Allegro STA6940M无刷DC马达PWM驱动方案

Allegro 公司的STA6940M是带PWM控制的无刷DC马达驱动器,集成了低功耗CMOS兼容的逻辑(3.5V-5.5V)和大电流高压功率MOSFET输出,输出电流有固定的关断时间和PWM控制,工作电压从10V到40V,正常工作电流4A,最大电流8A.本文介绍了STA6940M主要特性和优势, 功能方框图和典型应用电路以及参考元件数值.

STA6940M: Brushed DC Motor Driver IC With PWM Control

Combining low-power CMOS-compatible logic with highcurrent, high-voltage power MOSFET outputs, the STA6940M provides complete control and drive for brush DC motors. It provides internal fixed off time, pulse-width modulation (PWM) control of the output current, rated for 4 A normal operating level.

The CMOS logic section provides four modes of operation: forward and reverse normal drive rotation, outputs-off free spin (coast), and electronic braking.

The innovative multi-chip internal structure separates the main logic IC (MIC) from the four N-channel power MOSFETs. This results in lower thermal resistance and greater efficiency.

PWM control allows constant-current control of output while reducing heat generation and power losses by providing fixed off-time dual decay modes. The internal charge pump ensures full power availability for switching.

STA6940M主要特性和优势:

▪ Power supply voltage, VBB , 44 V maximum, 10 to 40 V normal operating range

▪ Logic supply voltage, VDD , 3 to 5.5 V compatible

▪ Output current, IO ,4 A average, 8 A maximum

▪ Output elements are all N-channel MOSFETs to reduce losses

▪ Internal charge pump

▪ Forward, reverse, free, and brake control modes available

▪ Constant-current control:

▫ Off-time 35 μs, fixed (Slow Decay mode)

▪ Internal Overcurrent Protection (OCP) circuitry

▫ Off-time 142 μs fixed (Fast Decay mode)

▪ Internal Thermal Shutdown (TSD) circuitry

▪ ZIP type 18-pin fully-molded package (STA package)

图1.STA6940M功能方框图

图2.STA6940M典型应用电路

参考元件数值: