The present disclosure relates to a bus interface system including a bus line, master integrated circuitry (IC), and slave IC. The master IC is coupled to the bus line and configured to transmit the data signal to the slave IC through the bus line. The slave IC is coupled to the bus line so as to receive the data signal from the master IC and includes a supply capacitor, which is configured to store power from the data signal and provide a supply voltage to the slave IC. When the bus line is in the low state, the supply capacitor is isolated from the bus line. When the bus line is in the high state, the supply capacitor is allowed to extract power from the data signal on the bus line.