Three-phase brushless motor controller ICs with sine wave drive

Toshiba Electronics has released two new three-phase brushless motor controller ICs based upon InPAC, the company's original automatic phase adjustment function.

This removes the need for phase adjustment and achieves high levels of efficiency at a wide range of motor rotation speeds. As a result, the devices can be used with motor drivers that have various voltages and current capacities as well as being used in combination with intelligent power devices at the output stages. The controllers (TC78B041FNG and TC78B042FTG) are intended for use in home appliances such as air-conditioners and air purifiers, and industrial equipment.

Manufacturers of home appliances and industrial equipment are increasingly using inverters to control fan motors, to meet market demand for improved energy efficiency and lower audible noise.

To obtain high-level efficiency in conventional systems, it is necessary to adjust the phase of the motor voltage and motor current for individual fan motors. Realising high efficiency over a wide range of rotational speeds — from almost zero rotations per minute (RPM) at start-up to high speeds of several thousand RPM — requires a large component count for phase adjustment. It also introduces the need for an MCU control system, which is complex and time-consuming to develop.

With the introduction of InPAC, Toshiba’s original new control technology, which automatically adjusts the phase of the Hall signal and motor current, the products are able to drive motors with an efficiency equivalent to that of an MCU control system, over a wide range of rotation speeds. InPAC delivers a high efficiency fan motor system with sine wave drive that reduces audible noise.

In addition, as the phase adjustment is performed automatically via simple settings, the lengthy development time for software and MCU adjustment is eliminated, thereby streamlining the development process. These controllers include a forward / reverse detection switch and motor lock detection. The number of pulses in the rotation pulse signal is selectable.

The TC78B041FNG is housed in a 7.6mm x 10.2mm x 1.6mm SSOP30 package and includes an error detection positive input. The TC78B042FTG is in a 5mm x 5mm x 1mm VQFN32 package and includes error detection on the positive and negative inputs.