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RE: DRV8302 GVDD, AVDD, PVDD all output zero voltage

February 8, 2016, 6:39 pm
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Hey Rick,

Our intention is to run this 3 phase BLDC www3.towerhobbies.com/.../wti0001p to move a >100kg car. The power is provided by a Hydrogen Fuel Cell. We would be targeting a PWM frequency of 10 000 kHz I believe

What do you mean by the phase connections are unusual?
Should we replace the current limiting resistors by something with a lower value (or short it)?
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DRV8302 GVDD, AVDD, PVDD all output zero voltage

February 8, 2016, 4:08 pm
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I am building a brushless motor controller for a motor rated at  60V and 80A using DRV8302 to drive the MOSFETs. We are are having some issues with the PVDD, GVDD and AVDD outputs on the DRV8302. We soldered and tested in the following conditions: Room temperature ~20C, chip soldered with solder paste and a hot air gun maxing out at 200C (we did not follow the soldering curve properly)

What's Working:

  • The buck converter seems to be working fine. It gives us about 5.3V on output which is a little high but gets better under small loads.
  • The PWRGD, FAULT and OCTW are all high, indicating no issues with the buck converter or the motor controller

What's Not Working:

  • GVDD, AVDD pins output 0V even when we run a
  • No gate voltage (GH_A, GL_A, GH_B, etc...) when we apply a 0V-5V PWM at 50% Duty Cycle through with H1 M_PWM set high

Things We Are Not Sure About:

  • CP1/CP2 outputs 0V
  • Our SS_TR is currently floating. Is this okay or does there have to be a cap to GND here?
  • BST_BK is an unstable 11V
  • RT_CLK is a stable 0.475V (is this good or bad?)

Any help would be good. You can find our circuit board design here for reference github.com/.../MotorController

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RE: DRV8302 GVDD, AVDD, PVDD all output zero voltage

February 8, 2016, 9:06 pm
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Hey Rick,

Are you about about the resistors R1-R6 in the schematic? I added them to avoid ringing.

Currently when we apply an input PWM signal (10Khz) to INH_(A/B/C) or INL_(A/B/C) we don't get any output signal on GH_(A/B/C) or GL_(A/B/C) on DRV8302.

Also the readings on DVDD and AVDD are 0V which according to the datasheet should be 3.3V and 6.0V respectively. We have tried 4 different ICs and are having the same problems.

Rumman

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RE: DRV8302 GVDD, AVDD, PVDD all output zero voltage

February 9, 2016, 6:15 am
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Hi Mike,

Sorry, I was not clear on my comment. R7, R8, and R9 are reducing the gate voltage of the low side FETs. This is not recommended as it increases the RDSon, lowering the overall efficiency of the system.

More information:

  • The PWRGD, FAULT and OCTW are all high, indicating no issues with the buck converter or the motor controller
    • PWRGD is a indication the buck is working. FAULT and OCTW are indications that the gate driver has no problems. The buck is independent of the gate driver.  

  • GVDD, AVDD pins output 0V even when we run a
  • No gate voltage (GH_A, GL_A, GH_B, etc...) when we apply a 0V-5V PWM at 50% Duty Cycle through with H1 M_PWM set high
    • Are you setting EN_GATE high? If not, the device is in a low power mode.
    • If connected to a power supply, do you see additional current draw when EN_GATE is set high?
  • CP1/CP2 outputs 0V
    • This should be corrected once you find the cause of GVDD/AVDD pins above.
  • Our SS_TR is currently floating. Is this okay or does there have to be a cap to GND here?
  • It is recommended to connect a cap. Please see second to last paragraph of page 15 for more details.
  • BST_BK is an unstable 11V
    • This is correct
  • RT_CLK is a stable 0.475V (is this good or bad?)
  • this is good.

FYI -- The most comprehensive information about the buck converter is available through the TPS54160 datasheet.

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RE: Importing PCB footprint files into SolidWorks

February 9, 2016, 9:57 am
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HI Rick,

One last question about the board mounting holes: how did you figure out the holes were type "T04" from the file "ThruHolePlated.ncd"? 

There were lots of hole types (e.g. "T13") but I wanted to know how you were able to determine what the "T04" type was.  Only thing I could figure was you matched up the number of holes in the board with the number of x,y coordinates for a given hole type in "ThruHolePlated.ncd."  Was this what you did, or are the "Txy" hole type symbols a documentation standard that can be used to determine the type of hole?

