초록 ▼

A sleep switch connected to a ramp pin, an undervoltage lockout circuit and a hysteretic differential comparator for use in the undervoltage lockout circuit are disclosed. An integrated circuit has a comparator that receives a voltage from the ramp pin which it compares with a control voltage. The s

A sleep switch connected to a ramp pin, an undervoltage lockout circuit and a hysteretic differential comparator for use in the undervoltage lockout circuit are disclosed. An integrated circuit has a comparator that receives a voltage from the ramp pin which it compares with a control voltage. The sleep switch connected to the ramp pin is activated when the ramp pin is below a predetermined voltage threshold at which point it puts the integrated circuit into a low power consumption sleep mode. The undervoltage lockout circuit includes a detection leg connected between the supply terminal and ground. A current supply is enabled when the voltage across a resistive portion of a detection leg rises above a first threshold. A differential comparator is responsive to the detection voltage for enabling the current supply. The differential comparator may include three transistors arranged to provide first and second detection thresholds so as to establish a hysteresis.

대표청구항 ▼

[ We claim:] [1.] An integrated circuit comprising:a ramp pin for connection to an external capacitor;a comparator connected to receive a voltage from said ramp pin to compare the ramp pin voltage to a control voltage;Vcc means for receiving a supply voltage;a regulator connected to said Vcc means f

[ We claim:] [1.] An integrated circuit comprising:a ramp pin for connection to an external capacitor;a comparator connected to receive a voltage from said ramp pin to compare the ramp pin voltage to a control voltage;Vcc means for receiving a supply voltage;a regulator connected to said Vcc means for generating a regulated voltage;a current source, connected to said regulated voltage, for supplying charging current to said ramp pin; anda sleep switch, connected to said ramp pin so as to be activated when said ramp pin is below a predetermined voltage threshold, for putting said integrated circuit into a low power consumption sleep mode when said sleep switch is activated by said ramp pin falling below the predetermined voltage threshold.