SCHMITT CIRCUIT

摘要

PURPOSE:To attain ease of setting of hysteresis width and DC bias by using a differential amplifier and a current mirror circuit so as to make the hysteresis width constant independently of the change in a power supply voltage. CONSTITUTION:An input signal is applied to a base of the 1st transisstor (TR)9 of the differential amplifier and a reference power supply 16 is connected to a base of the 2nd TR via a resistor 15. Then, a current of a constant current source 20 flows to the resistor 15 via a TR17 of current mirror constitution only when the TR9 is turned off. The voltage drop component by a current flowing across the resistor 15 is the hysteresis width and the voltage of the reference power supply 16 becomes the DC bias.