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Here is one 3 phases controler which has been build and works! I just placed the driver portion but if you want the micro (MC68HC912B32CFU8) I can place it there.. This controller is very smooth and even the power here is for a 250 Watts motor, you can taylor it to a smaller motor by changing the output FETS.
The motor I used was from Maxon (Swiss motor) but I think any other 3 phases DC motor could be used by selecting right output pair of N and P channel FETs.
Yes I suppose you could use 3 x 6203 to drive a brushless 3 phase DC motor. The dowside of using it (versus 3 pairs of FETs) is that the RDSon of the 6203 is 0.3 ohm! This is very very high. If your motor has very little power then it may be possible to use the ST 6203, but I do not see any advantages compared to 3 pair of FET (milli ohms RDSon)..
Anyway have fun..
The above schematic is for a stepper motor, not 3 phases DC brushless.
The one I uploaded is for 3 phases DC Brushless.
In case of a 3 phases brushless DC motor the current control is generally control on each phase switching. So as soon as the the set value (motor dependant) is reach, the switch is then turned off.
As far as the pair of FETs is concerned, I used the lowest RDS on I can place my hands on. Price difference between a very low RDS on an a medium one is not that great anyway. To select a pair use tree search by function (onsemi)
I have some achievements while using L6203 + L6506.
The motor is rotating and has enough strenght, but the heat sink is rather hot ( about 65 Celcium ). Is it normal?
How can I reduce current while holding the motor? Now I rely on L6203 current regulating capability.