| 摘要 |
<p>A differential current amplifier circuit formed in a semiconductor integrated circuit. When first and second resistors (R1, R2) have an equal value, the common base connection or the common collector connection (not shown) of first and second transistors (Q1, Q2) serves as virtual ground for the signal supplied at inputs (INA, INB), and a signal current component (i) flows neither to the first transistor (Q1) nor to the second transistor (Q2). Therefore, only direct currents (2I, 2nI) on which the signal current component (i) is not superposed flow into third and fourth transistors (Q3, Q4) connected to a current mirror pair, and no direct current source is required for this portion. The fourth transistor (Q4) is utilized as a constant-current source for a differential pair of fifth and sixth transistors (Q5, Q6), and the amplified signal component (2i2) is taken out from the output terminal (OUT) of the differential pair; i.e., a large current gain is obtained. Moreover, since the circuit constitution is relatively simple, the integrated circuit can be fabricated at a reduced cost.</p> |
