Patent ID: 7804287
Filing Date: 2010-09-28
Classification: H03K

Abstract:
1. In an industrial controller comprising a power supply providing a supply voltage and at least one input/output module, wherein the input/output module has at least one current-loop circuit and a logic circuit, which, at least in part, supplies a command signal to each current-loop circuit, the command signal indicating a desired current level for a load connected to the current-loop circuit, the current loop-circuit comprising: at least one load terminal connectable to a load; a control input receiving the command signal from the industrial controller; a current sensor providing a measured current value received by the load through the load terminals; a switching circuit having at least one solid state switch, the switching circuit receiving an error output and a supply voltage and based on the error output periodically connecting the supply voltage to the load terminal to control the current to the load according to the command signal; a low pass filter having multiple stages, wherein: a feedback circuit receiving the command signal, the current value, and the anticipating signal to provide the error output; wherein all solid state switches of the switching circuit operate exclusively in a switching mode, being driven to either fully on or fully off states; and wherein current from the switching circuit connects to the load terminal without passing through any additional solid state switching elements not operated in a switching mode.