One of the important properties of physical systems is reliability.of their functioning, in particular, reliability of functioning of logical control components of the systems. A new approach to partially programmable circuit design that allows masking stuck-at faults at gate poles of logical circuits is considered. The logical circuit consists of gates. It is supposed that only one gate pole may be fault. There are reserved programmable blocks configurable logic blocks (CLBs) based on Look Up Table (LUT) technology that may mask the fault. First, the suggested approach in contrast to the well-known ones, allows masking any stuck-at fault rather than a part of them. Second, the approach is oriented to deriving more simple masking circuit from CLBs based on a compact description of incompletely specified functions of subcircuits.