Guide how to set hardware overcurrent protection on ZS-X1xx BLDC drivers. Constant Current Mode/TRIP
[NOT YET TESTED]
Reading through the JY01 IC chip note (in attachement):
(...) Overload protection and current sampling resistance setting：JY01 has perfect overload protection function，it has overload protection and abnormal current protection function when the current sampling resistor value R is correct set. When Is pin voltage meet to 0.1V,overload monitoring will start,and turn to Constant current state,the drive current will not change, no matter the VR voltage getting higher or lower and the load getting bigger or less.In this state,JY01 will keep offering constant drive power to
motor. if the Is pin voltage meet to 0.2V or more ,the protection will activated in 4.5 μs.
R value selection method
R value formula I = 0.1/R
I：value of constant current (unit:Amp)
0.1: JY01 Is pin voltage
R:current limit resistance(unit:Ohm)
For example:working current:3A，set the safety constant current to 5A , when the current meet to 5A or more,the programme will keep the current at 5A.so according to formula
I=0.1/R, R=0.1/5=0.02 Ohm,so Overload protection and current sampling power resistor should be 20 mOhm
c) Blocking protection:the blocking protection will activated and stop output if the
motor not
start normal in 3 second, reduce the VR voltage to 0 to quit the protection, rise the VR voltage to restart the
motor.
We can set overcurrent protection by changing shunt resistor:
Currently it is set for 20A
0,1 [V] /20[A] =0,005 [ohm]
And that is the shunt on the board:
Example values of the shunt for setting the overcurrent limit:
I(overcurrent value)=0,1 (IC chip value=constant) /R (value of shunt resistor)
R=0,1/I
20A=0,005 [ohm]
10A=0,01[ohm]
5A=0,02 [ohm]
...
And so on.
Very usable safety feature.
But probably also could be useful to unlock more power from the board (not tested). Keeping in mind that there are limits in the tracks width, slew rate, thermal dissipation... (but few % should be doable) ?
30A=0,003[ohm]
JY02A same working principle but different values:
R value formula: I = 0.04/R (in attachement).
