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RE: DRV8432: Microstepping Mode, Externally Setting OC CBC Protection Threshold

March 17, 2017, 1:48 pm
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Hi Michael,

Setting up microstepping mode requires additional circuitry around the DRV8432. I will discuss this in more detail further down. Have you looked at the DRV8711, which has the ability to microstep, but requires external FETs?

DRV8432:
At a minimum, two current shunt amplifiers are needed along with two current sense resistors. This information can be seen on the DRV8412-C2-KIT schematic (IA-FB/IB-FB and IC-FB/ID-FB). Each current sense pair IA-FB/IB-FB can be combined into a single amplifier and resistor if desired. The current is then monitored by the mcu, which controls the outputs.

The OC_ADJ is intended for system protection. Many of the EVMs have the ability to adjust the value for demonstration purposes.
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DRV8432: Microstepping Mode, Externally Setting OC CBC Protection Threshold

March 17, 2017, 11:03 am
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Part Number: DRV8432

Hi,

I intend to use DRV8432 chip to run stepper motor in microstepping mode. I've reviewed DRV8432 data sheet but found no information on how to set up a microstepping mode. It's my understading that in order to do so I have to set up the chip for cycle-by-cycle (CBC) current limiting mode and be able to adjust OC threshold externally by using voltage DAC or otherwise. I looked up through this forum and found reference to DRV8412-C2-KIT that is capable of microstepping mode. I've then checked the schematic diagram of the driver board included with the kit and found that the circuit contains PWM DACs and allows for external OC threshold control. However, it's not clear so far as to how to choose the DAC's output voltage and OC_ADJ pin's resistor value for a given desired OC threshold value. The description of current limiting function in the DRV8432 datasheet is very limited and skimpy and it's insufficient to gain full understanding of circuit's functionality. So my questions are as follows.

1. Would you please provide a more in-depth explanation of current sensing and OC protection functionality, perhaps, with detailed block diagram of the circuitry involved?

2. Would you please provide a formula that accurately describes functional relationship between DAC output voltage, external OC_ADJ resistor's value, and desired OC CBC protection threshold?

3. What is the typical response time of the DRV8412 to the changes on the OC_ADJ pin?

Michael

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RE: Motor Driver for 3 phase motor

March 17, 2017, 2:22 pm
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RE: Motor Driver for 3 phase motor

March 17, 2017, 2:38 pm
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Hello Diederik,

Looking at the information provided. It looks they can be all driven by BLDC drivers. Please take a look at our BLDC portfolio here to find a driver that fits your application the best. Please let us know if you have any questions about a particular driver. Thanks

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Motor Driver for 3 phase motor

March 16, 2017, 11:21 pm
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Hi!

I've two dunkermotoren (3-phase) BG31 with hall sensors and one mvl BG3612.
My question is now which motor drivers I need to drive the motors. I'd like to use it with my Raspberry Pi.
I'll attach all the information I have. 

[View:/cfs-file/__key/communityserver-discussions-components-files/38/1406_5F00_Flyer_5F00_BG31.pdf:1230:0]

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RE: DRV8711 write issue after sleep

March 17, 2017, 2:50 pm
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Hello Michael,

We were not able to reproduce this fault. How are you controlling SCS? Also, what is the wait time between writes? Can you try to extend the time between writes? Thank you.
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DRV8711 write issue after sleep

March 25, 2016, 6:54 am
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I want to share this issue that I recently discovered on DRV8711:

if during sleep (SLEEPn forced L) the SPI is used to write 3 or more registers, then after resuming from sleep the first write access is skipped.

It doesn't care if during sleep you also do readings (before, after, interleaved or mixed to the writings) and also it doesn't care if after resume you do some readings before the write: it is affected only the very first write operation after exiting the sleep condition.

The very odd thing is that with just 1 or 2 writings in sleep all works good... the issue starts only if the writes are 3 or more.

As workaround I managed to do a verify of the value just written (reading back the register just after writing it) and then doing it again till the value is as expected.

For sake of semplicity I done that for every write access: then I verifyed that all write operations is now a couple of write-read accesses while the very first write operation after resuming from sleep become a write-read followed by a second write-read (as the first write fails while the second works fine).

That's all.


Gianfranco

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RE: DRV8816: disabled DRV8816 is not 'Z' at output!

March 17, 2017, 4:45 pm
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Hi Ralf,

c.) What I get is something between 12...15V when VBB is 15...35V WHY??
I get that result even without any external stuff only with pullup-47kOhm

The internal path activates at approximately 12V to protect the high side FET.

d.) MOST IMPORTANT QUESTION: ???? CAN I BE SURE THAT THE VOLTAGE AT OUTn WILL NEVER!! DROP BELOW 12V ????
Figure4: Pullup is connected like the most right picture
Yes, I can switch the load to GND
Pin 15 VPROPI is open in my app.

When the output is disabled, consider it a 12V zener to ground. With variations, it is possible to be slightly lower or higher across temperature. With a 47kOhm pullup to VM (and VM is >15V), the voltage at OUTn should be above 11V when the outputs are Hi-Z.
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DRV8816: disabled DRV8816 is not 'Z' at output!

March 13, 2017, 2:37 am
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Part Number: DRV8816

Hello Ti-forum,

my application has pullup (47kOhm) connected to output

when disabled I measure:

V-supply =35V -> V-output = 14V

V-supply= 15V -> V-output = 12V

measure DC-current with multimeter:

V-out <-> Gnd - 700µA (That's the pullup@35V)

V-out <-> V-supply - 45mA ??? why??

!! it gets 150mA in sleep-mode

please explain this

can I be sure, that V-out in disabled mode never is below 12V ??

please help..]

