SMPS oddities

Started by Bitman in sci.electronics.design10 years ago 14 replies

Hi all, I've been studying SMPSs for a while out of personal interest, and I stumbled upon an old schematic for a discrete component-based...

Hi all, I've been studying SMPSs for a while out of personal interest, and I stumbled upon an old schematic for a discrete component-based SMPS: http://bitman3.altervista.org/SMPS.png As I understand it, this is a self-oscillating SMPS operating in current mode. T302 is the main switcher, Th301 is the turn-off SCR, T301 acts as the voltage error amplifier whose output controls the m...


Super Low Profile >130W SMPS ???

Started by D from BC in sci.electronics.design9 years ago 19 replies

I'm looking for the flattest > 130W smps's around for study. Any output V. Offline isolation type. (Vin=120VAC 60Hz) Open frame. Here's the...

I'm looking for the flattest > 130W smps's around for study. Any output V. Offline isolation type. (Vin=120VAC 60Hz) Open frame. Here's the tough part: 8mm max.profile height The smps will be bolted to a heat sink which is not part of the total height. Perhaps a flat screen tv or monitor smps??? But I don't know where yet.. Any suggestions... D from BC myrealaddress@comic.com


Commercial SMPS series wired outputs

Started by Bill Stuart in sci.electronics.design8 years ago 11 replies

What is the procedure for wiring two commercial SMPS's in series to double the output voltage? You used to be able to do this easily with...

What is the procedure for wiring two commercial SMPS's in series to double the output voltage? You used to be able to do this easily with transformer supplies, but, as I understand, the SMPS's have a built-in sensing circuit. Thank you for any advice. Bill Stuart


Xfmr design for smps

Started by panfilero in sci.electronics.design6 years ago 2 replies

I have a couple questions, one is about identifying smps topology and the 2nd is about the 3rd winding in an example I found. I need to design a...

I have a couple questions, one is about identifying smps topology and the 2nd is about the 3rd winding in an example I found. I need to design a smps that can take Vin: 70V to 105V and output 5V at 1A I've chosen to use the mic9130 http://www.micrel.com/_PDF/mic9130.pdf On the front page of the datasheet there is a "Typical Application" schematic, which is not to far off from what I ne...


transformer design for smps

Started by panfilero in sci.electronics.design6 years ago 20 replies

I have a couple questions, one is about identifying smps topology and the 2nd is about the 3rd winding in an example I found. I need to design a...

I have a couple questions, one is about identifying smps topology and the 2nd is about the 3rd winding in an example I found. I need to design a smps that can take Vin: 70V to 105V and output 5V at 1A I've chosen to use the mic9130 http://www.micrel.com/_PDF/mic9130.pdf On the front page of the datasheet there is a "Typical Application" schematic, which is not to far off from what I ne...


SMPS Long-Term Reliability

Started by Cursitor Doom in sci.electronics.design2 years ago 15 replies

Gentlemen, I have a mountain of vintage scopes to fix up (mid 1970s onwards). Most if not indeed all seem to be suffering from problems with...

Gentlemen, I have a mountain of vintage scopes to fix up (mid 1970s onwards). Most if not indeed all seem to be suffering from problems with the power supply section. These were manufactured at around the time SMPS was taking over from linear, I would imagine, so before they ironed out the bugs in the early SMPS designs. My question is, what were the design flaws in the early power sup...


20 mA LED SMPS buggy

Started by Bernhard Kuemel in sci.electronics.design5 years ago 31 replies

Hi sed! I want to illuminate our hall with 7 white LEDs so we don't have to turn on the main light at night when we want to save energy or...

Hi sed! I want to illuminate our hall with 7 white LEDs so we don't have to turn on the main light at night when we want to save energy or avoid too much light. I started to build a SMPS with a TL494 PWM controller salvaged from an ATX SMPS [2]. Image/video gallery [0]. Before I hook it up to 230V AC (325V rectified) I'm testing it with 12V and something is wrong. When I decrease t...


PSpice Gain/phase model for S/H and quantization in software loop (digital SMPS)

Started by Klaus Kragelund in sci.electronics.design5 years ago 4 replies

Hi I have implemented a digital SMPS in a Cortex M3 controller. The feedback of the SMPS is done using the TL431 and opto coupler...

Hi I have implemented a digital SMPS in a Cortex M3 controller. The feedback of the SMPS is done using the TL431 and opto coupler feedback. The feedback is sampled by the ADC at 10kSa and the sampled values controls the duty-cycle of the SMPS. It is stable, but I would like to simulate the loop in PSPice. The ADC has sample and hold along with quantiziation that affects the gain/phase. Th...


SMPS circuit need

Started by Ivan Matacic in sci.electronics.design9 years ago 2 replies

Hi everyone! I need to get stabilized 6V/2A from a variable power supply (SLA battery) with about 5V (empty) to 8V (full). What is the best...

Hi everyone! I need to get stabilized 6V/2A from a variable power supply (SLA battery) with about 5V (empty) to 8V (full). What is the best solution for do this? Some kind of SMPS? -- www.elektronka.com


Need the topology for a current to current SMPS, not voltage to voltage SMPS

Started by RobertMacy in sci.electronics.design4 years ago 138 replies

Need a current to current SMPS, with greater than 95% efficiency. and NOT a transformer! because has to be variable. The output will be a...

Need a current to current SMPS, with greater than 95% efficiency. and NOT a transformer! because has to be variable. The output will be a 'defined' current-time profile. Output Power is low, less than 5-10W delivered. Voltage compliance is low, less than 10 Vdc. I'm having difficulty wrapping my brain around potential topologies, need some help here. Anybody ever do this, or have...


