Junkbox boost converter fun

Started by bitrex in sci.electronics.design5 years ago 10 replies

Here's a schematic of the junkbox HV supply I built. http://tinyurl.com/jnaj56p It's working okay. The only disappointing thing is that the...

Here's a schematic of the junkbox HV supply I built. http://tinyurl.com/jnaj56p It's working okay. The only disappointing thing is that the efficiency is a rather unimpressive 65% at 12 volts in, ~180 volts out at 20 mA current. Frequency of the switching waveform is about 60 kHz. Is there anything I can do with the design to improve this? There's some ringing at the drain connectio...


Boost Converter Efficiency Improvements

Started by David Jordan in sci.electronics.design8 years ago 262 replies

I need to generate approx. 200V at 20mA from a 12V supply. My first attempt is a multiplying SEPIC (i.e. the 2nd inductor is connected to the...

I need to generate approx. 200V at 20mA from a 12V supply. My first attempt is a multiplying SEPIC (i.e. the 2nd inductor is connected to the output of the first stage, instead of ground). It's working reasonably well but I'd like to improve the efficiency. I'm getting 80% efficiency at the moment which is acceptable but I'm sure it could be better. I'm using a couple of 100uH inductor...


LED driver from 3V supply

Started by sms in sci.electronics.design6 years ago 14 replies

I have a microcontroller whose GPIOs can only sink or source 4mA. I need to drive three 20mA LEDs, only one on at a time. The supply is about...

I have a microcontroller whose GPIOs can only sink or source 4mA. I need to drive three 20mA LEDs, only one on at a time. The supply is about 3-3.2V (two lithium AA cells). There's a DC to DC converter to 5V which I could also use if I had to. First I was going to use a hex buffer from the 5V supply, but it the specs show it drawing a lot of current in addition to the LED supply curr...


Coilcraft Model Converter Published!

Started by Tim Williams in sci.electronics.design5 years ago

The much-awaited(!??) calculator is here: http://seventransistorlabs.com/Calc/Coilcraft1.html The SPICE was easy; hard was writing, apparently...

The much-awaited(!??) calculator is here: http://seventransistorlabs.com/Calc/Coilcraft1.html The SPICE was easy; hard was writing, apparently half a kLOC of JS, just to graph the stupid thing... (Nope, no encryption or anything... ;-) ) But now that I've got that, I'll probably add fine-tuning adjustments so the user can manually fit it themselves. And yes, that's a precision model...


Slow SEPIC sim

Started by John Larkin in sci.electronics.design2 years ago 11 replies

I'm simulating a pretty simple SEPIC dc/dc converter in LT Spice. Just to hit the requested output voltage is taking maybe 10 minutes...

I'm simulating a pretty simple SEPIC dc/dc converter in LT Spice. Just to hit the requested output voltage is taking maybe 10 minutes and creating a 1.4 gbyte .RAW file. Are there some settings that would speed this up? The alternate solver does seem to be a bit faster. -- John Larkin Highland Technology, Inc lunatic fringe electronics


Sepic Charger

Started by captoro in sci.electronics.design7 years ago 13 replies

Hello all, I am attempting to design a sepic converter ( DC to DC) design. Basically s= olar panel to charge a battery. Therefore Input will...

Hello all, I am attempting to design a sepic converter ( DC to DC) design. Basically s= olar panel to charge a battery. Therefore Input will be anywhere from 6 to = 20v and OUTPUT 12v. I am making the following circuit: http://jordanofoz.com/tunecharger/52_mtc_43_evaluation_module_d.pdf I am doing the software part new and having nig problems with the duty cycl= e. I want to keep a con...


Turbo Royer/Baxandall in boost configuration

Started by bitrex in sci.electronics.design2 months ago 62 replies

Is it possible to take your standard Baxandall and tap the capacitor, take an aux winding off the secondary and feed a somewhat higher DC...

Is it possible to take your standard Baxandall and tap the capacitor, take an aux winding off the secondary and feed a somewhat higher DC voltage to the cap (through the usual two-diode supply handoff arrangement), and use it to feed the gate drive to the transistors as well, which would be clocked rather than self-oscillating. The goal would be to have a quiet step-up converter that co...


isolated DC/DC converter

Started by John Larkin in sci.electronics.design10 years ago 189 replies

This http://www.panoramio.com/photo/61564837 might work for powering a thing I'm doing. I can use a standard cheap Coiltronix dual-coil...

This http://www.panoramio.com/photo/61564837 might work for powering a thing I'm doing. I can use a standard cheap Coiltronix dual-coil inductor as the transformer. The complementary emitter followers will have no shoot-through and can have controllably slow switching edges, since they will just follow the base drive. Anybody got ideas for the base driver device? Ideally it would be s...


What type of Electrolytic Capacitors to Buy

Started by Anonymous in sci.electronics.design10 years ago 5 replies

I have a DTV converter box that went tits up on me. I used it for about 2 years without problems, then one day it took forever to turn on,...

I have a DTV converter box that went tits up on me. I used it for about 2 years without problems, then one day it took forever to turn on, but finally did. It worked fine for a few days. After turning it off, it refused to work again. Several times since then, I've turned it on to test the voltages between the power supply board and the main logic board and suddenly the green light comes ...


300V power supply.

Started by George Herold in sci.electronics.design4 years ago 40 replies

Hi all, So I'd like to make a 300 V supply. I don't really want to start from the AC line. So I've been looking for a DC-DC converter...

Hi all, So I'd like to make a 300 V supply. I don't really want to start from the AC line. So I've been looking for a DC-DC converter solution. I started here, (of course) http://www.analog.com/media/en/technical-documentation/application-notes/AN118fb.pdf Figure 13 looked nice. I then priced a pico 32195 transformer. ~$100! Ouch! (maybe I can find a cheaper one.) I then was tr...


