发明名称 |
Amplifier and filter having variable gain and cutoff frequency controlled logarithmically according to digital code |
摘要 |
A variable gain amplifier circuit is provided. The circuit includes an operational amplifier for amplifying and outputting an input signal according to a cutoff frequency and a gain, a feedback resistor for changing a first resistance according to a first digital control code value which determines the cutoff frequency, and an input resistor for changing a second resistance according to a second digital control code value which is determined based on a difference of the first digital control code value and a gain code value. The gain is determined by a ratio of the first resistance and the second resistance and linearly changes on a decibel (dB) basis according to the first digital control code value, the cutoff frequency is inversely proportional to the first resistance and linearly changes on a log scale, and the variable gain can be easily set using the control code. |
申请公布号 |
US8884693(B2) |
申请公布日期 |
2014.11.11 |
申请号 |
US201213713582 |
申请日期 |
2012.12.13 |
申请人 |
Samsung Electronics Co., Ltd. |
发明人 |
Lee Jong-Woo |
分类号 |
H03G3/20;H03G3/00;H03G1/00 |
主分类号 |
H03G3/20 |
代理机构 |
Jefferson IP Law, LLP |
代理人 |
Jefferson IP Law, LLP |
主权项 |
1. A variable gain amplifier circuit comprising:
an operational amplifier for amplifying and outputting an input signal according to a cutoff frequency and a gain; a feedback resistor for changing a first resistance according to a first digital control code value which determines the cutoff frequency; and an input resistor for changing a second resistance according to a second digital control code value which is determined based on a difference of the first digital control code value and a gain code value, wherein the gain is determined by a ratio of the first resistance and the second resistance and linearly changes on a decibel (dB) basis according to the first digital control code value, and wherein the cutoff frequency is inversely proportional to the first resistance and linearly changes on a log scale. |
地址 |
Suwon-si KR |