hz from network.
One question, i have battery life (2x900mah protected) for about 1 and half day. Is this OK?
Best regards.
One question, i have battery life (2x900mah protected) for about 1 and half day. Is this OK?
Best regards.
Sounds good jho.
Whats the matter TC...you got big shakey hands and poor eyesight like me!! LOL Thats why I rest my hand against the desk and use a 5 diopter magnifiying light when I solder!
@zogu...sounds like good batt life to me...what volts and ohms do you run with it all day?
Thats one thing I have been wondering too....what affect does increasing the value of the cap have...I know the voltage rating can go up no problem...but what about the uF?
Whats the matter TC...you got big shakey hands and poor eyesight like me!! LOL Thats why I rest my hand against the desk and use a 5 diopter magnifiying light when I solder!
@zogu...sounds like good batt life to me...what volts and ohms do you run with it all day?
Thats one thing I have been wondering too....what affect does increasing the value of the cap have...I know the voltage rating can go up no problem...but what about the uF?
I'm running at 5-5.5V, standard single coil smoktech cartos with tank. This is only combination I found till now which works with organic juices and it works really good. One cartomizer lasts for about ten days. At 3.7V there is no vapor production at all after few hours of using.
First cap can be anything from 10-100 uf, but it is always best to use values from datasheet, because it is calculated for best filtering of input voltage on all frequencies. For second cap there is formula in datasheet, if you lazy to read it
, basically there is only low limit (i think it is also about 22uf), but you can use everything to lets say 100000 uf. This is not calculated, but only important thing is that current does not reach more than 3amps for charging cap. Most important thing for us is that there will be no any difference in vaping because switching psu have constant current and only important thing is to build it according to datasheet.
I add to my mod 2 resistors on the both end of trimmer and now i have voltages ~ 3-6 volt. Voltage depends from quality of trimmer. I didn't find logarithmic trimmer, they should be better for smooth voltage regulation, i have very smooth from 3-5, and from 5-6 it is little to sensitive. Resistors are: one end of trimmer 2.62k, second and 12k, trimmer 2.5k. Attached is excel table where everyone can play with values (i'm sorry, it is not automatic, but it is easy to understand, i hope so
)Picture later, it is still very big, when i pack it in small box
Best regards.
works fine without electrolytic caps, module from China don`t have electrolytic caps.It`s a grate IC speciali if make custom PCB.
My KisBox: http://img189.imageshack.us/img189/1355/kisbox.jpg
Finally enough power... http://img823.imageshack.us/img823/2976/potkii.jpg ok, its 1,9ohm dual coil but what commercial mod can do that?
Finally enough power... http://img823.imageshack.us/img823/2976/potkii.jpg ok, its 1,9ohm dual coil but what commercial mod can do that?
looking good everyone, sorry I fell off the earth again. damn job is going to send me to the grave faster than death sticks every would have lol. I got a whole 3 weeks back home then back over to China.
lets see if I can pick a few of these. The pullup resistor I removed is for the enable pin, it is constantly connect to Vin with that resistor. if you don't remove it you waste current by applying a pulldown resistor big enough to counteract the pullup. I was trying to make the whole thing as efficient as possible and the pullup resistor is useless because if you don't remove it you need a big enough pullup to counteract the pulldown, so wasting current constantly.
For choices on input and output caps, I like to use at least twice what the input voltage is, especially on the output because the AC ripple from the switcher can swing pretty far. The stock input caps is fine(on battery input cap isn't as important, a "power supply" usually has so much ripple in it it's amazing though). 22uf on the output is ok but the ripple will be pretty bad. When the chip pulls from the input in the buck's on phase the input cap keeps the battery from seeing a big current jump. The output cap smooths the inherent noise in the output of the switcher. I used tantalum caps because I have a hardware cage at my disposal with free parts lol. After playing with the module I liked about 100uF using a power supply but 22 mic should work fine.
The big pisser about switchers is the inductor. I was playing around with replacing the inductor on the board, but a tiny inductor with high current capabilities is expensive. I found one about half the size in our cage but it was $50 each, so I didn't bother with messing with it. I might "borrow" lesser components, but a $50 inductor is a bit much lol.
lets see if I can pick a few of these. The pullup resistor I removed is for the enable pin, it is constantly connect to Vin with that resistor. if you don't remove it you waste current by applying a pulldown resistor big enough to counteract the pullup. I was trying to make the whole thing as efficient as possible and the pullup resistor is useless because if you don't remove it you need a big enough pullup to counteract the pulldown, so wasting current constantly.
