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RE: DRV8711: How can use it for driving stepper with encoder ?

October 2, 2017, 6:21 am
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Hi Oguz,

The DRV8711 is designed to control the motor voltage(current) at each step independently. If you want to create a closed loop system and regulate the voltage, please consider using a different device.

The DRV8704 is one that may fit your needs. It has many of the same features of the DRV8711 but is set up for PWM inputs. You can control the voltage/current using external circuitry.
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RE: DRV8302: Could you tell me about ”DRV8302 without using the buck regulator"?

October 2, 2017, 6:26 am
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Hi Sekigudchi-san,

The buck is completely separate from the driver and can be left unconnected.
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DRV8302: Could you tell me about ”DRV8302 without using the buck regulator"?

October 2, 2017, 2:33 am
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Part Number: DRV8302

Hi, team.

I have a question, after seeing the following thread.

e2e.ti.com/.../440369

My customer also wants to avoid using Buck Converter with DRV8302.

So question.

Q：There are comments below in the past submission thread, but aren't there any danger of causing latch-up etc?

> If you prefer the DRV 8302 you can simply leave all pins to the buck regulator unconnected.

> RT_CLK, COMP, VSENSE, PWRGD, PH, PH, BST_BK, PVDD 2, PVDD 2, EN_BUCK, and SS_TR = No Connect.

Best regards,

Masumi Sekigudchi

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RE: DRV8800: nFAULT being triggered; can't figure out why?

October 2, 2017, 6:33 am
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Hi Peeyush,

There are several potential causes of the outputs disabling.
1) Undervoltage -- you can observe VBB dropping
2) Overcurrent -- this is unlikely based on your description of 25 Ohms (10 Ohms series + 15 Ohms motor) and the fact nFAULT is not ~1.2ms consistently
3) Overtemperature -- this can occur quickly if the thermal pad is not connected. The device will then cycle in and out of overtemperature. As VBB increases, the amount of current increases and creates more heat.

Please connect the thermal pad.
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RE: DRV8432: What is the reset timing?

October 2, 2017, 7:19 am
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RE: DRV8432: What is the reset timing?

October 2, 2017, 8:02 am
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Hi Aaron,

Data was measured in the lab @ VDD = GVDD = 12V

I'm trying to understand the latency / setup&hold times for the RESET_AB / CD lines. What is the minimum pulse width for a reset signal? Does this pin have a deglitch? Are there any timing diagrams I can refer to?

At 25C, the minimum pulse width is about 30ns. There is no deglitch on this pin.
The delay from /RESET_AB falling to output disabled and /RESET_AB rising to output enabled is approximately the same (50ns).
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DRV8432: What is the reset timing?

September 26, 2017, 3:14 pm
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Part Number: DRV8432

Hi TI,

I'm trying to understand the latency / setup&hold times for the RESET_AB / CD lines.  What is the minimum pulse width for a reset signal?  Does this pin have a deglitch?  Are there any timing diagrams I can refer to?

Thanks in advance!

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BOOSTXL-DRV8301: EMI from the motor

October 2, 2017, 12:34 pm
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Part Number: BOOSTXL-DRV8301

Hello,

I'm designing a BLDC motor driver with the BOOSTXL-DRV8301 kit and LAUNCHXL-F28069M board. I haven't modified the boards and I can measure voltage spikes everywhere on the PCB with the oscilloscope. As soon as I enable the gate on the driver - the signals, grounds and 5V/3.3V buses gets noisy spikes even though the motor is not spinning at that moment. Actually it doesn't matter if the motor is spinning or not - if the gate is enabled - the signals gets noisy. If I measure the 3.3V bus on the driver's buck converter it hsd spikes reaching 5.5V amplitude. However - I have no problem spinning the motor and progressing through the Motorware labs up to 12a without any issues. The power supply is 32V switching PSU and its output is very clean on the oscilloscope. The strange thing is that when I bring the probe close like 1" to the motor enclosure (which is aluminium and not grounded) it starts to measure pulsed signal. When I touch the enclosure the signal gets some decent amplitude equal to the PSU voltage. If I ground the motor enclosure the spikes gets even worse. I doubt if measuring the signals with voltage probes is right because if I really get these spikes everywhere - then I'd have many false interrupts on the micro controller like reset events etc which I don't because I'm able to spin the motor for hours without any issues. The moment I disable the gates everything gets very nice on the oscilloscope again.

Give me some guidelines on what should I do in case I've got real problem with voltage spikes and motor inducing EMI.

Best,

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RE: BOOSTXL-DRV8323RS: support in MotorWare

October 2, 2017, 4:35 pm
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Hi Vladislav,

At this time manual edits are required.

Functionally the two devices are similar. The biggest changes are in the register maps.
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BOOSTXL-DRV8323RS: support in MotorWare

October 2, 2017, 7:20 am
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Part Number: BOOSTXL-DRV8323RS

Hello,

I am currently working on BLDC motor driving solution based on F28069M + DRV8301 booster module kit. I use MotorWare example projects as a foundation to my project and everything is working without problems. However now I want to test DRV8323RS Booster module and I can not find any library for this module in MotorWare. Can I find software library for this module somewhere? Or the only way is to manually edit drv8301.c and drv8301.h files (found in MotorWare) ?   

