Notches in ground planes for multi-power multi-channel board

Started by Anonymous in sci.electronics.design10 years ago 72 replies

All, I am designing a multi-channel board and I have individual linear regulators for each channel running off a common switcher. Now, my...

All, I am designing a multi-channel board and I have individual linear regulators for each channel running off a common switcher. Now, my concern is that due to the split power planes, which are like thin fingers running through the board, I will cause potential differences based on the current in different channels, especially, because I have a common ground plane. Now, I was thinking m...


synchronizing SMPS for ADC sampling noise reduction

Started by Jamie Morken in sci.electronics.design10 years ago 9 replies

Hi, I am working on a switcher with ADC sampling at the same frequency as the main switcher PWM frequency, they are already synchronized to...

Hi, I am working on a switcher with ADC sampling at the same frequency as the main switcher PWM frequency, they are already synchronized to reduce noise when sampling the ADC. There are also several small flybacks (10watts at 12Volts output) on the board, I am thinking of syncing their PWM as well, but I am wondering if syncing a flyback is the same as syncing a forward converter for ti...


POWER SUPPLY FIRE

Started by Anonymous in sci.electronics.design9 years ago 39 replies

Ok, I am helping a friend at a small company investigate a fire. He makes a 0-30 kV switching HV supply in a nice AL box. Uses 110V into a 15V...

Ok, I am helping a friend at a small company investigate a fire. He makes a 0-30 kV switching HV supply in a nice AL box. Uses 110V into a 15V switcher that drives his switcher that drives a coil and multiplier for 30 Kv at about 1mA. He just got a letter from a client, accusing his unit of starting the fire, and while I can't go into too many details, the question is: Has anybody e...


SWITCHER DESIGN Q.

Started by Anonymous in sci.electronics.design8 years ago 8 replies

I need a 12V to 24V stepup boost converter at 80 AMPS (very low duty cycle, 1 second on, 100 seconds off) So far the inductor looks...

I need a 12V to 24V stepup boost converter at 80 AMPS (very low duty cycle, 1 second on, 100 seconds off) So far the inductor looks like: F= 200 Khz L = 7-10uH So any Idea where to get kilowatt class inductor cores in small amounts for prototyping? Steve


day shot to hell

Started by John Larkin in sci.electronics.design8 years ago 48 replies

OK, I just got the first board from production this morning, for this spectroscopy controller thing. ftp://jjlarkin.lmi.net/First.JPG It...

OK, I just got the first board from production this morning, for this spectroscopy controller thing. ftp://jjlarkin.lmi.net/First.JPG It gets 12 volts in, which runs an LTM8023 switcher brick to make 3.3 volts. The 3.3 runs most of the logic on the board (including a Spartan 6 and a PLX PCIe bridge, both BGAs) and also drives four secondary switchers and some LDOs to make 1.2, 1.5, 1.8, ...


LTSpice Automation

Started by Tim Wescott in sci.electronics.design8 years ago 76 replies

Does LTSpice have much in the way of automation capabilities? I'm working on a switcher design, half in mathemagic land, half in grotty old...

Does LTSpice have much in the way of automation capabilities? I'm working on a switcher design, half in mathemagic land, half in grotty old real circuits land -- I want to simulate the controller with PWM voltages, and look at how the circuit responds. So I'd like to run the circuit with a bunch of different duty cycles. But it's a complex circuit, so I need a bunch of different PWM's...


Noise in electrolytic capacitors

Started by Nemo in sci.electronics.design8 years ago 25 replies

I am trying to evaluate whether to use tantalum versus OS-CON aluminium electrolytics as the output decouplers for some linear postregulators...

I am trying to evaluate whether to use tantalum versus OS-CON aluminium electrolytics as the output decouplers for some linear postregulators after a (relatively low noise) switcher. This is for a high gain amplifier that will be operating down to audio frequencies. I've come across references to aluminium electrolytics being noisy, but no firm details (kind of odd as there are lots of d...


Some measurements LM2596 3.3V switcher

Started by Jan Panteltje in sci.electronics.design6 years ago 3 replies

_____________________ | | ........ | . sense...

_____________________ | | ........ | . sense . -------- | Uin + --------. LM2596. -----^^^^^^^ ------ Uout | . GND . | 33 uH | | ........ | | === | k diode === --- 220 u | a 1N5822 --- 220 u ...


Type 2 compensation network design

Started by Bitrex in sci.electronics.design6 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.design6 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...


Buck Switcher, Modeled Behaviorally

Started by Jim Thompson in sci.electronics.design6 years ago

Buck Switcher, Modeled Behaviorally... http://www.analog-innovations.com/SED/BuckSwitcher_Behavioral.pdf ...

Buck Switcher, Modeled Behaviorally... http://www.analog-innovations.com/SED/BuckSwitcher_Behavioral.pdf ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 8...


highest voltage switcher (half or fullbridge)

Started by Jamie M in sci.electronics.design6 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.design6 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 ...


pre-regulator for LDO linear regulator

Started by panfilero in sci.electronics.design6 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.design5 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.design5 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.design5 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.design5 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.design5 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.design5 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...