Investing integrator circuit graphs
The type of feedback used in this amplifier is voltage series or negative feedback. The output of this amplifier is in phase by the input signal. What is the function of the inverting amplifier? This amplifier is used to satisfy barkhausen criteria within oscillator circuits to generate sustained oscillations. What are noninverting amplifiers used for? What is the function of the non-inverting amplifier? It is used to provide a high input impedance 5. Which feedback is used in the inverting amplifier?
What is an inverting input? What is the voltage gain of an inverting amplifier? What is the voltage gain of the Non-inverting Amplifier? What is the effect of negative feedback on the non-inverting amplifier? Input impedance will be increased and the output impedance will be decreased. Bandwidth will be increased Output noise of the amplifier will be reduced The impact of noise will be reduced. Thus, this is all about the difference between the inverting and non-inverting amplifiers.
In most cases, an inverting amplifier is most commonly used due to its features like low impedance, less gain, etc. Also, the same goes for input with the negative phase. The figure below represents the circuit of the non-inverting amplifier: In this case, to have an output of the same phase as input, the input signal is applied at the non-inverting terminal of the amplifier. But here also negative feedback is to be provided, thus, the fed-back signal is provided to the inverting terminal of the op-amp.
The closed-loop gain of the non-inverting amplifier is given as: It is to be noted here that an amplifier with an inverting configuration can be converted into a non-inverting one, just be altering the provided input connections. Key Differences Between Inverting and Non-Inverting Amplifier The key factor of differentiation between inverting and non-inverting amplifier is done on the basis of phase relationship existing between input and output. In the case of the inverting amplifier, the output is out of phase wrt input.
Whereas for the non-inverting amplifier, both input and output are in the same phase. The input signal in the inverting amplifier is applied at the negative terminal of the op-amp. On the contrary, the input in the case of a non-inverting amplifier is provided at the positive terminal. The gain provided by the inverting amplifier is the ratio of the resistances. As against, the gain of the non-inverting amplifier is the summation of 1 and the ratio of the resistances.
In the inverting amplifier, the non-inverting terminal is grounded. Whereas in the non-inverting amplifier, the inverting terminal of the op-amp is grounded.
ETHEREUM CLAIM
An integrator circuit based on opamp is shown in fig1. Such a circuit is also termed as an integrating amplifier. The circuit is somewhat similar to an opamp inverting amplifier but the feedback resistor Rf is replaced by a capacitor Cf.
The circuit diagram of an opamp as an integrator is shown below. Opamp integrator circuit diagram. Equation for the instantaneous output voltage of the opamp integrator can be derived as follows. Since the open loop gain of the present circuit is near infinity V2 can be assumed to be zero. Touch screens may be sorted into resistive type and capacitive type touch screens according to their touch sensing method. A resistive type touch screen has a configuration where resistive material is coated on a glass or transparent plastic plate and then polyester film is covered thereon.
The resistive type touch screen detects resistance variation to sense a touch point when its screen is touched. The resistive type touch screen has a limitation of being incapable of sensing a touch input when touch pressure is weak. A capacitive type touch screen may be supplied by forming electrodes at both or one side of a glass or transparent plastic plate.
The capacitive type touch screen can detects a touch point by applying a voltage between two electrodes and then analyzing a variation of capacitance between the two electrodes when an object, such as a finger, touches its screen. A capacitive type touch screen requires a circuit for measuring capacitance formed at one electrode or between two electrodes to sense a touch point.
Such capacitance measuring circuits have been used mainly for measuring capacitances of various circuits or devices. However, because various portable devices now provide touch input interfaces, the application range of capacitance measuring circuits for sensing a contact or proximity of a user is expanding. Capacitance measuring circuits used for touch screens of typical portable phones have limitations in that malfunctions arise by various noises caused by changes in the surrounding environments.
The present disclosure also provides a method for reducing input sensing errors due to noises generated from a touch input by applying the noise-robust integrator circuit to a sensor block for sensing a touch screen input. In accordance with an aspect of the present invention, provided herein is an integrator circuit, comprising: a first operational amplifier; a second operational amplifier; and a capacitor.
Inverting input terminals of the first and second operational amplifiers are configured to be connected to a first terminal of the capacitor through a first switch and a second switch, respectively. A second terminal of the capacitor is configured to be connected to a first potential and a second potential through a third switch and a fourth switch, respectively. The inverting input terminal and an output terminal of the first operational amplifier are configured to be connected to each other through a first feedback capacitor.