AC and DC Current Sensing

Started by panfilero in sci.electronics.design8 years ago 59 replies

I'm interested in sensing AC and DC currents, 0-8A nominally, but up to 160= A for 10msec current surges from both AC and DC sources... I'm after...

I'm interested in sensing AC and DC currents, 0-8A nominally, but up to 160= A for 10msec current surges from both AC and DC sources... I'm after the be= st resolution I can get... I don't know if it's possible to do this for bot= h AC and DC off the same current sense circuit... I was thinking a shunt th= rough a current sense amplifier then to an RMS to DC converter IC... but I'= m not sure...


usb keyboard to ps2 converter circuit

Started by Anonymous in sci.electronics.design7 years ago 5 replies

Need to adapt a usb keyboard so I can plug it into a PS2 KVM Connector changing adapter will not work. Needs some active circuitry. Have...

Need to adapt a usb keyboard so I can plug it into a PS2 KVM Connector changing adapter will not work. Needs some active circuitry. Have not found anything handy other than expensive commercial devices. Anyone know of a schematic handy??


How does negative impedance cobverter enable impedance matching ?

Started by Anonymous in sci.electronics.design4 years ago 26 replies

Could some guru on this news group shed some light on how a negative impedance converter achieve impedance matching ? I know the basic working...

Could some guru on this news group shed some light on how a negative impedance converter achieve impedance matching ? I know the basic working principles of this device, but must be missing some subtle point. Thanks in advance.


Bypass capacitors

Started by panfilero in sci.electronics.design10 years ago 13 replies

Hello, I've been trying to find some bypass caps that I plan on using with a DC/DC Converter (ADuM5000). And the datasheet recommend a...

Hello, I've been trying to find some bypass caps that I plan on using with a DC/DC Converter (ADuM5000). And the datasheet recommend a low inductance 0.1uF and 10uF. So, I've been googling around to try and find out what I should choose here, and I'm not sure. First I ran into this article http://www.akm.com/AppsNotes/layout2.pdf which says "we recommend using aluminum electrolytics. Thes...


Back emf when unplugging coil?

Started by George Herold in sci.electronics.design2 years ago 19 replies

Hi all, I've got a coil driver 3 amps max. coils are ~10 ohms and I'd have to look up the inductance... big open air coil. So a user had a...

Hi all, I've got a coil driver 3 amps max. coils are ~10 ohms and I'd have to look up the inductance... big open air coil. So a user had a problem and it looks like the pass transistor blew. (2N6059... I did this design ~15-20 years ago.) The circuit is a simple opamp voltage to current converter. And has never had problems before (that I know of.)* So the tech at the school who is r...


SCR Selection

Started by panfilero in sci.electronics.design9 years ago 10 replies

I'm trying to design an SCR based overvoltage crowbar circuit for a 100V to 24V DC/DC converter...I'm having some trouble finding the right part,...

I'm trying to design an SCR based overvoltage crowbar circuit for a 100V to 24V DC/DC converter...I'm having some trouble finding the right part, here's my specs My max load current is 1A. I have a 3A fast acting fuse at my input to the DCDC. I want an SCR that can handle 4A long enough for my fuse to pop, I want this to happen if my output goes to 30V... so, I went off to go look for such...


Suggestion - dc / dc converter 500 - 1000W

Started by gm in sci.electronics.design5 years ago 6 replies

Hi. I have played around lead alum battery from John Bedini and i must say i am quite exited about all this. Fast charging ( 12V / 85Ah under...

Hi. I have played around lead alum battery from John Bedini and i must say i am quite exited about all this. Fast charging ( 12V / 85Ah under 45 minutes ), you can discharge it to almost 0V etc. Anyhow, there is bunch info on this on the net. Really good battery, with "small" problem. The standard voltage of fully charged battery is around 11.5 to 12,5 V so when i hook up some standard...


a little filter

Started by John Larkin in sci.electronics.design8 years ago 51 replies

We make a box that can output a lot of fiberoptic logic signals, light on/off. One existing mode is PWM, where frequency is 125 MHz/N,...

We make a box that can output a lot of fiberoptic logic signals, light on/off. One existing mode is PWM, where frequency is 125 MHz/N, and "on" resolution is 1 ns. I have a customer who needs a remote analog signal, 0-1 volt, that he can update in a microsecond or two. He'd like 10 bit resolution. So I figured that an optical/electrical converter could drive a lowpass filter at the far...


A flyback based on the new Infineon SiC

Started by Piotr Wyderski in sci.electronics.design1 year ago 2 replies

Some time ago James Arthur sent here a notification about the IMBF170R1K0M1XTMA1 SiC MOSFET. I have just re-prototyped one of my wide input...

Some time ago James Arthur sent here a notification about the IMBF170R1K0M1XTMA1 SiC MOSFET. I have just re-prototyped one of my wide input range flybacks, and the results are excellent. The performance is comparable to the one with the 1700V C2M Cree part, but the converter's structure is much simpler, which is good for reliability. Thanks, James. Best regards, Piotr


speaking of substrate diodes...

Started by Anonymous in sci.electronics.design1 month ago 2 replies

leads to this one... https://www.dropbox.com/s/cgaxalnn3hhf315/RRIO_Logamp.jpg?raw=1 where we use the substrate diode of a RRIO opamp as a...

leads to this one... https://www.dropbox.com/s/cgaxalnn3hhf315/RRIO_Logamp.jpg?raw=1 where we use the substrate diode of a RRIO opamp as a logarithmic current-to-voltage converter. There are better ways to do this, but maybe none so cute. -- Father Brown's figure remained quite dark and still; but in that instant he had lost his head. His head was always most valuable whe...