RE: BOOST-DRV8711: SPI MISO Not Functioning

July 27, 2017, 9:40 am

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Were you able to find a resolution to this? I am seeing similar issues but when interfacing the BOOST-DRV8711 with the C2000 based LAUNCHXL-F28377S.

I am wondering if the issue resides with a mismatch of the logic levels of the uControllers and the DRV8711. Both our controllers are 3V3 logic and I find no-where in DRV8711 documentation to definitively say one way or another but it would appear it is a 5V device based on its VMax=5.5V for all logic pins (at least nothing makes a mention of it running at 3V3 other then the BoosterPack Standard).

dev.ti.com/.../ this app states "compatibility" when it would be apparent logic levels would disqualify any direct "compatibility"

Can anyone at TI confirm the ability of the DRV8711 to interface directly with 3V3 devices?

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RE: DRV8302: DRV8302 nFault issue

July 27, 2017, 10:52 am

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Hello, that's me. Not a professor btw, just a PhD student.

Concening to your first question the nFAULT pin goes low al long as the EN_GATE stays high. If EN_GATE is set low nFAULT generally goes high again (not always though).

here are the screenshot u requested they look quite understandable although in italian. Let me know is something is not clear the EN_GATE signal is the green/grey one:

EN_GATE vs AVDD

EN_GATE vs DVDD

EN_GATE vs GVDD

EN_GATE vs nFAULT

EN_GATE vs PGND

EN_GATE vs PVDD1

EN_GATE vs PVDD2

As said they are in their tolerance. and there is no shorts around. Also the Buck reg works fine.

RE: DRV8302: DRV8302 nFault issue

July 27, 2017, 11:08 am

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I also have to specify that in the schematic I sent, the DRV8301 is represented. Although I'm using the DRV8302 which has the same footprint as the DRV8301. All of the pin should be connected correctly anyway. I've also substituted the pullup resistors of M_OC and M_PWM with 0ohm resistors and put R_DTC =50kohm after I had the first problems but id didn't fix anything.

I'm controlling the DRV with a 3,3V microcontroller.

When the EN_GATE goes high, nFAULT goes low and even if a PWM is applied to INH_X pins, no signal reaches the  gates of the mosfets. This happens most of the times.  Sometimes instead the EN_GATE starts to toggle (although the microcontroller sets it high) at a frequency of around 180Hz as the microcontroller would go in reset state.

In this document there is the top and bottom layer.

(Please visit the site to view this file)

RE: BOOST-DRV8711: SPI MISO Not Functioning

July 27, 2017, 11:20 am

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Well, I it appears logic levels was not the problem...it works just fine at 3V3. I was able to resolve after looking at timing a bit more closely. implementing the Cock Delay (Clock Phase) was necessary -- As the datasheet refers to it as "Rising Edge with Delay":

SpiaRegs.SPICCR.bit.CLKPOLARITY = 0;
SpiaRegs.SPICTL.bit.CLK_PHASE = 1;

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]

RE: DRV8834: DRV8834 drive unipolar and bipolar step motor

July 27, 2017, 12:56 pm

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Hi Jeff,

How does the customer plan to drive the unipolar motor ( indexer mode or phase/enable mode)?

Is there a schematic showing how the two motors will be driven?

DRV8834: DRV8834 drive unipolar and bipolar step motor

July 27, 2017, 9:05 am

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Part Number: DRV8834

Dears,

     My customer want to use drv8834 to drive 2-phase bipolar and unipolar step motor.

Because they want use the same PCB at different appication.

I know DRV8834 can drive bipolar well.  But I'm not sure if it can drive 5-lead unipolar step motor like below picture.

Thanks

Jeff Chen

RE: DRV10975: DRV10975 EMC ISSUES

July 27, 2017, 2:43 pm

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Glad to see that the performance has improved. 

400Hz seems to very low. My first guess would be electrical or mechanical frequency of the motor.

What is the motor RPM and # of poles?

Thanks,

Seil

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RE: DRV10983: EVM GUI, difference in RPM between Motor Speed values

July 27, 2017, 3:24 pm

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Vlad,

  GUI calculates RPM base on Electrical Period (uS), From data you showed by using Electrical Period to calculate RPM are closer what you measured.

Best regards,

Janet

 

 

DRV10983: EVM GUI, difference in RPM between Motor Speed values

July 27, 2017, 11:29 am

≫ Next: RE: BOOSTXL-DRV8305EVM: When should I be running Lab 5b) ?

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Part Number: DRV10983

Hi,

I am using the DRV10983 to drive a motor. I did some RPM measurements (using different loads and speeds) with the DRV10983 EVM GUI and a separate laser RPM measurement system.

The Motor Speed (RPM) value displayed in the GUI is closest to the laser measurement. Motor Speed in Hz and Electrical Period converted to RPM are both different from the displayed Motor Speed RPM.

Here are my measurements, I use an 8 pole motor, and used the formula RPM=f(Hz)*(2/nr poles)*60 or RPM=f(Hz)*120/8:

Motor Speed (RPM)

244,18

644,053

1390,18

283,447

652,458

1307,76

267,094

649,351

1218,52

Motor Speed (Hz)           Conv2 RPM

17,1                                     256,5

45,2                                    678

96,3                                  1444,5

19,4                                  291

45,5                                  682,5

91                                    1365

18,5                                 277,5

45,2                                 678

85,1                                1276,5

Eelectrical Period (us)   Conv2 RPM

61420                                    244,2201237

23160                                    647,6683938

10780                                    1391,465677

52830                                    283,9295855

22940                                    653,8796861

11420                                    1313,485114

54920                                    273,1245448

23150                                    647,9481641

12260                                    1223,491028

Why is there a difference between the Motor Speed (RPM) and the Motors Speed (Hz) and Electrical Period (us) when converted to RPM? From what and how do you compute the Motor Speed (RPM) value in the DRV10983 EVM GUI?

