Ladies and gentlemen,
we use the DRV8701P in a prototype design. After some experience with this chip we would like to ask you to answer the following questions: The capacitor listed on page 28 with "bulk" is indicated with min. 10uF. Is there a way to calculate the capacitance of this capacitor? Does the size of the capacity depend on the motor current? The manual does not provide any facts at this point!
Another problem arises from the fact that we have to regulate the speed of a connected DC motor in both directions of travel. The aim is to keep the rotational speed of the engine constant over its entire working range. An external potentiometer gives a voltage to a CPU and the motor connected to the DRV chip must reach a speed proportional to the voltage. We adapt the PWM in each case. For this purpose, we measure the generator voltage of the motor in a gap (no PWM present; IN1=IN2=0) of approx. 0.5 to 1.0ms and transmit it to the motor controller. When the motor is at standstill, a constant voltage of approx. 0.7V is applied between contacts SH1 and SH2! We cannot distinguish this voltage from the generator voltage! The controller erroneously suspects that the motor is rotating. Is there a proposal from TI on how the problem can be solved?
We look forward to hearing from you.
With kind regards
F. Giesen
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RE: DRV8701: nFault during driving div. motors
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DRV8701: nFault during driving div. motors
Part Number: DRV8701
We would like to use the DRV8701 chip. The circuit is supposed to control different UNKNOWN motors in the area of model toys. The motor types range from brushed motors to bell-shaped armature motors. Depending on the motor type, the error output nFault is set at low current (approximately 200mA) and the chip reaches the intended waiting time of a few ms. The wiring diagram corresponds to the appendix. The chip is controlled by an STM 3.3V CPU via the two channels In1 and In2.
Can TI support help us?
[View:/cfs-file/__key/communityserver-discussions-components-files/38/Motor-sheet-V1M4.pdf:1230:0][View:/cfs-file/__key/communityserver-discussions-components-files/38/Motor-sheet-V1M4.pdf:1230:0]
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RE: DRV8302: DRV8302 to be used with two phase motor
On page 25 of datasheet, I see no vias on phase 3 "shunt" toward GND. Can you check if there should be no VIAS there as it is shown on page 25 datasheet? I marked them red on picture copied from datasheet.
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RE: BOOSTXL-DRV8323RS: Problem identifying using BOOSTXL-DRV8323RS board and the LaunchXL-F28027F
Hi Gary,
Thanks for the feedback. Keep us posted and we will see how best we can resolve. As mentioned, spec wise the amplifiers are fairly similar so perhaps we are dealing with a subtle setup issue.
Some other brainstorming, the voltage divider scaling is about 30% higher on the DRV8323 EVM due to the extended voltage range of the device. For low inductance motors the back-emf will contribute significantly to the observer error. It may be ideal to match the divider ratio or even adjust it to be more suited for your 24V operation range.
-Nick
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RE: DRV8703D-Q1: Excessive conducted emissions from charge pump activity
Mark,
Good news! I talked to the IC designer for this part, and there should be no issues for adding the resistor on CPL as you suggest.
The only concern with adding the resistor in series with the CPL gate would be the voltage drop across the 100ohm resistor. This should be fine for lower I_DRIVE settings. The biggest impact would be that I*R voltage drop on the 100-Ohm resistor could impact the Rds(on) of your external high-side FETs when you drive them at slightly lower gate-drive voltage.
That said, if you are seeing acceptable performance from you system, you should be fine!
Good news! I talked to the IC designer for this part, and there should be no issues for adding the resistor on CPL as you suggest.
The only concern with adding the resistor in series with the CPL gate would be the voltage drop across the 100ohm resistor. This should be fine for lower I_DRIVE settings. The biggest impact would be that I*R voltage drop on the 100-Ohm resistor could impact the Rds(on) of your external high-side FETs when you drive them at slightly lower gate-drive voltage.
That said, if you are seeing acceptable performance from you system, you should be fine!
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DRV8703D-Q1: Excessive conducted emissions from charge pump activity
Part Number: DRV8703D-Q1
I’m seeing conducted emissions when the DRV8703 is not held in sleep mode, with a fundamental around 130-140kHz and many higher-order harmonics. This happens whenever the H-Bridge predriver is not in sleep mode, even when both the outputs are driven low. I suspect the charge pump is the cause, since it has harmonics that are a good match with the spectral peaks I need to suppress. Are there any recommendations for filtering the charge pump?
This may be related to a similar, earlier post about "disturbance".
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RE: DRV8302: DRV8302 to be used with two phase motor
Hi Zhivko,
Yes, there should be vias at the location highlighted. Thank you for pointing this out.
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RE: DRV8835: absolute maximum ratings
Hi Rick-san,
Are there absolute maximum ratings for AOUT1/2 and BOUT1/2 voltage of SN1401039?
Our customer have overshoot voltage as 0.8V in their board.
Can I propose the following absolute maximum ratings to our customer?
Best Regards,
itabi
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DRV8835: absolute maximum ratings
Part Number: DRV8835
Hello,
Are there absolute maximum ratings for AOUT1/2 and BOUT1/2 voltage ?
Our customer cares about the spike voltage at above output pins that is generated when the motor is suddenly disconnected or some other factor.
