SLVSHO5 April 2024 DRV8215
PRODUCTION DATA
The DRV8215 is a high-performance integrated H-bridge motor driver with integrated speed and voltage regulation along with additional integrated features like stall detection, current sense output, current regulation, and protection circuitry.
The integrated speed regulation feature maintains maintains constant motor speed over varying battery voltages. The voltage regulation feature saves energy by driving the motor with a programmable lower terminal voltage. control in the device thereby reducing external components on a PCB and saving cost. The principle is based on counting the number of current ripples appearing in the motor current waveform due to commutations.
The DRV8215 contains PWM and PH/EN interfaces along with an I2C interface for configuration and detailed diagnostics. The EN/IN1 & PH/IN2 pins control the full bridge, which consists of four N-channel MOSFETs that have a typical RDS(ON) of 240mΩ (including one high-side and one low-side FET). Motor speed can be controlled with pulse-width modulation (PWM), at frequencies between 0 to 200kHz. The PMODE bit in I2C registers allows to control the H-bridge solely through I2C commands, reducing the number of GPIO inputs.
The integrated current regulation feature limits motor current to a predefined maximum based on the VREF and IPROPI settings. The IPROPI signal can provide current feedback to a microcontroller during both the drive and brake/slow-decay states of the H-bridge. The gain select bits allow high accuracy current sensing down to 10 mA average motor current. The RDS(ON) of the low-side MOSFET and the overcurrent protection limit changes according to the gain select bits, thereby leading to optimized solutions for different values of motor current. The DRV8215 also has I2C programmable registers to configure a hardware stall detection feature based on the IPROPI current sensing signal.
The integrated protection features protect the device in case of a system fault. These include undervoltage lockout (UVLO), overcurrent protection (OCP), and overtemperature shutdown (TSD). Fault conditions are indicated on the nFAULT pin. Additionally, the overvoltage protection (OVP) feature puts the driver into the brake state when the motor is spun manually while the device is in sleep mode or when the H-bridge is disabled. This prevents the back EMF induced high voltages on the supply rail that could potentially damage the driver and other circuits in the system.
To reduce area and external components on a printed circuit board, the device integrates a charge pump regulator and the corresponding capacitors. The separate full-bridge (VM) and logic (VCC) supplies allow the full-bridge supply voltage to drop to 0V without significant impact to RDS(ON) and without triggering UVLO as long as the VCC supply is stable. The nSLEEP pin provides an ultra-low power mode to minimize current draw during system inactivity.