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L6474 overheating

Question asked by mouser on Sep 8, 2015
                                                               
           
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 70 deg. C.

            while this did provide a convenient opportunity to test my ISR handling             a 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, my             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.
           
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