Hi All,
Here is a question about the current limit if the LT1166. My circuit is almost the same as Figure 9. in the datasheet
and I have attached it. I'd like the current limit to work more than 1A so I selected the 1.3 ohm Rsense.
However the output current clamped about 3.6A peak as attached LTSpice simulation result [V(n012)=Vin, V(n009)=Vout, I(R9)=Iout]. Why is not the output current clamped about 1A? Is my understanding about the current limit function wrong?
Regards,
Kazu
The current limit function is not a smooth function, but rather a hysteretic trip point (and not very precise) that shuts down the output stage for a period of time set by capacitances in the circuit (was only intended to minimize FET stress in a fault condition). If you have a specific current limit in mind, it isn’t too hard to add a transistor to each FET that will form a fast limiter function (the sense resistor could turn on a Vbe and the transistor collector could shunt away gate current from the FET).
If fairly accurate and/or variable current control is of interest, one might consider an LT1970-based circuit.