Abstract: According to a first aspect of this disclosure there is provided a voltage controlled current path. The voltage controlled current path comprises a first stage arranged to conduct current once the voltage at an input node of the first stage exceeds a threshold value. The amount of current that passes through the first stage is a function of the voltage at the input node. A second stage is arranged to pass a current that is a function of the current passing through the first stage.

Abstract: Distortion in a combined sample and hold circuit and multiplexer can be reduced by dividing the sample and hold circuit and the multiplexer up into main and compensation signal channels, and considering the total error signal that arises during an acquire phase across both the switches of the multiplexer and the input switches of the sample and hold stage as a single error signal that has to be compensated. This compensation is then achieved by causing the same error voltages to be induced in both the main and compensation channels of the whole MUX and sample and hold circuit, such that errors can be made to cancel, thus improving the performance of the stage.

Abstract: A pre-charge circuit is provided for pre-charging the input node of a capacitive component to which the multiplexer output is fed to a charge level that is close to or approximates the signal output level of the multiplexer when its output is next switched. In order to reduce the level shifting burden on the amplifier in the pre-charge circuit, each pre-charge circuit input channel has a respective capacitor that is able to be switched in and out of series with the respective multiplexer channels, such that the respective capacitors track the signal levels on the multiplexer channels. The provision of the corresponding capacitors for each MUX channel reduces the input current to the pre-charge amplifier, and allows for the level shifting burden to be taken by the capacitors, leading to more stable and lower power operation.

Abstract: Distortion in a combined sample and hold circuit and multiplexer can be reduced by dividing the sample and hold circuit and the multiplexer up into main and compensation signal channels, and considering the total error signal that arises during an acquire phase across both the switches of the multiplexer and the input switches of the sample and hold stage as a single error signal that has to be compensated. This compensation is then achieved by causing the same error voltages to be induced in both the main and compensation channels of the whole MUX and sample and hold circuit, such that errors can be made to cancel, thus improving the performance of the stage.

Abstract: A signal gate is provided where the gate can be low impedance to allow a signal to pass or be high impedance to block it. The signal gate has two output nodes arranged such that during the blocking mode spurious signals passing through the gate by way of parasitic components are presented as common mode signals at the output nodes.

Abstract: A signal processing apparatus that includes a circuit in which a signal processing function is performed during a first time period, the signal processing apparatus including or being associated with a switch or a filter in a power supply to the signal processing apparatus so as to disconnect the signal processing apparatus from the power supply or to filter the power supply during a second time period that is coincident with at least part of the first time period.

Abstract: According to a first aspect of this disclosure there is provided a voltage controlled current path. The voltage controlled current path comprises a first stage arranged to conduct current once the voltage at an input node of the first stage exceeds a threshold value. The amount of current that passes through the first stage is a function of the voltage at the input node. A second stage is arranged to pass a current that is a function of the current passing through the first stage.

Abstract: A signal gate is provided where the gate can be low impedance to allow a signal to pass or be high impedance to block it. The signal gate has two output nodes arranged such that during the blocking mode spurious signals passing through the gate by way of parasitic components are presented as common mode signals at the output nodes.

Abstract: An amplifier, comprising: an input node; an output node; a gain stage having a gain stage inverting input, a gain stage non-inverting input and a gain stage output; a feedback capacitor connected in a signal path between the gain stage output and the gain stage inverting input; a sampling capacitor connected between the input node and the gain stage inverting input, and a controllable impedance in parallel with the feedback capacitor, wherein the controllable impedance is operable to switch between a first impedance state in which it does not affect current flow through the feedback capacitor, and a second impedance state in which it cooperates with the feedback capacitor form a bandwidth limiting circuit.

Abstract: Example embodiments of this disclosure can provide an apparatus, a system, and a method of correcting for charge lost from a sampling capacitor as a result of an analog to digital conversion being performed. In an embodiment, there is provided a method of operating an analog to digital converter comprising at least a first sampling capacitor used to sample an input signal, where the method can further comprise a correction step of modifying the voltage across the at least first sampling capacitor, the correction step being performed prior to commencing an acquire phase.

