Flyback primary inductance changes

Started by Piotr Wyderski in sci.electronics.design4 years ago 7 replies

I would like to build an off-line switcher based on the TinySwitch4 family. It implies f=132kHz. Then, VOUT=15V@0.5A....

I would like to build an off-line switcher based on the TinySwitch4 family. It implies f=132kHz. Then, VOUT=15V@0.5A. V_IN_MIN=120V, V_IN_MAX=374V (85-265VAC). I typed these values into the Schmidt's calculator to get a rough estimate: http://schmidt-walter-schaltnetzteile.de/smps_e/spw_smps_e.html L_PRI=7.36mH. OK, so now use PI Expert Online, provided by the manufacturer: Automatic ...


stonehenge regulator

Started by John Larkin in sci.electronics.design3 years ago 35 replies

I have a 48 volt power supply and I want to drive a lot of relays and uPs and FPGAs and stuff, so I figured I'd knock it down to 12...

I have a 48 volt power supply and I want to drive a lot of relays and uPs and FPGAs and stuff, so I figured I'd knock it down to 12 volts first. We have LM2567HV-ADJ in stock, a 52 KHz Simple Switcher probably designed by druids during the last ice age. Figured I'd breadboard the reg just for fun. A boy gets tired of typing all day. https://www.dropbox.com/sh/ajtqs7c1nswfhey/AABi7r0gchlj...


inverting switcher

Started by John Larkin in sci.electronics.design3 years ago 14 replies

I have +12 from a wart, and I need -1.2 and -5 to power some analog stuff and ECL. I can do...

I have +12 from a wart, and I need -1.2 and -5 to power some analog stuff and ECL. I can do this https://www.dropbox.com/s/3b0iff93k1k2ct6/TPS_Inv_1.JPG?raw=1 Problem is, I don't want to run Tina and there is no LT Spice model. It may go into burp mode at my modest load currents, so I could get a lot of output ripple. It might want some lead compensation too. I guess I should br...


nice little switcher

Started by John Larkin in sci.electronics.design3 years ago 12 replies

https://www.digikey.com/product-detail/en/linear-technology-analog-devices/LTM8078IY-PBF/161-LTM 8078IY-PBF-ND/10668252 It has a nice...

https://www.digikey.com/product-detail/en/linear-technology-analog-devices/LTM8078IY-PBF/161-LTM 8078IY-PBF-ND/10668252 It has a nice combination of input and output range, and the size is insane: about 1/4" square. It will do forced synchronous, burst, or synchronized switching. I wonder if it can be persuaded to convert a positive rail to two negative outputs. Sadly, LT Spice does no


GaN With the Wind

Started by Anonymous in sci.electronics.design2 years ago 38 replies

As I design yet another little switcher, I notice it's getting more and more tempting to swap ye olde MOS FET for a shiny new...

As I design yet another little switcher, I notice it's getting more and more tempting to swap ye olde MOS FET for a shiny new GaN-speck. Electrically superior in almost every respect, the GaN FETs' drawbacks are thermal (not a problem in this case), and their tee-nine-sie .9x.9mm bare-chip packages. e.g. T.I. CSD19831Q3: 100V, Rds(on)=50mohm, Cin=350pF, Coss=70pF, Crss=13pF EPC EPC...


dual neg switcher

Started by Anonymous in sci.electronics.design2 years ago

I'm on my 3rd day of BOM minimization of my big timing board, trying to consolidate enough parts so we can load the pick-and-place, which has...

I'm on my 3rd day of BOM minimization of my big timing board, trying to consolidate enough parts so we can load the pick-and-place, which has 200 feeder slots. The board has about 750 parts, over 200 bypass caps! We have +24 volts and need -7 and -5. The current design uses a Cuk converter to make -7, then an LM2991 linear to make -5. Lots of parts. Looks like I can switch 24 to (about...


160 vdc power rabbit hole...

Started by DJ Delorie in sci.electronics.design10 months ago 9 replies

Before I got too far down the rabbit hole... sanity check time :-) tl;dr: I want to run servos off nonisolated 160 vdc background: I'm...

Before I got too far down the rabbit hole... sanity check time :-) tl;dr: I want to run servos off nonisolated 160 vdc background: I'm updating this: http://www.delorie.com/electronics/bldc/ So the old driver used an external motor power supply (I had a 80VDC linear but it's big and used hard to get parts) and a separate external 15V driver supply (closed box switcher). The servos I'...


