In your circuit. I am not sure why you need the Rsense resistor. If I understand your circuit, you're forcing the base current to remain fixed so that it will limit the amount of current flowing between the emitter and collector. The pair of diodes is to limit the voltage. Should a higher Vcc be used the pair of diodes would clamp the voltage and limit the base current. The Rsense resistor is not providing any feedback. If you want a feedback current limiter you need to use a something like a TL431 adjustable zenor (replacing the pair of diodes). The TL431 adj. pin is connected to the trace between the NPN emitter and the Rsense transistor so that as the voltage drop across the Resense resistor increases, TL431 zener voltage falls reducing the NPN base current. That said, you may run into problems running a motor that presumably has moderate current levels. The NPN transistor will act as a resistor dispating a lot of energy as heat, and has the protential of failure, if it gets too hot. BJT have a negitive thermal coefficient, meaning that the hotter they get, the more current they will pass. For instance an NPN transistor at 25C with a static base current might permit 1A to pass. At 150C it might permit 2A to pass. For example see this datasheet for the 2N3055 on page 3 showing the hfe plot at -55C 25C and 150C. http://www.onsemi.com/pub_link/Collateral/2N3055A-D.PDF
I'd use the sense voltage with a comparator towards a precise threshold. It then could switch on a MOSFET or BJT, depending on which makes the lower power dissipation for your rated current/voltage.
I need a simple current limiter for a project (a brushless motor driver in particular, as I'm pretty sure I will accidentally short the supply sooner or later).
In my case, the parameters are - Vcc = 12V, Ilimit = 10mA.
Can I get some feedback please? Is there a way to make it simpler/better/both?
10mA? Are you sure? How small is your motor?
That is quite a common circuit.
The diodes can be replaced with a LED. One less part and you get a bonus power LED.