New answers tagged pwm
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In addition to the other comments/answers, when the GPIO pin is not actively driving a logic HIGH output signal or a logic LOW output signal, the 10 kΩ pull-up resistor on the GPIO pin will likely turn ON the NPN transistor by default, which turns on the PNP transistor, which turns on the LED. (Imagine disconnecting the GPIO pin from the rest of ...
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When the GPIO is low the the NPN transistor is OFF (open). Thus, the PNP transistor base is floating (not terminated). Provide a valid weak termination. Place a high value resistor between base of the PNP and the 5V line. This should keep the PNP transistor always in a valid state.
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First consider an AC coupled PWM signal. Its peak-peak amplitude is constant at (let's say) 5V, regardless of the duty cycle. And its mean value is ... 0 ... regardless of the duty cycle.
Now use a DC restorer to define the DC level of its negative peaks at 0V. The positive peaks are now 5V.
All you need to do is low pass filter it, and the output value ...
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By using a negative clamp and a LPF of any order to give desired BW yet attenuate PWM ripple, the result is a DC +AC signal proportional toward the PWM duty cycle.
answered yesterday
Tony Stewart Sunnyskyguy EE75
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But with this configuration ampere comes from the 12V DC supply goes too high like 10A. Even with this ampere I can't achieve 1KV.
What kind of modifications should I make? Is this kind of design
suitable for this?
Looking at the inductors in the transformer you have primary at 1 uH and secondary at 100 uH. Given that the coupled inductor ratio is 1:...
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In order to reduce , temp rise , power loss , voltage loss and resistance of the switch, it’s current rating needs to be at least 5x your load for good performance. It must also be a low logic voltage capable switch such as Vt=1V.
It you chose wisely , you should not need a heatsink, but may need to consider the far great choices of SMT or get a TO220 size ...
answered 2 days ago
Tony Stewart Sunnyskyguy EE75
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Your approach is fine. Here are a few pointers.
The chosen MOSFET has higher resistance at the voltage you are driving. The datasheet is your friend. The device just starts conducting at that range.
There are no shortage of MOSFETs which had lower \$V_{GS}\$
TSM 2314 for example.
3. Place a diode across the fan connection for fly wheeling the reverse ...
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It's been a while but, for future reference, I found this on Aliexpress "within" the PN 2510 2.54 mm KF2510 3+1P KF2510-4AW.
I say "within", because there's normally only one search result with that, and the listing has the connectors in question.
Cheers!
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Yes, I think it should be possible. Going from the datasheet of the TLC5955, one of the mentioned applications is "LED video displays".
If I understand correctly, you plan to connect one channel/pin to a group of shared cathodes (-), which is a column in you matrix. A row in the matrix has shared anodes, and only one row should be on at the same time. If ...
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It depends on the current through each MOSFET. But if power comes from your 3 A Power supply strips seems wide enough to avoid any voltage drop. Pretty sure the voltage drop will be much higher in your connectors.
So I think 1st PCB is OK.
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When in doubt, read the datasheet, apply some circuit design knowledge, and maybe go dig up some applications notes. The SG3525 has become a standard part, so there may even be books written around it.
If you look in the datasheet, you'll see that the error amplifier gain is stated as a transconductance, with a range of \$1.1\mathrm{mS} < G_m < 1.5\...
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I will advice you to design your system on MATLAB/SIMULINK. Ensuring it works from there, you can decide on what controller to use. There are so many controllers but from you design you will need to know the frequency and the total harmonics required.
First design with MATLAB or any other simulation tool you know
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One possibility is that you placed MOSFETs too far from IC and you have parasitic inductivity. As the problem persist when adding gate resistance, it would mean that ringing is not an artifact of gate driver circuitry, rather a load problem.
Further you say, that when changing the motor with a different one, this problem vanishes. In my opinion, you have ...
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I can control the brightness with a PWM signal into the CTRL pin. But how do I control the on/off of the LEDs?
