| 摘要 |
A novel power amplifier output stage is taught which provides rail-to-rail output voltage swings, high current source and sink capability, which is capable of class AB operation to provide low distortion amplification. The power amplifier of this invention is suitable for fabrication in integrated circuit form, thereby achieving the small size necessary for use with miniaturized disk drives, as well as low cost and high reliability. A first transistor is driven by the output of a transconductance amplifier, in response to an input control current. The first transistor is configured together with the transconductance amplifier to provide a current which can be sensed and from which a feedback signal is provided to the transconductance amplifier to establish the first current having a known relationship to the input control current. A second transistor is used which is driven by the output of the transconductance amplifier, the second transistor being sized significantly larger than the first transistor, to provide a sizable output current in response to the input control current and with feedback control being provided by the first transistor. Low drop out voltage regulators using the novel current amplifiers of this invention are also taught.
|