Thank you in advance,

Vladislav

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RE: DRV8302: Could you tell me about ”DRV8302 without using the buck regulator"?

October 2, 2017, 5:27 pm
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Hello Duncan-san,

I am working with Mr. Sekiguchi.
I have one more question.
Is the die of buck converter completely different from the converter's one?

Best regards,
M. Tachibana

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RE: DRV8302: Could you tell me about ”DRV8302 without using the buck regulator"?

October 2, 2017, 6:03 pm
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Hi Tachibana-san,

Yes, the buck converter is a separate die from the gate driver die.

The buck converter is a TPS54160.

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RE: DRV8800: nFAULT being triggered; can't figure out why?

October 2, 2017, 6:10 pm
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Hi Rick,

I've re-soldered the chip to the board with thermal pad connected this time and there isn't any difference. It's FAULTing at exactly the same Vbb as before (17.5V). I've verified that the Vbb is very stable. The datasheet mentions three more FAULT causes viz. charge pump fault, short-to-supply and short-to-ground. Can you please explain what each of these mean and could I be hitting any of them?

Any other ideas?

Thanks,
Peeyush Garg
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RE: DRV8302: Could you tell me about ”DRV8302 without using the buck regulator"?

October 2, 2017, 6:24 pm
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Hello Duncan-san,

Now I understand. Thank you for your perfect explanation.

Best regards,
M. Tachibana
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RE: BOOSTXL-DRV8301: EMI from the motor

October 3, 2017, 12:13 am
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I realised that the signal spikes are the same on the ground also, so from the micro controller perspective - the signal must be the same and clear. I mean - if I have a 1V spike on the ground and 1V spike on the 3.3V bus (at the same time) this is still 3.3V with reference to the ground.

I'd be thankful if you give me some tips on "living" with the noise and measurements I may take to keep the signals clear and safe.

Best,
Georgi
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RE: BOOSTXL-DRV8301: EMI from the motor

October 3, 2017, 8:34 am
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Hi Georgi,

Thank you for continuing your investigation and confirming the ground spikes occur at the same time.

There will always be some noise in the system, but it is important to connect the scope ground to a ground close to the point to be measured.

Also, I have seen cases where either the scope ground is not effective or the power supply and scope are connected to different system grounds.
Connecting the scope chassis ground and the power supply ground together helped.

Would you please check this?
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RE: DRV8313: input the SPWM signal generated by PCA9685 to DRV8313，the output signal glitch。

October 3, 2017, 8:39 am
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Hi Kou,

What is CH1 and CH2 connected to?
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RE: DRV8800: nFAULT being triggered; can't figure out why?

October 3, 2017, 10:59 am
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Hi Peeyush,

From the datasheet:
The VCP voltage level is internally monitored and, in the case of a fault condition, the outputs of the device are disabled.

The VCP should be approximately 12V above VM when operating properly.

Short to supply or ground:
The current flowing through the high-side and low-side drivers is monitored to ensure that the motor lead is not shorted to supply or ground. If a short is detected, the full-bridge outputs are turned off, flag nFAULT is driven low, and a 1.2-ms fault timer is started.
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RE: DRV8305-Q1: About the advantages of using blanking time

October 3, 2017, 11:35 am
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Hi Harukawa-san,

Sorry for the delay.

To answer your first question from the other post:

Q1.

When Blanking Time is enabled,

　CaseA : Input switch and output switch of CSA turn OFF

　CaseB ：Input switch of CSA turn OFF

　CaseC ：Output switch of CSA turn OFF

Which one is correct?

CaseC is correct. The output is switched off during the blanking time. The CSA output is disconnected, and the external voltage on the CSA signal will depend on the circuitry.

If there is an RC filter, the output voltage will act like a sample/hold circuit. This will allow the mcu to read the current after the switch has occurred.

One possible advantages of using the blanking time is to minimize the effect of inrush current during switching. This is especially true if there are capacitors in the circuit.
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DRV8305-Q1: About the advantages of using blanking time

October 2, 2017, 10:28 pm
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Part Number: DRV8305-Q1

I previously queried the advantages of blanking time with E2E below.
e2e.ti.com/.../2265799

However, the answer was not obtained, I will ask again.

For information on Figure 49 (blanking time is invalid) and Figure 50 (blanking time enable), see page 38 of the document(tidubk5a.pdf).

[View:/cfs-file/__key/communityserver-discussions-components-files/38/tidubk5a.pdf:1230:0]

By enabling the blanking time, it masks the time when ringing occurs, and it does not affect the output of AMP.
If blanking time is disabled (CS_BLANK = 0 ns), input of ringing when gate input turns on/off of AMP is captured as it is.

I understand it this way.

However, even if you do not use blanking time, I think that there is no problem if you use the output after the ringing has subsided.
If this understanding is correct, the blanking time has no meaning.

Q1.
Please tell me the advantage of using blanking time.
What is the meaning of using blanking time?

*
For example,
When masking ringing with soft, can we reduce the load of software by using blanking time?
If so, is this an advantage of blanking time?

-Harukawa

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