sine generatore redux

Started by Spehro Pefhany in sci.electronics.design9 years ago 16 replies

(wrong ng first.. 8-( ) Tried a 32MHz PIC24 as a DDS using a 16usec PWM cycle (8 bit), running from 3.3V. Three 32-bit phase accumulators. I...

(wrong ng first.. 8-( ) Tried a 32MHz PIC24 as a DDS using a 16usec PWM cycle (8 bit), running from 3.3V. Three 32-bit phase accumulators. I used the Bell 202 frequencies. With a simple RC filter (5K6/10n -> 10K/10n).. no calculation, just guesstimated, I get pretty decent behavior (2nd harmonic 35 dB down):- http://speff.com/Spectrum_1200Hz.BMP http://speff.com/Spectrum_2200Hz.


Some MOSFET Questions

Started by Anand P. Paralkar in sci.electronics.design7 years ago 2 replies

Hi, I am developing two circuits - a H-bridge inverter and a boost converter, both of which use a MOSFET(s) with a PWM drive and resistive...

Hi, I am developing two circuits - a H-bridge inverter and a boost converter, both of which use a MOSFET(s) with a PWM drive and resistive load. I observe: a. The rise time measured across the drain and source *reduces* as the output load (as in more amps taken at a given output voltage) on these circuits *increases*. b. On the boost converter, for very light loads, the dra...


voltage regulator

Started by Michael Robinson in sci.electronics.design10 years ago 4 replies

This is an idea for a voltage regulator for an antique six-volt vehicle. It has an old-school generator with pole shoes. The aim is to PWM the...

This is an idea for a voltage regulator for an antique six-volt vehicle. It has an old-school generator with pole shoes. The aim is to PWM the field at a frequency on the order of 1kHz, or a few hundred Hz, to avoid the heat sink that linear regulation would require. I built such a voltage regulator for a modern 12 volt vehicle a while back, using a voltage reference, an op amp and a vco....


Filter cap at dc motor input

Started by pimpom in sci.electronics.design6 years ago 12 replies

I'm rebuilding an old machine for a local company by replacing all the electronics with my own design. It uses a 24V DC brushed motor with an...

I'm rebuilding an old machine for a local company by replacing all the electronics with my own design. It uses a 24V DC brushed motor with an integral reduction gear. The original drive circuit used a couple of SCRs for speed control and current was limited to 3.5A. My circuit uses high frequency PWM (~22kHz). (The motor control is only a small part of the overall design). My design w...


square wave to sine filter

Started by John Larkin in sci.electronics.design4 years ago 15 replies

https://www.dropbox.com/s/t4fv4gvx9f8hbqd/LPF_Trans.jpg?raw=1 Input is a PWM square wave from an ARM. This makes a nice looking sine, 3rd...

https://www.dropbox.com/s/t4fv4gvx9f8hbqd/LPF_Trans.jpg?raw=1 Input is a PWM square wave from an ARM. This makes a nice looking sine, 3rd harmonic down almost 40 dB. It's a sallen-key lowpass with a 12 dB bump at 10 KHz. It works a lot better than an equivalent-part active bandpass. Maybe the bandpass wastes resources rejecting stuff below the fundamental, where there is nothing to rej...


Peculiar oscillation in LMR23630 buck when it drops out of regulation

Started by Phil Hobbs in sci.electronics.design2 years ago 13 replies

Hi, all, Sort of a strange one. Our class-H thermoelectric cooler driver uses an LMR23630 sync buck regulator running off +5V and ground,...

Hi, all, Sort of a strange one. Our class-H thermoelectric cooler driver uses an LMR23630 sync buck regulator running off +5V and ground, synched to a 2.156 MHz clock, and with a buffered PWM controlling the set point. The feedback divider has three resistors: the usual two, which connect to the output and ground, and a third one from the buffer output. That lets the MCU vary the ...


neede simple pwm controller

Started by Yzordderrex in sci.electronics.design4 years ago 7 replies

I am looking at doing a multi-purpose experimental battery charger board. (M-PEBCB). I use a 48v battery grid to run my house. It is 8...