Abstract: A signal processing apparatus that includes a circuit in which a signal processing function is performed during a first time period, the signal processing apparatus including or being associated with a switch or a filter in a power supply to the signal processing apparatus so as to disconnect the signal processing apparatus from the power supply or to filter the power supply during a second time period that is coincident with at least part of the first time period.

Abstract: Example embodiments of this disclosure can provide an apparatus, a system, and a method of correcting for charge lost from a sampling capacitor as a result of an analog to digital conversion being performed. In an embodiment, there is provided a method of operating an analog to digital converter comprising at least a first sampling capacitor used to sample an input signal, where the method can further comprise a correction step of modifying the voltage across the at least first sampling capacitor, the correction step being performed prior to commencing an acquire phase.

Abstract: An analog to digital converter comprising at least one sampling capacitor connected to a sample node, and a pre-charge circuit arranged to cause the voltage on the sample node to substantially match the input voltage prior to the analog to digital converter entering an acquire mode in which the sample node is connected to the input node by a sample switch.

Abstract: A signal processing apparatus that includes a circuit in which a signal processing function is performed during a first time period, the signal processing apparatus including or being associated with a switch or a filter in a power supply to the signal processing apparatus so as to disconnect the signal processing apparatus from the power supply or to filter the power supply during a second time period that is coincident with at least part of the first time period.

Abstract: An amplifier, comprising: an input node; an output node; a gain stage having a gain stage inverting input, a gain stage non-inverting input and a gain stage output; a feedback capacitor connected in a signal path between the gain stage output and the gain stage inverting input; a sampling capacitor connected between the input node and the gain stage non-inverting input, and a controllable impedance in parallel with the feedback capacitor, wherein the controllable impedance is operable to switch between a first impedance state in which it does not affect current flow through the feedback capacitor, and a second impedance state in which it cooperates with the feedback capacitor form a bandwidth limiting circuit.

Abstract: A signal processing apparatus that includes a circuit in which a signal processing function is performed during a first time period, the signal processing apparatus including or being associated with a switch or a filter in a power supply to the signal processing apparatus so as to disconnect the signal processing apparatus from the power supply or to filter the power supply during a second time period that is coincident with at least part of the first time period.

Abstract: A sampling circuit comprising: an input node; a first signal path comprising a first sampling capacitor and a first signal path switch in a signal path between the input node and a first plate of the first sampling capacitor; a second signal path comprising a second sampling capacitor and a second signal path switch in a signal path between the input node and a first plate of the second sampling capacitor, and a signal processing circuit for forming a difference between a signal sampled onto the first sampling capacitor and a signal sampled onto the second sampling capacitor.

Abstract: A sampling circuit comprising: an input node; a first signal path comprising a first sampling capacitor and a first signal path switch in a signal path between the input node and a first plate of the first sampling capacitor; a second signal path comprising a second sampling capacitor and a second signal path switch in a signal path between the input node and a first plate of the second sampling capacitor, and a signal processing circuit for forming a difference between a signal sampled onto the first sampling capacitor and a signal sampled onto the second sampling capacitor.

Abstract: An analog to digital converter comprising at least one sampling capacitor connected to a sample node, and a pre-charge circuit arranged to cause the voltage on the sample node to substantially match the input voltage prior to the analog to digital converter entering an acquire mode in which the sample node is connected to the input node by a sample switch.

Abstract: A reference circuit for use with a charge redistribution analog to digital converter, having a capacitor array, the reference circuit comprising: an input for receiving a signal; an output for supplying a reference voltage to at least one capacitor of the charge redistribution capacitor array; a storage capacitor for storing the reference voltage; a voltage modification circuit for comparing the reference voltage stored on the storage capacitor with the reference signal, and based on the comparison to supply a correction so as to reduce a difference between the reference voltage and the reference signal, the correction being applied during a correction phase; and a first switch for selectively connecting the storage capacitor to the input during an acquisition phase.