Bootstrapped, AC-coupled differential amplifier
First Claim
1. An ac-coupled differential amplifier having a high common mode rejection ratio and input impedance and having a bootstrapped input stage, said amplifier comprising:
- first and second operational amplifiers each having a first input, a second input, and an output;
first and second RC high-pass input filter means, each comprising capacitor means connected to said first input of one of said first and second operational amplifiers and resistor means connected between ground and said first input of one of said first and second operational amplifiers; and
first and second bootstrap capacitor means, each connecting said resistor means in one of said first and second RC high-pass input filter means to said second input of one of said first and second operational amplifiers.
0 Assignments
0 Petitions
Accused Products
Abstract
An ac-coupled differential amplifier having a high common mode rejection ratio (CMRR) and input impedance is disclosed. The ac-coupled amplifier includes a bootstrapped input stage and first and second operational amplifiers, each having a first input, a second input, and an output. The bootstrapped input-stage has a pair of RC high-pass filters, each of which is comprised of a capacitor connected to the first input of each of the operational amplifiers and a pair of resistors connected in series between ground and the first input of each of the operational amplifiers. A pair of bootstrap capacitors connect between each of the series connected resistor pairs of each of the two RC high-pass filters and the second input of each of the operational amplifiers.
75 Citations
24 Claims
-
1. An ac-coupled differential amplifier having a high common mode rejection ratio and input impedance and having a bootstrapped input stage, said amplifier comprising:
-
first and second operational amplifiers each having a first input, a second input, and an output; first and second RC high-pass input filter means, each comprising capacitor means connected to said first input of one of said first and second operational amplifiers and resistor means connected between ground and said first input of one of said first and second operational amplifiers; and first and second bootstrap capacitor means, each connecting said resistor means in one of said first and second RC high-pass input filter means to said second input of one of said first and second operational amplifiers. - View Dependent Claims (2, 3, 4, 5, 6, 7)
-
-
8. An ac-coupled differential amplifier having a high common mode rejection ratio and input impedance and having a bootstrapped input stage, said amplifier comprising:
-
first and second operational amplifiers each having a first input, a second input, and an output; first and second RC high-pass input filter means, each comprising a capacitor connected to said first input of one of said first and second operational amplifiers and first and second filter resistors connected in series between ground and said first input of one of said first and second operational amplifiers; first and second bootstrap capacitors, each connecting said first and second filter resistors in one of said first and second RC high-pass input filter means and said second input of one of said first and second operational amplifiers. - View Dependent Claims (9, 10, 11, 12, 13)
-
-
14. A bootstrapped input stage providing a high common mode rejection ratio and input impedance for a differential amplifier having a first input, a buffered first input, a second input, a buffered second input, and differential outputs, said bootstrapped input stage comprising:
-
first and second RC high-pass input filter means, each comprising a capacitor connected to one of the first and second inputs of said differential amplifier and first and second filter resistors connected in series between ground and one of the first and second inputs of the differential amplifier; and first and second bootstrap capacitors, each connecting said first and second filter resistors in one of said first and second RC high-pass input filter means and one of the buffered first input and the buffered second input of the differential amplifier. - View Dependent Claims (15, 16)
-
-
17. An ac differential amplification circuit for amplifying the difference between two input signals comprising:
-
a differential input stage having an input impedance means and having a bootstrapped ac-coupling means, said input impedance means receiving the input signals and producing first and second output signals in response thereto, and said bootstrapped ac-coupling means having first and second inputs and producing at least a first output signal and at least a second output signal; first and second buffer means each having an input and an output, with said output of each of said buffer means respectively connected to separate ones of said first and second inputs of said bootstrapped ac-coupling means; and differential amplifier means having first and second differential inputs and a differential output, said first and second differential inputs being respectively connected to separate ones of said inputs of said first and second buffer means and to receiving separate ones of said first and second output signals of said input impedance means. - View Dependent Claims (18, 19, 20, 21, 22)
-
-
23. A method of providing a high common mode rejection ratio and input impedance for a differential amplifier having a first input, a buffered first input, a second input, a buffered second input and differential outputs, said method comprising the steps of:
-
connecting first and second capacitor means to the first and second inputs of the differential amplifier, respectively; connecting first and second filter resistor means between ground and the first and second inputs of the differential amplifier, respectively; connecting first and second bootstrap capacitor means between said first and second filter resistor means and the buffered first and second inputs, respectively. - View Dependent Claims (24)
-
Specification