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RE: Importing PCB footprint files into SolidWorks

February 9, 2016, 10:23 am
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Hi Brad,

The DrillDrawing.gbr helped identify the holes. To the right of the board is the legend. I knew there were 8 mounting holes, so it was easy to deduce the size and whether they were plated.

From the file, you can see there is only one entry with 8 holes. They are 115 mils and plated. That moved me on to finding a 115mil hole in the ThruHolePlated.ncd file. I searched for 115 and found the T04 above it. Then I searched for T04 and found 8 entries under the T04 heading. From there it was on to interpreting the information. I have done this before, so I was fairly confident I was reading it correctly. Plus if I was in doubt, I had the DrillDrawing.gbr to confirm.

There was some confusion about the last couple of entries because of truncated digits, and no Y. This is were I used the gerber viewer to confirm the Y was 050000 for both.

By the way I missed the big heading "BOARD DIMS" last time, and measured the board with a viewer.

Hope this explains it.

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RE: DRV8844 with sense resistor?

February 9, 2016, 10:27 am
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Hi Thorsten,

We will investigate and reply soon.

Can you provide a brief description of your application (motor, voltage, current, any other details)? Perhaps we have a better fit.
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RE: Importing PCB footprint files into SolidWorks

February 9, 2016, 11:43 am
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Hi Rick,

OK, that's what I thought you might have done. It makes sense. I suppose the "Txy" notation does mean something, but for my purposes, correlating the number of holes to the hole type code in ThruHolePlated.ncd should be sufficient. Thanks again for all your help and suggestions!

Brad.
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Importing PCB footprint files into SolidWorks

February 1, 2016, 6:14 am
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I would like to import the PCB design files for the board used in the DRV8312-69M-C2-Kit into SolidWorks.  Unfortunately, SolidWorks (and CircuitWorks) cannot import Gerber files.  Could someone at Ti convert the board Gerber files into IDF format?

For reference:

The Gerber files I need converted are in the following folder within the ControlSuite:

"controlSUITE\development_kits\DRV8312-C2-KIT_v128\~DRV8312EVM-HWdevPkg\DRV8312_RevD_HWDevPKG"

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RE: DRV8308 - recommended and safe values for charge pump capacitors

February 9, 2016, 11:49 am
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I spoke with our designer, and there would be some potential issues with changing the CP1/2 capacitor value, and that would require analysis. But as for the VCP to VM cap, that can be made bigger if you'd like.

Best regards,
RE
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RE: DRV8835: Output Configuration with four independent Resistive Loads

February 9, 2016, 1:20 pm
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Hi Rick,

Thank you for the confirmation on our configuration. Our maximum VM Level is specified as 10.5 Vdc, so we will be within the DRV8835 spec. We will follow up the EVM - that is a good idea. Many thanks for your assistance.

Best regards,
Colin Campbell
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DRV8835: Output Configuration with four independent Resistive Loads

February 6, 2016, 1:15 am
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Hi TI,

I'm planning to use the DVR8835 to drive an output configuration consisting of four independent resistive loads, each connected from a single Output pin to the common Ground reference (GND). Hence in this configuration, all four Output Bridges would operate independently - there is no load connected between a pair of Outputs (e.g. AOUT1 to AOUT2). The Data Sheet infers that this is a legal configuration with the state of each Output being independently set by its associated Input (with consideration for the MODE pin setting). Could you please confirm that this configuration is practical for use of the DRV8835? Many thanks for your assistance.

Best regards,
Colin Campbell

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RE: DRV8844 with sense resistor?

February 9, 2016, 4:09 pm
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Hi Thorsten,

I realized you are probably looking for stepper control. The DRV8844 can be modified to control steppers using sense resistors.

Pin 6 is the low side FET source for OUT1 and OUT2. Pin 9 is the low side FET source for OUT3 and OUT4. Pins 14, 28, and PPAD is VNEG, the negative supply (dual supplies) or ground (single supply).

Sense resistors can be added from pins 6 and 9 to pins 14,28, and PPAD. If doing so, the voltage difference between pins 6 or 9 and pins 14,28,PPAD should be less than +/-0.6V.