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DRV8880: AutoTune Feature for 5 A Stepper Motor

March 19, 2017, 9:37 am
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Part Number: DRV8880

Hi,

I want to use the AutoTune feature of DRV8880 with a stepper motor with 5 A current(RMS). Is it possible to use external MOSFETs driver with DRV8880 for use with higher stepper motor currents as the internal driver is limited to a maximum current of 2 A ?

Also is it possible to set the micro stepping to 1/256 instead of 1/16th, in firmware just like DRV8711 ?

As per my understanding, DRV8711 does not have the AutoTune feature which is available in DRV8880. How can I get both features, AutoTune and 256 microsteps, for 5 A stepper motor drive ?

Please advice.

Best Regards.

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UC2625 Gate Driver

March 15, 2017, 12:11 am
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Hi,

I am trying to use UC2625 in a design. Planning to drive N-channel MOSFETs on high and low-sides.

UC2625 PU outputs are in open-drain configuration, PD outputs are something like push-pull or totem-pole. (PU active low, PD active high)

Are there any gate drivers, to accept these two inputs? Or what kind of gate driver should I implement?

Thanks!

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RE: DRV8816: disabled DRV8816 is not 'Z' at output!

March 20, 2017, 12:54 am
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Hi Rick,
that was very helpful.
My internal Reference is 5V, so also 11V is high enough.
I can use those devices for my app
Thank you
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RE: Motor Driver for 3 phase motor

March 20, 2017, 1:43 am
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Hi! 

Thanks for your fast reply!
I think it's easier to use single drivers. I'm a newbie, isn't the driver doing that automatically?

I wonder if there's any documentation available concerning raspberry pi? I'd use Python.

Kind regards,

Diederik

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RE: Motor Driver for 3 phase motor

March 20, 2017, 1:48 am
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Thanks for your reply! I think I need a BLDC driver for a two phase motor in case of the BG3612, but why does Rick Duncan say I need a brushed dc driver?
When I was experimenting, I thought the BG3612 Motor worked like an AC motor, I had to change the phases to view a movement of the motor.

Kind regards
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RE: BOOSTXL-DRV8323RH: DRV8323RH Sinusoidal drive

March 20, 2017, 1:59 am
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Hi,Rick-san

Thank you for your answer about DRV8323RH.
I have one more question.
Can this product capable of deep angle control ?

Best,Regars
Fukazawa
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BOOSTXL-DRV8323RH: DRV8323RH Sinusoidal drive

March 1, 2017, 12:09 am
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Part Number: BOOSTXL-DRV8323RH

Dear Expert

I have question about New product DRV8323RH.

Is this product sine wave drive ?

Best,Regars.

Fukazawa

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RE: DRV8860: DRV8860 output channels question

March 20, 2017, 5:16 am
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Hi Rick,

My customer made a test. We saw the Energizing wave every time we wrote data to the data Register, even the data is the same. Is there anything wrong with the code?

it set 3ms Energizing with 50kHz 50% duty PWM output at D1/ D2/ D8/D9 channel(0x0303). and write 0x0303 to data register every 20ms.

/*
 * main.c
 */

uint32_t tick=0;
void SysTickIntHandler(void)        // 1 ms
{
    tick++;	
    if(tick>100)
    {
	if(tick % 20 == 0)
	Write_Data_Reg(0x0303);       // D0,D1.D8, D9
    }
}

void main(void)
{
    SysCtlClockSet(SYSCTL_SYSDIV_5 | SYSCTL_USE_PLL | SYSCTL_XTAL_8MHZ |
                           SYSCTL_OSC_MAIN);//40MHz
	
    SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOA);
    SysCtlDelay(SysCtlClockGet()/4);

    All_GPIOInit();
    ConfigureUART();
    tick_init();

    IntMasterDisable();
    pwm_set(0xC1C1,0x0303);//Fre: 50khz energizing time:3ms D0,D01;D8,D9 ON
    IntMasterEnable();
	
    my_printf("Hello World.\n");
    while(1)
    {
		//SysCtlDelay(100000);
	}
}

the output wave form as below, we  saw OUT0/ OUT1 output 3ms Energizing every 20ms (the interval we write 0x0303 to data register)

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DRV8860: DRV8860 output channels question

March 9, 2017, 8:20 pm
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Part Number: DRV8860

Dears,

DRV8860 have 8 channels output with the function of energizing and PWM chopping. I have a question about the channels when driving more than 1 solenoid. 

Just for an example:

I set the Control Register as:  300ms energizing time with 25% PWM chopping, and output via out 1 channel by setting Data Register to 0x01 . after 300ms later, OUT1 will output an 25% duty cycle PWM wave.  And then I need to drive another solenoid such as output channel 2. 

Could you please tell me that what the output status of OUT1 channel when I write 0x03 to the Data Register at now? is there an another 300ms Energizing wave at OUT1 simultaneously with OUT2? or keep 25% duty cycle output at OUT1?

Thanks a lot.

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RE: DRV8711: Can DRV8711 operate without SPI?

March 20, 2017, 5:36 am
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Hi TS,

SPI is required for DRV8711 operation. The SPI interface is required to enable the outputs (CTRL register, bit 0).
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DRV8711: Can DRV8711 operate without SPI?

March 20, 2017, 2:45 am
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Part Number: DRV8711

Hi,

One of my customer willing to use DRV8711, but they do not want SPI control.

I'm afraid the DRV8711 can enable and work normally without SPI line.

But only related thread I found from E2E is below.

( https://e2e.ti.com/support/applications/motor_drivers/f/38/p/573994/2105671#2105671 )

the result of above thread is use SPI1.

Is it possible for DRV8711 with only Optional STEP/DIR Pins?

If then, how can I disable SPI controls? just make low pin 16?

thanks,

TS

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