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RE: DRV8825: Currents measured from ISENA/B are not qualitatively similar to expected microstepping curves

March 24, 2017, 4:52 pm
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Hello Louis,

The reason why segments are exceeding the 33.3us is because at the moment the internal PWM clock began a new cycle, the current has not reached the chopping limit. Since the drive cycle begins at the start of the PWM clock, the current may take longer until it reaches the regulation limit but the PWM frequency will still be 30kHz.
Hence, your capture analyzes the current behavior but it doesn't represent the PWM frequency of the internal clock if that makes sense. Thank you.
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DRV8825: Currents measured from ISENA/B are not qualitatively similar to expected microstepping curves

March 24, 2017, 9:15 am
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Part Number: DRV8825

I am using the DRV8825 driver to microstep a stepper motor in a circuit with the following parameters:

  • Motor coil resistance: 2.5 Ohms
  • Motor coil inductance: 2.5 mH
  • Motor supply voltage: 28 V
  • ISENA/ISENB resistance: 0.220 Ohms
  • Current setting: 1 A
  • Decay mode: fast

The motors successfully rotate given step commands.  I do not have a current probe for my scope, so to verify microstepping operation, I attempted to make a measurement across each coil's current sense resistor.  When the H-bridge applies power across the coil, the voltage on the sense resistor is proportional to the winding current, since it is in series with the motor.  Since we are using fast decay mode, this is also true during decay, however, the polarity through the coil swaps, so I need to be aware that the voltage at the sense resistor will invert.  Taking that into account, I expected to see a waveform similar those in the DRV8825 manual for the front half of each PWM cycle, with more severe fall rates due to the fast decay vs. slow and mixed shown in the datasheet.

However, I'm seeing the following voltage trace at ISENA with the motor holding:

The most confusing thing is that there are segments exceeding the 33.3 us that the 30 kHz PWM would chop at.  Is it not possible to analyze the current draw behavior using the sense resistor voltages?  Am I misinterpreting the meaning of this trace?

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RE: BOOST-DRV8711: SPI MISO Not Functioning

March 25, 2017, 1:13 pm
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I don't have a 430 available, and I need the feature set of the 432 for my project.

The VM voltage is 12 V.

I am still encountering the same issue with a brand-new, out of the box MSP432 with fresh BOOST-DRV8711 hardware. Any other ideas?

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BOOST-DRV8711: SPI MISO Not Functioning

February 24, 2017, 11:48 am
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Part Number: BOOST-DRV8711

I am working to configure the DRV8711 BoosterPack using the SPI register interface on the DRV8711 IC. The MCU I am using is the MSP-EXP432P401R LaunchPad. My code uses the most recent version of MSP432Ware's DriverLib. I use CCS v6.1.
I have been unable to read the registers because the SDO line on the BoosterPack is always logic high. I suspect that the SPI interface on the IC is broken (the SDO pin is perhaps stuck in a high-z state, defaulting to its pull-up value), or I am missing something in my code setup. Below are a couple of screen captures: the first is a write to the CTRL register, and the second is a read from that register. My timing meets the datasheet requirements, and I have tried both clock phase modes with the same results. The SDO line remains high at all times.
For reference, the signals are, from top to bottom, CS, CLK, SDI, and SDO.
Write:
Read:


I am at a loss on this. All of the appropriate pins are configured according to the IC's datasheet and the pinout on the BoosterPack. My code is attached. It starts with a single write to the CTRL register, followed by repeated reads in an endless loop. I have tried this with other registers; all have ended with the same results. What other debugging steps can I try?[View:/cfs-file/__key/communityserver-discussions-components-files/38/main.c:1230:0][View:/cfs-file/__key/communityserver-discussions-components-files/38/BoosterPackInterface.h:1230:0]
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RE: Survey 1/256 Microstep Moto Driver

March 26, 2017, 10:49 am
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Hi Cao Cao,

The closest matching device is the DRV8823, but it does not have 1/256 microstep.

If 1/256 is required, there are two choices. Use the DRV8711 or create your own pattern with the DRV8881E. In both cases, you will need 2 devices.

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Survey 1/256 Microstep Moto Driver

March 26, 2017, 3:13 am
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Hi Team,

May I know TI has function can compare Panasonic device AN44071? Also meet 1/256 microstep request.

I think use two Motor Driver implement is better. Could you help us to comment this? Thanks

[View:/cfs-file/__key/communityserver-discussions-components-files/38/AN44071A_5F00_E.pdf:1230:0]

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DRV8711: Fult happen over 20 V

March 26, 2017, 11:52 am
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Part Number: DRV8711

Dear friends

I used DRV8711 to drive our stepper motor. When we worked under the 20V, every thing is ok and the motor worked smoothly. but when we want to work over 20V, the fault happened. please let us to know me, what should I do for solve this problem and what is this fault? 

Many many thanks for your kind help. 

hadi

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RE: DRV595: FAULTZ pin behaviour

March 26, 2017, 8:01 pm
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Hi Anders,

As you said, the reserved setting for FS0~FS2 can't be used in the application.

In previouos waveforms shown above, the ripple on the FAULTZ pin has 1.2MHz frequency, which is the samae as FS setting, so I think it should be related to the PWM switching. I think you need to check the EMI and the signal integration on your board, or solder and grounding on the board. 

About the chip temperature, the device has thermal protect - the device gets into shuntdown mode if the internal die temperature exceeds 150°C+/-15°C.

