SLVSEE8B November 2019 – May 2021 DRV8899-Q1
The DRV8899-Q1 device is an integrated motor-driver solution for bipolar stepper motors. The device integrates two N-channel power MOSFET H-bridges, integrated current sense and regulation circuitry, and a microstepping indexer. The DRV8899-Q1 device can be powered with a supply voltage from 4.5 to 45 V and is capable of providing an output current up to 1.7-A peak, 1-A full-scale, or 0.7-A root mean square (rms). The actual full-scale and rms current depends on the ambient temperature, supply voltage, and PCB thermal capability.
The device uses an integrated current-sense architecture which eliminates the need for two external power sense resistors. This architecture removes the power dissipated in the sense resistors by using a current mirror approach and using the internal power MOSFETs for current sensing. The current regulation set point is adjusted by the voltage at the VREF pin. These features reduces external component cost, board PCB size, and system power consumption.
A simple STEP/DIR interface allows for an external controller to manage the direction and step rate of the stepper motor. The internal indexer can execute high-accuracy microstepping without requiring the external controller to manage the winding current level. The indexer is capable of full step, half step, and 1/4, 1/8, 1/16, 1/32, 1/64, 1/128 and 1/256 microstepping. In addition to a standard half stepping mode, a noncircular half stepping mode is available for increased torque output at higher motor RPM.
The current regulation is configurable between several decay modes. The decay mode can be selected as a slow-mixed, mixed decay, smart tune Ripple Control, or smart tune Dynamic Decay current regulation scheme. The slow-mixed decay mode uses slow decay on increasing steps and mixed decay on decreasing steps. The smart tune decay modes automatically adjust for optimal current regulation performance and compensate for motor variation and aging effects. Smart tune Ripple Control uses a variable off-time, ripple control scheme to minimize distortion of the motor winding current. Smart tune Dynamic Decay uses a fixed off-time, dynamic decay percentage scheme to minimize distortion of the motor winding current while also minimizing frequency content.
The device integrates a spread spectrum clocking feature for both the internal digital oscillator and internal charge pump. This feature combined with output slew rate control minimizes the radiated emissions from the device.
A torque DAC feature allows the controller to scale the output current without needing to scale the VREF voltage reference. The torque DAC is accessed using a digital input pin which allows the controller to save system power by decreasing the motor current consumption when high output torque is not required.
A low-power sleep mode is included which allows the system to save power when not actively driving the motor.