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- เผยแพร่เมื่อ 12 มิ.ย. 2024
- Dave explains the Dickson Doubler building block circuit. a.k.a diode charge pump.
Use a spare microcontroller pin, some diodes, and capacitors to create a useful voltage doubler or voltage multiplier.
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Thank you! This tutorial is nine years old so you may never see my comment. I couldn't get my circuit to work until I saw your tutorial and built your circuit.
By far my favorite, and in my opinion the most informative EE, youtuber. Very good video as usual
Great video, even after 9 years!
Micro controller spec sheets warn against driving capacitive loads, so buffering the io pin may be required. Great video mate! Thanks.
I was wondering as well weither a current-limiting resistor was necessary (on both chip pins actually: +3V and clock). Driving a 1uF cap straight from a pin definitely gets me anxious.
You aren't really driving a capacitive load though, you are just changing the reference voltage. Nearly all of the energy in the system is going to come from the VCC pin in the circuit that charges the cap once your clock pin goes low and the cap voltage is lower than VCC.
@@AustinSteingrube What is VCC, is it stand for voltage charging circuit?
@@ryanb1874 "VCC" stands for "Common Collector Voltage". It is basically just your positive voltage supply. Nothing fancy.
@@AustinSteingrube is there really a difference between positive, and negative voltage, material, or like affecting, electron migration?
Hey that is my registered key for DaveCAD!!!
Now I'll have to buy another license....
Another great vid Dave!
thanks Dave, this is exactly what I was looking for to work around some issues with a project
I'm totally new to electronics - and your vlog has helped me in a lot of ways
Dear good sir, I'm so lucky that I found your channel. Now I can use this method for my capstone project! Thank you so much. I love your teaching. So easy to understand the theory. It helps alot when you do the exxperiment right after.
I love this series. I am learning so much from this videos. Thank you!
Excellent video. Although I've built it in the past already I like the video very much and please, keep those tutorials/lectures comming.
Wow amazing, I went to school for computer engineering years ago and I came across this video. You're amazing btw, but this video gave me so much nostalgia! I miss working on EE stuff.
This is awesome. Done this a while ago on a project but good to see the application again. :)
This is my favorite series from you right now, keep it goin
13:13 got me with the license popup there!
A brilliance derived by brilliants.
Loving this series Dave! Always fun and interesting. Keep up the good work!
Hi mate,I think that your videos are brilliant & very informative as always & i have learned a fair amount from them .Keep up the good work,cheers.
Wow, this is very good. Did not know you could do a pump stage like that.
Thanks.
Always very helpful, thank you Dave, it' s a pleasure to watch your video
Thank you Dave. This helps me a few times.
fantastic video! Fashion show, audio at the end, never know what'll happen next. Content is great. Love it!
What I like most about his videos are: He removes empty parts of video, like while he is writing something to board; I mean at 4:58 no graph - at 4:59 colorful graph plotted and his speech goes like there is no video edit, magic happened,
Love the war games quote at the end. Great job as always Dave
Awesome electronics videos! Great work!
Hi Dave, I love your fundamentals friday. Greetings from Germany.
I think what you're missing is that a charged capacitor maintains the voltage across itself (ΔV_C) as long as no current passes through it (incl. leakage). Furthermore, ΔV_C(t) is always continuous.
Look at the circuit when PWM = 0V. Point 1 is 3V_{DC}, so the capacitor can charge to 3V.
Later the PWM voltage = cap bottom lead voltage = 3V, and the capacitor maintains ΔV_C = 3V it charged up earlier; the voltage at the top lead is therefore 3V + ΔV_C = 6V (with reference to ground).
ASMR circuit explanations is what that is.
You definitely should! First try to understand how it works. Then you see why it's always good to have a bunch of them lying around in the parts drawer. Just yesterday I needed a square wave with variable frequency (from .1 to 1kHz) to flash some LEDs. If you're fine with fixed 50% duty cycle, search for "mini-astable ne555". A NE555, one resistor and two caps, that's it. It's also a circuit I like, because it's "unusual", in that it uses the output pin itself for the timing.
Thank you for this very educational video.
"Please renew license" LOL
I want your T-shirt mate!!
Another great tutorial!
that shirt scene got me laughing me heart out lmao , i love you man.
I have a Communications Electronics Exam in 2 hrs :( Please guys wish me luck ! .. Dave ,, you are so greaaat !
