Part Number: DRV8305-Q1
Hi,
1.
Although min and max values are listed in the data sheet,
Request data in graph form showing temperature change (temperature drift) of
"Current sense amplifier gain error", "DC input offset" and "Reference buffer error".
2.
About Current sense AMP
At present, Current sense AMP can not follow when
differential input voltage: 4mV,
cycle: 30μs,
duty: about 50% input,
event not occurring in output is occurring.
What kind of reasons can be considered?
best regards
Hi Min-su,
[quote user="Min-su Kim"]
1. Juntion temperature
I developed the board with DRV8323RH and TMS320F28069. And I succeed to control BLDC motor with 6-step and SVPWM method.
VM is 50V. When I enabled the DRV8323, the juction temperature rise above 80 degree in celcius. temperature was measured by thermal camera.
Is it OK? Although the operating range is upto 120 degree in celcius, I worry about the high temperature
[/quote]
Temperatures above 80C are OK, but you should assess if this temperature rise is expected in your system. Is the increase in temperature due to the regulator , switching frequency, something else?
[quote user="Min-su Kim"]
2. BEMF problem
I use 50V power source. If motor generate the voltage over 20V by the external force, VM might be over 70V.
In the situation, DRV8323 can operate?
[/quote]
Any voltage over the absolute maximum can damage the device.
Part Number: DRV8711
Tool/software: Code Composer Studio
Hi, I'm using the BOOST-DRV8711 with the Launchpad using an MSP430G2553. I'm trying to figure out how to use the DRV8711 to move a motor controller. TI has example code I've uploaded with code composer studio, BOOST-DRV8711_FIRMWAREV1.1.out. I've started the GUI which interfaces with this and the motor runs great. My objective is to write my own application in the MSP430 to run the motor, but I can't decipher anything from the example firmware. There's nothing discussing accelerations or velocities. Is there something more straightforward I can learn from? I'm not sure where to start. I've used the 8711 users manual and can successfully write to the registers. I can move the motor poorly by toggling the step pin. How do I find functions to execute move profiles. Where do I find the documentation?
thx
Matt
Part Number: BOOSTXL-DRV8320H
Tool/software: Code Composer Studio
I am posting some questions regarding modifications to the BOOSTXL-DRV8320H code. Some have been answered already and I am posting the answers as well for future reference. Some questions still need answering.
Can it operate independent of the GUI?
Yes, if you apply inputs to the gate driver yourself and ignore the Launchpad.
Can it be modified to read a potentiometer for speed control?
The potentiometer input is tied to the MCU but not used in the software today. So you can use it for this purpose if you write your own code.
One parameter of the GUI is the number of poles in the motor. Is it a problem if I don’t know the number? The motor still functioned on the “8” pole setting.
This is so that the GUI can tell you the motor RPM. If you don’t know, then the RPM readout isn’t accurate.
Part Number: BOOSTXL-DRV8301
Hello everyone.
I tried to check if BoosterPack DRV8301 is compatible with Launchpad F28379D. I was sure, that it is. But BoosterChecker told me, they are not. The problem was in BoosterPavk Pin #29 and Launchpad Pin #69, as shown on the picture. BoosterPack sends Phase C current feedback, and the launchdap pin is "CMPIN". But ASAF, Compare function is muxed with ADC. So the Pin #69 of the launchpad can be used as ADC input. The launchpad schema is a little strange with names: ADCINA4 pin of the MCU is named as "Analog Out". The picture is shown.
What should I do? I still think, that there's some mistake or name mismatch. I don't believe, that this launchpad for motorcontrol purposes is not comatible with motorcontrol boosterpack.
Thank you, Mark
I've figured out these devices are compatible, I've already spinned a motor. But unfortunately, ADCREFHI is set to 3V at LAUNCHXL-F28379D, and the BoosterPack has it's scale up to 3.3V, so there are some problems. I have Launchpad of Rev 1.1, but i can see, that Rev 2 has also reference at the level of 3V =(
Part Number: DRV8711
Hello TI Support.
I have a DRV8711 and stepper motor 24HS39-3008D (BIPOLAR configuration where torque is 4.0Nm and inductance 3.0mH/1kHz). Power supply is 36V or 48V.
DRV8711 shall works with 1/32 microsteps and up to 200kHz steps frequency.
I am testing this driver using DRV8711EVM and external steps/dir generator to obtain good acceleration (from 1kHz to 200kHz).
I have a problem with settings because I can obtain only 60kHz and motor stops. What is the correct settings?
