Brushless Motor Pre-Driver IC for Start-Stop Automotive Applications

Toshiba Corporation announced the launch of TB9080FG, a three-phase brushless motor pre-driver IC for general automotive applications, which realizes low-noise and highly efficient motor operation through a sinusoidal wave drive and lead angle control. Mass production is scheduled to start in September this year (annual production volumes are expected to reach 3 million units). Engine noise in vehicles equipped with an idling reduction system (so-called "start-stop" operation) disappears when the system is activated, with the effect of making noise from car air conditioners much more audible.

Demand for a method to cut air conditioner noise is increasing, but mechanical solutions, such as optimization of blade shape in blower fans, the major noise source, and noise absorbent material in air ducts, fall short of realizing low noise. The TB9080FG replaces 120-degree rectangular wave control with sinusoidal wave control that cuts noise from the blower fan motor electronically. Optimized lead angle control also contributes to the increased efficiency of the motor operation.

Specifications of the new pre-driver ICs include: 6 channels (boost dc-dc high side with 3 channels and low-side with 3 channels); 50 microAmps of sleep current; an operating voltage range of 7-18 Vdc; an operating temperature range of -40 to +125 degrees C; an external pwm ratio or dc input voltage value is used as the targeted rotational speed to which the IC compares the actual rotational speed as measured by a hall sensor; protection features include over-current detection, over-temperature detection, over-voltage protection, low-voltage detection of Vcc, internal and external temperature detection, external temperature limiter circuit and motor lock detection. The TB9080FG is packaged in a LQFP64 (12mm × 12mm × 1.4mm).

Key features of the TB9080FG include: Use of a third harmonic wave realizes sinusoidal wave control, contributing to quieter motor operation. Digital filter circuits control external pwm signal, securing a slow motor start that avoids overshoot. A built-in data table supports use of motors with a range of pole numbers, from 4 to 12 poles. Motor current is measured and the lead angle automatically controlled in 1 degree increments, contributing to motor operation efficiency. Motor rotation speed is controlled by comparing the target figure and the signal from external hall element sensors.