BIFET vacuum tube replacement structure
US5648664A · kind A · utility
Inventors
Key dates
| Filing date | Jan 20, 1995 |
| Grant date | Jul 15, 1997 |
| Priority date | — |
| Expiry date | Jan 20, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10D30/831
Abstract
A BIFET vacuum tube replacement structure includes a plurality of devices that replicate the characteristics of a vacuum tube. The vacuum tube replacement structure has the same pin-out as the vacuum tube being replaced and so can be exchanged directly for a vacuum tube in an audio amplifier. The vacuum tube replacement structure is suitable for use in a wide range of audio amplifier applications without modification to the audio amplifiers. Further, there is no noticeable degradation to the human ear in the sound quality when the vacuum tube replacement structure is used in an audio amplifier in place of a vacuum tube. A unitary device that is a combination of a high impedance bipolar like transistor and a unipolar junction field effect transistor, that is referred to as a BIFET, is used in the vacuum tube replacement structure. In one embodiment, the bipolar like transistor is formed in combination with the gate of the unipolar junction field effect transistor. The vacuum tube replacement structure faithfully replicates input signals at low levels and also slowly and uniformly compresses the input signals at higher drive levels and under overdrive conditions.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.