Is it possible to take your standard Baxandall and tap the capacitor, take an aux winding off the secondary and feed a somewhat higher DC...

Is it possible to take your standard Baxandall and tap the capacitor, take an aux winding off the secondary and feed a somewhat higher DC voltage to the cap (through the usual two-diode supply handoff arrangement), and use it to feed the gate drive to the transistors as well, which would be clocked rather than self-oscillating. The goal would be to have a quiet step-up converter that co...

This http://www.panoramio.com/photo/61564837 might work for powering a thing I'm doing. I can use a standard cheap Coiltronix dual-coil...

This http://www.panoramio.com/photo/61564837 might work for powering a thing I'm doing. I can use a standard cheap Coiltronix dual-coil inductor as the transformer. The complementary emitter followers will have no shoot-through and can have controllably slow switching edges, since they will just follow the base drive. Anybody got ideas for the base driver device? Ideally it would be s...

Hi all, So I'd like to make a 300 V supply. I don't really want to start from the AC line. So I've been looking for a DC-DC converter...

Hi all, So I'd like to make a 300 V supply. I don't really want to start from the AC line. So I've been looking for a DC-DC converter solution. I started here, (of course) http://www.analog.com/media/en/technical-documentation/application-notes/AN118fb.pdf Figure 13 looked nice. I then priced a pico 32195 transformer. ~$100! Ouch! (maybe I can find a cheaper one.) I then was tr...

leads to this one... https://www.dropbox.com/s/cgaxalnn3hhf315/RRIO_Logamp.jpg?raw=1 where we use the substrate diode of a RRIO opamp as a...

leads to this one... https://www.dropbox.com/s/cgaxalnn3hhf315/RRIO_Logamp.jpg?raw=1 where we use the substrate diode of a RRIO opamp as a logarithmic current-to-voltage converter. There are better ways to do this, but maybe none so cute. -- Father Brown's figure remained quite dark and still; but in that instant he had lost his head. His head was always most valuable whe...

Some time ago James Arthur sent here a notification about the IMBF170R1K0M1XTMA1 SiC MOSFET. I have just re-prototyped one of my wide input...

Some time ago James Arthur sent here a notification about the IMBF170R1K0M1XTMA1 SiC MOSFET. I have just re-prototyped one of my wide input range flybacks, and the results are excellent. The performance is comparable to the one with the 1700V C2M Cree part, but the converter's structure is much simpler, which is good for reliability. Thanks, James. Best regards, Piotr

I'm working on a PCB that contains nearly 30 resistors in a ladder configuration, each step switched in or out by a SMT solid state relay. It's...

I'm working on a PCB that contains nearly 30 resistors in a ladder configuration, each step switched in or out by a SMT solid state relay. It's essentially a decade box for a specific application. The relays are controlled by a micro and all is powered by a boardmount enclosed CUI AC/DC switching converter, supplying up to 400mA. The resistors are electrically isolated from the SM

I have seen designs where there is a cutout in the groundplane under the power inductor in e.g. a buck converter. Inductor is nominally...

I have seen designs where there is a cutout in the groundplane under the power inductor in e.g. a buck converter. Inductor is nominally a "shielded" one. I assume it is to prevent some kind of "shorted turn" effect? What do you think? Might a continuous plane be better? It could help to shield any field leakage and reduce emissions and circuit noise. I am asking generally, but say 1...

I'm designing another 3-phase PM alternator simulator, and I need a roughly +-60 volt floating power supply. It will feed three PWM half-bridges...

I'm designing another 3-phase PM alternator simulator, and I need a roughly +-60 volt floating power supply. It will feed three PWM half-bridges to make the three output phases. Here's my first pass at the dc/dc thing. https://www.dropbox.com/s/bwt1vgbb2j94p1d/23S942_x1.jpg?raw=1 Those Coilcraft planar transformers are radical. 300 watts, surface mount, under a cubic inch. They have a ...

So in the continuing saga of cotton spark detection, I need to make an isolated 2-output DC-DC converter to power an RS-485 link and a small...

So in the continuing saga of cotton spark detection, I need to make an isolated 2-output DC-DC converter to power an RS-485 link and a small SBC--about 2W altogether. This isn't a terribly low-noise application, so I was thinking about using the Bourns SRF0703-471M "coupled inductor" as a flyback. The question is, what's the coefficient of couping? There's no way to find out from the ...

I'm looking for a small, inexpensive H-bridge, or full-bridge IC, including MOSFET switches, for a forward-converter application. (My old...

I'm looking for a small, inexpensive H-bridge, or full-bridge IC, including MOSFET switches, for a forward-converter application. (My old favorite HIP4080 series has 20 pins and requires external FETs.) Most of the ICs with internal switches that I've found are meant for driving motors, and seem to have slow switching speeds. 40 volts and 2 amps are my minimum requirements. The LMD18200 ...

