Substrate bias generating circuit

Abstract

Abstract PURPOSE:To attain an external compensation for the variance in substrate bias voltage due to the variance of production processes, by varying the load capacity of an inverter constituting a ring oscillator. CONSTITUTION:A charge pump is driven by giving waveform shaping to the output signal of a ring oscillator. The output voltage of the charge pump is set at the substrate bias voltage of a 64K-bit dynamic memory, for example. A linear relation is obtained between the substrate bias voltage and the oscillation frequency of the ring oscillator. A capacitor is connected between inverters constituting a ring oscillator via a fuse element. The load capacity of an inverter is varied by cutting the fuse element. Then the oscillation frequency changes.

Inventors

• 👤 Shozo Saito
• 👤 斎藤　昇三

Bibliographic Details