Patent ID: 6949973
Filing Date: 2005-09-27
Classification: H03F,H03K

Abstract:
1. A signal amplifier comprising: an inverter circuit comprised of sub-inverters connected to each other in multiple stages and made up of p-channel transistors and n-channel transistors; a reference circuit having a circuit configuration corresponding to said inverter circuit and comprised of sub-inverters connected to each other in multiple stages and made up of p-channel transistors and n-channel transistors; a selection circuit for independently selecting the p-channel transistor and the n-channel transistor from each other with the same combination as the combination of the selection of the p-channel and n-channel transistors in said inverter circuit and reference circuit; and a selection control circuit for comparing a first driving capacity serving as a driving capacity of the p-channel transistor selected in said reference circuit with a second driving capacity serving as a driving capacity of the n-channel transistor selected in said reference circuit, and outputting a control signal to said selection circuit so as to achieve a balance between the first driving capacity and the second driving capacity based on the result of comparison, thereby controlling said selection signal; wherein said selection circuit controls operations of the p-channel transistors and the n-channel transistors in said inverter circuit in response to an input signal of said inverter circuit and the control signal outputted from the selection control circuit.