The mechanical subsystems of mechatronic products use many stepping motors, which consume excessive current so as not to go out of step and therefore generate much heat.
Active gain control (AGC) uses a simple technique to solve this problem, enhancing the value of products.
To provide sufficient margin for the motor torque required, motor control drivers (MCDs) generally supply a motor drive current greater than the peak current at the maximum load. This means that extra current continues flowing all the time. In order to minimize unnecessary current consumption, a sensor or a microcontroller is used to monitor the changes in load conditions, thereby adjusting a motor drive current according to the load conditions. This feedback process requires extremely complicated control. Toshiba offers motor driver ICs incorporating AGC technology, which sense a motor's load torque and automatically optimize a motor drive current. This makes it possible to prevent a motor from going out of step while simplifying high-efficiency motor control.
AGC technology automatically adjusts a motor drive current according to a motor's load conditions in order to reduce extra current, thereby considerably reducing the amount of heat generated by the motor driver IC and the motor. This helps reduce overall heat generation in a system and the resulting degradation.
Toshiba offers an extensive lineup of stepping motor drivers fabricated using a BiCD process that provides high accuracy and high-current capability. Toshiba's stepping motor drivers are available in bipolar and unipolar configurations.
(*1) TB67S105 & TB67S145 不支援 micro-stepping
廣泛的產品陣容
高階技術提供客戶解決方案需求及問題
Toshiba's original ADMD technology tracks input current more closely than the conventional mixed-decay mode, making highly efficient motor control possible at high rpm.
Toshiba's original ACDS technology enables motor drive with highly accurate constant current without requiring external current-sensing resistors.
The reduced part count also helps reduce the board area and the bill-of-material (BOM) cost.
AGC is Toshiba’s unique stepping motor technology to automatically optimize the drive current in real time according to load torques. It helps reduce unnecessary current and drastically cut power consumption and heat generation.
It has built-in circuits for detecting abnormalities such as low-voltage (UVLO), overcurrent (ISD), and overheating (TSD).
This makes it possible to build a highly reliable system.
(Note: The built-in error detection function differs depending on the product.)
Whereas the full-step drive turns the currents of the two windings on and off and rotates them by a fixed angle, the micro-step drive can rotate them at a step angle finer than the basic step angle by changing the current ratio of the two windings in a stepwise manner.
The range is 1/4, 1/8, 1/16, 1/32, and 1/64 (steps).
The step angle is 360 degrees divided by the total number of poles.
For the four poles, 360 degrees/4 = 90 degrees.
Assuming there is a 36-pole motor, 360 degrees/36 = 10 degrees, and the single-step operating angle of the full-step mode is 10 degrees.
One step angle of the half-step mode is 1/2 of the full-step mode.
One step angle of the micro-step mode can be selected to be 1/4 of the full-step mode and a finer step angle.
(Example 1/4)
Fabricated using a state-of-the-art high-voltage analog process (130-nm BiCD process), Toshiba's stepping motor drivers combine low-voltage control circuitry with high-voltage DMOS output drivers on the same monolithic structure. Consequently, high-voltage motor drivers rated at 84 V can be housed in the small WQFN48 (7 mm × 7 mm) package, which helps reduce the solution size.
Toshiba offers various stepping motor drivers that deliver the substantial benefits of AGC. Stepping motor drivers with a clock input and those with a phase input are both available. If you want to evaluate your product plan or design using a stepping motor incorporating AGC technology, reference designs are available for download.
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