Dumb LTSpice question - subckt model

Started by Anonymous in sci.electronics.design8 years ago 12 replies

I've never used a mfr model that was a subckt before; I've always added the .MODEL to the LTSpice library file, or edited an existing...

I've never used a mfr model that was a subckt before; I've always added the .MODEL to the LTSpice library file, or edited an existing device. This Vishay MOSFET has a more complex model though, and she ain't loadin' Jim. LTSpice says it can't find the model for M1. I even tried putting the definition right in the .asc, still no joy. I followed the LTSpice help info, as best I could. A...


Soldering to glass

Started by Piotr Wyderski in sci.electronics.design3 years ago 22 replies

I have recently conducted some research on binding SMD components with glass and ceramic substrates using pure indium and indium alloys. The...

I have recently conducted some research on binding SMD components with glass and ceramic substrates using pure indium and indium alloys. The results are very satisfactory, and the technique may find some applications in HV and high power density solutions. One can directly solder a MOSFET to a ceramic heatsink or a string of HV resistors to an insulating glass plate without prior metalis...


inductor for HV flyback supply

Started by Winfield Hill in sci.electronics.design6 years ago 71 replies

I've created all kinds of HV circuits in the last 5 years,** and each one needs an external HV supply. So I really need some simple...

I've created all kinds of HV circuits in the last 5 years,** and each one needs an external HV supply. So I really need some simple HV-supply circuits to plop onto these PCB's to make them self-sufficient. Today's circuit is a basic flyback, to convert a 12V,1A wallwort source to 500V max, at 5-10W load. I used a UC3843B running at 100kHz driving a MOSFET switching a 47uH indu...


MOSFET selection for boost converter problem

Started by John Nagle in sci.electronics.design6 years ago 30 replies

I've been working on a power supply for antique Teletype selector magnets. These need 120VDC 60mA for the first 2ms or so of each bit time,...

I've been working on a power supply for antique Teletype selector magnets. These need 120VDC 60mA for the first 2ms or so of each bit time, but the sustain voltage needed is only 3-4V. So I've built an isolated boost supply and interface board, all powered from a USB port. The whole project is on Github: https://github.com/John-Nagle/ttyloopdriver where there's an explanation of how...


Can we PLEASE stop using these shitty symbols?

Started by Tim Williams in sci.electronics.design6 years ago 139 replies

Proof in case: http://www.ecnmag.com/sites/ecnmag.com/files/legacyimages/ECN/Articles/CS-1109-Figure_02.jpg It's bad enough that AoE3...

Proof in case: http://www.ecnmag.com/sites/ecnmag.com/files/legacyimages/ECN/Articles/CS-1109-Figure_02.jpg It's bad enough that AoE3 stooped to using those MOSFET symbols. (The only problem I can find with the tome! Why did it have to be such an important, and deceptive, problem!? Please Win, if you fix this in a reprint, I will send you the finest bottle of liquor I can find.) ...


A gate driver circuit

Started by bitrex in sci.electronics.design3 years ago 25 replies

Test rig for the mighty ADuM4120. 30 volts to the right power supply line and 3.3/5 volt logic level to the left. A very nice isolated...

Test rig for the mighty ADuM4120. 30 volts to the right power supply line and 3.3/5 volt logic level to the left. A very nice isolated gate driver. And at over $4 a piece in singles a real bummer when someone who isn't me wrecks one up by accident connecting the MOSFET source/drains wrong on the high-side/low-si


gate driver

Started by John Larkin in sci.electronics.design8 years ago 13 replies

I need a mosfet gate driver, to drive two n-fets in a half-bridge (totem pole) config, 5 volts nom in, with some sort of bootstrap for the...

I need a mosfet gate driver, to drive two n-fets in a half-bridge (totem pole) config, 5 volts nom in, with some sort of bootstrap for the upper fet gate. Switcher output will be around 2.5 volts at 5 amps, so the gate drives don't have to be monstrous. I've been working with LTC4442 on a breadboard, but it's really erratic. Sometimes it's beautiful, and sometimes the gate drive breaks ...


