Smooth Motor Rotation

Issue & Solution

Issue ...

Achieving cost reduction of the PCB motor

Cost reduction is now trending for manufacturers of motor boards for multifunction printers, (MFP). There are multiple stepping motors used for feeding paper, etc.

Costs for MFP motor boards is quite high due to the amount of needed motors.

Stepping motors are used for paper handling, paper feeding, finishers, sorters, and scanners in MFPs.

Proposals were required to reduce total costs of motor units.

Then what is our solution…

Low-heat Stepping Motor Drivers Reduce PCB Layers

Board cost can be reduced by moving from a 4 layer board to 2 layer board.

Even the scanning section benefits from smoother motor rotation.

AKM's Motor Driver with its low heat generation makes 2 layer boards possible.

Comparing AKM's AP103x and a competitors part with thermography shows AKM's high-efficiency motor driver generates less heat. This opens the possibility of a 2-layer board from 4-layer, which reduces BOM cost. Furthermore, the scanning parts gains the additional benefit of smoother rotation than the competition using the AKM motor.

The AP103x series is a highly efficient driver IC which adopts AKM's original, "Active Decay Control", method. This is the optimal control method, which reduces current ripple. The maximum output current is 2.0A/1.5A/1.0A. 4mm, 24-pin or 5mm, 32 pin QFN packages are available.

High Efficiency with Low Heat Generation

With AKM's unique, "Active Decay Control", which constantly monitors motor current with fast-decay when current exceeds a target level, a reduction of current ripple occurs while maintaining capable current. This drives a motor highly efficiently while suppressing heat generation.

Smooth Motor Driving with Low Vibration

The AP103x is capable of both high precision current control and micro stepping drive for 2W1-2 phase excitation from 2 phase excitation. It features smooth motor rotation and low vibration.

Active Decay Control

Reduce Man-hours in Design

"Active Decay Control", adjust motor current automatically. Therefore, design time can be reduced with the elimination of the Decay setting controlled by external parts.

Reduce Man-hours in Design

Rotational Distortion step= 800Hz/W1・2 phase excitation

*AVG: Averaging value of Encoder Output Frequency

α: Frequency Variation


Stepping Motor Driver IC


DC Motor Driver IC

Low Heat + Smooth Motor Rotation

Motor Drivers

AKM has stepping motor driver lineups that cover wide voltage and current ranges with protection functions for both bipolar and unipolar motors. Various input interfaces are available such as parallel interface, clock-in interface and serial interface with speed control function.

Active Decay Control

- High Speed response & Low Current Control -

Low Heat + Smooth Motor Rotation by Fast Decay Control

Time Optimization of Fast Decay mode reduces package heat generation. It is possible to reduce the number of substrate layers and down size the system due to low heat generation.

15 to 20°C lower than the competitors!

Competitor A/B

H-Bridge Operation Sequence

Since the Fast Decay mode is operated only when it is necessary, heat generation will be suppressed. Therefore the total cost can also be suppressed (4 layers → 2 layer board etc.).

Smooth Motor Rotation

Current ripple is suppressed by executing Fast Decay operation only when necessary, which will achieve smooth motor rotation.

Motor current is constantly monitored and Fast-decay mode is executed only when the current exceeds the target value. Low power consumption, less unevenness of the motor rotation and less vibration are achieved. The motor torque performance is improved with smooth rotation.

Current Control Image

Ripples of traditional type are not small because Fast Decay operation is executed periodically. Since Active Decay controls while maintaining responsiveness, ripples can be kept small.

Active Decay Control
Traditional Control

No External Parts, no individual motor setting

Require No External Parts for Decay Setting. Individual motor setting is not necessary.