SUBSTRATE BIAS CIRCUIT OF MEMORY DEVICE

摘要

PURPOSE: A substrate bias circuit of a memory device is provided which can reduce the power consumption and also can reach a VBB level rapidly. CONSTITUTION: A substrate bias circuit of a memory device comprises: an oscillation part(10) to oscillate; a first pumping part(42) and a second pumping part(44) with different electrostatic capacity pumping charges to generate a substrate bias voltage(VBB); a first driver(22) and a second driver(24) each pumping charges through the first pumping part and the second pumping part by receiving an oscillation signal generated in the oscillation part; and a substrate bias voltage level detection part(50) selecting the driving of the first driver and the second driver by detecting the substrate bias voltage. The circuit uses a pump capacitor(34) with a large capacitance and a pump capacitance with a small capacitance together until the substrate bias voltage reaches a desired value stably, and then if the substrate bias voltage level detection part detects that the substrate bias voltage reaches a stable voltage level, the circuit uses only the pump capacitance with a small capacitance. Therefore, the circuit reduces the power consumption and can reach the stable substrate bias voltage rapidly.