Method and apparatus for Class AB audio amplifier output stage voltage protection
US9225303B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Jul 11, 2014 |
| Grant date | Dec 29, 2015 |
| Priority date | — |
| Expiry date | Jul 11, 2034 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F2203/30117
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An output circuit for a class AB push-pull amplifier includes an upper cascode output stage and a lower cascode output stage. The upper cascode stage includes first and second PMOS transistors connected in series between a positive power supply node and an output node, the first PMOS transistor configured to receive a first complementary input signal. The lower cascode output stage includes first and second NMOS transistors connected in series between a negative power supply node and the output node, the first NMOS transistor configured to receive a second complementary input signal. The output circuit also includes a bias circuit configured for providing a first bias voltage to a gate node of the second NMOS transistor and a second bias voltage to a gate node of the second PMOS transistor, in which the first and the second bias voltages being substantially proportional to the output voltage.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.