I am looking at doing a multi-purpose experimental battery charger board. (M-PEBCB). I use a 48v battery grid to run my house. It is 8 strings of 27M deep cycle Sears Die Hard. I am looking to do a 100A/48V charger w/PFC. I also have a 12v charger that needs a controller and I would also like to experiment with MPPT algorithms. I intend to use a PIC to develop the current command signal. ...


Accuracy of resolver required for PMAC motor computation

Started by mook johnson in sci.electronics.design8 years ago 6 replies

Most of the motors we deal with have motor full blown resolvers for motor commutation. The design engineers are wringing their hands about...

Most of the motors we deal with have motor full blown resolvers for motor commutation. The design engineers are wringing their hands about the required resolution for the R2D conversion. I know it doesn't require 16 bit resolution but how low can you go. Assume 10,000 RPM with a 10KHz PWM and sample rate. This will be FOC controlled with a inner PID phase current loop and external PI...


Will my speed controller work on my drill press?

Started by John Doe in sci.electronics.design2 years ago 10 replies

I'm not asking for insurance. I have better than usual free veterans' healthcare. And I take responsibility for my actions. AC 10-220V 4000W...

I'm not asking for insurance. I have better than usual free veterans' healthcare. And I take responsibility for my actions. AC 10-220V 4000W PWM AC Motor Speed Controller I have a motor speed controller that works for controlling some of my saws. I'm wondering if there are any major obvious problem with trying it on my drill press. Will it burn up my controller? I like that controlle...


Time track with Rigol DSO

Started by bitrex in sci.electronics.design2 years ago 28 replies

I have a Rigol DS1102E. I know that some DSO have a "time track" feature that allow you to demodulate and plot the RMS value of a PWM signal...

I have a Rigol DS1102E. I know that some DSO have a "time track" feature that allow you to demodulate and plot the RMS value of a PWM signal with respect to time on a cycle-by-cycle basis for e.g. tuning control loops. I don't immediately see a feature like that available on this scope, is there a way to coax it into providing similar info that would be valuable for that task using any ...


Super cryo cooler arrived today

Started by Jan Panteltje in sci.electronics.design4 years ago 31 replies

The superconductortechnologies super filter with a super conducting RF filter and

The superconductortechnologies super filter with a super conducting RF filter and


Linear Actuator Control

Started by Anonymous in sci.electronics.design6 years ago 18 replies

Hi, I am trying to control the following motor using PWM http://www.progressiveautomations.com/media/catalog/pdf/PA-04.pdf I am trying...

Hi, I am trying to control the following motor using PWM http://www.progressiveautomations.com/media/catalog/pdf/PA-04.pdf I am trying to see the power requirements for this linear actuator. Its 12V and 12A motor at full load. How much Amp Hour lead acid battery is required to move it like 20 degrees after every hour? The motor will not be running constantly. It will increment


Reading spec sheets (meanwell LDD-700LW)

Started by Scott M in sci.electronics.design4 years ago 40 replies

I'm trying to design an interface to a meanwell LDD-700LW, a constant current regulator for LEDs. I'm having trouble understanding the spec sheet....

I'm trying to design an interface to a meanwell LDD-700LW, a constant current regulator for LEDs. I'm having trouble understanding the spec sheet. (I'm no guru and spec sheets often confuse me a little). It has a PWM input to provide dimming. If left floating, some internal pullup causes the device to go full on. If pulled to ground, it turns the light off. Cycled at some rate, it p


Error Amplifier Design for SG3524

Started by Myauk in sci.electronics.design10 years ago 4 replies

Dear All, I am now making a 48 V to 120V Boost Converter (with a single series 560uH 10A inductor) using PWM IC SG3524, and I am a little...