I used a charge pump to create a negative rail for a couple of my projects (which worked a treat). Maybe you should give that a mention some day.
Awesome video! I could have used this months ago during my school project. Lol.
As usual, kudos on a job well done! I have been simulating your circuits using EasyCircuit and was surprised that a) your circuits really do as you say, and b) that EasyCircuit results are very accurate. Also, at the end of most of your videos I find myself thinking (using a chipmunk voice) gee Dave!
If anyone's wondering what the name at 1:21 actually is here's the reference Greinacher circuit
in en.wikipedia.org/wiki/Voltage_doubler#Greinacher_circuit
Used as a source, the current to the load is coming from the capacitor charged up to 3V, which charges the grounded capacitor up to 6V thanks to that boosting effect. The cap gets re-charged (to at most 3V) when PWM = low, and THAT current comes from point 1; when PWM = high, the diode blocks reverse current from cap to point 1.
There shouldn't be a point where both cap terminals are 3V once the thing's running, unless your load is so big that the cap gets fully discharged.
Great new series you started here, I like it a lot! (Though I hope the videos don´t get even longer...). Do you take suggestions for future topics?
Damn too clever for me. You really know your electronics.
Awesome Video! Love it!
Incredibly helpful! Thank you, Dave!
i have no idea what the heck hes talking about, but i subscribed to him
Please renew licence, Love it.....
When the PWM goes high, you are lifting the "ground" of the cap to +3v. This lifts point 1 to +6v through the cap. The current comes from the charge stored across the cap.
Why didn't you use dual diodes on the watch to save space?
Oh, and you forgot to mention you can use this method to generate negative supplies...!
The ansewer is weared by dave... it's called ne555 (you can use the magic ne555 in astable mode) :) or you can use the pwm module on pic. Everythigs than generate an oscillating signal can work. (sorry for my english :) )
Thank you
Great video thanks
And Dave loves them
really useful thanks
Dave on the cat walk... he should have dubbed in Right Said Fred - "I`m Too Sexy" for that, lol maybe next time
A bright future in modelling me thinks.
Excellent!
Thankd dave...very Educative. I actually had an issue with a low dc voltage in my latest design..this will surely help out.
I was thinking....do you have any video on how to perfectly use Oscilloscopes, especially when powered by AC mains...to avoid damaging your circuits by a blast..tnks
fantastic!
I did a quick google and I found values ranging from 20 microamps to 1 milliamp, so if you shop around it shouldn't be a problem.
Dear Dave, I love your blog :) Would you like to make a video that describes the difference between tantalum, mlccs, electrolytic, etc. caps related to frequency? would be nice! Greets from Austria, not Australia ;)
Depends on the uC and the load but e.g. Atmega328 provides 40mA and similar uCs provide similar current I guess. The MSP430g2253 for example provides 20mA max current per pin. Furthermore you have to drive the driver as well ;)
cool trick, understood (most of) it
Prefer these over tear downs from a learning perspective - wish you did more
I'm interested in how you'd handle 3.3v to 5v for ttl serial interfacing (extending on this video topic)
So much information
I would really like to see you read the AC Line frequency vs a RTC or your rubidium clock with a micro-controller! That would be very interesting to see....
Magic.
Could you use 2 transistor astable multivibrator to provide the signal for the multiplier? What frequency should it resonate in?
Also if the same one multivibrator was at the end of this, providing 9V pulses to this circuit and a piezo buzzer would it work?
What about the inrush current exceeding the maximum output current of the micro? At start up the output pin will be effectively shorted to ground through a diode.
lol that gets crazy... in lab at university it took 2 months just to learn how to use the software and its design rule checks to build a simple bandpass filter.. fyi you can do the same filter i did on that chip with only a few resistors, caps and transistors
Most of the pic micros, can sink only 20 mA, on the entire port i think. So whether we need a current limitting resistors. Or do we need to sdjust the fz, and there by increasing the importance to reduce the current?
Great vid
Dave, can I power it from a sine RF signal of say 15MHz, or does it need to be a square wave? I would like to use this as a DC-DC doubler for feeding a 14V varicap from 12v. I choose 15MHz so that the second harmonic is just above the HF (30MHz) to avoid interference to my RF circuit.
Very nice video, reminds me of using the XOUT pin of a PIC16C711 in1994 for generating -4V for an OPAMP. Still thinking if i should have tried harder finding a real RRIO opamp, since my input voltages were only down to 0V, hehe. Oh please don't point out RRIO OPAMPs to me available in 1994 :P
I see later in the video on the Agilent UI that you maybe used a dc offset of 1.5 to get the full 3. Is that in fact how you achieved the full 3V?