The CRTL pin will control the LEDs on and off. As David said, 0 % duty cycle will turn them off.
Should I send a PWM signal with a 0 % duty cycle (is it possible?), or switch off the LED driver with an external transistor?
No external ...
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ESCs are used for brushless DC motors (BLDC). But PWM is used in both DC and BLDC. The topology of a ESC consists of a 3-phase inverter with back emf feedback to know when to switch (complicated circuitry).
Commercial ESCs are designed with a PWM signal input. This happens to be the same as per the servo motors. They take a 50Hz PWM that ranges from 5% to ...
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PWM means Pulse Width Modulation, which is a method used in many power electronics applications to get a variable output voltage from a fixed input voltage. ESC means Electronic Speed Controller, the thing that converts the battery DC voltage to the Ac voltage your motor needs using PWM.
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What is your technical definition of a PWM controller? – Andy aka
@Andyaka A circuit that changes the duty cycle of a constant frequency
pulse wave outputs in response to analog inputs
OK, just like an LTC6992 then.
Does anyone knows if it is a useful practice to build a PWM controller
from discrete components or not and why?
I'd say it's not ...
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You can control the noise pickup by using the usual copper-foil of planes, to be magnetic shields. And the planes are of course fine electric-field shields, as long as you tie the E_field collection regions to the larger Ground system to prevent radical upsets of the pieces of metal by "displacement currents".
I suggest you design your discrete analog sense/...
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According to the datasheet both EN/IN1 and PH/IN2 can take a PWM signal input of maximum 100kHz which propagates to the output if the driver is configured correctly.
There is 3 different modes for this driver, it looks like you are interested in the "PWM" mode.
To enable the PWM mode, you'll need to connect MODE pin to VDD:
(Page 14, Table 3)
Then, ...
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It looks like this mode has a couple different modes actually, so you should read over them to see which one works good for you. Probably PWM mode. See section 7.3.1.1. It says there,
The inputs can be set to static voltages for 100% duty cycle drive, or they can be pulse-width modulated (PWM)
for variable motor speed. When using PWM mode (MODE = 1), ...
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The controller's current capability must meet or exceed the current requirement of the motor. If it exceeds the current capability, the price may be higher than it would have been if you had been able to find one with a 30 amp rating. The efficiency may be a little lower. If the current capability is too low, the motor may not start reliably or it may have ...
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like Tagli said it's better to change CCxM than disabling the output but there is a case
where you need the 2 channels (complentary pwm )to be low. so the solution for this is to change the polarity of one channel by setting CCxNP bit in the CCER register here is the modification in the code ( this part is only for 1 step)
TIM1->CCMR1 |= ...
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You're driving the negative input directly from V9. As such, the negative feedback is disabled and C1 does nothing but absorb current. You probably wanted a series resistor between V9 and the negative input.
You also have far too much hysteresis. With your output around -13V, your positive input is hanging at -6.5V. Your negative input is driven by V9 ...
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Voltage source V9 is dictating the across C1. Therefore, C1 is not charged or discharged through R9 and you will not see the typical RC charge and discharge curves like you drew them.
You are just probing the voltage of this voltage source.
Not familiar with the tool you use, but if possible, remove V9 and give C1 an initial voltage.
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The Hall transitions should be exactly 60 degrees apart. It's not uncommon to add in a few degrees advance on motors that will run only in one direction, but if this is a bidirectional motor, they are generally zero advance.
There are three things that can practically alter the switching points -
The position of the sensors themselves. They may actually be ...
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You have TIM_CR2_CCPC bit set, which makes CCxE, CCxNE and OCxM bits preloaded. The actual bits are updated when a COM event occurs. So I guess you need TIM1->EGR |= TIM_EGR_COMG; after changing those bits.
However, disabling the output may not be the correct thing to do. Please consider updating CCxM bits to 0b100 or 0b101, which forces them to inactive ...
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This is what the Break functionality is for, as the reference below says
Break input to put the timer’s output signals in reset state or in a known state.