Dear All, I am now making a 48 V to 120V Boost Converter (with a single series 560uH 10A inductor) using PWM IC SG3524, and I am a little bit confused with the use of error amplifier input pins (pin 1 and pin 2) and the compensation pin (pin 9). A typical example application circuit (see figure 13) divides the reference voltage 5V to 2.5V, and feeds it to pin 2 as reference. The output is ...


Power NPN transistor N344AB

Started by slampen in sci.electronics.design11 years ago 29 replies

Hi, My Peugeot 406 heater blower control module ceased to work the other day, and its power transistor is open. Must be an NPN since it is...

Hi, My Peugeot 406 heater blower control module ceased to work the other day, and its power transistor is open. Must be an NPN since it is supposed to PWM the blower motor to earth (-12V). When searching N344* I find a lot of references to 2N344n.. (2N3440, 2N3442... etc) but not this the exact version. I've uploaded an image of the 'fat' case here: http://kuntigi.net/download/N34...


Best bang-for-buck uC

Started by bitrex in sci.electronics.design4 years ago 94 replies

IMHO the best bang-for-buck uP available right now is the ATTiny85. Luxurious 8K of program memory, 512 bytes RAM, 512 bytes flash, 4 ADC...

IMHO the best bang-for-buck uP available right now is the ATTiny85. Luxurious 8K of program memory, 512 bytes RAM, 512 bytes flash, 4 ADC channels, 2 hardware PWM outputs, 20 MHz clock @ 5 volts. Under a buck in quantity at Mouser:


the ultimate LED regulator or close enough

Started by Anonymous in sci.electronics.design9 years ago 3 replies

I live on a boat and an always delt with electrical efficiancy. And its time to upgrade from my super bright LED to some of these new 3 and 5...

I live on a boat and an always delt with electrical efficiancy. And its time to upgrade from my super bright LED to some of these new 3 and 5 watt leds. The ulimate dc dc buck bost swiching regulator input 3 to 18 vdc output regulated 2.3 vdc to 13.8 vdc regulated current 3A regulated 10% duty @ 10khz 10A both pwm and 100%duty I would like to be able to Run the light wi...


BLDC Motor Drive waveforms

Started by Harry Dellamano in sci.electronics.design8 years ago 6 replies
PWM

Attached is a waveform of one winding of a three phase trapezoid drive motor with another phase PWM drive on the bottom. This 3 phase 4 pole...

Attached is a waveform of one winding of a three phase trapezoid drive motor with another phase PWM drive on the bottom. This 3 phase 4 pole motor is rotating at 1500 RPM with 120Vdc, 20KHz and about 8.0 amps peak on each winding. My drive electronics but someone else's (enemy) software. https://www.dropbox.com/s/p7yg8peujjkzvac/DSX_20130802022721.pdf My question, does that current wave...


NTC Inrush Current Limiter to limit DC motor acceleration?

Started by John Doe in sci.electronics.design10 years ago 1 reply
PWM

What would happen if you soldered an NTC Inrush Current Limiter to the positive terminal of your cordless drill DC motor, in series with the...

What would happen if you soldered an NTC Inrush Current Limiter to the positive terminal of your cordless drill DC motor, in series with the lead coming from the pulse width modulator (PWM) trigger speed control? Would that make the drill response laggy? Does the resistance change time vary much? What is that attribute called? Thanks.


LTC6992 TimerBlox, jitter at low duty cycles

Started by Joerg in sci.electronics.design7 years ago 6 replies

Folks, Got an LTC6992 in the -3 version which goes from 0% to 95% duty cycle, controlling a fairly massive PWM stage. It lives inside a...

Folks, Got an LTC6992 in the -3 version which goes from 0% to 95% duty cycle, controlling a fairly massive PWM stage. It lives inside a (stable) PID loop and works ok except at very low duty cycles under 2%. There is breaks into a jitter and because I am driving big capacitive loads that results in tons of wasted power. Also, it quite abruptly turns off at a fraction of a percent inst...