Patent ID: 8698534
Filing Date: 2014-04-15
Classification: H03M

Abstract:
1. A current-mode interpolation buffer, for receiving a first rough voltage, a second rough voltage and at least one bit of a digital code and outputting an analog voltage, the current-mode interpolation buffer comprising: a current source, receiving the at least one bit of the digital code, outputting a first current, and drawing a second current, wherein amperages of the first current and the second current are dependent on the at least one bit; a first differential transistor pair, having a first control terminal and a second control terminal respectively receiving the first rough voltage and the analog voltage, a reference terminal coupled to the current source for receiving the first current, and a current terminal pair generating a first differential current; a second differential transistor pair, having a first control terminal and a second control terminal respectively receiving the second rough voltage and the analog voltage, a reference terminal coupled to the current source for draining the second current, and a current terminal pair generating a second differential current; and an output stage, having a first input terminal pair and a second input terminal pair respectively coupled to the current terminal pair of the first differential transistor pair and the current terminal pair of the second differential transistor pair, and generating the analog voltage according to the first differential current and the second differential current, wherein the analog voltage belongs to a rough range from the first rough voltage to the second rough voltage.