ST aims to be the leader in multimedia convergence applications and power solutions, offering one of the world’s broadest product portfolios, including application-specific products containing a large proprietary IP content and multi-segment products that range from discrete devices to high-performance microcontrollers, secure smart card chips and MEMS (Micro-Electro-Mechanical Systems) devices.
The Company provides solutions for a wide array of Digital Consumer applications, with a particular focus on set-top boxes, digital TVs and digital audio, including radio. In the Computer Peripherals arena, ST provides leading solutions in data storage, printing, visual display units, power management for PC motherboards, and power supplies. A wide range of ST’s ASSPs power sophisticated Automotive systems such as engine control, vehicle safety equipment, door modules, and in-car infotainment The Company also supplies industrial ICs for factory automation systems, chips for lighting, battery chargers and power supplies, as well as chips for advanced Secure Access applications.
Motor controllers can be manually, remotely or automatically operated. They may include only the means for starting and stopping the motor or they may include other functions.
An electric motor controller can be classified by the type of motor it is to drive such as permanent magnet, servo, series, separately excited, and alternating current.
A motor controller is connected to a power source such as a battery pack or power supply, and control circuitry in the form of analog or digital input signals.
PWM controls use pulse width modulation to regulate the current sent to the motor. Unlike SCR controls which switch at line frequency, PWM controls produce smoother current at higher switching frequencies, typically between 1 and 20 kHz. At 20 kHz, the switching frequency is inaudible to humans, thereby eliminating the hum which switching at lower frequency produces. However, some motor controllers for radio controlled models make use of the motor to produce audible sound, most commonly simple beeps.
A PWM controller typically contains a large reservoir capacitor and an H-bridge arrangement of switching elements (thyristors, Mosfets or transistors).
An H-bridge is an electronic circuit which enables a voltage to be applied across a load in either direction. These circuits are often used in robotics and other applications to allow DC motors to run forwards and backwards. H-bridges are available as integrated circuits, or can be built from discrete components.
A stepper motor (or step motor) is a brushless, synchronous electric motor that can divide a full rotation into a large number of steps. The motor's position can be controlled precisely, without any feedback mechanism (see
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