Thanks and best regards,
Hiro
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RE: BOOSTXL-DRV8323RS: Problem identifying using BOOSTXL-DRV8323RS board and the LaunchXL-F28027F
(Please visit the site to view this file)Hi Gary,
Did you download the reference code as below link to run the lab02c for motor identification?
https://e2e.ti.com/support/microcontrollers/c2000/f/902/t/635499
I tested a hobby motor on boostxl-drv8323RS board with F28027F launchPad, the motor is low resistance and low inductance, the input voltage of dc bus is 12V. Used lab02c to identify the motor parameters properly, and used lab10a to run the motor with 8000rpm. Attached the use.h for your reference.
#define USER_MOTOR_Rr (NULL)
#define USER_MOTOR_Rs (0.1002901)
#define USER_MOTOR_Ls_d (1.410408e-05)
#define USER_MOTOR_Ls_q (1.410408e-05)
#define USER_MOTOR_RATED_FLUX (0.006071886)
#define USER_MOTOR_MAGNETIZING_CURRENT (NULL)
#define USER_MOTOR_RES_EST_CURRENT (4.0)
#define USER_MOTOR_IND_EST_CURRENT (-3.5)
#define USER_MOTOR_MAX_CURRENT (15.0)
#define USER_MOTOR_FLUX_EST_FREQ_Hz (100.0)
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RE: BOOSTXL-DRV8323RS: Problem identifying using BOOSTXL-DRV8323RS board and the LaunchXL-F28027F
(Please visit the site to view this file)Hi Gary,
I tested a hobby motor on boostxl-drv8323RS board with F28027F launchPad using the reference code as below link
The motor is low resistance and low inductance, the input voltage of boostxl board is 12V. It seems the lab02c identified the motor parameters properly, and lab10a ran the motor with 8000rpm well. Attached the use.h for your reference.
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RE: BOOSTXL-DRV8323RS: Problem identifying using BOOSTXL-DRV8323RS board and the LaunchXL-F28027F
Thanks Yamming,
It is good to know that the same setup is working for you. This could point to a problem with something I am doing. I am out of office for a few days, but now I suspect maybe my 24 volt power supply could be inducing some noise or I have something else going on. I expect that you added the 0.1uF capacitors to your DRV8323 board for C9, C10, and C11?
I will try a different power supply and start looking at the signals with a scope as well on Monday and let you guys know what I find.
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RE: BOOSTXL-DRV8323RS: Problem identifying using BOOSTXL-DRV8323RS board and the LaunchXL-F28027F
Gary,
Right. Added 0.1uF for phase voltage sensing (C9,C10,C11).
Right. Added 0.1uF for phase voltage sensing (C9,C10,C11).
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RE: DRV10987EVM: GUI parameter file
Hey Eric,
After trying to recreate the problem a few different ways on the bench, can you confirm that the USB2ANY Firmware is of 2.7.0.0? You should have gotten an error to update the firmware upon opening the GUI but the firmware could have been updated to the incorrect version.
You can check by using the USB2ANY Firmware Loader.exe or USB2ANY Explorer.exe found by default in C:\Program Files (x86)\TI USB2ANY SDK\bin.
Another thing you can check is the markings on the IC and make sure it says DRV10987.
Also, can you provide a screenshot of the entire GUI window along with the error?
Thanks,
-Cole
After trying to recreate the problem a few different ways on the bench, can you confirm that the USB2ANY Firmware is of 2.7.0.0? You should have gotten an error to update the firmware upon opening the GUI but the firmware could have been updated to the incorrect version.
You can check by using the USB2ANY Firmware Loader.exe or USB2ANY Explorer.exe found by default in C:\Program Files (x86)\TI USB2ANY SDK\bin.
Another thing you can check is the markings on the IC and make sure it says DRV10987.
Also, can you provide a screenshot of the entire GUI window along with the error?
Thanks,
-Cole
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RE: DRV11873: Lock Detection functionality
Hi
I appreciate if you could reply.
BestRegards
I appreciate if you could reply.
BestRegards
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RE: MSP-EXP430G2: Cannot read the data of DRV8711 on BOOST-DRV8711
Hi RIck,
Would you please provide your comments?
Best regards.
Kaka
Would you please provide your comments?
Best regards.
Kaka
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RE: DRV10987EVM: GUI parameter file
Hi Cole,
The below is our USB2ANY firmware version for your check again. It seem V2.7.0.0 version.
BTW, the below is full screen error message inculde GUI for your check again and now use OS is WIN10.
Regards,
Eric
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RE: DRV8884: Motor Current not stable
Why the driving current of DRV8884 is not stable?
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RE: DRV8805: Please kindly help to confirm: does drv8805 or drv8806 match customer motor or not.
Hi LI Iwan,
The DRV8803, DRV8804, DRV8805, and DRV8806 can drive the motor. Other bipolar stepper motor drivers like the DRV8846 or DRV8884 can also be used if the motor is connected in a bipolar configuration.
There are a few questions about the application.
1) What is the voltage at the common pin?
2) Is current regulation desired?
3) Will a zener be used to increase the decay?
4) Is using the motor in bipolar an option?
Another option is the TPL7407L, although the device does not have the integrated protection features of the DRV88xx devices (overcurrent, short-circuitr, under voltage, and overtemperature with fault indicating output).
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DRV8805: Please kindly help to confirm: does drv8805 or drv8806 match customer motor or not.
Part Number: DRV8805
Please kindly help to confirm: Does drv8805 or drv8806 match customer motor to replace sla7033.And please help to recommend more cost-effective device。
Thanks a lot!
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