The inverting input terminal and an output terminal of the second operational amplifier are configured to be connected to each other through a second feedback capacitor. And non-inverting input terminals of the first and second operational amplifiers are configured to be connected to a third potential. The third potential may be the same as the second potential. A first reset switch may be configured to be connected between the inverting input and the output terminals of the first operational amplifier in parallel with the first feedback capacitor, and a second reset switch may be configured to be connected between the inverting input and the output terminals of the second operational amplifier in parallel with the second feedback capacitor The first switch and the third switch may be driven by a first clock, and the second switch and the fourth switch may be driven by a second clock.
On-intervals of the first clock and the second clock may be alternately represented on the time axis. Part of the on-intervals of the first clock and part of the on-intervals of the second clock may occur simultaneously. Alternatively, when one of the first clock and the second clock is in on-state, other one may be in off-state.
The capacitor may be formed by a sensing pattern and a driving pattern formed in a capacitive type touch screen. One of both terminals of the capacitor connected to the first operational amplifier and second operational amplifier may correspond to the sensing pattern. The sensing pattern may be disposed at outer side of the touch screen compared to the driving pattern.
In other words, the sensing pattern may be disposed closer to a touching object like a finger than the driving pattern. One of both terminals of the capacitor connected to the first and second operational amplifiers may be an in-flowing path of noise input by cable or wireless.
In accordance with another aspect of the present invention, provided herein is an input sensing circuit of a capacitive type touch screen where a sensing pattern and a driving pattern are formed. The input sensing circuit comprises: a first operational amplifier; and a second operational amplifier. The sensing pattern is configured to be connected to an inverting input terminal of the first operational amplifier through a first switch and connected to an inverting input terminal of the second operational amplifier through a second switch, respectively.
The driving pattern is configured to be connected to a first potential and a second potential through a third switch and a fourth switch, respectively. The inverting input terminal and an output terminal of the first operational amplifier are configured to be connected to each other through a first feedback capacitor, and the inverting input terminal and an output terminal of the second operational amplifier are configure to be connected to each other through a second feedback capacitor.
And non-inverting input terminals of the first and second operational amplifiers are connected to a third potential. The first switch and the third switch may be driven by a first clock, and the second switch and the fourth switch are driven by a second clock. In accordance with still another aspect of the present invention, a switched capacitor integrator circuit is provided.
The switched capacitor integrator circuit comprises an inverting switched capacitor integrator circuit; and a non-inverting switched capacitor integrator circuit connected to the inverting switched capacitor integrator circuit. The inverting switched capacitor integrator circuit may integrate electric charges which are charged in the sampling capacitor with time to output a negative voltage, and the non-inverting switched capacitor integrator circuit may integrate electric charges which are charged in the sampling capacitor with time to output a positive voltage.
At least a portion of integration time interval of the inverting switched capacitor integrator circuit may not overlap integration time interval of the non-inverting switched capacitor integrator circuit. The sampling capacitor may be formed by a sensing pattern and a driving pattern formed in a capacitive type touch screen. One of both terminals of the sampling capacitor, which is connected to the inverting switched capacitor integrator circuit and the non-inverting switched capacitor integrator circuit, may be an in-flowing path of noise input by cable or wireless.
In accordance with still another aspect of the present invention, an integrator circuit is provided. The inverting integrator circuit may integrate electric charges which are charged in the capacitor with time to output a negative voltage, and the non-inverting integrator circuit may integrate electric charges which are charged in the capacitor with time to output a positive voltage.
One of both terminals of the capacitor, which is connected to the inverting integrator circuit and the non-inverting integrator circuit, may be an in-flowing path of noise input by cable or wireless. At least a portion of integration time interval of the inverting integrator circuit may not overlap integration time interval of the non-inverting integrator circuit.
The integrator circuit comprises: a first operational amplifier; a second operational amplifier; and a capacitor. Inverting input terminals of the first and second operational amplifiers are configured to be connected to a first terminal of the capacitor, respectively. The inverting input terminal and an output terminal of the first operational amplifier are configured to be connected to each other through a first feedback capacitor and a first switch connected in series, and the inverting input terminal and an output terminal of the second operational amplifier are configured to be connected to each other through a second feedback capacitor and a second switch connected in series.
A first reset switch may be configured to be connected between the inverting input and the output terminals of the first operational amplifier in parallel with the first feedback capacitor, and a second reset switch may be configured to be connected between the inverting input and the output terminals of the second operational amplifier in parallel with the second feedback capacitor. Although the present invention has been described with reference to specific embodiments, the scope of the present invention is not limited thereto.
Therefore, it will be readily understood by those skilled in the art that various modifications and changes can be made thereto without departing from the spirit and scope of the present invention defined by the appended claims.
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