I had delivered my t-shirts Thursday (555), they are sweet.
Also looks like a great way for me to generate a higher voltage to switch on my N-Channel high side MOSFETs...
Hey Dave!
Why can you use your standard 1N4007 diodes at 10 kHz ? Isn't the reverse recovery time too high for 10 kHz ?
Wouldn't you want a current-limiting resistor or something on the PWM output? Otherwise it seems the instantaneous current would exceed the microcontroller's absolute maximum rating.
I wonder if the switching input from the microcontroller is drawing too much current for a tiny uC. Would be better to put a kind of driver (MOSFET?) on this line?
thanks
you forgot to link the voltage doubler video in the description!
Hi Dave just trying to replicate your circuit. At 24min you say oops wrong polarity. Does that mean I should be using a negative signal. I was under the impression from the beginning that it was a positive signal inducing a negative charge on the capacitor? I am using a SSR 40d as my signal so I can do either.
Any help appreciated Thanks Raef
How does the capacitor on the left charge. Is it from the +3VDC through the Capacitor and and back to ground via the signal generator ??
where did you get that 555 t-shirt, i want one as well
Marc
I want to ask two things:
First is that voltage dropped mostly on diodes , maybeyou can use MOSFET instead of diode? Maybe more power efficient also.
Another concern, imho when you drive capacitive load, it increases requirements to capacitor on microcontroller power circuit, because on battery powered setup initial stage of capacitor charge will draw relatively significant current, and will cause also significant supply voltage drop (which will lead to supervisor shutdown, or glitches)
A method to increase the power of this kind of charge pump is to multi-phase interleave them, I got a 3-phase voltage inverter charge pump in my product and it just works fine, transformer eliminated!
Hi Dave, I saw that you changed the red (2) to a (1) @5:52 :D
Gotcha :)
enjoyed the multiplier vids, have you done anything on the jewel thief circuit and how it works?
Big Clive is the Joule thief guy, he even created the name .
Its also worth saying that negative voltages can be generated by inverting the circuit
would a fundamentals friday on decoupling caps be beneficial? is their enough information to cover for a video? if anyone could do it dave can! ;)
Hi Dave, great tutorial. Question, how do did you connect the voltage multiplier to your o-scope? The doubler does not appear to have one common ground reference and it does not look like you used differential probes. Thanks!
Have a play with the circuit. Both inputs and output do have a common gnd reference.
I see the light, thanks.
Google is your friend. Can be done so many ways. Using an opamp or an NE555 or inverters. The heck even the basic 2 transistor a-stable will do it.
from those i have, the one with the highest reverse current is the mur820(8A 650mV Vf) with 5µA and the one with the lowest is the bat85 (200mA 240mV Vf) with 500nA. Compared to the nothing special 1n4148 (200mA 500mV Vf) with 7nA (all at 25V 25ºC, Imax Vf min), yeah that's a lot but still dont think that's gonna affect the doubler in any way except for the higher voltage due to less losses on the diodes. Not sure about those with miliamps of Ir but maybe those were the old ones?
hi thanks for your explanation of voltage doubler. i wonder that is voltage doulber effect current ? i mean normalla monitor lighting of small inverters consume 12 v 1,5 a because of transformer. Can i use it instead of inverter ? i want less current consumption.
hey dave how about explaining joule thieves next? to continue white the voltage multipliers/converters idea. Also really useful what you dont have a clock signal or a really low voltage source like a single 1,5v AAA
Hi EEVblog!
I would use 2 transistors, 1 PNP and 1 NPN for a Inverter Circuit. What do you think?
i don't see the link for the coch. walton voltage * vid that you mentioned in this vid, or whatever it is called. Just FYI
What I don't understand is the PWM is 3V with reference to ground, point 1 is 3V to ground. So across the first cap coming from the PWM is 3V and 3V so where is the current coming from?
Nice, Thanks
It may be a silly question, but how can I easily get this kind of squarewave or i have to run something else and use a microcontroller. Or just to use some sort of chip or oscillator, (like mc34063 but i don't want to use an inductor) i don't know. For example if only want to double the voltage to power something up.
Excellent video - can you focus on microcontroller voltage inverter next time? How to make -5V from +5V?
If you take the output back to the input, will the voltage keep escalating?