Motor Drivers Forum - Recent Threads

DRV8312 commutation scheme

Johan Stenström — Wed, 19 Jun 2013 21:49:43 GMT

Hi,

I have a question about Figure 11 in the DRV8312 datasheet. How come in eg. S1 at 75 percent it alternates between driving A to B and B to A? I'VE also noticed that the same scheme isn't utilized in the BLDC Sensored project (DRV8312-C2-KIT). Why not?

Best Regards, Johan

Losing pulses in a stepper motor angular positioning using the DRV8824

Inaki Mutuberria — Tue, 18 Jun 2013 16:25:13 GMT

I have some problems to control a stepper motor connected as "bipolar serial" (4 wires, A-A', B-B') with a step angle of 1'8º/pulse.

To test the application, I have settled up a demo rig with a DRV8824 Evalution Module which is controlled throughout a Tegra processor.

In this application, we have to move the motor exactly an angle 180º (half a revolution) at regular intervals, always in the same clockwise direction (CW).

Therefor, we generate a perfect PWM pulse beacon of 100 cycles that we send to the STEP signal of the DRV8824. Each cycle includes a 2 ms ON time square wave followed by a 2 ms OFF time. We also control the DIRECTION (DIR) signal to set the motor direction (CW by default, when drived to GND).

The issue arises depending on the direction we choose. If we toggle the direction with every beacon (one beacon CW, next ACW, next CW, next ACW, etc...) using the DIRECTION signal, we can do thousands of 180º cycles without losing the initial reference position.

However, if we send all beacons without changing the direction (all of them always CW or always ACW), we start to lose the original 0º or 180º positions in a few cycles, acting as if the motor receives more or less of the 100 rising edges sent within every beacon. We can check that each beacon exactly contains the required 100 pulses, neither 1 more or 1 less, watching the entire beacon in the oscilloscope.

Have you got any idea for the reason of this behaviour? Any suggestion to work it out?

Thank you in advance for your collaboration.

Best regards,

Iñaki

A question about DRV8812 EVM

Xuemeng Zhang — Mon, 17 Jun 2013 20:25:35 GMT

Recently we bought DRV8812EVM, hoping to test its microstepping feature on stepper motors. After downloading the FW(CPG004_RB_MSP430F1612_Firmware_LMD_TI) into its MCU and running the windows application coming with the kit, I am not able to make the stepper run as expected, although I could change the control signals(e.g, Vref_A).

I tried to call TI but none was available to help. I think I might get some help here since many of you may actually worked on it. Please let me know where the problem might be and what I need to study in order to solve it. Thanks a lot in advance!

DRV8432 General Question on Heat Buildup

John Cole — Wed, 19 Jun 2013 06:12:55 GMT

I have a general question on the DRV8432. We're using this in a dual full-bridge setup and our team is wondering if lowering the PWM frequency will somehow reduce heat generation. Wild shot, I know, but right now we're running at about 10kHz on the PWM frequency and we can lower it significantly to 1,000 or maybe even 200 Hz.

Thank you for your help!

John

PWM problem

Johan Stenström — Tue, 18 Jun 2013 07:47:15 GMT

Hi, We're working on a project involving control of a BLDC from Faulhaber (3564) with rather low inductance. When loading the motor (sensored, velocity control) a ticking sound appears. I tried to take a closer look at the phases with a scope and caught the following (figure attached):

It shows Hall C (green) and the three phases (A yellow, B blue, C magenta). When switching commutation state, phase B alone is on for a short while. It doesn't look right and I wonder if this could be the cause of the noise? And what can I do about it? The same behavior is seen with the BLDC-Sensored example project.

DRV8332 /3PH Motor

�� 23 — Mon, 17 Jun 2013 17:34:54 GMT

Hello!

I have some questions about controlling 3PH motor with DRV8332.

We developed DRV8332 controll circuit by referring the application diagram in datasheet(figure 8),

and BOM of DRV8312-C2-KIT were used.

During the experiment,

We used battery as a power, the current was up to 6A in full speed(about 6000rpm) while unloaded,

PWM duty cycle was up to almost 100%.

Here's the concerning..

1.How do DRV8332 work on three phase motor output?

We are not sure about the current,

we think it is too high in unload motion.

or maybe we should measured phase current individually ?

