L6474 overtemperature

[Ma Ser]

Posted on May 28, 2018 at 16:37

Goodmorning,

i'm using the steval 3d printer board as prototype for my project, i need to use NEMA 23 motors and hold in torque for some time (even hours).

after 1 or 2 minutes the l6474 return overtemperature error, and remove the power from the motor.

i note this:

l6474 ia about 70-80�C 

the bootstrap circuit overheat until 120�c, in particular the capacitor C_FLY is 125 deagrees.

i set this parameters:

TON_MIN = 4 us

TOFF_MIN = 21 usTOFF_FAST = 10 usFAST_STEP = 16 usTSW = 44 us

SLEW_RATE L6474_CONFIG_SR_075V_us

but the temperature don't change.

can you help me?

Thanks in advance

MA

#l6474 #steval-3d #stm32

[Enrico Poli]

Posted on May 29, 2018 at 15:48

Hi

What about the target current? What is the TVAL value?

Enrico

[Ma Ser]

Posted on May 29, 2018 at 17:28

 ,

 ,

hi Enrico,

/// L6474 torque regulation DAC reference current max value

 ,

♯ define L6474_TVAL_MAX_VALUE (4000)

Matteo

[Enrico Poli]

Posted on May 30, 2018 at 14:29

Hi Matteo,

A continuous output current of 4 A will easily bring the device to the thermal shutdown, but you also say the charge pump circuitry overheats. It is anomalous even if the load current is set to maximum.

Please verify the following:

- VBOOT supply is ok (it should be 10 V above VS)

- The parameters you listed are properly set into the device (read back them using the GetParam command). The configuration can be changed only when the power stage is disabled. 

Enrico

[Ma Ser]

Posted on May 30, 2018 at 17:33

hi Enrico,

VBOOT is 27.2 V 

i power the board vith 18.2, so i think it's fine

which parameter you need?

Matteo

[Enrico Poli]

Posted on June 04, 2018 at 13:26

You need to double-check if the parameters related to the current control algorithm are updated into the device or not:

TON_MIN = 4 us

TOFF_MIN = 21 us

TOFF_FAST = 10 us

FAST_STEP = 16 us

TSW = 44 us

Enrico