2014-06-25 06:57 PM
I'm builting a mini drive using the L6474. Got it all working and it runs smooth, but the driver runs very hot and I measured the charge pump and the voltage is only 5volts p-p max (manual says it should be 10vp-p)
The pump is running about 900K-1mhz but only swinging about 5 volts. and when the motor is running slow, it goes as low as 3 .5 volts. The slower you spin the motor the hotter it gets, (very hot, over 100C) and when you speed it up it runs cooler. Im guessing the upper mosfets aren't being fully turned on, generating the heat. Any ideas ?2014-06-30 08:21 AM
The chatge pump frequency you measured seems too high. This is probably the cause of the overstress of the circuitry.
Are you using an external clock source? If possible, can you measure the clock frequency through the OSCOUT pin? Enrico2014-06-30 03:58 PM
2014-07-07 12:38 AM
Ok. Can you share the configuration of the IC?
Did you check if the power outputs are commutating at high frequency? Enrico