Level shifting circuitry and corresponding enable signal generating circuitry provides improved leakage current control while eliminating the need for supplying reference voltage input in the enable signal generator. Also provided are a computer program or a computer program product, an arithmetic unit or a processing device, and a rechargeable battery charger or a rechargeable battery-operated device. Formation of droplets in the integrated droplet generator comprising FFDs with different dimensions of the microchannels occurs with strong coupling between the FFDs and produces droplets with varying sizes and size distributions. The valve connects the work-space and crankcase allowing the pressure to equalize when the mean pressure of the work-space exceeds the crankcase pressure by a predetermined amount.