In practical applications of automatic control theory, one often deals with situations where the controls must range in some domain, in particular, take only nonnegative values. In this case, popular synthesis methods such as modal and optimal control are not applicable. We propose methods for stabilizing the output variables in linear time-invariant SISO systems under nonnegative (unilateral) control constraints. The main idea is to implement the controls in the form of saturated linear functions whose saturation values coincide with the constraints on the controls. As an illustration of our algorithms, a pulsed DC voltage converter with an on/off switch control is considered. The results of simulation in Matlab Simulink are presented.