The document analyzes sleep mode energy consumption in CMOS circuits using power gating switches. It proposes adding power gating switches to an 8-bit arithmetic logic unit (ALU) circuit to reduce leakage current and sleep energy. Simulation results show that leakage current in the ALU is reduced from 5.914mA without power gates to 0.78mA with power gates added. Power gating switches help minimize leakage paths and cut off power to inactive circuit parts, significantly lowering sleep mode energy usage.