Hello,
Could you please let me know the IVM, IVM(sleep) value at VM=16V?
Best Regards,
Ryuji Asaka
↧
DRV8870 / IVM, IVM(sleep) at VM=16V
↧
RE: [DRV8312] Switching problem with high current pulse
Hi Fitz,
Could you give a drawing of your question for us to better understand you problem?
Also the COMP minitor should have some filter/blanking structure to remove the switching noise caused by parasitic inductance mainly.
Best regards,
Could you give a drawing of your question for us to better understand you problem?
Also the COMP minitor should have some filter/blanking structure to remove the switching noise caused by parasitic inductance mainly.
Best regards,
↧
↧
RE: [DRV8312] Switching problem with high current pulse
Hi Wilson,
To quickly discuss, I would describe the problem as:
Example: When switching line is A->B, phase C is floating. At the beginning, Va, Vb, Vc = 9.5V (all floating). So If I set RESET_A, RESET_B high and RESET_C low to enable phase A, B, still floating phase C on DRV8312 to do PWM. Right after that, there is a high pulse of I-total which is set as input for COMP1. This make COM1P event occurs and clear all PWM signal to do fault protection.
Regards,
Fitz
To quickly discuss, I would describe the problem as:
Example: When switching line is A->B, phase C is floating. At the beginning, Va, Vb, Vc = 9.5V (all floating). So If I set RESET_A, RESET_B high and RESET_C low to enable phase A, B, still floating phase C on DRV8312 to do PWM. Right after that, there is a high pulse of I-total which is set as input for COMP1. This make COM1P event occurs and clear all PWM signal to do fault protection.
Regards,
Fitz
↧
RE: Parametrs SPI communication DRV8308
Hi. I ask CPOL(pulse direction), CPHA(phase) signal SCK. On time diagram datesheet is not understand.
↧
Parametrs SPI communication DRV8308
Hello. What are parameters SPI communication DRV8308(what is level on SCK without impulse(no communication)?; data is sampled on the leading (first) or trailing (last) edge of SCK?). I developmental select this parameters, but I want confirmation.
↧
↧
RE: [DRV8312] Switching problem with high current pulse
Hi Fitz,
Let me assuming this way. Firstly, switch from A->B, floating C. Non-complementary. So in PWM OFF, the current is retaining through AB low side (Slow decay). Then the next commutation, Ex. A floating, C->B PWM. The retaining(recirculation) current of AB will take both AB fast decay and AB Slow decay based on the ON/OFF of B low side. So there will be sometime before the AB current decay to zero, the I_total will be the I_drive_CB + I_slowdecay_AB. This is the possible current makes your system tripped. Complementary PWM should reduce this I_total.
Usually how long time will be the COMP OC output? if it is ~mS level, it should be the one discussed above. If it is ~uS level, it should be the parasitic inductance bouncing discussed on previous post. We can mask this period in the current feedback loop.
Best regards,
Let me assuming this way. Firstly, switch from A->B, floating C. Non-complementary. So in PWM OFF, the current is retaining through AB low side (Slow decay). Then the next commutation, Ex. A floating, C->B PWM. The retaining(recirculation) current of AB will take both AB fast decay and AB Slow decay based on the ON/OFF of B low side. So there will be sometime before the AB current decay to zero, the I_total will be the I_drive_CB + I_slowdecay_AB. This is the possible current makes your system tripped. Complementary PWM should reduce this I_total.
Usually how long time will be the COMP OC output? if it is ~mS level, it should be the one discussed above. If it is ~uS level, it should be the parasitic inductance bouncing discussed on previous post. We can mask this period in the current feedback loop.
Best regards,
↧
RE: DRV8850 VPROPI pin voltage..
Hi Ravi,
The voltage of VPROPI is just the Iout/2000*R_VPROPI. If you have 3K resister, when Iout = 2A, the voltage seen should be 3V. Must be < (VCC-1V)
But to get the wanted output voltage, you need to use the proper decay ways. Follow 7.3.3 of the datasheet.
Becuse the Iout/2000 to the pin is only based on the high side FETs.
Best regards,
The voltage of VPROPI is just the Iout/2000*R_VPROPI. If you have 3K resister, when Iout = 2A, the voltage seen should be 3V. Must be < (VCC-1V)
But to get the wanted output voltage, you need to use the proper decay ways. Follow 7.3.3 of the datasheet.
Becuse the Iout/2000 to the pin is only based on the high side FETs.
Best regards,
↧
DRV8850 VPROPI pin voltage..
Hi,
We are using DRV6650 in our design for motor drive. As per equation VPROPI resister set as 3K for 2.5 A current. we can get voltage as per theory :I*R/2000, but we cannot get voltage. we get only 0.160V.
My query on voltage of VPROPI pin. How much voltage is shown at this pin?
Is there any formula for voltage measurement?
regards,
Ravi Chaudhari
↧
RE: [DRV8312] Switching problem with high current pulse
Dear Wilson,
Yes, the current pulse is not far 1us. It's the parasitic inductance bouncing. I will try to increase the filter for COMP module then inform you the result later.
Thank you for your support.
Regards,
Fitz
Yes, the current pulse is not far 1us. It's the parasitic inductance bouncing. I will try to increase the filter for COMP module then inform you the result later.
Thank you for your support.
