Abstract: A charging system supplies a charge current from a power supply to a power storing apparatus. A shunt resistor is connected to a charging path through which the charge current flows. An amplifier is configured to amplify a voltage across the shunt resistor. A controller is configured to control the charging circuit on a basis of an output from the amplifier. A power supplying circuit is configured to supply a drive voltage to the amplifier. The power supplying circuit includes a first feed path including a diode connected between an input terminal and a power supply terminal of the amplifier and a second feed path including a switch connected between the power storing apparatus and the power supply terminal of the amplifier. The switch is configured to be turned on when a charge voltage of the power storing apparatus exceeds a threshold voltage.

Abstract: The electricity storage device control circuit includes a voltage detector and a voltage controller. The voltage detector is configured to detect voltages of a plurality of electricity storage devices. The voltage controller is configured to individually control the voltages of the plurality of electricity storage devices by performing, based on a detection result by the voltage detector, at least one of discharging or charging of electrostatic energy stored in the plurality of electricity storage devices.

Abstract: To provide a signal transmission system which can increase the number of slave stations being coupled with a simple configuration, A master station 10 communicates with a plurality of slave stations 20 each having an antenna 25. The slave station 20 includes a frequency converter 26 for converting a signal of a radio frequency band received through the antenna into an intermediate frequency band signal, and an E/O converter 27 for converting an electrical signal into an optical signal. The master station 10 includes O/E converters 14a to 14c for converting signals received from the slave stations 20 into electrical signals, respectively, a synthesizer 17 for synthesizing the signals thus converted into the electrical signals and a frequency converter 18 for converting the synthesized signal into a radio frequency band signal.