Constant-current regulator with redundant bus control

Abstract

A constant-current regulator regulates and monitors the current fed to one or more downstream loads. It also serves to even out the current fed to the downstream load or loads at the control level or when there is a change in the control level. In order to enhance the security and reliability of operation of such a constant-current regulator when installed in a control and monitoring circuit, control signals having a similar regulating/monitoring content are applied to the constant-current regulator by means of two separate busses (3, 4) in a mutually independent manner. The constant-current regulator is used to carry out a separate plausibility/conformity check of the control signals from the first bus (3) and the control signals from the second bus (4). If a lack of plausibility/conformity is ascertained for the control signals of the first bus (3), the control signals of the second bus (4) are taken as the basis for operation of the constant-current regulator. On the other hand, if a lack of plausibility/conformity is ascertained for the control signals of the second bus (4), the control signals of the first bus (3) are taken as the basis for operation of the constant-current regulator.