Clock signal generator and operating method thereof

Abstract

A method of generating clock signals includes: receiving a bandgap reference voltage from a bandgap reference circuit; generating a first current having a first curvature characteristic based on the bandgap reference voltage; generating a second current having a second curvature characteristic based on the bandgap reference voltage; generating a first complementary to absolute temperature (CTAT) current by adding the first current to the second current; receiving a temperature-variable voltage and a temperature-fixed voltage from a voltage generator; generating an offset current based on the temperature-variable voltage and the temperature-fixed voltage; generating a reference current by adding the first CTAT current to the offset current; and generating the clock signals by alternately discharging a first capacitor and a second capacitor based on the reference current, and charging the first capacitor and the second capacitor based on a power voltage.