Current detection circuit and power supply semiconductor integrated circuit

A power supply semiconductor integrated circuit, comprising:

• one input terminal and a plurality of output terminals;
• a plurality of current control transistors connected respectively between the input terminal and the plurality of output terminals;
• a control circuit for controlling the plurality of current control transistors;
• a plurality of current detection circuits that detect an open state or a short state of the respective plurality of output terminals by converting each of a current and a predetermined reference current into a voltage and comparing the voltage, the current being proportional to a current flowed in the plurality of output terminals by the plurality of current control transistors;
• an external terminal for connecting an external resistor;
• and
• a reference current generation circuit that generates the reference current in accordance with a voltage of the external terminal generated by flowing a current in the external resistor, wherein
• each of the plurality of current detection circuits includes:
• a first transistor including a control terminal to which a same voltage as a voltage applied to a control terminal of the current control transistor is applied;
• a first current-to-voltage converter that converts a current flowing in the first transistor into a voltage;
• a comparator including one input terminal to which a detection voltage converted by the first current-to-voltage converter is input and the other input terminal to which the voltage that is current-to-voltage converted from the reference current is input as a comparison reference voltage;
• and
• a hysteresis circuit for providing hysteresis to a comparison operation of the comparator,
• the hysteresis circuit includes:
• a current source circuit that generates a current of a predetermined magnitude that is added to or subtracted from the current flowing in the first transistor;
• and
• a switch connected in series with the current source circuit, and
• the switch is switched to an on state or an off state by an output of the corresponding comparator, thereby a current flowing in the first current-to-voltage converter is increased or decreased by an amount of the current of the current source circuit, and the detection voltage changes relative to the comparison reference voltage and thereby the hysteresis circuit provides hysteresis to the comparison operation of the comparator.