i try to make bipolar stepper motor driver i make two h bridge with ir 2110 motor supply volt 48 V motor work with no load and low speed and very low torque and mosfet heat up fast i try work at 31 Khz and try change it to 15 Khz and same problem change bootstrap capacitor from 4.7 mF to 22 mF and 47 mF and same problem i use circuit like :
use mosfet = IRFP064
D1 ,D4 =BY399
D2,D3,D5,D6 = 1N4148
R3 ,R4 ,R7 ,R8 =1 K ohm
R1 , R2 ,R5 ,R6 = 10 ohm and try change to 33 ohm
C2 , C6 =100nf
C1 , C5 =4.7 mf change 22 mf change 47mf
Vcc 12V
Vdd 5V
PWM 5V

 

Try taking out R3 and R7 (or greatly increasing the value, maybe 100K). The high side driver bootstrap is having to provide 12 volts / 1000 ohms or 12 ma. at low frequency, the gate voltage might be drooping on the high side.

 

i will try