| 摘要 |
An amplifier having floating inverting and non-inverting inputs and a stabilized direct output voltage level. The amplifier comprises a preamplifier (10) and an output amplifier stage (20). The preamplifier (10) comprises a differential amplifier which comprises a first and a second transistor (T1, T2) between whose emitters a first resistor (R1) is arranged and whose emitters are connected to the positive direct power-supply terminal (2) by a first and a second current source (I1=I, I2=I) respectively. The collector of the second transistor (T2) is connected to the negative power-supply terminal (3) via a third current source (I3=3.5I) and is coupled to the output (7) of the arrangement via a second resistor (R2). Two transistors (T3, T4) having commoned bases carrying a reference voltage (VR) are arranged in cascade with the third current source (I3). The collectors of these transistors are connected to the positive power-supply terminal (2) via a fourth and a fifth current source (I4= I, I5=I) respectively and are coupled to the first and the second input (5,6) of the output amplifier (20) respectively. This output amplifier (20) comprises two opposite conductivity type transistors (T5, T6) whose collectors are connected to the output (7). The resistance value of the second resistor (R2) is such that the direct voltage at the output (7) as a result of the current flowing through this resistor (R2) in the quiescent state is equal to half the supply voltage.
|