The break can be generated by the BRK input which has a programmable polarity and an
enable bit BKE in the TIMx_BDTR Register.
There are two solutions to generate a break:
• By using the BRK ...
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Add gate-drain capacitors on M3 and M7. You can also add a series gate-drain resistance, but you already have effectively 500 ohms on each. 1000pF should get you in the range of 2us, but you could probably dial it in more experimentally. If you want to use a smaller cap, you could add series gate resistors. This is one of the better controlled methods, ...
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Increase the value of C6 as @Andyaka suggested.
You can also change the pulse signal properties to increase the rise time and fall time. Also, making rise time and fall time too high will increase the power dissipation.
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Conceptually, you want something like this:
simulate this circuit – Schematic created using CircuitLab
When you turn M1 on, the current rises in the solenoid, charging the magnetic field up. When you turn it off, the current decreases towards zero, flowing through the diode or upper MOSFET. If you PWM fast enough relative to the inductance, the ...
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The manufacturer gives a suitable frequency range above 20 kHz to avoid a buzzing of the fan in the audible frequency range. As long as you don't mind this or your setup does not even produce any hum you will be fine.
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The solution is to update the value synchronously instead of at random time. Perhaps in the overflow interrupt, if no other way is available. You don't say which STM32 you use, but some models have timers that have a preload feature which latch in the actual count from the register when counter starts a new cycle, you should fix your issue by enabling ...
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If I understand correctly, you are wondering about the voltage step (circled in red) and not really about the spike (red arrow).
Frequency is low (~400Hz) and this step is a significant fraction of a millisecond long, so we're not dealing with high speed stuff. So I'm thinking about resistance, not inductance. Or a misbehaving power supply.
First thing to ...
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Having a datasheet that explains operation of a component is critical for integration in an embedded system such as drone. Unfortunately there is a surprising lack of technical data in the RC world mostly because RC enthusiasts arent driving their components with microcontrollers. I tried to drive a brushed motor with an ESC driven by an arduino just similar ...
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may i add my answer here.
you can charging + use it the same time, the chemistry in your lead battery will balancing it self. that's why automotive tends to use alternator with secondary magnet from your battery it self.
yes it could be your charger design have "superior design" which cut off whenever certain point voltage drop. but unfortunately your ...
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You can't charge the battery while drawing power from it at the same time It isn't like a bucket of water where you can dump in on one side and suck out on the other. It is more like a T-intersection on a pipe where water can only flow in the middle pipe in one direction at a time. But you can draw power from the charger to power your load and charge the ...
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In summary, my original idea (using a crude constant-voltage power supply) will not work due to resistance in the circuit and motor.
Using BEMF could actually reduce part count (one goal that I originally should have stated), and would actually work.
Thank you DKNguyen, and Bruce Abbott for your thoughtful and thorough responses.
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You're on the right track. It looks like your PWM is implemented correctly. I do recommend writing an SVM PWM modulation routine, as you will need it down the line. You should also try and get your motor to spin open loop using either sinusoidal PWM or SVM PWM. It should spin smoothly without drawing a significant amount of current.
With respect to your ...
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Voltage seems to jump up at the time when both channels are off -- so your power supply has poor load regulation or you have too much wires resistance that connect power supply with your circuit.
Voltage spikes are generally not dangerous here and caused by fast switching off of M1 and M2 transistors. To mitigate, you can add 100..1k resistor between M1/M2 ...
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Since I know that if you power a brushed motor with a constant-voltage
power supply, it will always rotate at about the same speed,
About the same speed, but not the same. In fact as you load the motor more its speed drops linearly, all the way to zero at stall. This is caused by the motor's internal resistances (brushes, armature windings etc.) that ...
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Your idea is wrong and won't work. But there is a very similar idea that will work.
"a brushed motor with a constant-voltage power supply, it will always rotate at about the same speed" No. If you load it a lot, it will slow down a lot.
Your idea is to basically monitor the average voltage across the motor terminals and adjust the PWM so that a constant ...
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