2.When we pull up the load of motor, speed and current(measured from battery) were falling

Is there any methods could let us maintain or increase the current while loaded?

3.The current of DRV8332 could up to 8A, how do we process when our PWM signal is already set to 100% duty cycle?

some newbie questions, please provide us some useful information.

Thank you!

best regards,

Weber

DRV8301 current sense ADC & isolator

asaygl — Fri, 31 May 2013 11:54:51 GMT

Hello,

Since DRV8301 has its own current sense amplifiers and our microcontroller has adc modules, we don't want to use an external ADC converter, but we still want to isolate DRV8301's output of current amplifiers from the microcontroller as the motor noise became a huge problem for us. Unfortunately, we couldn't find a good solution for an analog isolator, do you have any suggestions for us?

Thanks,

Asa

DRV8301-HC-C2-KIT

camilo silva — Tue, 18 Jun 2013 18:44:39 GMT

Hi Texas

I am Camilo Andres Silva A. I work in Plintec Ltda. Colombia

I have a customer that he want to buy a DRV8301-HC-C2-KIT for a brushless motor but i am not sure if this Kit can support 60v-60A.

I was reading the features and i see that "Kit supports 60V and 82.5A full scale range" but i dont know if this is true.

I hope that you can help me

Thanks, best regards

Heat sink size selection for the DRV8432

Rob Greenewald — Thu, 13 Jun 2013 20:40:10 GMT

Hello, I am designing a motor controller board, and I need to size the heat sink. I have the EVM, and the heat sink that comes with the module is very large. I need to be able to use the chip with a much smaller heat sink. The most I will be driving with the chip will be dual brushed DC motors. They are both 24 volt and will max out their current draw at 3 amps each. Any suggestions on minimum suggested heat sink size will be greatly appreciated. Thank you,

Rob

Questions about DRV8332

Jackson Hsu — Mon, 17 Jun 2013 09:23:40 GMT

Hi,

Recently TI announce a new product, DRV8332. Is it the right forum for DRV8332?

Thanks!

DRV8802 CP1, CP2, VCP

HIDE — Tue, 18 Jun 2013 06:00:19 GMT

Hi,

Is there any voltage specifications for CP1, CP2, VCP on DRV8802?

On the datasheet p.3, it is recommended to use 50V capacitor between CP1 and CP2, and 16V capacitor at VCP, but I'd like to know specified voltage range at CP1, CP2 and VCP.

Best Regards,

Hide

DRV8432 Problems CBC Adjustment

John Cole — Tue, 18 Jun 2013 05:17:32 GMT

We're using a DRV8432 in a Dual FB, CBC current limit configuration. We are experiencing problems when we change the current limit resistor. Originally, we started with a 22k resistor and operations work as expected. When we try to adjust the CBC with a 47k resistor (we are trying to limit current to around 6A per motor), we see reduced function and sometimes freezing. We put an scope on the motor ports while the motor was attached, and you can see power on one of the poles start to collapse. We are running PWM at about 10khz.

This is our schematic:

And these are some shots from the scope:

Driving a Stepper Motor with the CPG004_DRV8812 EVM

Naji Naufel — Tue, 17 May 2011 16:21:31 GMT

Hi,

I have a DRV8812 EVM with which I am trying to drive a bi-phase stepper motor. I am assuming that I would have to sequence the Phase pins in the correct order manually to see the motor rotate.

Is there any control in the GUI that will spin the motor for me?

Is there a reference design for the on-board MSP430 that spins a stepper motor? Is the code that comes on the CD it?

Am I better off getting a DRV8824/25 EVM? Would it spin a motor for me via a GUI button?

Motor Controller Development Process Based Upon TI DRV8301

Ashley Bryant — Sat, 15 Jun 2013 09:48:20 GMT

We use motors for two types of Remotely Piloted Aircraft System [RPAS] function:

To power individually controllable ducted-fan / propeller propulsion units (4) using speed control (potentially up to 20,000RPM, but more likely initially up to 10-15,000RPM). The power/torque curves are defined by the fan / propeller power curves. (We also have dyno load systems that motors can plug into).
To drive a camera payload gimbal in pan, tilt and roll using PWM position control.

I want to test a range of motors (11V up to 10A, 11V up to 20A, 22V up to 30A), can I do this using the one DRV8301 high current kit? My goal is to be able to develop high-efficiency controllers and confirm performance (volts, amps, watts & speed accuracy) against industry standard controllers (that don’t have variable gain control).

