What is a Switched-Capacitor Converter?
A typical switched-capacitor converter contains four large MOS switches, which are switched in a sequence to typically invert, double, or halve the input supply voltage. Energy transfer and storage are provided by external capacitors. During the first part of the switching cycle, the input voltage is applied across one capacitor (C1). During the second part of the switching cycle, the charge from C1 is transferred to a second capacitor C2. The most traditional switched-capacitor converter configuration is an inverter, where C2 has its positive side referred to ground, and its negative side delivers the negative output voltage. After a number of cycles, the voltage across C2 will be pumped up to the input voltage. Assuming no load on C2, no loss in the switches, and no series resistance in the capacitors, the output voltage will be exactly the negative of the input voltage. In reality, the charge transfer efficiency (and thus the output voltage accuracy) depends on the switching frequen