I will have to read the motor’s RPM over I2C and use it in a control algorithm. For that I can either use the value from the Motor Speed 1&2 or Motor Period 1&2 registers. Which register would you advise to use, which one would be more accurate?

Thank you.

Best regards,

Vlad

RE: BOOSTXL-DRV8305EVM: When should I be running Lab 5b) ?

July 27, 2017, 3:26 pm

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Sure! 

Just a suggestion, maybe a InstaSpin/Motion team member would be appropriate. 

RE: DRV8824: V3P3OUT capacitance

July 27, 2017, 5:01 pm

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Hi Rick-san,

Thank you for your reply.
I will suggest the customer to use the recommended capacitor.

Thanks,
Naoki Aoyama

RE: DRV595 application circuit

July 27, 2017, 10:12 pm

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Hi Simon,
Thank you for the explanation, I think I understand it. DRV595 has over-current detection internally, but it just shut down the output when output current exceeds the THR. Now you wan to monitor the output current and adapt the input amplitude accordingly.
I think this is feasible, you could insert a current sense resistor in series with the thermal module load(after the LC filter), and use an op amplifier to measure the voltage drop on the resistor. TI also has the solution for this application, please refer to www.ti.com/.../sboa170a.pdf.
Best regards,
Shawn Zheng

DRV8884: Quad level input

July 27, 2017, 10:56 pm

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Part Number: DRV8884

Hello,

Our customer use the DRV8884.

The customer apply voltage to Decay pin.

Perhaps, there are three threshold voltage at Decay pin.

Vth1: between Vi1 and Vi2

Vth2: between Vi2 and Vi3

Vth3 between Vi3 and Vi4

Could you tell me the value of threshold voltage?

I know it operates correctly by input 100mV, 300mV, 1V, 2.9V.

The customer want to know the tolerance. 

one more question

When the customer use Slow/Slow decay, is it possible to left open the Decay pin?

Best Regards,

Naoki Aoyama

RE: DRV10975: DRV10975 EMC ISSUES

July 28, 2017, 12:25 am

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Dear Seil:

FYI, Thanks. 

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DRV8872-Q1: nFAULT timing under OCP and TSD

July 28, 2017, 2:02 am

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Part Number: DRV8872-Q1

Hi,

I would like to know correct timing of nFAULT under OCP and TSD.

1. OCP

If the output current exceeds Iocp for 2 us (tOCP), the driver should turn off, but will there be delay before nFAULT goes high?

After 3ms(tRECOVERY), when it will automatically restart, is nFAULT also returned to Low?

2. TSH

Is there a delay in the output change of nFAULT as in the above case?

Is there any reference data to know the time it takes for the device to cool down after it stops at TSD?

For example, when ambient temperature is 125 ° C on the evaluation board, it took approximately how long it took to return.

In OCP, the automatic recovery is 3 ms, so I'd like to know about the approximate level, like a few usec or msec.

Best regard,

Tomoaki Yoshida

RE: DRV8872-Q1: Rds_on vs Iout worst characteristics

July 28, 2017, 3:26 am

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Hi Rick-san,

Thank you for your support.

Rds_on is described in the data sheet, but the condition is for output current 1A.
They are thinking maximum output current is up to 1.5A and Vm is from 7V to 16V.
Since ambient temperature can not be assumed yet, it is good for them a graph of temperature vs Rds like above number 2.
Or can I know the worst Rds_on at Ta_max or Tj_max?

Best regards,
Tomoaki Yoshida

DRV8872-Q1: Rds_on vs Iout worst characteristics

July 26, 2017, 9:57 am

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Part Number: DRV8872-Q1

Hi support team,

In order to identify the worst conditions under their use conditions, out customer would like the following data.

1. Rds_on vs Iout Graph worst condition

2. RDS(on) vs Tj worst condition

3. VTRIP vs Tj worst condition

For the number 2 and 3 above, there was a typical conditionand ambient temperature in the data sheet.

Although the design must be established under the worst condition in their use conditions, the worst condition of the electrical characteristics of the data sheet is more stringent than their condition.

Is there no way to calculate the worst value under usage conditions with simulation etc. even if there is no graph?

Best regards,

Tomoaki Yoshida

DRV8824-Q1: AVref vs A/Bout pin problem

July 28, 2017, 3:41 am

≫ Next: Survey TI Three Phase Motor Driver

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Part Number: DRV8824-Q1

Dear sir,

below figure is our AVref voltage and Bout2 current signal

we think Bout2 current's high frequency is because of AVref voltage's

Is there any setting or solution to filter out the chopping frequency on Bout2?

we think this high frequency may cause motor's high frequency noise.

and need to decrease it's effect on motor.

Thanks for your fully support!!!

Survey TI Three Phase Motor Driver

July 28, 2017, 3:45 am

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Hi Team,

May I know TI Three Phase Motor Driver has FOC with Sensorless solution?

Input 24VDC  and Output current 2A-3.5A

Could you help comment below question or if you have best solution please advise me, thanks.

for DRV8313, we can use current shunt monitor  Rsensor feedback information to MCU?