This paper deals with design of a digital circuit for the Maximum Power Point Tracking (MPPT), especially analysis of its energy consumption. The circuit is based on a widely used direct tuning algorithm called Perturb & Observe (P&O). The digital circuit was designed at Register Transfer Level (RTL) using the descriptive language Verilog. The proposed digital circuit was synthesized in standard 130 nm CMOS technology, where also Place and Route (P&R) was performed.