SLVSHN2 July 2024 DRV8962-Q1
PRODUCTION DATA
The following schematic shows the DRV8962-Q1 driving a stepper motor.
The full-scale current (IFS) is the maximum current driven through either winding. This quantity will depend on the VREF voltage and the resistor connected from IPROPI pin to ground.
IFS x AIPROPI = VVREF / RIPROPI
The maximum allowable voltage on the VREF pins is 3.3 V. DVDD can be used to provide VREF through a resistor divider.
The IFS current must also follow Equation 4 to avoid saturating the motor. VM is the motor supply voltage, and RL is the motor winding resistance.
If the target motor speed is too high, the motor will not spin. Make sure that the motor can support the target speed.
For a desired motor speed (v), microstepping level (nm), and motor full step angle (θstep), determine the frequency of the input waveform as follows -
θstep can be found in the stepper motor data sheet or written on the motor itself.
The frequency ƒstep gives the frequency of input change on the DRV8962-Q1. 1/ ƒstep = tSTEP on the diagram below. Equation 6 shows an example calculation for a 120 rpm target speed and 1/2 step.
Connect the IPROPI outputs corresponding to the same H-bridge together. IPROPI1 and IPROPI2, when connected together, reprsent the current of coil A of the stepper (connected between OUT1 and OUT2) during drive and slow-decay (high-side recirculation) modes. Similarly, IPROPI3 and IPROPI4, connected together, will reprsent coil B current.
When two IPROPI pins are connected together, the effective current mirror gain will be 424 μA/A typical. The resistor from the combined IPROPI pin to ground should be selected accordingly.