| 摘要 |
The invention relates to a transconductance amplifier, intended to supply current variations di when it receives voltage variations dv, with a desired conversion coefficient Gm called transconductance: Gm=di/dv. The amplifier comprises a PMOS transistor (MP1) and an NMOS transistor (MP2) connected by their drains, their gates both being connected to the voltage input receiving dv; the source of the first transistor is connected to a constant current source (IB1) and to a resistor (R) and to the drain of a third MOS transistor (MN3) of the same type as the first; the sources of the second (MN2) and third (MN3) transistors are commoned, the gate of the third transistor being connected to the drains of the first and second; the output is connected to a circuit (MN4) which mirrors the current of the third transistor. The resulting amplifier has good linearity and can be used in a sample and hold device used to sample charges. |
