OSCILLATOR FOR GENERATING HIGH VOLTAGE OF FLASH MEMORY DEVICE

摘要

PURPOSE: An oscillator for generating high voltage of flash memory device is provided to output a stable high voltage by outputting an oscillating signal having a varied period according to the change of a power supply voltage using a reference voltage. CONSTITUTION: A detecting circuit(100) has a delay circuit(110), a first detecting circuit(120), and a second detecting circuit(130). The first detecting circuit(120) has resistors(111-116) and NMOS transistors(117,118). Resistors(111-116) are connected between a supply terminal of a reference voltage(Vref) and a drain of the NMOS transistors(117). The NMOS transistor(117) has a current path formed between the resistor(116) and the NMOS transistor(118) and a gate connected to a drain. The NMOS transistors(118) have a current path formed between a source of the NMOS transistors(117) and a ground voltage(Vss) and a gate connected to a bias circuit(200). The second detecting circuit(130) has NMOS transistors(121-124) and capacitors(125-127). The bias circuit(200) has an inverter(210) and a MOS transistor(220).