Linear power FETs

Started by Anonymous in sci.electronics.design4 years ago 44 replies

I'm making another fast pulse generator, shopping FETs, and noticed a few possibly interesting gizmos: RF MOSFETs. They're built for linear...

I'm making another fast pulse generator, shopping FETs, and noticed a few possibly interesting gizmos: RF MOSFETs. They're built for linear operation. At a glance, they seem to have fairly beefy SOA curves. Up to 600V, too. "N-channel enhancement mode linear RF power MOSFET Ideal for class AB and C industrial, scientific, medical, and commercial applications. VDSS = 500 V ID25=


BLDC controller and ATF16V8B/GAL16V8B/PAL16V8B

Started by Anonymous in sci.electronics.design8 years ago 52 replies

BLDC controller: http://173.224.223.62/motor I am thinking about moving the PIC 3 feet away (closer to the control panel= ) from this...

BLDC controller: http://173.224.223.62/motor I am thinking about moving the PIC 3 feet away (closer to the control panel= ) from this board. There are 6 outputs in 6 possible states. Each pair of= MOSFET can be in HI, LO or KILL (both HI and LO) states. I can add an I/O= expander or shift register to minimize the connections, but that increase = the chance of KILL states due to comm...


500A power source

Started by Winfield Hill in sci.electronics.design3 years ago 41 replies

In my search for a 8 to 10V, 500A source, needed for 2 seconds, I've been looking at LiFePO4, and LTO (Lithium Titanate) cells, in 38120...

In my search for a 8 to 10V, 500A source, needed for 2 seconds, I've been looking at LiFePO4, and LTO (Lithium Titanate) cells, in 38120 and 66160 sizes. All types of suppliers, plus completed battery systems, with charge balancing electronics. Sheesh, it's enough to make one's head spin. BTW, a simple "12V" battery has a bit too much voltage, an extra burden on power MOSFET(s)...


LLC with an explicit discrete Lm

Started by Piotr Wyderski in sci.electronics.design3 years ago 15 replies

I need a number (~20) of fixed voltages in the range of 4-20V. Isolated and non-isolated, for SIC MOSFET gate drivers, 20V for a small D class...

I need a number (~20) of fixed voltages in the range of 4-20V. Isolated and non-isolated, for SIC MOSFET gate drivers, 20V for a small D class audio amplifier, 3.3V and 5V for logic and 10V for some auxiliary circuits. The input voltage is in the range of 10.8-15V, maybe 40W in total. Due to the number of output rails the complexity of the secondary sides does matter. This basically kil...


MOSFET with best drain current per dollar or per area

Started by Chris Jones in sci.electronics.design6 years ago 28 replies

It is tempting to make a spot welder from the Maxwell ultracapacitors e.g. the 3000F ones rated for 1900 Amps each. There is something nice...

It is tempting to make a spot welder from the Maxwell ultracapacitors e.g. the 3000F ones rated for 1900 Amps each. There is something nice about the idea of a spot welder that does not draw large pulses of current from the mains, and a cordless spot welder would be a novelty. I figure that something in the region of 10kA to 30kA output current would make it useful enough to justify the...


AN: Spice Model for Vishay VOM1271 Posted

Started by Jim Thompson in sci.electronics.design7 years ago

A rudimentary behavioral model of the Vishay VOM1271 PhotoVoltaic MOSFET Driver has been posted... see VOM1271.zip on the Device Models &...

A rudimentary behavioral model of the Vishay VOM1271 PhotoVoltaic MOSFET Driver has been posted... see VOM1271.zip on the Device Models & Subcircuits page of my website. ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASI...


Circuit for producing 10ns pulses of several amps

Started by Mr.CRC in sci.electronics.design10 years ago 43 replies

Hi: I have been using MOSFET drivers to pulse LEDs at currents of up to 21A (for 100s of ns to several microsecond pulses) and down to about...

