artem
Advanced Member level 4
hip4082 dc motor application
The app note link :
https://www.st.com/stonline/products/literature/an/1703.pdf
To what level did you decrease the motor voltage ? Did you decrease it to level when spikes at motor was less than max 80 V for hip chip?
I see spikes more than 80 V at Ahs. Also IR app note pays attention to under voltage case where max voltage on bootstrap is increased too . Could you try to insert resistor serially with bootstrap diode D2 and zener 12 V parallel to C2 (according to first schematics). That is to restrict max voltage on bootstrap capacitor.
What is the V/div on scope wavefor for document in last attachment for V(Ahb – Ahs) diagram ?
Can you try to put tvs between ground and Ahs but close to bridge side to eliminate the current loop to hip chip for about 75 V limiting value (to filter spikes when AHO is OFF) ?
What is the type of bootstrap capacitors do you use? MLCC , conventinal ceramic , electrolytic ...?
Added after 20 minutes:
Check te voltage on C5 does it filter spikes as it should ? is it place as close as possible to bridge ?
Increase its value to more than 1 uF and use high quality capacitors . Reduce the current loop for freewheeling diode when inductance voltage on Ahs goes high than motor power supply .
The app note link :
https://www.st.com/stonline/products/literature/an/1703.pdf
To what level did you decrease the motor voltage ? Did you decrease it to level when spikes at motor was less than max 80 V for hip chip?
I see spikes more than 80 V at Ahs. Also IR app note pays attention to under voltage case where max voltage on bootstrap is increased too . Could you try to insert resistor serially with bootstrap diode D2 and zener 12 V parallel to C2 (according to first schematics). That is to restrict max voltage on bootstrap capacitor.
What is the V/div on scope wavefor for document in last attachment for V(Ahb – Ahs) diagram ?
Can you try to put tvs between ground and Ahs but close to bridge side to eliminate the current loop to hip chip for about 75 V limiting value (to filter spikes when AHO is OFF) ?
What is the type of bootstrap capacitors do you use? MLCC , conventinal ceramic , electrolytic ...?
Added after 20 minutes:
Check te voltage on C5 does it filter spikes as it should ? is it place as close as possible to bridge ?
Increase its value to more than 1 uF and use high quality capacitors . Reduce the current loop for freewheeling diode when inductance voltage on Ahs goes high than motor power supply .