Hi Duncan-san,
Thank you for the reply.
> How did the customer measure this resistance?
My customer has measured the internal resistance value under the following conditions.
VM = 24V, MODE = 0, nSLEEP = 0 (Sleep Mode)
The resistance value was calculated by measuring the sink current value when voltage was applied to the SH1 terminal.
They need this resistance value for disconnection detection circuit of the motor line.
The data sheet of the gate driver DRV 8301 has specifications of the gate output impedance (Rgate_off) during standby mode.
This value is 1.6k-ohm (MIN) to 2.4k-ohm (MAX).
Best Regards,
Hiroaki Masumoto
Part Number: DRV8703-Q1
Dear Support team,
Our customer will use DRV8703-Q1 in their application.
Please answer the question from them.
In "7.4 Device Functional Modes" on page 38 of the data sheet, it is explained as follows:
"While the nSLEEP pin is brought low, all external H-bridge FETs are disabled.
The high-side gate pins, GHx, are pulled to the output node, SHx, by an internal resistor
and the low-side gate pins, GLx, are pulled to ground."
And I understand that high-side gate pins, GHx, are pulled ground for turn off the high-side external FET.
If so, the SHx pins also are pulled to ground.
< Question >
If my understanding is correct, what value is the resistance of the impedance to the ground of the SHx pin during sleep mode?
There is no need to guarantee the resistance value.
(With the information from the customer, the measured resistance value is about 2.5kΩ.)
Best Regards,
Hiroaki Masumoto
Part Number: DRV8703-Q1
Hi Team,
Does the DRV8703-Q1 have the ability to detect whether the motor is present on the H-Bridge outputs? Would the device be affected in some way if there is pull-up resistor to battery on one of the motor outputs to do the diagnostics?
Thank you,
Jared
Cole and Rick,
I am really trying to determine which driver to use for my application, so could you help me understand why I might pick the DRV10970 over the DRV8308 and vice versa?
My application has the following parameters.
One thing that I haven't quite figured out is the drive angle and whether or not it affects torque.
Thank you,
Jim
Part Number: DRV10970
I am in the process of selecting a motor driver/controller and I have narrowed it down to the DRV10970, DRV8308 or DRV8307. I need to drive Faulhaber 2-pole BLDC motors from 1000-8000 RPM. The motors have digital Hall sensor outputs, so having Hall sensor rotor position feedback functionality is a requirement. In addition, the driver/controller must use Trapezoidal 3-Hall Commutation to maximize torque output.
After reviewing the datasheets, I can see clear differences between the DRV8307 and DRV8308 with the configurability. And it appears that the DRV8307 will automatically switch to single-Hall Commutation when the speed is "relatively" constant, so that seems to rule out the DRV8307. It also appears that the DRV8308 can be forced to use 3-Hall Commutation by setting the BASIC bit, is this correct?
As for the DRV8308 vs. the DRV10970, the DRV8308 is about 2 years older than the DRV10970 and they appear to have almost the same functionality, just implemented differently. Is this correct? Are there any differences in the output drive or otherwise that would affect driving a motor under variable torque load (specifically, an increasing torque load for tensioning in my application).
Thank you,
Jim
Part Number: DRV8811
Hi,
Our customer has been testing the DRV8811 with a stepping motor.
He has observed the current of motor windings.
The waveforms of the current is as follows.
There are spike noises on the current waveforms.
I have some questions.
What is the cause the spikes generate?
Is it affected by "cogging"?
Thank you in advance.
Best regards,
Takishin
Part Number: DRV8872-Q1
Dear team,
DRV8872-Q1 has internal 100k pull down resistors on the input pins IN1 and IN2. What is the minimum and the maximum value we have to assume for this typical value of 100kOhm?
thanks
Lutz
Hi Lutz,
The minimum value is in the datasheet under the Iih specification (Iih max = 100uA @ 3.3V or 33kOhms).
Most queries are for the minimum value to ensure an external resistor can reach the proper Vih value.
If you still need the maximum value, this will take a little more time to obtain. Please let us know if you need it.
Hey Noah,
No problem, I'm happy to help.
I will clarify that the limit for current is 2A continious and 3A peak. Essentially, the motor spins up in open loop until it it hits the value defined in the "Lock Detect Current Threshold" on the advanced settings tab in the Lock detect section. Then the motor tries to restart.
As a result, I see a few options to figure out what's happening. Here are some experiments for you to run:
Hope we solve your problem,
-Cole
Hey Jim,
Let me address your questions:
Hope this helps,
-Cole
Thanks for the detailed response Cole. I think that helps with my decision making.
There's one additional item/feature that I'd still like to get clarification on: drive angle and how it affects torque. Can either of you give any explanation?
Thanks,
Jim
Hi Rick,
A small update. Not sure if will help. I am using a ceramic bulk capacitance of 10uF. I tried replacing it with 10uF electrolytic but no difference was observed. However, if I increased it to 100uF, the threshold at which it falls actually became lower by 2V to 13V. So, it would now FAULT at 13V instead of 15V. So, then I thought of completely removing bulk capacitance at all just to see what happens. Guess what, the threshold voltage increased by about 1V to 16V. Now this seemed a bit contradictory to what is in the datasheet. More bulk capacitance should have helped with current stability and increasing it should have possibly bumped the threshold of FAULT voltage a little bit. What are your thoughts?
I can't seem to figure out the issue. Anything else I can try to diagnose/debug the issue?
Thanks,
Peeyush Garg
Part Number: DRV8800
I've designed a board using DRV8800 to drive a small DC brushed motor. I first tested my circuit on a prototype board and when it seemed to work fine for the entire range of voltage that I'm going to support (8V to 24V), I got some PCBs fabricated based on the recommended layout. The only difference between the prototype and the PCB design was that I had shorted the RSENSE to GND in the prototype version but decided to use a 0.2ohm RSENSE instead for the PCB.
The problem I'm running into is that on PCB everything works fine up until VBB is about 15V and then it starts hitting the FAULT condition. I was able to marginally extend it to about 17.5V by shorting out the RSENSE on the PCB as well. So, essentially making it the same as the prototype and the VTRIP reads 0V. The scope reading of nFAULT shows variable downtime of about 1.5ms to 2.5ms. As another experiment, I connected a 10 ohm resistor in series with motor (R = 15 ohms) and I could get VBB to further a little more to about 18V before faulting.
I'm really stumped now that I've got several boards manufactured as well. What am I doing wrong?
I'm attaching the VOUT (with and without motor connected) and nFAULT scope output as well as the picture of the relevant section of the PCB for your reference. The board was hand soldered by me so please excuse my soldering skills.
Part Number: DRV8704
Hi,
I just wanted to confirm there is no way to know when the DRV8704 enters a current chopping mode. I'm seeing this is the only thing that is missing when moving from the DRV8701 (SNSOUT feature).
Is there any way to obtain when the IC enters current chopping mode? I didn't see anything in the SPI outputs for this.
Thank you!
Mat