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Solution InstaSPIN-BLDC Slide 15
If one motor requires more current than can be delivered by the DRV8312, then consider using the DRV8301 board. Now, the DRV8301 is just a gate driver. It does not actually have the integrated power FET inside of it and that allows any power FETs to be hooked up to this device. On this particular board which runs at 50 volts, the power FETs are rated for 120 amps. So, this will be able to muscle its way through quite a big motor load. Now, take a look at the diagram shown here and one can actually see what the DRV8301 looks like and how it is typically connected up in a power circuit. It has the PWMs that are coming from the motor controller which can be selected to be either 3 or 6 because it does have its own integrated dead-time generator if that feature is chosen. Also, over on the three-phase NMOS gate driver outputs, a high side charge pump is being used which allows 100% duty cycle to be achieved on the PWMs if that is to be used. The dual feedback off amps used are actually pretty fast. They allow 1% settling times as low as 300 nanoseconds and that is partly due to the fact that the slew rate of these amplifiers is 10 volts per microsecond. So, for all applications except for the ones that require extremely high switching frequencies, these amplifiers should be good enough. Also, notice the designer does not need to have a separate power supply for the microprocessor. Actually there is a bump converter that will actually supply the voltage for the processor. So, again, this is a very integrated solution, a very complete solution and it allows to scale the output stage to whatever power requirements that is needed by selecting the FETs to drive the motor.
PTM Published on: 2013-01-24