September 26, 2000

Development of a "SLA7611M" 3-phase stepping motor driver IC for OA equipment such as PPC and LBP -Integration into one-chip and one-package for the first time


Recently Sanken Electric Co., Ltd. developed a 3-phase stepping motor driver IC "SLA7611M" (operating power supply voltage range: 10~30 V, output current: 3 A MAX, product size: Width 31 x Height 16 x Thickness 5 mm) for PPC and LBP (laser beam printers), and began shipping samples starting on October 1.

Conventional 3-phase stepping motor driver ICs are one package which contain multiple chips, or multiple packages where the power section and control section are separate. In the new SLA7611M product, the control section and power section are integrated into a monolithic IC using our company's unique BCD process technology. By integrating into a single chip and package, we achieve significant miniaturization (about 75% reduction in volume) and lower cost compared with our company's previous products. Sample price is 800. We plan to start mass production in 2001, and to sell 500,000 units/year for the immediate future.

Stepping motors are frequently used to drive OA equipment, and currently the mainstream choice is a 2-phase stepping motor, due to the ease of design and low price. However, with the functional improvements in OA equipment, there is greater demand for smoother, higher speed motor rotation and motor construction with more phases. The 3-phase motor has appeared as an aspect of this move to more phases. The SLA7611M samples which we began to ship recently are ICs compatible with full-step and half-step -- the basic drive methods for 3-phase stepping motors. They have a built-in sequence circuit for driving the motor, and the motor can be rotated simply by inputting a speed clock, so software design is easy. Furthermore, the output element employs a DMOS structure which keeps loss and heat generation low, and operation is possible with minimal switching loss. The IC also has the following features.

[Product features]
(1) Low on-resistance (0.4) MOSFET is used for the output element
(2) Compatible with full-step and half-step drive
(3) Enables clock input system (forward/back rotation, hold, stop) control
(4) Employs total current control type self-exciting PWM control
(5) Built into compact Zip 18-pin molded package
In the area of ICs for driving 3-phase stepping motors, Sanken Electric began mass production in September of last year of a control IC (SI-7600/SI-7600ID) used in combination with a power section MOSFET array, and by placing this new product on the market, our plan is to work to raise our domestic share of all ICs for OA equipment motor drive from the current 60% (survey by our company) to 70%.

<REFERENCE>
BCD process technology
This is original Sanken technology for integrating bipolar (used for analog circuit control), quick-operating CMOS which is suitable for digital control circuits, and DMOS wafer process technology which is suitable for high current output. This allows incorporation of control circuits, sensor processing circuits and peripheral function circuits like microcomputers with our leading power semiconductors, so that multi-function devices can be integrated into a single chip.
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