two switcher circuits

Started by Anonymous in sci.electronics.design2 years 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.design3 years 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.design3 years 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...


A PIC based boost converter

Started by Jan Panteltje in sci.electronics.design11 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...


High voltage pnp's (250 volts)

Started by Hul Tytus in sci.electronics.design2 years 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 years 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.design10 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.design10 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??


Where the F can i get SwCADIII?

Started by Robert Baer in sci.electronics.design10 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.


Large capacitance varicaps, where are thee?

Started by Joerg in sci.electronics.design10 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....


MicroController control for switching regulator

Started by RogerN in sci.electronics.design6 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 ...


fans in series

Started by Anonymous in sci.electronics.design8 months ago 35 replies

Has anyone run bldc fans in series? I want to run three 12v fans from a 48v supply, with a resistor or something in series I guess I could be...

Has anyone run bldc fans in series? I want to run three 12v fans from a 48v supply, with a resistor or something in series I guess I could be cautious and put a cap and a 12v TVS across each fan. Hmmm, 3 fans and 4 TVSs might work. Worst case, I can make a 48 to 12 switcher. Here's the idea: https://www.dropbox.com/s/5hx2hzrq4edd3ye/P944_Load_Module_1.jpg?raw=1 -- I yam ...


new 30MHz to 300MHz switcher - worlds smallest laptop adapter

Started by Jamie M in sci.electronics.design9 years ago 64 replies

Hi, Here's a new SMPS switcher apparently coming out next year for...

Hi, Here's a new SMPS switcher apparently coming out next year for laptops: http://phys.org/news/2013-12-circuit-laptop-charger-brick.html It apparently has a "power reclaiming scheme" for higher efficiency, would this be conventional sync rectification or some other thing? It looks like power electronics is in for a big (r)evolution once the 300MHz+ designs start to spread! cheer...


gate driver

Started by John Larkin in sci.electronics.design8 years ago 13 replies

I need a mosfet gate driver, to drive two n-fets in a half-bridge (totem pole) config, 5 volts nom in, with some sort of bootstrap for the...

I need a mosfet gate driver, to drive two n-fets in a half-bridge (totem pole) config, 5 volts nom in, with some sort of bootstrap for the upper fet gate. Switcher output will be around 2.5 volts at 5 amps, so the gate drives don't have to be monstrous. I've been working with LTC4442 on a breadboard, but it's really erratic. Sometimes it's beautiful, and sometimes the gate drive breaks ...


charge pump/boost converter

Started by bitrex in sci.electronics.design7 years ago 57 replies

For a hobby project, I'd like to be able to generate +48 volts or so from +5 volt USB. Current requirements are small, maybe 15 mA or so?...

For a hobby project, I'd like to be able to generate +48 volts or so from +5 volt USB. Current requirements are small, maybe 15 mA or so? I'd like uh, low noise (I don't have an exact spec so this is just kind of existential at this point), so maybe a charge pump would be in order rather than a boost switcher? Does anyone make a charge pump IC that I could feed an external clock to...


Todays's tronix project, LM2596 switcher as a current source

Started by Jan Panteltje in sci.electronics.design7 years ago 9 replies

Todays's tronix project, LM2596 switcher as a current source. For the big battery loader would it not be nice to have a current source that was...

Todays's tronix project, LM2596 switcher as a current source. For the big battery loader would it not be nice to have a current source that was simple, and made from stuff I already have in the box. The big ebay modules are cheap, but a bit of overkill. Had once (upon a time) made a little test board for the LM2596-3.3V version, that I actually use for any other volts > = 3,3 with the ai


My first switcher

Started by George Herold in sci.electronics.design7 years ago 28 replies

Hi all, Well I get to do a SMPS. There are boat loads of IC's out there and I'm looking for recommendations. (I better go re read AoE3) I...

Hi all, Well I get to do a SMPS. There are boat loads of IC's out there and I'm looking for recommendations. (I better go re read AoE3) I need a number of output voltages. +15V, +5V, -5V, -15V. and +24V. maximum current of 0.5A on any one. My current plan is to run the whole thing from a 24V wall wart or brick. Price and size is not too much of an issue, I guess fewer external pa...


Junkbox switch for a switcher

Started by bitrex in sci.electronics.design6 years ago 33 replies

I need to throw together a ~150 volt supply at a few 10s of mA to test a circuit idea, but I don't have much in the way of MOSFETs in my junk...

I need to throw together a ~150 volt supply at a few 10s of mA to test a circuit idea, but I don't have much in the way of MOSFETs in my junk box to build a switcher from. The only high-voltage device I have in stock is a couple Fairchild FQP2N60Cs, rated for 600V and 2 amps. That might be a possibility. I also have some lower voltage power devices, and I'm wondering if there would b...


Removing voltage-multiplier-related flyback SMPS switching glitches

Started by Anonymous in sci.electronics.design6 years ago 13 replies

A problem encountered with medium-to-fast current-mode flyback switchers, when combining high-ratio multi-winding flyback inductors with...

A problem encountered with medium-to-fast current-mode flyback switchers, when combining high-ratio multi-winding flyback inductors with multipliers: When Q1 switches on, a large current surge flows as Cpump charges from Cmult1 via D2. At Q1, the surge magnitude is multiplied by the transformer ratio. On simulation, U1 senses this via Rs and cuts Q1 off instantly, crippling the switcher -- ...


LT spice, leakage inductance

Started by John Larkin in sci.electronics.design5 years ago 227 replies

I'm simulating a flyback switcher and noticed that any K < 1 in the transformer radically slows down the sim, which is annoyingly...

I'm simulating a flyback switcher and noticed that any K < 1 in the transformer radically slows down the sim, which is annoyingly slow already... 90 seconds to sim 60 ms of startup and a little pulsed load blip. Maybe 6:1 slower with a little leakage inductance. So I only include leakage inductance to tweak the snubber. -- John Larkin Highland Technology, Inc picosecond