Sep 11, 2013 
Contributes to reduced noise and size, minimizes rotational variations in single-phase fan motors.
LAPIS Semiconductor Co., Ltd., a ROHM Group Company, has recently developed 8-bit microcontrollers equipped with an oscillator circuit that provides more than twice the accuracy compared with previous models.
The ML610Q101 and ML610Q102 utilize motor control technology optimized for controlling rotation in single-phase fan motors. In addition, the industry-leading high-accuracy oscillator circuit reduces rotational variations, while multiple timers minimize noise.
A hysteresis differential comparator*１ is also built in that allows a Hall element to be used, contributing to lower costs. Additional features include a compact 16pin package 4mm X 4mm, ensuring compatibility with small fans, and high noise immunity (cleared the ±30kV level in IEC61000-4-2 noise testingr*2 ), making them ideal for applications with demanding noise requirements, such as industrial equipment.
In recent years, as electronic equipment becomes more compact, devices such as PCs and servers require smaller cooling fan motors. CPU servers that process large amounts of data often utilize multiple cooling fans, and if there are variations in the rotation of each fan a buzzing sound can be generated due to differences in the wind noise frequencies. Also, if the change in current during ON/OFF switching in the motor coil current control is too large, irritating electromagnetic noise can result. Overcoming these obstacles requires smaller microcontrollers with high accuracy rotational control.
In response, LAPIS Semiconductor has developed an integrated oscillator circuit and a regulator for logic power supply that does not require external capacitance, providing a two-fold improvement in oscillator accuracy compared with conventional models – the highest in the industry. This minimizes rotational variations with single-phase fan motor rotation control, while numerous timers provide quiet, high efficiency performance through soft switching*3operation. As a result, the number of parts required can be reduced, since there is no need to add an external oscillator or capacitors for the logic power supply regulator. Plus, the compact package enables smaller mounting boards to be used.
Carefully designed circuit and layout have enabled high noise immunity, making it possible to clear the ±30kV level, which exceeds the measurement limit of Class 4 (±15kV), the highest class defined by the IEC61000-4-2 standard established by the IEC (International Electrotechnical Commission). This makes the LSIs suitable for use in industrial equipment with stringent noise requirements
A complete support system is provided, including an ML610Q102 reference board and software development environment that make it easy to begin evaluation of the ML610Q101 and ML610Q102. Manuals, support tools, and other materials are also offered on our website (registration required).
