US 4,361,771 A · Voltage summation circuit

Abstract

A voltage summation circuit receives a series of input voltage signals and provides an output voltage signal which represents a summation of the input voltage signals. The voltage summation circuit includes first and second capacitors, a current mirror, and an input switch. During a first clock phase of each cycle in which an input voltage signal is received, the input switch connects the first capacitor to the input to charge the first capacitor as a function of the input voltage signal. During a second clock phase the input switch connects the first capacitor to the current mirror to discharge the first capacitor. The current mirror is connected to the second capacitor, so that the change in charge on the first capacitor during the second clock phase results in a similar change in charge on the second capacitor. The charging and discharging of the first capacitor during the first and second clock phases is repeated for each input voltage signal. The total change in charge on the second capacitor, and thus the total change in the output voltage signal, represents a summation of the input voltage signals.

Claims16

Dependent claims

A summation circuit for providing an output signal which represents a summation of a series of first input signals, the summation circuit comprising:

first capacitor means;
second capacitor means, the output signal being a function of a charge on the second capacitor means;
means for charging the first capacitor means as a function of each first input signal;
means for discharging the first capacitor means to provide a first current which is a function of each first input signal;
and
means for providing a second current which is a function of the first current, and being connected to the second capacitor means to control the charge on the second capacitor means as a function of the second current.

3 more elements

A summation circuit for providing an output signal which represents a summation of a series of input signals, the summation circuit comprising:

an input for receiving the series of input signals during a series of cycles, respectively;
first capacitor means;
first current mirror means having a first current path through which a first current flows and a second current path through which a second current flows which is a function of the first current;
first switching means for connecting the input and the first capacitor means during a first phase of each cycle to provide a charge on the first capacitor means which is a function of the input signal, and for connecting the first capacitor means and the first current path of the first current mirror means during a second phase of each cycle to provide the first current;
and
second capacitor means connected to the second current path and to the output, the output signal being a function of charge on the second capacitor means, and wherein the second current during each cycle changes charge on the second capacitor means as a function of the input signal received at the input during the cycle.

3 more elements

Dependencies are inferred from the claim text.

Voltage summation circuit

Life of this patent

Voltage summation circuit

Life of this patent

Abstract

Claims16