JAJSSE7 November 2023 DRV8214
PRODUCTION DATA
The DRV8214 is a high-performance full-bridge motor driver with ripple counting for position detection, motor speed and voltage regulation, stall detection, integrated current sense, and integrated current regulation.
The Ripple Counting feature integrates DC motor relative position and speed detection 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. Motor speed regulation feature maintains constant motor speed over varying battery voltages. The voltage regulation feature saves energy by driving the motor with a programmable lower terminal voltage.
The DRV8214 uses a standard 2-pin (EN/IN1& PH/IN2) PH/EN-PWM interface and 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 240 mΩ (including one high-side and one low-side FET). Motor speed can be controlled with pulse-width modulation (PWM), at frequencies between 0 to 200 kHz. The PMODE bit in I2C registers allow operating the H-bridge in two different control modes. I2C interface reduces number of GPIO inputs in high motor-count systems and reduces firmware control effort.
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 DRV8214 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 0 V 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.