Hi team,
when I use DRV110 drive the Electromagnetic brake, I found if my pwer supply is 48V, then the VIN is going to be 15V, because of the function of 15V zener diode inside, but the OUT pin PWM frequency became unstable, and the Electromagnetic brake make a audible noise.
when I add a 12V zener diode at the VIN pin， let the 15V zener diode does not work, the
issue is solved.
Does the 15V zener work cause this issue?
when I use DRV110 drive the Electromagnetic brake, I found if my pwer supply is 48V, then the VIN is going to be 15V, because of the function of 15V zener diode inside, but the OUT pin PWM frequency became unstable, and the Electromagnetic brake make a audible noise.
Zener is clamping the voltage, but it is recommended to limit the current when the voltage is higher than Vz. Can you increase R25 to 36 K and see if it helps.
1- Would you please let me know what are DRV110_VIN and +48V_Brake_SW?
The resistor should be in serries with input voltage.
2- Would you please capture VIn voltage, Load current, OUT voltage. Please check the out voltage frequency as well. ?
1. DRV110_VIN is just a net name，no other places connect it， +48V_Brake_SW is the power supply of DRV110。
2. yellow： DRV110_VIN RED: load current 【measured at the power on stage】
yellow: OUT RED: load current
1. DRV110_VIN is just a net name，no other places connect it， +48V_Brake_SW is the power supply of DRV110
1- Would you please confirm that the local bulk caps are placed close to Vin pin
yellow: OUT RED: load current
the PWM frequency looks fines. It seems that the device is providing minimum Duty cycle during IHOLD which means that the ILOAD > IHOLD. have you checked the required minimum Ihold value for the load?
Also the reason for current changes during the I hold is not clear. is the load changing?
Have you checked the load with DRV110 EVM as well?
Hi，
1. Would you please confirm that the local bulk caps are placed close to Vin pin---- yes， they are placed closed to Vin pin
2. the load is a Electromagnetic brake, Ipeak 2.2A，I hold 0.64A, the actual value R105 is 69.8K, R108 is 0R,R114 is 0.25R in the schematic above
the load is coil， I do not think it will change
3. I measure the wave after adding a 12V zenner diode at Vin, There is no signal like the one in the red circle below
4. I do not have a EVM， How can I get one？
