150W current source, with a current-mode switcher

Started by Winfield Hill in sci.electronics.design6 years ago 14 replies

Here's something for y'all to knaw on, a 150W current-source SMPS, made with a current-mode controller. It has external monitoring and...

Here's something for y'all to knaw on, a 150W current-source SMPS, made with a current-mode controller. It has external monitoring and programming with 0-to-5V signals. Most power supplies have low-Z voltage-source outputs, and when operated in current-limit mode they simply servo the voltage to the achieve the desired output current. A true current source has a low effective output capac...


Jumper to replace Inductor

Started by rickman in sci.electronics.design5 years ago 44 replies

I want to use a linear regulator on a board where a buck switcher had been designed in. No problem on the chip, there are thousands with a...

I want to use a linear regulator on a board where a buck switcher had been designed in. No problem on the chip, there are thousands with a compatible footprint for this TSOP-5 package. I need to replace the inductor with a jumper, something that can be SMT assembled and of course, inexpensive. The pads are spaced so a 1206 would reach but it is a bit wide with the pads only 47 mils ...


Junkbox switch for a switcher

Started by bitrex in sci.electronics.design5 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...


really nice little switcher

Started by John Larkin in sci.electronics.design5 years ago 32 replies

http://www.ti.com/product/tps54302?keyMatch=TPS54302&tisearch=Search-EN-Everything The data sheet doesn't say much about thermals, and it looks...

http://www.ti.com/product/tps54302?keyMatch=TPS54302&tisearch=Search-EN-Everything The data sheet doesn't say much about thermals, and it looks scary to me to make a 15 watt switcher in a SOT23-6 without a power pad, so I got the eval board and tried it. It's unusual in that it accepts 28 volts input and has internal soft-start and spread-spectrum. And it's cheap. https://dl.dropboxu...


Li-Ion questions (charger, fast-cycling)

Started by Joerg in sci.electronics.design5 years ago 14 replies

Hi Folks, Just bought another Li-Ion deal with charger: https://images-na.ssl-images-amazon.com/images/I/41HL6Xmx1qL._SX466_.jpg The...

Hi Folks, Just bought another Li-Ion deal with charger: https://images-na.ssl-images-amazon.com/images/I/41HL6Xmx1qL._SX466_.jpg The charger is like this little guy, a switcher that can deliver 1 amp: https://images-na.ssl-images-amazon.com/images/I/41HL6Xmx1qL._SX466_.jpg The typical battery is two cell bundles in series so 8.4V max. To my surprise the charger has 10.2V open loop...


Wall wart spurs

Started by Phil Hobbs in sci.electronics.design5 years ago 20 replies

So this quantum limited photoreceiver again. After spending yesterday finding several fractional-decibel bits of buried treasure, it's...

So this quantum limited photoreceiver again. After spending yesterday finding several fractional-decibel bits of buried treasure, it's shot-noise limited above 30 nA in a full 1 MHz bandwidth, which is pretty good. CPH3910s rock, and the optimal drain current is a tradeoff: as you increase it, e_N goes down slowly but C_iss goes up rapidly. It has an LM2594 switcher right in the box, wh...


Class D commercial audio amp

Started by N_Cook in sci.electronics.design5 years ago 65 replies

Using PWM input to a Si8244BB predriver soic. After the inductor HF cut filter, on the 8 ohm speaker load there is about 1.5V pk-pk 200Kz...

Using PWM input to a Si8244BB predriver soic. After the inductor HF cut filter, on the 8 ohm speaker load there is about 1.5V pk-pk 200Kz constant level of switcher waveform, is that normal? what sort of background level would be normal ?


Removing voltage-multiplier-related flyback SMPS switching glitches

Started by Anonymous in sci.electronics.design5 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 -- ...


SMPS Topologies

Started by Cursitor Doom in sci.electronics.design4 years ago 62 replies

Gentlemen, What's the exact technical term for the switcher topology where you only have one large toroidal (typically) transformer right at...

Gentlemen, What's the exact technical term for the switcher topology where you only have one large toroidal (typically) transformer right at the mains entry point which takes line AC and outputs it at a lower voltage level whereupon it's fed into the bridge rectifier and thence into a large storage cap whereupon it can be chopped up, regulated and finally filtered, there being no othe...


LT spice, leakage inductance

Started by John Larkin in sci.electronics.design4 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


Flyback primary inductance changes

Started by Piotr Wyderski in sci.electronics.design3 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 ...


I screwed up (....again)! Need cap help.

Started by mpm in sci.electronics.design3 years ago 7 replies

The circuit is a 52kHz simple switcher (LM2575HVT-5.0) The current demand is 150mA (min), and 750mA (max possible), with normal being about 220...

The circuit is a 52kHz simple switcher (LM2575HVT-5.0) The current demand is 150mA (min), and 750mA (max possible), with normal being about 220 mA (upwards of 95% of the time). The input voltage is about 50 volts (it's really a stack of four 12-volt batteries under charge, but I bleed off a little so as not to run right up to the part's max voltage limit). Anyway, the datasheet cal


Early switcher with schematic

Started by bitrex in sci.electronics.design3 years ago 5 replies

I've been looking for an LTSpice model for a thyratron like the 2D21 for a while, anyone have one? probably not too difficult to DIY a...

I've been looking for an LTSpice model for a thyratron like the 2D21 for a while, anyone have one? probably not too difficult to DIY a behavioral model I guess...


T904 board

Started by John Larkin in sci.electronics.design2 years ago 5 replies

Here's another big board. https://www.dropbox.com/s/bfepc9wsaxwgs8p/T904_PCB_1.JPG?raw=1 This is the main part of a test set to production...

Here's another big board. https://www.dropbox.com/s/bfepc9wsaxwgs8p/T904_PCB_1.JPG?raw=1 This is the main part of a test set to production test a laser controller. Upper-left is a MicroZed, which is the compute/FPGA and communications bit. Upper right are a couple of the cute LTM switcher bricks. This connects to the DUT, an oscilloscope, a DVM, and a Keysight counter, so there's ...


stonehenge regulator

Started by John Larkin in sci.electronics.design2 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.design2 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.design2 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.design1 year 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.design1 year 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...


Spice problems

Started by Robert Baer in sci.electronics.design7 years ago 5 replies

Firstly, only the latest LTSpice IV is available,and sources insist only WinXP "or better" will run it. So tried to get old SwitcherCAD...

Firstly, only the latest LTSpice IV is available,and sources insist only WinXP "or better" will run it. So tried to get old SwitcherCAD III; unobtanium. Said, WTF, loaded the LTSpice IV exe, ran it; looks OK - no errors anyway. BUT I have this National Semiconductor Spice file and it barfs on it "Unknown schematic syntax .SUBCKT LM185/27C 99 2" and do not knowhow to fix th...