two switcher circuits

Started by Anonymous in sci.electronics.design2 months ago 31 replies

...

https://www.dropbox.com/s/keynlhs9ktzivyh/LTM8078_dual_neg_1.asc?dl=0 https://www.dropbox.com/s/htzvrbnd8qx3ooi/LTM8078_plus_minus_1.asc?dl=0 -- John Larkin Highland Technology, Inc Science teaches us to doubt. Claude Bernard


LT Spice alternate solver

Started by Anonymous in sci.electronics.design2 months ago

I have a sim that hangs up unless I use the alternate solver. Is there a directive I can put in my circuit to force that? Or is there only the...

I have a sim that hangs up unless I use the alternate solver. Is there a directive I can put in my circuit to force that? Or is there only the persistant setting in the tools/control panel menu? Good news: the latest update finally includes the LTM8078 switcher! I'm teaching it how to convert +24 into -5 and -2.5. -- John Larkin Highland Technology, Inc Science teache...


A quiet SEPIC negative supply

Started by Winfield Hill in sci.electronics.design2 months ago 8 replies

I needed to add a -3.3V to -6V supply to my RIS-796A 250A pulser, analog version. The PCB didn't have much space, so I implemented a simple...

I needed to add a -3.3V to -6V supply to my RIS-796A 250A pulser, analog version. The PCB didn't have much space, so I implemented a simple inverting switcher with an LM2840 buck converter. See circuit and layout on file U7=LM2840_sch+pcb.jpg in the DropBox folder: https://www.dropbox.com/sh/rfqohfvubj9pddh/AAC9dSrWbeJmY9iq_rODYonIa?dl=1 There's also a sub-folder with relevant...


Type 2 compensation network design

Started by Bitrex in sci.electronics.design9 years ago 3 replies

I'm working through the excellent text on SMPS design "Switching Power Supplies A to Z", by Sanjaya Maniktala. Right now I'm reading the section...

I'm working through the excellent text on SMPS design "Switching Power Supplies A to Z", by Sanjaya Maniktala. Right now I'm reading the section on the feedback loop and stabilization. As a first-order rule of thumb to achieve stability, Mr. Maniktala suggests that the loop gain transfer function of the switcher intersect the 0 dB point at approximately 1/6th the switching frequency, with a s...


A PIC based boost converter

Started by Jan Panteltje in sci.electronics.design8 years ago 43 replies

A PIC based boost converter The old design as discussed here last week had problems starting oscillating with heavy capacitive loads. The...

A PIC based boost converter The old design as discussed here last week had problems starting oscillating with heavy capacitive loads. The efficiency was only about 50 % too. The TI super switcher chip is invisibly small and difficult to obtain without forking out $$$ for shipping and maybe customs. That left the junk(well its valuable) box. I already have 2 PICs 18F14K22 in this design, p...


highest voltage switcher (half or fullbridge)

Started by Jamie M in sci.electronics.design8 years ago 17 replies

Hi, Just curious what the highest voltage switcher people here have built? :) cheers, Jamie

Hi, Just curious what the highest voltage switcher people here have built? :) cheers, Jamie


Interesting blog entry about switching power supplies and Steve Jobs

Started by Joel Koltner in sci.electronics.design8 years ago 31 replies

Steves Jobs would've had you believe that the computer industry ripped off Apple's idea to use a switcher as their power supply in the Apple...

Steves Jobs would've had you believe that the computer industry ripped off Apple's idea to use a switcher as their power supply in the Apple II. Reality is, of course, rather different -- this is an interesting article that provides a well-researched history of what really happened: http://www.arcfn.com/2012/02/apple-didnt-revolutionize-power.html Not that Jobs and Apple didn't create ...


High voltage pnp's (250 volts)

Started by Hul Tytus in sci.electronics.design1 month ago 50 replies

sci.electronics.design, comp.arch.embedded high voltage pnp's (250v) Anyone know of a good pnp transistor spec'd up to 250 volts, a...

sci.electronics.design, comp.arch.embedded high voltage pnp's (250v) Anyone know of a good pnp transistor spec'd up to 250 volts, a probable current limit of 1 amp and designed as a switching device. It's to serve as the switcher in a variable frequency (pulse width held constant) power supply. So far a 2n2907 has been tried, with a 100ma 50 volt limit, with impressive results. Zete...


switcher LC output filter problem

Started by bitrex in sci.electronics.design2 months ago 6 replies

Driving an LC network as so to generate a sine: I'd like to calculate some values that make a nice sine into the grounded load but also...

Driving an LC network as so to generate a sine: I'd like to calculate some values that make a nice sine into the grounded load but also minimize the loss in the switches driving the filter. I'm not sure this is the topology I want or how to go about picking those values in this situation. Version 4 SHEET 1 940 680 WIRE


pre-regulator for LDO linear regulator

Started by panfilero in sci.electronics.design8 years ago 3 replies

can anyone explain how the pre-regulator circuit with a pmos threshold setting the differential voltage across a linear regulator works? the...

can anyone explain how the pre-regulator circuit with a pmos threshold setting the differential voltage across a linear regulator works? the situation is you have a dc/dc switcher going to a linear regulator, and you use a pmos to keep your dropout voltage at a minimum set by the pmos threshold voltage I saw this thing on the eevblog video, link below http://www.eevblog.com/2012/03/20/...


LTC Switcher CAD3 ?

