A hold circuit has a purpose to provide a hold circuit capable of controlling a hold error of an analog hold in the minimum during transferring. A hold circuit keeps a voltage signal, whose voltage level is compensated by operational amplifiers Amp.sub.1 and Amp.sub.2, at capacitances C.sub.1 and C.sub.2 by two steps, and holding and transferring of voltage data is performed at the different timing. The accuracy is compensated, as well.
A method and circuit arrangement for processing analog signals in applications in which low energy consumption is of the essence. An integrator topology where the active charge-transferring element is preferably a source-follower-type transistor in which one input terminal is arranged so as to be substantially independent of the input signal and in which the essential signal path elements of the circuit topology are connected in a fixed manner. Preferably, the circuit arrangement is realized so that it comprises separate transistors for sampling and charge transfer. Thus it is possible to connect an input signal in a fixed manner in an input terminal of the sampling transistor, and an input terminal of the charge-transferring transistor can be connected in a fixed manner to a constant voltage. By using a signal processing circuit according to the invention, it is possible to avoid circuit non-idealities caused by parasitic capacitances.
A computational circuit that includes a pair of operational amplifiers, wherein one of the amplifiers receives an analog input voltage. Switching circuits are provided to selectively connect the outputs of the operational amplifiers to a common node and to respective inputs thereof via feedback lines. Capacitors are provided at the common node. A digital signal actuates the switching circuits so that one switching circuit is opened when the other is closed.
A method and circuit arrangement for processing analog signals in applications in which low energy consumption is of the essence. An integrator topology where the active charge-transferring element is preferably a source-follower-type transistor in which one input terminal is arranged so as to be substantially independent of the input signal and in which the essential signal path elements of the circuit topology are connected in a fixed manner. Preferably, the circuit arrangement is realized so that it comprises separate transistors for sampling and charge transfer. Thus it is possible to connect an input signal in a fixed manner in an input terminal of the sampling transistor, and an input terminal of the charge-transferring transistor can be connected in a fixed manner to a constant voltage. By using a signal processing circuit according to the invention, it is possible to avoid circuit non-idealities caused by parasitic capacitances.
An active matrix liquid crystal drive circuit comprising an input-signal storage capacitor for storing an analog input signal, a differential amplifier which alternately presents a first operative state in which the output thereof is returned to the inverting input terminal thereof in a negative feedback manner and a second operative state in which the output is returned to the non-inverting input terminal thereof through a polarity inverting output buffer circuit in a negative feedback manner, and an output-voltage storage capacitor for storing an output voltage of the differential amplifier. In the first operative state, the voltage stored in the input-signal storage capacitor is applied to the non-inverting input terminal, and the output voltage which is returned to the inverting input terminal in a negative feedback manner is stored in the hold capacitor. In the second operative state, the voltage of the output-voltage storage capacitor is applied to the inverting input terminal and the output of the buffer circuit is output as a liquid crystal drive voltage.
A computational circuit that includes a selector for providing an input to one of a plurality of sample/hold circuits. The outputs of the sample/hold circuits are provided to a multiplexer. The output of the multiplexer is provided to a computational portion, such as a multiplier.
