Next-generation new stepper motor driver IC

Toshiba Electronics Europe GmbH has launched the TB67S579FTG, a next-generation stepper motor driver IC featuring Advanced Microstep Technology. This two-phase, bipolar stepper motor driver utilises a constant current control method. With its advanced functions, it achieves high efficiency, low vibration, and low noise in motor operation. Target applications include office equipment, such as printers and scanners, as well as a wide range of commercial and industrial equipment, including surveillance cameras, projectors, ATMs, 3D printers, sewing machines, and many more.

The high-efficiency stepper motor driver IC is the company's first product featuring the newly developed Advanced Microstep Technology, including three key functions: second-generation Active Gain Control (AGC2), the newly developed Automatic Wave Generation System (AWGS), and the newly developed Continuous Microstepping. Continuous Microstepping significantly reduces vibration and noise, especially during low-speed rotation, by creating a continuous, sinusoidal motor drive current waveform.

Typical microstep control methods need increasing the input clock (CLK) frequency in proportion to the number of microsteps. Automatic Wave Generation System (AWGS) is a function that allows driving a stepper motor in microstepping mode using a single CLK signal as needed for full-step rotation control. Even in applications where a stepper motor is initially driven in full-step mode, to quickly generate torque and then switch to microstepping for lower vibration and noise, a smooth transition can be achieved without the need to adjust control signals. As a result, the processing load on control devices such as MCUs can be significantly reduced.

Generally, a stepper motor is continuously driven at the maximum current needed under peak load conditions. Active Gain Control (AGC2) detects the induced voltage during motor operation to determine the load and automatically adjusts the required motor drive current. This mechanism enables the motor to operate with the minimum required current under light-load conditions, allowing for higher efficiency and, therefore, lower power consumption. AGC2 also improves the current waveform and torque by realising a 'full' full-step operation.

In addition to the conventional GPIO configuration interface, the device offers a flexible serial configuration interface, enabling easy adjustment of advanced features such as microstepping, AGC2, and decay modes without increasing pin count or system complexity.

The device's output stage (covering the upper and lower transistors) has an RDS(ON) of just 0.6Ω (typ.). When in sleep mode, the device draws a maximum current of 1µA. To simplify system integration, the driver operates with a single motor power supply, ranging from 4.5V to 34V. The product also employs the company's Advanced Current Detection System (ACDS), eradicating the necessity for external current sense resistors. The built-in charge pump circuit does not require an external capacitor. Eliminating the need for these external components enables substantial space savings in the mounting area and reduces the BoM cost.

Additional features include Advanced Dynamic Mixed Decay (ADMD), which can achieve up to 30% higher rotation speed without increasing noise and vibration. The driver IC also implements comprehensive protection functions, including overcurrent detection, thermal shutdown, under-voltage lockout, error flag output, and open-load and stall detection. The integrated stall detection function reliably identifies motor lock conditions, enhancing operational safety and preventing potential damage to mechanical components and electronics.

The TB67S579FTG is housed in a small VQFN48 package, measuring just 7mm x 7mm.