Regards,
Fitz
↧
↧
[DRV8312] Switching problem with high current pulse
Dear TI's experts,
I'm using DRV8312 to do sensorless BLDC algorithm without TI's library. I met a problem with the switching schematic:
When a phase is in Hi-Z stage, at the first times working, its voltage was near 9.5V. Then I do switching none complementary and this Hi-Z phase is changed to current returning switch, it is connected to PGND immediately. This cause very high current (I-total) and make the COMP output toggle to high. This effect to TZ module that I use to do current protection. Thus the current fault is always active in stage switching transition.
Could you please share me if I do something wrong? or is there any way to avoid this situation?
Regards,
Fitz
↧
RE: DRV591 part number
↧
DRV591 part number
On the datasheet for the DRV591 there are different part numbers listed can you tell what the difference is between DRV591VFP and DRV591VFPG4
↧
RE: DRV8840 I0~I4 pin voltage level
Hi Shimizu,
I think what you see is normal. The 100k pull down internal are not the only impedance to GND, there are other circuits there. Also the 100k is just a named value.
For those Ix pins, they are input pins. We can tie to 3.3V/5V or GND directly or with smaller resistor to make it more stable.
Best regards,
↧
↧
RE: General getting-started BLDC driving/control questions
Hi Mike,
This sounds like quite a challenge. We will contact our experts for their opinions.
In general, the InstaSPIN devices do not operate at 5V. When you say 5V, what is the lowest voltage? What are your space and cost constraints?
This sounds like quite a challenge. We will contact our experts for their opinions.
In general, the InstaSPIN devices do not operate at 5V. When you say 5V, what is the lowest voltage? What are your space and cost constraints?
↧
RE: Importing PCB footprint files into SolidWorks
Hi Rick - thanks for providing this information! I'll review the files to make sure I understand the syntax. If I understood correctly the T04 object was defined in the Gerber file and was used for all the mounting holes. So, the hole "object" T04 was defined, and then instantiated (used) in 8 locations. Did the hole locations also come from the Gerber file DrillDrawing.gbr?
↧
RE: DRV8840 I0~I4 pin voltage level
The "other" circuits on I0 and I4 actually are some MUX for test. So what we see is normal.
Best regards,
↧
DRV8840 I0~I4 pin voltage level
Hi
My customer is using DRV8840.
He has a question about I0~I4 pin voltage level.
Please see the attached file.
Customer noticed abnormal voltage level of I0 and I4 pin.
I0 pin is pulled up 5V through 4.7k-ohm.
We think that I0 pin voltage is 4.77V by "5V / (4.7k-ohm + 100k-ohm) *100k-ohm" in this situation.
But I0 pin voltage is 4.17V.
* 100k-ohm is IC internal resistor.
And I4 pin is abnormal, too.
I4 is opened. but I4 pin voltage is 0.3V.
Another pin which is connected to GND is 0V.
This issue occurs at 3 customer board which is customer's all board.
Is this correct device spec?
Your EVM, too?
I'm sorry. I don't have EVM of DRV8840.
Could you confirm this issue at 5V pull up on your EVM, please?
Best regards,
Shimizu
[View:/cfs-file/__key/communityserver-discussions-components-files/38/DRV8840.pptx:1230:0]
↧
↧
RE: Importing PCB footprint files into SolidWorks
Hi Brad,
The hole locations was taken from the ThruHolePlated.ncd file. I then used a gerber viewer on the DrillDrawing.gbr file to confirm the locations, plus confirm the hole sizes.
The hole locations was taken from the ThruHolePlated.ncd file. I then used a gerber viewer on the DrillDrawing.gbr file to confirm the locations, plus confirm the hole sizes.
↧
RE: Need +/- 2.5% speed regulation with DRV10983 on a fractional motor liquid pump.
Hi Michel,
Our experts have been notified and should reply soon.
Our experts have been notified and should reply soon.
↧
RE: General getting-started BLDC driving/control questions
Possible with sensorless
•RPM, for continuous motion, from very slow speed (how slow is the real discussion) to max motor RPM.
•Acceleration/deceleration curves.
Additionally Possible with hall sensors
•Hold position, like a stepper motor.
Additionally Possible with encoder
•Count "steps", i.e., changes in pole positions (with n pole pairs per rev)
•Single "step", like a stepper (where this will correspond with a small output angle, determined by n and the gear ratio
•"Micro step" (Is this practical with a BLDC motor?)
Not sure what you mean by this one
•Force control/feedback by modulating/measuring drive current (via PWM I presume)
For most of what you want to do I would recommend using stepper motors. Either sensorless or with an encoder. If you want to use BLDC you pretty much need to use motors with encoders.
•RPM, for continuous motion, from very slow speed (how slow is the real discussion) to max motor RPM.
•Acceleration/deceleration curves.
Additionally Possible with hall sensors
•Hold position, like a stepper motor.
Additionally Possible with encoder
•Count "steps", i.e., changes in pole positions (with n pole pairs per rev)
•Single "step", like a stepper (where this will correspond with a small output angle, determined by n and the gear ratio
•"Micro step" (Is this practical with a BLDC motor?)
Not sure what you mean by this one
•Force control/feedback by modulating/measuring drive current (via PWM I presume)
For most of what you want to do I would recommend using stepper motors. Either sensorless or with an encoder. If you want to use BLDC you pretty much need to use motors with encoders.
↧