Now I have settings like on attachment.[View:/cfs-file/__key/communityserver-discussions-components-files/38/24HS39_2D00_3008D.pdf:1230:0]
Part Number: DRV8308
What is the balance between PWM frequency, duty cycle and the control loop for closed-loop control with Clock Frequency Mode?
I have an application that normally needs a motor RMS current of 5 to 20 mA and has a maximum current limit of 340 mA (calculated from the maximum torque limit). The motor has low winding inductance (85 uH) and resistance (5.5-ohm). I plan to operate the DRV8308 with a supply voltage of 8.5 V. Due to the low winding inductance, the di/dt is very fast, so I would like to understand the relationship between using a high PWM frequency and the ability to manage speed and current.
Also, if the PWM Ton time (PWM pulse width) is shorter than the Current Limit blank time (TBLANK), does the Current Limit circuitry even have an impact? (I presume the blank time is reset at the beginning of every PWM cycle.)
As for the PWM output for the MOSFET pre-drivers (assuming 120° commutation, not sine-wave-drive), my understanding is that the duty cycle is based on the output of the speed control loop (differentiator, integrator, digital filter, etc.) which results in a 12-bit duty cycle to be applied as Ton for the next PWM cycle. That said, if the PWM frequency is set to 200 kHz, the PWM cycle time is 1/200 kHz = 5 us. Then with the 12-bit duty cycle, the PWM Ton time can be as small as 5 us / 4095 = 1.22 ns (e.g. a 50% duty cycle would have a 2.5 us Ton time or a count of 2048 where 2048*1.22 = 2.5 us). Is this the correct understanding of how the PWM output works?
However, a minimum PWM Ton time (PWM pulse width) of 1.22 ns doesn't even seem realistic since it would require a transistor gate charge of about 0.15 nC just to turn on with the DRV8308 maximum output drive current of 130 mA (rise time = gate charge [C] / pre-driver current [A]). That doesn't even allow the FET to fully conduct and a power MOSFET with that low of a gate charge is not readily available to the masses.
Overall, I'd like to make sure I am correctly understanding the closed-loop speed control operation and the associated PWM output duty cycle operation and timing resolution. Once I correctly understand those and the relationship between PWM Ton time and Current Limit blank time, I believe I can determine how to properly use the DRV8308 in my application.
Thank you,
Jim
Part Number: DRV8800
I've designed a board using DRV8800 to drive a small DC brushed motor. I first tested my circuit on a prototype board and when it seemed to work fine for the entire range of voltage that I'm going to support (8V to 24V), I got some PCBs fabricated based on the recommended layout. The only difference between the prototype and the PCB design was that I had shorted the RSENSE to GND in the prototype version but decided to use a 0.2ohm RSENSE instead for the PCB.
The problem I'm running into is that on PCB everything works fine up until VBB is about 15V and then it starts hitting the FAULT condition. I was able to marginally extend it to about 17.5V by shorting out the RSENSE on the PCB as well. So, essentially making it the same as the prototype and the VTRIP reads 0V. The scope reading of nFAULT shows variable downtime of about 1.5ms to 2.5ms. As another experiment, I connected a 10 ohm resistor in series with motor (R = 15 ohms) and I could get VBB to further a little more to about 18V before faulting.
I'm really stumped now that I've got several boards manufactured as well. What am I doing wrong?
I'm attaching the VOUT (with and without motor connected) and nFAULT scope output as well as the picture of the relevant section of the PCB for your reference. The board was hand soldered by me so please excuse my soldering skills.
Part Number: DRV8711
Hi everyone,
I am currently working on a driver solution for steppers with encoder that can handle 10 Amps. I found the way to do 10 A out with external FETs (DRV8711EVM), however, I want to implement a magnetic encoder to my stepper to make this system closed.
So here is my question, can i regulate the output voltage of the driver, with the information that comes from the encoder.
I mean, is it possible to control the external FETs with this regulated voltage and increase/decrease the OUT voltages by doing so.
I viewed the datasheet however could not find any answer to my question.
Any help would be appreciated.
Thanks in advance,
Oguz
Hi, Rick-san
I appreciate your support.
I immediately sent the circuit diagram and waveform data to the private mail.
If you see it and have any questions, please reply to me.
The content you asked is、
Current sense connect a 2mΩ shunt resistor between the input terminals (SP1-SN1) of the amplifier.
A current of 2A flows in the shunt resistor at a period of 30μs.
During the above operation, the current sense AMP output(SO1) continues to output "no Pulse".
Please let me know what caused the problem.
Best regards