SLVSCP2F January 2015 – June 2020 DRV10975
PRODUCTION DATA.
After it is determined that the motor is stationary and after completing the motor initialization with either align or IPD, the DRV10975 begins to accelerate the motor. This acceleration is accomplished by applying a voltage determined by the open loop current setting (OpenLCurr[1:0]) to the appropriate drive state and by increasing the rate of commutation without regard to the real position of the motor (referred to as open loop operation). The function of the open loop operation is to drive the motor to a minimum speed so that the motor generates sufficient BEMF to allow the commutation control logic to accurately drive the motor.
Table 4 lists the configuration options that can be set in register to optimize the initial motor acceleration stage for different applications.
Description | Reg Name | ConfigBits | Min Value | Max Value |
---|---|---|---|---|
Open to closed loop threshold | SysOpt4 | Op2ClsThr[4:0] | 0.8 Hz | 204.8 Hz |
Align time | SysOpt4 | AlignTime[2:0] | 40 ms | 5.3 s |
First order accelerate | SysOpt3 | StAccel[2:0] | 0.3 Hz/s | 76 Hz/s |
Second order accelerate | SysOpt3 | StAccel2[2:0] | 0.22 Hz/s2 | 57 Hz/s2 |
Open loop current setting | SysOpt2 | OpenLCurr[1:0] | 200 mA | 1.6 A |
Open loop current ramping | SysOpt2 | OpLCurrRt[2:0] | 0.23 VCC/s | 6 VCC/s |