Hi: I have been using MOSFET drivers to pulse LEDs at currents of up to 21A (for 100s of ns to several microsecond pulses) and down to about 22ns for 1A pulses into 1mm^2 power LEDs. I can't get any faster with the drivers I've tried than about 20ns for "parity" optical output power with the 1.0A CW max current typical of blue 1mm^2 LEDs. (see note 1 below) I wish to achieve 10-20n...


internal nodes GRRRRR

Started by Anonymous in sci.electronics.design6 months ago 8 replies

Some LT Spice models have invisible internal nodes that are hard ground. So you can't float them off ground. LTC4444 mosfet driver for...

Some LT Spice models have invisible internal nodes that are hard ground. So you can't float them off ground. LTC4444 mosfet driver for example, half-bridge with + and - power rails. Bummer. I'll just fake the gate driver with a couple of BVs. That will run faster anyhow. I guess I could run the 4444 grounded and AC couple into the gates with DC restore. Lotta hassle. -- ...


MOSFET Coss(er), Coss(tr), Eoss, etc

Started by Winfield Hill in sci.electronics.design7 years ago 15 replies

Power MOSFETs have highly-nonlinear capacitances. For the new super-junction types, voltages 500V to 800V, nonlinearity can be severe, up...

Power MOSFETs have highly-nonlinear capacitances. For the new super-junction types, voltages 500V to 800V, nonlinearity can be severe, up to 100x. A new Coss spec, effective capacitance, comes in time related (tr) and energy related (er) forms, with a stated voltage, usually 80% of breakdown. It's a fixed capacitance that matches the FET's charging time or energy consumption. Old...


Exceeding Vgs rating

Started by Pimpom in sci.electronics.design5 years ago 94 replies

I'm designing a small simple circuit in which a MOSFET drives a low-power load. The very low frequency gate drive may, on rare occasions,...

I'm designing a small simple circuit in which a MOSFET drives a low-power load. The very low frequency gate drive may, on rare occasions, exceed the max Vgs rating of 12V by about 1V, possibly 2V. There are a number of ways to limit the gate voltage but I want to avoid them and keep the circuit as simple as possible, and it won't cause a disaster if the transistor fails. What do you thi...


IRF3205 -- string trimmer?

Started by mkr5000 in sci.electronics.design2 years ago 12 replies

Every time I turn around I have to repair (or attempt to) some piece of crap. This time a Troy-bilt string trimmer (20V Lithium...

Every time I turn around I have to repair (or attempt to) some piece of crap. This time a Troy-bilt string trimmer (20V Lithium battery). Battery is good, motor is fine but what I thought might be a switch is a rather sophisticated circuit the has an 8 pin IC, quite a few passive components and an IRF3205 mosfet. This "switch" has a low resistance across the battery so it's shot.


Old plasma screen Y_SUS anomalies

Started by legg in sci.electronics.design1 year ago 2 replies

An older and poorly-documented plasma screen (LG 42PC3DV) apparently went 'pop' and developed dark screen. It had the usual bad 5V rail caps...

An older and poorly-documented plasma screen (LG 42PC3DV) apparently went 'pop' and developed dark screen. It had the usual bad 5V rail caps (x9) of the era (mfrd 6 months in 2006), and an overloaded -VY rail. I fixed those issues, to discover that Y_SUS waveform had no 'set-down' ramp. The mosfet generating that ramp can and does produce a -ramp, but only at the termination of the p...


Damn, burned out my 100-watt 50-ohm resistor!

Started by Winfield Hill in sci.electronics.design6 years ago 24 replies

A major meltdown last Friday for my 8ns 1kV SiC MOSFET pulser. After set of tests at 400V and 4MHz repetition rate, with everything working...

A major meltdown last Friday for my 8ns 1kV SiC MOSFET pulser. After set of tests at 400V and 4MHz repetition rate, with everything working fine, I had to increase the frequency. A loose hand slip and I was at 10MHz. That's when the smoke appeared. Blew out a 1-ohm gate resistor, both TO-247 MOSFETs, both 24V gate drivers, the flying regulator and the 150Mbps 50kV/us isolator, a...