COMPARATOR CIRCUIT WITH HYSTERESIS

PURPOSE:To attain ease of circuit integration by forming a hysteresis value through the use of the ON-resistance of a MOSFET to decrease an error because it is not required to employ a resistor manufactured by a different process. CONSTITUTION:MOSFETs Q10, Q11 controlled at a Vctl terminal are located between a 1st input IN1 and an output OUT. With the MOSFETs Q10, Q11 turned off, an output voltage is simply increased or decreased depending on the quantity of the 1st input IN1 and a second input IN2. When the MOSFETs Q10, Q11 are turned on, the circuit acts like a comparator circuit having a hysteresis depending on the ON-resistance ratio of the MOSFETs. Thus, whether or not hysteresis is provided is selected freely and since the ratio of the ON- resistance depends only on the size of the MOSFETs Q10, Q11, the more excellent ratio is obtained in the circuit manufactured by one and same process like an integrated circuit.