Electric circuit, charge control device, charge system, and control method

A charge system, comprising:

• a secondary battery that charges and discharges power;
• detecting means for detecting a state of the secondary battery;
• an electric circuit including a semiconductor switch that is inserted in a positive side power line connected to the secondary battery, and converting means for converting an input voltage input to an input side terminal to a predetermined output voltage and for outputting the output voltage from an output side terminal, the output side negative terminal of the converting means being connected to the positive side power line, and the output side positive terminal of the converting means being connected to a terminal that controls an opening and closing of the semiconductor switch;
• and
• control means for controlling a switching of the semiconductor switch by controlling the on and off states of the output voltage of the converting means provided to the electric circuit,
• wherein the control means acquires the state of the secondary battery detected by the detecting means, and controls the switching of the semiconductor switch according to the state of the secondary battery.

An electric circuit, comprising:

• a semiconductor switch that performs switching between conduction and disconnection of a switching object line;
• and
• a control circuit that supplies a switching control signal, which represents a control potential for the switching, to the semiconductor switch as a potential difference signal with respect to a reference potential of the semiconductor switch, and that controls the switching,
• wherein the reference potential of the semiconductor switch is consistent with a potential of the switching object line, and
• the control circuit generates the switching control signal according to an input control signal input as a potential difference signal with respect to a potential different from the potential of the switching object line.

An electric circuit, comprising:

• a semiconductor switch that with respect to a power line that supplies power by a potential difference between a reference potential line showing a reference potential and an applied potential line showing an applying potential, sets at least one of the reference potential line and the applied potential line as a switching object line and that performs switching between conduction and disconnection of the switching object line;
• and
• a control circuit that supplies a switching control signal, which represents a control potential for the switching, to the semiconductor switch as a potential difference signal with respect to a reference potential of the semiconductor switch, and that controls the switching,
• wherein the reference potential of the semiconductor switch is consistent with a potential of the switching object line, and
• the control circuit generates the switching control signal according to an input control signal input as a potential difference signal with respect to the same potential as that of the reference potential line.