3phase PI filter inductors and caps

Started by Jamie Morken in sci.electronics.design9 years ago 3 replies

Hi, I am making a filter between a SMPS and a 3phase brushless DC generator, the SMPS draws pulses of current at 200kHz, with a peak draw of...

Hi, I am making a filter between a SMPS and a 3phase brushless DC generator, the SMPS draws pulses of current at 200kHz, with a peak draw of 12Amps. The rectified voltage of the brushless DC generator peaks at 385VDC. The SMPS rise/fall switching time is will about 20ns. here is the schematic of the filter in ltspice: http://rocketresearch.nekrom.com/new/3phase_PI_filter/3phase-filt...


3phase PI filter inductors and caps

Started by Jamie Morken in sci.electronics.design9 years ago 3 replies

Hi, I am making a filter between a SMPS and a 3phase brushless DC generator, the SMPS draws pulses of current at 200kHz, with a peak draw of...

Hi, I am making a filter between a SMPS and a 3phase brushless DC generator, the SMPS draws pulses of current at 200kHz, with a peak draw of 12Amps. The rectified voltage of the brushless DC generator peaks at 385VDC. The SMPS rise/fall switching time is will about 20ns. here is the schematic of the filter in ltspice: http://rocketresearch.nekrom.com/new/3phase_PI_filter/3phase-filt...


SMPS feedback loop phase and gain margin

Started by Jamie Morken in sci.electronics.design9 years ago 2 replies

Hi, What is a good way to increase the stability of a SMPS feedback loop? I have a SMPS that uses this algorithm: if inductor current > ...

Hi, What is a good way to increase the stability of a SMPS feedback loop? I have a SMPS that uses this algorithm: if inductor current > current_limit, pulse off Duty cycle = ((desired voltage - current voltage) * gain) - (Inductor current * gain2) I am not sure how to put in the analog or digital adjustments for making sure the feedback loop is stable. I am reading up on these p


Proprietary SMPS design tools, what for?

Started by Joerg in sci.electronics.design8 years ago 30 replies

Today I and probably others received the announcement of the umpteenth SMPS "iteractive design simulator", EDesign Studio or whatever from ST....

Today I and probably others received the announcement of the umpteenth SMPS "iteractive design simulator", EDesign Studio or whatever from ST. I am not even going to try it. I've hung up on those things a long time ago, after WebBench from National flagged the third of my designs as "cannot be ..." (all in mass production now). The millisecond you try something unorthodox which I always ...


Rewinding a shorted SMPS transformer

Started by Jim Flanagan in sci.electronics.design8 years ago 9 replies

I have a defective SMPS transformer which I cannot replace and am contemplating rewinding the primary which has shorted internally. I've...

I have a defective SMPS transformer which I cannot replace and am contemplating rewinding the primary which has shorted internally. I've rewound 60Hz power transformers in the past with no problems. What are some pitfalls that I might run into when attempting this. Any help is appreciated. Thanks Jim


Surge Protection

Started by Chris in sci.electronics.design11 months ago 36 replies

Hi, What is the best choice currently for protecting SMPS circuitry in the event of surge at mains switch-on? I'm talking about the PSU...

Hi, What is the best choice currently for protecting SMPS circuitry in the event of surge at mains switch-on? I'm talking about the PSU sections of oscilloscopes, typically, so under normal working conditions less than one Amp drawn at 240V (as it is here in europe). I read somewhere that the front end of an SMPS momentarily looks like close to a short circuit resulting in very large ...


SMPS housekeeping electronics power question

Started by Anonymous in sci.electronics.design5 years ago 4 replies

Could some electronics guru please clarify a bit ? How is power to the control electronics circuitry of an SMPS provided -- power for...

Could some electronics guru please clarify a bit ? How is power to the control electronics circuitry of an SMPS provided -- power for controller/PWM module ? Any hints, suggestions or pointers to relevant information would be helpful.


Re: POWER SUPPLY FIRE

Started by Ross Herbert in sci.electronics.design9 years ago

On Fri, 20 Feb 2009 13:05:36 -0800 (PST), osr@uakron.edu wrote: :Ok, I cant post pics, creative lawyering. : :It was not the SMPS, focus is...

On Fri, 20 Feb 2009 13:05:36 -0800 (PST), osr@uakron.edu wrote: :Ok, I cant post pics, creative lawyering. : :It was not the SMPS, focus is now off the clients unit and onto :operational procedures involving fuses. : :Steve Can you say in what regard the focus is now on fuses? As I have said before, an SMPS which experiences a full short circuit of the output will self protect an...


Battery Charger SMPS, How'd they do it?

Started by RogerN in sci.electronics.design9 years ago 5 replies

I'm wanting to come up with a battery charger that is basically a SMPS with microprocessor controlled voltage and current limiting. Here's a...

I'm wanting to come up with a battery charger that is basically a SMPS with microprocessor controlled voltage and current limiting. Here's a link to something similar: http://www.amainhobbies.com/product_info.php/cPath/2_389_390/products_id/18362 So, how do you think they are getting 250W 10A at ~0 to near 30V from a 11V to 28V input? Would this be SEPIC, multiple SEPIC's in parallel...


Isolation Transformer Substitute

Started by D from BC in sci.electronics.design10 years ago 7 replies

Anybody know where I can get a cheapo 115VACin to ~163VDCout ~200W smps with good isolation? The idea is to dodge buying a ~200W isolation...

Anybody know where I can get a cheapo 115VACin to ~163VDCout ~200W smps with good isolation? The idea is to dodge buying a ~200W isolation transformer. And to avoid doing something goofy like: E*bay 12V smps + E*bay automotive inverter with 'Pure Sine'. D from BC British Columbia Canada.