Slide 1 Slide 2 Slide 3 Slide 4 Slide 5 Slide 6 Slide 7 Slide 8 Slide 9 Slide 10 Slide 11 Slide 12 Slide 13 Product List
Motor Signal Chain Overview Slide 3

The drive stage circuit is responsible for amplifying the control signal to the proper current and voltage level required to spin the motor. The ideal drive stage is efficient, linear, and introduces very little distortion. High efficiency minimizes power loss in the FETs while high linearity and low distortion insure accurate control over the motor. Any distortion or non-linearity introduced into the control signal by the drive stage will negatively affect motor performance. There are several common drive stage architectures including discrete gate drivers plus FETs, pre-driver plus FETs, integrated motor drivers, and integrated power modules (AKA IPMs). Pre-drivers typically integrate the gate drivers, protection, current sense amps and sometimes power management. Integrated motor drivers integrate the gate drivers, protection, FETs and often times current regulation and control circuitry. IPMs are high voltage / high current drive stage modules that are composed of gate drivers, FETs, and often times protection and current sensing circuitry. The advantages of using external FETs include higher current and better thermal performance due to the lower RDSON of the discrete FETs and the ability to scale output current by selecting different rated FETs for different applications. Integrated drivers on the other hand take up less board space, have lower BOM counts, are higher performance, have robust protection, and are very simple to design with. Customers need not worry about the design complexities and challenges of a discrete drive stage – everything is taken care of with an integrated driver. IPMs are also very easy to design with, especially when dealing with high voltage / high current applications, but can be costly.

PTM Published on: 2011-06-15