Best regards,

Shawn Zheng

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RE: DRV8701: DRV8791 Evaluation GUI Software won't run

March 27, 2017, 1:43 am
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Hi Luis,

Thank you for the tips, but I have run into two situations when I followed the instructions in the user's manual.

1. First computer - CCSv6.1.1 already installed.  I downloaded GUI Composer v6.1.1, but it has stopped responding for hours.  I have tried to re-install, but the results are the same; the installation always stops at the same place.

2. Second Computer - CCS not installed.  The DRV8701EVM software always shows Loading Application and stops

Do you know what else is missing? 

Thank you

regards,

Kevin

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DRV8702-Q1: SH1 sleep mode has voltage 0.8V

March 27, 2017, 2:47 am
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Part Number: DRV8702-Q1

Hi, I have a question about the voltage of SH1. If nSLEEP=0, the output of SH1 is not in high-Z, the voltage measured is 0.8V,but it should be 2.2V(high-Z). Thanks. 

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RE: UC2625 RC-OSC Pin Behaviour?

March 27, 2017, 5:44 am
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Thanks for reply.

So, is it a 0-5V PWM ?

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RE: DRV3220-Q1: DRV3220 RVSET question

March 27, 2017, 5:50 am
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Hi Anthony,

Our experts have been notified and should reply soon.

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DRV3220-Q1: DRV3220 RVSET question

March 27, 2017, 2:27 am
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Part Number: DRV3220-Q1

Hi Team,

I have some question regarding RVSET on DRV3220.

1. Can measure the die temperature via SPI register value? I can't find it on datasheet.

2. What is Max output current/voltage value from RVSET pin? Customer doesn’t want to know the Max rating on RVSET pin. They want to know what voltage or current can be occurred from RVSET pin because she concern MCU damage if RVSET pin is connected to MCU directly.

 3. For low temperature as -40℃, will same formula be adopted?  

Die Temp’=(1.6141V – RVSET voltage) / 3.3mV

4. I think that we can use RVSET for two purpose as ① to set up ADREF/VDDIO overvoltage and undervoltage ② to check  relative IC temp’. Do you have another reason for RVSET pin except two purpose?  

5. Are you accept to measure die temperature with RVSET pin voltage?  I don’t want to recommend RVSET measurement in order to measure exact di temperature on DRV3220 because the RVSET is not meant to give the exact temperature and is more of a relative measurement compared to room temperature for each unit.. Need your advice.

Thanks

Anthony Kim

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RE: DRV8301: Strange behavoir

March 27, 2017, 5:55 am
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Hi Simone,

Have you read section 8.1.1 of the revision F datasheet:

The DRV8301 gate drivers may not correctly power up if a voltage greater than 8.5 V is present on any SH_X pin
when EN_GATE is brought logic high (device enabled) after PVDD1 power is applied (PVDD1 > PVDD_UV).
This sequence should be avoided by ensuring the voltage levels on the SH_X pins are less than 8.5 V when the
DRV8301 is enabled through EN_GATE.

Do you have this condition?
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DRV8301: Strange behavoir

March 27, 2017, 1:53 am
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Part Number: DRV8301

Hello.

I'm having exactly the same problem well explained in the thread "DRV8301 : Trickle Charge Circuitry and Internal Handshake".

I'm driving two DC motors with a terminal fixed to VCC and the other driven in PWM. When i drive the motor 1 the low side driver of motor 2 goes in a state where it ignores the logic input. 

Even more strange is that after about 1 second of 50kHz pulses the low side driver starts to work again.

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RE: DRV8837: what is the minimum voltage provided by the VM pin of the DRV8837?

March 27, 2017, 6:16 am
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dear luis:

application：Intelligent lock，

motor specs: Voltage range for use:  DC:1.5V~4.5V,   Rated load: n=200g-cm  , At Rated voltage and rated load<=80mA, 

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RE: DRV8711: Fult happen over 20 V

March 27, 2017, 7:28 am
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Hello Hadi,

You should be able to run your motor over 20V, this device max operation range is 52V. 

What kind of power supply are you using? Do you have limiting current set in your power supply? Could you please read the status register?
Also, please probe the FAULTn pin and see if is driven low.

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RE: DRV8701: DRV8791 Evaluation GUI Software won't run

March 27, 2017, 8:00 am
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Hello Kevin,

Can you try a newer version of CCS? The latest version is CCSv7.1 Are you downloading from here? Thank you.

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RE: DRV8307: BLDC Motor driver abnormal operation

March 27, 2017, 8:21 am
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Hello TS,
Our experts have been notified and will reply as soon as possible.
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DRV8307: BLDC Motor driver abnormal operation

March 26, 2017, 4:14 pm
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Part Number: DRV8307

Hi,

I'm beginner for motor driver, and have a problem with using TI's DRV8307

The symptom is as below.

-> when repeat start and stop in turn, discover the symptom that do not start.

: The motor emits a high requencty sound.(in a view of the step motor, it seems out of phase.)

Opeatation sequence :

 ON sequence : ENABLE On -> PWM operate 1% ~ 100% 1ms period 1% step.

 OFF sequence : 1% ~ 100% 1ms period 1% step ENABLE Off

What do you think the root cause is?

Hall Position recognition failure?

Incorrect operating procedure when driving motor?

Regards,

TS

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