Having established the required performance, we will need to translate the test environment into a final controller design. I am therefore seeking to get a clear understanding of what TI components will be required to develop the final controller. Clearly there will need to be the right Piccolo MCU programmed with appropriate firmware and we will have, let’s say an 11V voltage rail. What other elements are required to develop a complete motor controller and what are the approximate masses of each individual component?

My final question relates to the selected Piccolo MCU. Can this MCU drive more than one motor (i.e. up to a maximum of 4 motors), with each motor being speed controlled individually or do I require four Piccolo MCU’s, one for each motor? If I can use one Piccolo to drive 4 motors, then clearly I can save weight.

DRV8834 cad file

Louis Mason — Wed, 06 Feb 2013 21:30:15 GMT

I'm looking all over for a drv8834 .bxl file. Does anybody know where I can find it?

If the file is not available, does anyone know the process or a good tutorial for creating a schematic file to be used with Eagle?

EDIT: Found a tutorial for using the technical documentation, but we would much rather have access to the bxl file for conversion if it exists.

DRV8412 is dead??? help please...

Ivan Debelec — Mon, 10 Jun 2013 10:05:30 GMT

Hello,

I'm working on system for stepper motor driving, and I'm using DRV8412...

I'm working in mode 1 (M1=0, M2=0, M3=0)... PVDD=24V, GVDD=12V, motor is Bipolar 3A, 1,8ohm, 6,8mH...

PWM is 50kHz...

I'm creating four PWM signals which loks like this:

Im trying to move in full step, and I have 100% of PWM duty cycle when i want to grow my current to some value...When I reach that value i'm chopping that current with 50% duty cycle... I'm using Piccolo 28027 to create pwm, and till now i was using PWM chopper module and i get rotation and very big torque... Now when i put this signal from picture my DRV8412 is dead, but i dont know why... When I connected my pwm signals to input at first it was ok and my motor was rotating fine... I tried few times and it was OK in both directions... Then suddenly my drv8412 was dead.... Then i changed PCB where i had another DRV and that drv drop dead too... When i dont have PWM inputs connected my power consumtion from drv8412 is aprox 85mA and when it was working it was aprox 50mA...

Can you please help me and tell me where I'm wrong and what i have to change to get my driver to work fine????

DRV8301 current sense circuitry

Mitch Hanks — Fri, 14 Jun 2013 16:37:41 GMT

The DRV8301 has two current sense amplifiers which in the example circuit are shown to be used to amplify currents through resistors that have been placed in two of the three individual low side paths to ground (between the pull down resistor and ground in each case). In this configuration the system has visibility of the current 2/3 of the time but when current is going through the 3rd phase there is no way to read current. My question: why is the current not sensed in the path between the point where the three phases join together on the low side and ground? Is there an advantage to sensing two phases individually instead of the sum of all three? Also, why only two of the three phases - is this a cost reduction?

Thanks,

DMH

DRV8821 Vcp Issue

Gregory Reneff — Thu, 13 Jun 2013 22:53:33 GMT

According to the datasheet, Vcp should be 12V relative to Vm, however on my board I'm getting Vcp=-.7V relative to Vm, when Vm=12V. What could account for this low voltage? I think I'm getting some shoot through since the upper transistors of the H bridge won't shut off correctly, and there's also some chatter in the motor that lessens when I apply a higher voltage to the Vcp pin.

--Greg

A problem of DRV8432 DC MOTOR DRIVE

woo young KIM1 — Wed, 05 Dec 2012 08:24:11 GMT

Hello, My name is Woo-Yong KIM in south-korea.

I bought DRV8432 last week, and made a circuit. please view the AUTOCAD schemetic.

ut my circuit has a problem.

While driving dc motor single direction, the DRV8432 is work well(I use dual full bridge 1motor-1drive).

But the momentum of changing direction, DRV8432 die....

I check the pin of DRV8432. and find Vdd, BST_C, OUT_C, PVDD_C are Short-Circuit.

please repeat quickly and sorry to my poor English Skill.

and Thank you.

High Current LMD18200 replacement

Giuliano Messina — Mon, 10 Jun 2013 15:41:44 GMT

I would like advice on a replacement for the LMD18200 with a higher continuous current rating, preferably in the 6-10A range (higher is fine as well...just not imperative).

