BACK BIAS VOLTAGE GENERATOR

摘要

A back bias voltage generator is provided to improve a reliability of transistor junction by maintaining constant level to the back bias voltage regardless of change of external voltage(Vcc). The generator comprises: a reference voltage generating part(23) for generating an internal voltage(VREG) of constant level compared to internal voltage control signal(VREF); a back bias voltage sensor(24) for outputting an oscillation enable signal(OSCEN) according to the exteranl voltage(Vcc) and an oscillation enable signal(OSCEN) accroding to the internal voltage(VREG); an oscillator(25) for generating an oscillation signal in accordance with the OSCEN and outputting VBBOKB signal to the reference voltage generating part(23); and a back bias voltage pumping part(26) for generating a back bias voltage(VBB).