For choices on input and output caps, I like to use at least twice what the input voltage is, especially on the output because the AC ripple from the switcher can swing pretty far. The stock input caps is fine(on battery input cap isn't as important, a "power supply" usually has so much ripple in it it's amazing though). 22uf on the output is ok but the ripple will be pretty bad. When the chip pulls from the input in the buck's on phase the input cap keeps the battery from seeing a big current jump. The output cap smooths the inherent noise in the output of the switcher. I used tantalum caps because I have a hardware cage at my disposal with free parts lol. After playing with the module I liked about 100uF using a power supply but 22 mic should work fine.
The big pisser about switchers is the inductor. I was playing around with replacing the inductor on the board, but a tiny inductor with high current capabilities is expensive. I found one about half the size in our cage but it was $50 each, so I didn't bother with messing with it. I might "borrow" lesser components, but a $50 inductor is a bit much lol.
Hey illuxion..you didnt miss much here...and yeah work can be a pain...whoever came up with that idea anyway. LOL
So on your pics in the first page you have a 200uf cap on the output and none on the input...is that still the optimum or do you suggest 100uf for the output now? If 200uf is best..can I use 2 100uf's in parallel?
The little bit of testing I did with these modules I was impressed...well except for the couple caps explosions..which was my fault...but nice power output and easy to modify.
So on your pics in the first page you have a 200uf cap on the output and none on the input...is that still the optimum or do you suggest 100uf for the output now? If 200uf is best..can I use 2 100uf's in parallel?
The little bit of testing I did with these modules I was impressed...well except for the couple caps explosions..which was my fault...but nice power output and easy to modify.
One thing about these boards. People mostly recommend to connect "enable" switch between positive wire and "enable" pin on the board. This is the wrong way. If you have a look to datasheet, you will see that there is the 7V protection zener between "enable" pin and ground. So if you connect this pin to positive more than 7V (2 LiIon batteries in series), the zener will burn. The whole board should still work, but less reliable.
I used in my power supply this schematic.
If you don't want the indicator LED, just use a short instead.
For 2 batteries in series R1 can be 8-20 kiloohms, R2 depends of a LED, 1-12 kiloohm.
I used in my power supply this schematic.
If you don't want the indicator LED, just use a short instead.
For 2 batteries in series R1 can be 8-20 kiloohms, R2 depends of a LED, 1-12 kiloohm.
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wrong. You don`t burn nothing, but must put that 100k resistor from + to EN pin. resistor+ zenner stabilized internal voltage at 7V, you may have 30V on IN nothing it`s damage. That resistor 100K it`s critical, without resistor will burn zenner.Respect schematic from datasheet
@slimest your version it`s good also.
@slimest your version it`s good also.
HUH? LOLwrong. You don`t burn nothing, but must put that 100k resistor from + to EN pin. resistor+ zenner stabilized internal voltage at 7V, you may have 30V on IN nothing it`s damage. That resistor 100K it`s critical, without resistor will burn zenner.Respect schematic from datasheet
@slimest your version it`s good also.
You "must put that 100k resistor from + to EN pin", yet Slimest's version which is "good also" doesn't use one.
Please explain a bit more, I seem to be missing something.
anything on the output is ok with a battery, the app notes for the 2307 say 22uF using 3.3v output, I just happened to have a bunch of 10v 220u tantalum caps on my desk so I used them lol. I run mine with either batteries or a power supply and the supply I use is really dirty 9v supply so I use the big boys to tame it a bit. There is a tiny cap on the input(I think 33uF), it just helps reduce some ringing on the output.
wrong. You don`t burn nothing, but must put that 100k resistor from + to EN pin. resistor+ zenner stabilized internal voltage at 7V, you may have 30V on IN nothing it`s damage. That resistor 100K it`s critical, without resistor will burn zenner.Respect schematic from datasheet
@slimest your version it`s good also.
Why? The way these modules come out of the box is for constant on with 3.3v output. We don't want them always on so you remove the pull up resistor that connects Vin to En and replace that with a small resistor from En to gnd. 100k from Vin to En is ALWAYS ON, instead I use 100K to gnd to keep it off, then my microswitch from Vin to En to actually turn the switcher on. I found if I left the node floating with no pulldown it was slow to turn off, when I released the button it would slowly drift off(about a second or 2). using 100k to gnd when I released the button it shuts off instantly.
The diode on the board is from Gnd to the switch pin, it's used to handle the bias of the switch pin before the inductor and it's actually optional although when you start running higher current the inductive kick does some odd things without it. There's another tiny diode between gnd and Vout that I removed, it's just there to make sure whatever device this is powering doesn't suck vout below ground. since we was essentially using a resistor(which is all an atty is) there is no reason to have the catch diode on the output.
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So why I am wrong?
And why 100k resistor is critical if you use max 8 volts input but not 30V? In our case we have max 1.4 volts drop on 5-10k resistor, in's small enough. Shure if you use 30V input, there is 24 volts drop, 20 times more. In this case 100k will do.Respect to Ohm's law
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