Started by Robert Baer in sci.electronics.design8 years ago 69 replies

Switcher cad?? NO transformers. NO saturable inductors. NO selection of ferrite core materials. NO selection of ferrite core...

Switcher cad?? NO transformers. NO saturable inductors. NO selection of ferrite core materials. NO selection of ferrite core sizes or shapes. WTF??


Flyback transformers, small, high power, where?

Started by Joerg in sci.electronics.design8 years ago 66 replies

Folks, Got to do a flyback design, 120VAC to 24VDC or so, at about 15-20W. Will run in full PFC fashion with the ouput voltage sloshing...

Folks, Got to do a flyback design, 120VAC to 24VDC or so, at about 15-20W. Will run in full PFC fashion with the ouput voltage sloshing around, meaning peaks more like 20W but average power under 15W. 100kHz switcher frequency, because of a dearth of available PFC-flyback chips at higher and because EMC above 150kHz would be tough here. Most likely we'll use the LT3798. Here is the pick...


Where the F can i get SwCADIII?

Started by Robert Baer in sci.electronics.design8 years ago 30 replies

*NOT* version four, but version THREE? The baby bird GooGull gives "references" like Yahoo which does not have what was advertised, a PDF...

*NOT* version four, but version THREE? The baby bird GooGull gives "references" like Yahoo which does not have what was advertised, a PDF reference, Linear's site which has version four and it is not switcher at all, etc ad nauseum bs. I had it but the HD went a bit bad and now it is non-functional.


polymer aluminum cap

Started by John Larkin in sci.electronics.design8 years ago 23 replies

I designed a 0.9 volt power supply using LTM8023 switcher bricks, and used an aluminum bulk filter cap. It turns out to have too much...

I designed a 0.9 volt power supply using LTM8023 switcher bricks, and used an aluminum bulk filter cap. It turns out to have too much ESR, and I got a lot of output ripple, 0.6 volts p-p at 1/3 the switching frequency, some weird sub-cycle oscillation. It only started oscillating as my customer kept adding more and more code to the FPGA, increasing core current. There are two fixes: incre...


Large capacitance varicaps, where are thee?

Started by Joerg in sci.electronics.design8 years ago 117 replies

Folks, Looked at Digikey and some others. Where are those huge capacitance varicaps? The ones with several hundred pF of range for AM radios....

Folks, Looked at Digikey and some others. Where are those huge capacitance varicaps? The ones with several hundred pF of range for AM radios. All gone lalaland by now? Even the ones I found in the 100pF range are either obsolete or not recommended for new designs. What I am trying to do: I need to control a switcher chip in frequency because I've got a very resonant load to deal with....


Seeking: ~120V DC 20A supply

Started by David Lesher in sci.electronics.design8 years ago 35 replies

Three of us are working on an electric car conversion. We're now working on the "home" charger for it. For that, we are seeking a digitally...

Three of us are working on an electric car conversion. We're now working on the "home" charger for it. For that, we are seeking a digitally controllable switcher supply with ~120V output, at up to 20-30A. At these power levels, 240VAC supply is more likely. Obviously new this will be $$$$, but I wonder if anyone knows of a surplus candidate. We currently ^H^H^H presently have a 48V 750...


MicroController control for switching regulator

Started by RogerN in sci.electronics.design4 years ago 72 replies

I'm wanting to use a microcontroller to control the output of a switching regulator, maybe something like a LM2576 simple switcher. I see the...

I'm wanting to use a microcontroller to control the output of a switching regulator, maybe something like a LM2576 simple switcher. I see the adjustability is on the feedback lead but what's the best way make it adjustable from a microcontroller. I'm guessing the feedback may be used in switching timing, ie, I guess I can't just use a DAC and get an output of 1.23V more than the DAC ...


Emerson LPS-10x-M Alternatives

Started by Tim Wescott in sci.electronics.design7 years ago 22 replies

So, I'm working on a motor drive board for a customer. Due to a desire for performance improvements within the existing space, we're going from...

So, I'm working on a motor drive board for a customer. Due to a desire for performance improvements within the existing space, we're going from the traditionally-accepted brute-force power supply to a switcher. I have this nice board and software set that's carefully designed to treat the power supply with kid gloves -- and it works very well with the power supply that we used for prot...


2N4261 modern days replacement

Started by Sergey Kubushyn in sci.electronics.design7 years ago 13 replies

Can anybody point to something available now to replace 2N4261 transistor? It will be used in its primary role, as fast...

Can anybody point to something available now to replace 2N4261 transistor? It will be used in its primary role, as fast switcher. --- ****************************************************************** * KSI@home KOI8 Net < > The impossible we do immediately. * * Las Vegas NV, USA < > Miracles require 24-hour notice. * *********************************************************


Buck switcher chips

Started by Phil Hobbs in sci.electronics.design7 years ago 11 replies

So we've got the +-40V sorted out, thanks to all. The next bit to re-examine is the two buck regulators, both LM2594s, one for +5 and one for...

So we've got the +-40V sorted out, thanks to all. The next bit to re-examine is the two buck regulators, both LM2594s, one for +5 and one for -15. The TI LM2594MX-ADJ is about $1.40 in 100s, and there are zillions in stock. The ONsemi clone, LM2594D, is only 64 cents, but it looks like Digikey is the only distributor with any stock, and they have less than one reel. I like the me...