Also, we have recently released several stepper motor drivers that may be of interest.
The DRV8880 with AutoTune automatically adjusts the current at each step to minimize current ripple. With a STEP/DIR interface control is simple.
The DRV8881E has a AutoTune plus a PH/EN interface and 2 VREF inputs, allowing high levels of microstepping.
The DRV8880 has integrated current sensing, eliminating the need for external sense resistors.

All three have EVMs available for evaluation.
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RE: DRV8302 GVDD, AVDD, PVDD all output zero voltage

February 9, 2016, 5:40 pm
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Hello Rick,

Thanks for the help. We removed R7-R9 and it fixed a few things such as 

  • AVDD - now 6.6 V
  • DVDD - now 3.3 V

Yes we are setting EN_GATE high and yes we see ~40mA current draw when we set EN_GATE HIGH

The problems we are currently having include

  • FAULT is low (around 0.8V)
  • Gate driver voltage for all 6 MOSFETS is at 0V

Things we're not sure about

  • When we test across CP1/CP2 we get 170mV at ~500kHz
  • Is the SS_TR cap absolutely necessary? We didn't attach one because the initial torque required to move the car is very large, therefore we wanted the output rise time to be as short as possible
  • The DRV8302 get's hot when PVDD1/PVDD2 are connected to 20V+

Updated schematic

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DRV8701 current chopping

February 9, 2016, 10:27 pm
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Hello,

I recently developed a brushed DC servo drive using the DRV8701 IC, and I was wondering if it is a good idea to feed the VREF pin with a low pass filtered PWM signal from my microntroller, to be able to adjust the motor's maximum current by software, and gain the ability to perform torque control.

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DRV8305 Damage

February 9, 2016, 10:28 pm
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Hi everyone..

I'm using TMS320F28035 with DRV8305 motor driver. My custom board two layers. Top layer control unit. Bottom layer power unit and there are 6 mosfets (SUM110N06-3M9H-E3). I'm using BLDC_Sensorless project in constrolsuite(Trapezoidal control). When i don't connect motor all signal ok, but when i connect motor DRV is falling (PVDD_UVLO2). It doesn't appear short circuit. When i close all fault DRV on fire. How to fix this situation.

Thanks for your helps..

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DRV8803 PWM duty cycle floating point handling relate issue

February 9, 2016, 11:21 pm
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Hi 

I have query on PWM signal input to DRV8803. Did the IC handle floating point Duty cycle input. I theink it is not working . I got same values for 50.1 to 50.9 and sudden variation for 51. How can i rectify this problem. did the problem is in my MCU side or in driver IC side. I am Driving Proportional flow control valve with PWM input.

 for 

PWM duty Cycle in %

Flow output in LPM

50.1

1.8

50.2

1.8

50.3

1.8

50.4

1.8

50.5

1.8

50.6

1.8

50.7

1.8

50.8

18

50.9

1.8

51

3.06

Thanks and regards

K.Manjunathan

PSGIAS

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RE: DRV8844 with sense resistor?

February 9, 2016, 11:21 pm
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Dear Rick,

thats good news. Thank you for your fast reply. Indeed this is a stepper motor application. In this case we are reworking an old design, switching from THT to SMD technology while keeping most of the design. For new projects I'll keep my eye on the DRV8880.

With kind regards,

Thorsten Ostermann

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DRV8844 with sense resistor?

February 9, 2016, 10:20 am
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I'm looking for a replacement for the good old L298. DRV8844 seems what I'm looking for, but I'm not sure if I can add sense resistors for external current regulation to the device? The functional block diagramm in section 8.2 of the DS implies that there are seperate negative outputs for each half-bridge, but I can not see which VNEG pin belongs to which bridge. So I assume they are connected internaly?

With kind regards,

Thorsten Ostermann

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Solution to emulate incremental encoder

February 9, 2016, 11:37 pm
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Hello,

To get a brushless motor position, we can have 2 solutions:

- Use a Resolver

- Use incremental encoder.

I'm using the Delfineo F28377D on the evaluation board (IDDK377DKit)

Sometime we will need to use the Resolver solution but need to generate the equivalent incremental encoder signal for other device.

So we need to emulate the incremental encoder signal QEPA, QEPB, QEPI from the measured position get by resolver solution.

Are the an hardware and/or software solution to generate this with the F28377D?

Thank

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