DSP-ASIC based voltage feedback switching regulator chip for electromechanical contactor

Industrial power control systems are developed rapidly toward more complex and highly integrated systems. One of the main switching components, an electromechanical contactor, has remained basically the same during the last 20 years. An electronic control device, described in this paper, improves the contactor stability and offers new features to the design of the motor control center. The heart of the control device is a digital, voltage controlled switching regulator, limiting the coil current to a safe value in the voltage range, which is three times the nominal voltage of the controlled coil. In the digital solution, the benefits of robust digital filter and PWM structures and Sigma Delta A/D-converter are combined to create a very small size control ASIC, which is able to operate in a noisy environment and to control reliably a nonlinear inductive load.<>