L6474 overheating

estie · ‎2015-09-05

Posted on September 05, 2015 at 23:10

I am using three L6474s to drive NEMA23 format motors.

Using the default register configurations the chips are rapidly getting very hot and causing a TH_WRN condition.

I found a post here that stated that the default config caused high frequency switching which produced ''strong'' heat dissipation. It also recommended some alternative configuration, the main change of which was reducing TON_MIN from 20.4 µs to 4µs . There was also suggest that some configurations lead to the control algorithm being unstable.

I did that and reduced slew-rate and now the chips are getting to a much more reasonable circa 60 deg. C.

while this did provide a convenient opportunity to test my ISR handling FLAG input change, it seems odd that the chip is not supplied with a better default configuration.

What kind of motor loading is the default config suitable for?

Now with about six configurable parameters for internal algorithm, this semi-arbitrary set of values seems more of a hack than an engineered solution.

Is there any guidance on how to tune these parameters to reduce dissipation and avoid possibly unstable configurations?

Thanks.

Gigi · ‎2015-09-07

Posted on September 07, 2015 at 14:24

Ciao

I suggest touse the following forum for question related to stepper or monolitic drives

https://my.st.com/public/STe2ecommunities/motordriver_ics/Lists/Motor%20Driver%20ICs%20and%20Boards

Ciao

Gigi

estie · ‎2015-09-08

Posted on September 08, 2015 at 12:49

Thanks Gigi, I'll repost this on that forum.

So that I can better understand where to put things,could you explain what the 'Motor control firmware' in the title of this forum relates to.

Gigi · ‎2015-09-08

Posted on September 08, 2015 at 13:55

Ciao

At the moment for ''Motor Control Firmware'' we intend primary the STM32 FOC control for three phase brushless motor. (We covere here also topic related to the HW for 3ph motors)

For question regarding stepper or other kind of motor drives based on IC (like L64xx family) is better to use the other forum.

Ciao

Gigi

estie · ‎2015-09-09

Posted on September 09, 2015 at 18:18

Thanks Gigi,

I posted it where you suggested but after four views and no replies, clicking on the message gives no content. I tried to post anew but no the interface has no place to enter a title, so I have a message called ''no title''.

Looks like the forum software is in state of flux too.

estie · ‎2015-09-09

Posted on September 09, 2015 at 18:25

No idea what is going on with the forum software today. clicking on my copy of this msg that I posted there returns:

<<

There are no items to show in this view of the ''Motor Driver ICs and Boards'' discussion board. To create a new item, click ''New'' above.

>>

:?