Hi All, I have a need to generate +100mV DC to drive a load which is capable of sourcing up to ~50mA but will typically see high impedance....

Hi All, I have a need to generate +100mV DC to drive a load which is capable of sourcing up to ~50mA but will typically see high impedance. Easily available I have a clean 24V source and 208VAC. My intent is to drop from 24V to ~1.8V using a buck converter then follow it up with a 1.0V precision shunt (ADR510 or other) followed by a 9:1 precision resistor divider. Buffer the 100mV

Hi, I'm trying to build a 2-200 MHz isolation amplifier. For 13 dBm I need abt. 120 mA peak current, 70 mA quiescent. The circuit is a...

Hi, I'm trying to build a 2-200 MHz isolation amplifier. For 13 dBm I need abt. 120 mA peak current, 70 mA quiescent. The circuit is a voltage to current converter, followed by a double cascode. 2N3904 is too slow, BFQ19S is too hot, it would do 1 GHz, but brings me negative input impedance, gain peaks and so on. I'm playing with the usual ferrite beads, but that does not bring com...

I have the following simple converter: CD4093 drives the power logic shift register's NPIC6C596A OE pin with 500kHz square wave signal...

I have the following simple converter: CD4093 drives the power logic shift register's NPIC6C596A OE pin with 500kHz square wave signal with duty cycle 40%. Both chips are powered from 5V, the shift register is set to all ones. Hence I have 8 modulated open drain channels, everything works as expected. Now I connect a 1:1 transformer wound on a PC40 6mm toroid (AL=2300), 16 turns each. The p...

So, I had this application requiring really absurd amounts of ripple rejection--it's a piezo driver in a laser wavelength locker that (for...

So, I had this application requiring really absurd amounts of ripple rejection--it's a piezo driver in a laser wavelength locker that (for historical reasons) has to run off a fairly crappy dual isolated 48V DC-DC converter. The 48V has almost a half volt of ripple at 47 kHz, and the output noise needed to be in the nanovolts. As we've discussed here before, ordinary cap multipliers ar...

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...

Hi all! I need simulation file for this IC. If someone has it, please share with me. I found here some files for UC3843, UC3842, but they...

Hi all! I need simulation file for this IC. If someone has it, please share with me. I found here some files for UC3843, UC3842, but they are current mode, and I want something with voltage mode for flyback converter, which has voltage regulated from 30V to 300V. So I will be gratefull for model UC3825 or information how to simulate in Pspice PWM modulator with Soft Start and limit max cur...

Dear All, I'm currently evaluating the AD7793 \Sigma-\Delta converter. I'm using an A= duino Due (SAM3X8E) connected to the ADC through SPI...

Dear All, I'm currently evaluating the AD7793 \Sigma-\Delta converter. I'm using an A= duino Due (SAM3X8E) connected to the ADC through SPI with CS permanently ti= ed low. I use the Arduino's SPI library to control the SPI UART and AD's li= brary (available on-line) to access the ADC. After correcting a couple of bugs in both libraries, I'm able to read the A= D7793 on-chip registers but...

A simplistic VGA to XYZ-scope converter like this: just uses a passive resistor network to linearly scale the RGB components and sum...

A simplistic VGA to XYZ-scope converter like this: just uses a passive resistor network to linearly scale the RGB components and sum them to monochrome. However I don't think this really works for a "modern" SVGA output because the gamma will be wrong; you have to apply a nonlinear gamma-expanding transform prior to i

Prototyping a little toy for the kiddos out of junk box parts... I have a IV-9 Numitron connected up on a PCB to a 74LS47 BCD to 7 segment...

Prototyping a little toy for the kiddos out of junk box parts... I have a IV-9 Numitron connected up on a PCB to a 74LS47 BCD to 7 segment driver. uP is a 3.3 volt ATTiny (Adafruit "Trinket" devboard) powered via an on-board LDO directly off a 3.7 V 150mAh lipo. 3.7 volts is boosted to around 5 to power the 74LS and Numitron segments via an eBay special micro boost converter with shutdo...

I need to make an isolated DC-DC switching converter with a 9:1 output range and 5:1 input range. Power is about ten watt. Resulting 45:1 duty...

I need to make an isolated DC-DC switching converter with a 9:1 output range and 5:1 input range. Power is about ten watt. Resulting 45:1 duty cycle range looks tricky to make work well. So far I am most tempted to boost to an intermediate rail (which takes up the 5:1 range) and then convert from that over the 9:1 range. The intermediate rail could be useful for other purposes too. H...