Oscillator circuit for EEPROM high voltage generator

摘要

A semiconductor oscillator circuit for an EEPROM high voltage charge pump utilizes a current generating means to charge a first and a second capacitor alternatively. The charging current produced by the current generating means is inversely proportional to the ambient temperature. The charging current is proportional to the supply voltage and consequently, the oscillator frequency output remains constant over a variable voltage supply. Such a constant frequency characteristic makes a low voltage operation possible, but slows down the oscillator frequency as temperature increases. The slowing of oscillator frequency limits the charge pump output voltage and enhances the lifespan of the EEPROM cells.