It does NOT need to be a drop-in replacement, just a device with the same functionality at higher current rating. Thank you.

equivalent driver

Iragouda Patil1 — Wed, 15 May 2013 03:54:43 GMT

i am looking for quad/dual/single channel high side driver ,that driver is eqivalent to LMD18400,and logic input/output must be 3.3v operation,

Can any suggest part number .

Regards

Patil

HVACIMTR: AC Induction Motor for TMDSHVMTRPFCKIT, Phisical Parameters

Mitrofan Curti — Mon, 03 Jun 2013 19:35:22 GMT

Hello,

I have a question concerning HVACIMTR Induction Motor.

This kind of motor is to be sent to me from TI store. Considering that this process may last 10-20 days, I'd like to have it's physical parameters, in order to simulate it in simulink.

The question is:

* Where can I find these parameters (rotor stator resistance, rotor stator and mutual inductance, rated parameters ''current, power, voltage, frequency, angular speed'')?

* If someone already have them, please share them with me. I'd be grateful to have them as well.

Thank You!

DRV8818 EVM software

ken steiner — Wed, 12 Jun 2013 19:25:15 GMT

Hi,

Can I get the source code for the DRV8818 EVM PC based software? The firmware source code is included, but not the host source code? I would like to understand how you set up the D/A values, along with any other tricks that may help in my development.

Thanks,

Ken Steiner

Zenon Corporation

DRV8301 Resetting

Zac Bogart — Sat, 08 Jun 2013 00:12:29 GMT

We are using the DRV8301 in a motor driver. At high currents (13-16A) the 8301 is resetting as follows:

The contents of the Control Register reset to their default values

The Fault pin does not drop (stays high), The Fault register does not indicate ANY faults (in any bits, nor in the "fault" bit via SPI)

The OC mode is set to 01 so that the gate drives will completely shut down if we hit the current limit. It's not happening. (We have also tested OC mode at 3 so that we're sure it's not participating in this problem.)

The OC_Adjust_set is set very high (20) Rds-on = 13.5 mOhm = 48A. so it won't trigger.

We have read the AP note SLVA552 regarding noise on the DVDD line. We have a cap (10 uf) directly on the Dvdd pin (thorugh a via) with the other side of the cap directly on the ground pad on the chip (thorugh a via). DVDD is very clean: no spikes, solid 3.3V (ish). (Per the datasheet, the only fault that will do what we're seeing, without reporting a fault, is the DVDD undervoltage.)

EN_GATE is a bit noisy with narrow spikes coming down to about 2.5V When the chip resets we do NOT get a scope trigger on this line below 2V.

The ground pad on the chip is very well soldered to the ground plane.

PVDD is nominally 26V pulling down to 19V at 13A of motor current (5A coming from the PSU) (The PSU is a linear, unregulated, bulk supply.)

Checking between the ground tab and other parts of ground plane proximate to the mosfets, we see about .8V of ground ringing coincident with the mosfet switching edges. Some of it is false (airborne interference) but most of it is real.

We are using Infineon IPU138N08N3 mosfets. They appear to perform nicely. Heating appears appropriate to the power being transmitted. (They gett a bit too hot at 1.5W consumption)

Our belief now is that our board layout needs to be improved. We will start that soon. However, we prefer to find the "smoking gun" before we proceed. We're looking for advice about where to look, what to probe, poke or bolster. What can cause the chip to reset this way?

Thanks for any advice.

DRV8801: Fault condition, Rsense, charge pump, thermal pad

Holger Kaag — Thu, 06 Jun 2013 07:36:45 GMT

Hi TI-forum,

Brush-motor design using DRV8801. Prototypes, hand soldered by skilled personal. UBB=24V, Inom=480mA, Iblock=2A

If Rsense is 120mOhm and a blocked motor cause more than 500mV at SENSE pin, what will happens first, will the device damaged or will the protection stop current flow?

I see some prototypes with nFault=low but functional (UBB=ok). In datasheet block diagram there several abbreviations for fault conditions: abbreviation "STB" and "STG" are for ..?

charge pump: if UBB=24V, what voltage level should VCP and CP1/CP2 go for?

will device be functional if the thermal pad is not connected to GND (pin12/pin2)?

Thanks in common. Holger