Patent ID: 8368429

Claim:
A hysteresis comparator, comprising: a reference voltage generating unit to be applied with a first voltage on one end side, the reference voltage generating unit to divide the first voltage by use of a plurality of resistors, the reference voltage generating unit to generate a reference voltage; a comparison amplifying unit provided between a high potential power supply and a low potential power supply, the comparison amplifying unit having first and second transistors composing of a differential pair, the first transistor having a gate receiving an input voltage, the second transistor having a gate receiving the reference voltage; a third transistor provided between the other end of the reference voltage generating unit and the low potential power supply; a fourth transistor provided between the high potential power supply and the low potential power supply, the fourth transistor having a gate receiving an output signal of the comparison amplifying unit; a first current source having one end connected to the high potential power supply, the first current to allow a first current to flow to the other end side; a fifth transistor having a first terminal connected to the other end of the first current source, the fifth transistor being diode-connected; a sixth transistor provided between a second terminal of the fifth transistor and the other end of the reference voltage generating unit, the sixth transistor having a gate connected to a gate of the third transistor and a first terminal of the forth transistor, the sixth transistor to connect between the second terminal of the fifth transistor and the other end of the reference voltage generating unit based on a potential of the first terminal of the fourth transistor; a second current source having one end connected to the high potential power supply, the second current source to allow a second current to flow to the other end side, the second current being n times (n is 2 or larger) as large as the first current; a seventh transistor having a first terminal connected to the other end of the second current source, the seventh transistor having a gate connected to a gate of the fifth transistor, the seventh transistor to constitute a current mirror circuit with the fifth transistor, the seventh transistor to output an output voltage; and eighth and ninth transistors provided between a second terminal of the seventh transistor and the low potential power supply, the eighth and ninth transistors being cascade-connected, the eighth and ninth transistors to turn on during an operation of the comparison amplifying unit.