TPS54302 again

Started by Anonymous in sci.electronics.design11 months ago 3 replies

TPS54302 is a wonderful little synchronous switcher chip. 3 amp switcher in SOT-23, under a dollar. It does radical spread-spectrum pwm but...

TPS54302 is a wonderful little synchronous switcher chip. 3 amp switcher in SOT-23, under a dollar. It does radical spread-spectrum pwm but the dc output is quiet. We're designing a small box that contains about 400 power relays. To reduce coil power, we'll run the relay coils at 12 volts and bump them up to 24 briefly when we change setups. One issue is whether the switcher can switch 2...


Substitute LM2676 simple switcher

Started by g c in sci.electronics.design11 months ago 3 replies

Hi LM2676S-ADJ lead-free are hard to get now. Has anyone tried substituting LM2670 series with success? I am looking at the datasheets trying...

Hi LM2676S-ADJ lead-free are hard to get now. Has anyone tried substituting LM2670 series with success? I am looking at the datasheets trying to find a trap. Not using sync. Need a direct substitute without any changes to surrounding passive parts if possible. Geoff


switcher ringing noise

Started by John Larkin in sci.electronics.design9 months ago 34 replies

I used to love the LTM8078 dual switcher module. But it rings hard at around 400 MHz at every switch transition. This is called a...

I used to love the LTM8078 dual switcher module. But it rings hard at around 400 MHz at every switch transition. This is called a "Silent Switcher!" I breadboarded a 24-to-5 volt switcher with an ancient bipolar LM2576. It switches at 50 KHz. And at every switching edge, it rings at about 40 MHz. We tried all sorts of stuff on both switchers. Nothing so far has any effect on the ringing...


testing the TI switchers

Started by John Larkin in sci.electronics.design3 weeks ago 19 replies

I really like the TPS5 family of tiny little switchers, but their Spice models are, to be kind, absurd garbage. The first switcher on our board...

I really like the TPS5 family of tiny little switchers, but their Spice models are, to be kind, absurd garbage. The first switcher on our board simulates input power of 12 volts * 9 tera-amps. We're well along on pcb layout of a new delay generator, but I really want more confidence that everything will work first pass. So in parallel we're prototyping the switchers. https://www.dropbox....


Clever ways to get +/- volts from MC34063

Started by Tim Wescott in sci.electronics.design11 years ago 19 replies

I've got a 24V incoming supply, and a need for a number of supplies (+12, +5, -5, and +3.3). The +/- 5V supplies are for a bit of analog...

I've got a 24V incoming supply, and a need for a number of supplies (+12, +5, -5, and +3.3). The +/- 5V supplies are for a bit of analog circuitry on a largely digital board, so they have low current requirements. My plan for the +5V supply is to just hang a 78xx05 off the +12V. +12V and +3.3V are going to come from switchers off of +24V. Anyone have any suggestions for a clever way ...


Flyback vs half-bridge

Started by Phil Hobbs in sci.electronics.design9 years ago 160 replies

So, I'm goofing off playing with small switchers. (Well, not exactly goofing off, but there are somewhat more pressing tasks waiting....) As...

So, I'm goofing off playing with small switchers. (Well, not exactly goofing off, but there are somewhat more pressing tasks waiting....) As I said in George's thread, "Opamp w/ Vsupply > 36V", I built a small half-bridge supply with positive and negative voltage doublers. I'm not that keen on it, because (a) it uses a fair number of parts for what it does, and (b) it has a nasty ins


TI parts in LT Spice

Started by John Larkin in sci.electronics.design2 months ago 17 replies

TI has encrypted Pspice models for many of their parts, but I can't persuade LT Spice to run the switchers I want to use. Any thoughts...

TI has encrypted Pspice models for many of their parts, but I can't persuade LT Spice to run the switchers I want to use. Any thoughts on that? One of my guys says he can run their Cadence sim, but I'd prefer LT. Parts are TPS54302, TPS563300, TPS562208. I'd consider paying a consultant to get them to work in LT Spice. If sim is too much hassle, we'd solder.


simulating TI switchers

Started by John Larkin in sci.electronics.design1 month ago 10 replies

We are using TPS54302 and TPS562208. I haven't been able to get their Pspice models to work in LT Spice. They throw goofy errors, or run...

We are using TPS54302 and TPS562208. I haven't been able to get their Pspice models to work in LT Spice. They throw goofy errors, or run but at fs speeds and make no useful progress. TI apparently has their own sim, Cadence maybe, that might run these parts. Does anyone know how to do that, run the TI models with the TI software? Or to get the Pspice models to run usefully in LT Spic...