Part Number:DRV8824
Hi,
One of my customer prepares to use TI's motor driver DRV8824, but lots of devices are breaking down when test.
Please can you help whether there's any problem on below schematic?
(Please visit the site to view this file)
Stepping motor they used is NMB's PM42L-048-XKL9.
Configuration
- 1/8 Microstepping Mode
- Mixed Decay
- Vref = 300mV, Rsense = 100mΩ → IFS = 600mA
- Reset, Sleep : High (Fixed)
- Fault, Home, V3P3OUT = NC
- Step Period : 240us
DRV8824 damaged symptom
- Output pin FET and Freewheeling diode damaged
- Mainly damaged in high side, sometimes in low side.
- High Side Breakage Symptoms: Output pin, 24V power short, Freewheeling diode 0V when measuring forward voltage
- Low Side Breakage Symptoms: Output pin and Ground short, Freewheeling Diode Forward voltage measurement 0V
DRV8824 damage situation
- Among 3 pockets, there is a pocket that breaks mainly MotorDriver (DRV8824) (Pocket: Driving stepping motor that discharges money)
- One of the three pockets was not damaged during a month, but another pocket was damaged when counting about 400 to 500 sheets.
Scope measurement
- Counting four DRV8824 output pins with scopes while counting papers in frequently damaged pockets
- Trigger setting on BOUT2 pin 27V rising edge
- No counting of 300 triggers while counting by 100, Motor stopped while counting 400 from 300, and triggers on that bundle too
- Yellow: AOUT1, Blue: AOUT2, Pink: BOUT2, Green: BOUT1
- Damaged area is yellow AOUT1 High Side damaged
- The back electromotive force is measured from -7V to 47V (in another experiment, the back electromotive force is observed up to 60V)
External Freewheeling diode (RB068L100) Experiment
- External Freewheeling Diode soldering near the connector
- High side and low side per output pin.
- The Freewheeling Diode (RB068L100) specification is Schottky Diode Vr = 100V, Iout = 2A
- Extended breakdown time compared to pre-soldering of external Freewheeling diode
- If it had been broken at about 400 ~ 500, after soldering, it would be broken after 5000 sheets.
- The external freewheeling diode is not damaged and the DRV8824 output pin is damaged.
thanks,
TS