Overvoltage protection circuit, voltage detection circuit, comparator, charge/discharge control circuit, and semiconductor device

A comparator, comprising:

• a first comparison circuit including:
• a first input transistor including a gate to which a first input voltage is to be applied and a source connected to a first power supply terminal;
• a first transistor including one end connected to a drain of the first input transistor;
• a second transistor including a drain, a gate, and a source connected to the own gate of the second transistor, the second transistor being configured to supply a constant current to any one input transistor out of the first input transistor and a second input transistor;
• and
• a third transistor connected in cascade to the second transistor,
• the first comparison circuit being configured to supply a first comparison result signal to another end of the first transistor, the first comparison result signal including a signal level corresponding to whether a voltage applied to the gate of the first input transistor is higher than a threshold voltage of the first input transistor;
• a second comparison circuit including:
• the second input transistor including a gate to which a second input voltage proportional to the first input voltage is to be applied and a source connected to the first power supply terminal, the second input transistor being configured to transition from an OFF state to an ON state after the first input transistor in an OFF state transitions to an ON state in a process in which the first input voltage rises;
• and
• a fourth transistor including a drain, a gate, and a source connected to the own gate of the fourth transistor, the fourth transistor being configured to supply a constant current to another input transistor out of the first transistor and the second input transistor,
• the second comparison circuit being configured to supply a second comparison result signal to the drain of the another input transistor, the second comparison result signal including a signal level corresponding to whether a voltage applied to the gate of the second input transistor is higher than a threshold voltage of the another input transistor;
• and
• a bypass transistor including a gate connected to the gate of the first input transistor, a source connected to the own gate of the bypass transistor, a drain connected to a drain of the second input transistor, and a back gate connected to the first power supply terminal, the bypass transistor being configured to establish conduction between the own drain and the own source of the bypass transistor when a voltage exceeding a threshold voltage of the second input transistor is applied to the gate of the second input transistor.