Differential charge reduction
AssigneeAnalog Devices, Inc.
InventorsScott G. Bardsley, Peter Derounian, Franklin M. Murden
Life of this patent
Estimating the term…
Abstract
One embodiment relates to an apparatus configured to cancel charge injected on a node of a differential pair of nodes. A dummy circuit element can inject charge on an inverted node to cancel charge injected on a non-inverted node by a switch when the switch is switched off. In addition, another dummy circuit element can inject charge on the non-inverted node to cancel charge injected on the inverted node by another switch when the other switch is switched off. These dummy circuits elements can be cross-coupled.
Claims21
An apparatus comprising:
- a first switch configured to receive a first differential input and to provide the first differential input to a first node when switched on;
- a second switch configured to receive a second differential input and to provide the second differential input to a second node when switched on, wherein the first node and the second node are a differential pair of nodes;
- a first dummy circuit element configured to inject charge on the second node to cancel charge injected on the first node by the first switch when the first switch is switched off;
- and
- a second dummy circuit element configured to inject charge on the first node to cancel charge injected on the second node by the second switch when the second switch is switched off.
An apparatus comprising:
- an amplifier comprising a non-inverted input and an inverted input;
- and
- a plurality of channels, each of the plurality of channels comprising:
- a pair of amplifier input switches comprising:
- a first switch configured to receive a first switch input, provide the first switch input to the non-inverted input of the amplifier when switched on, and to electrically isolate the non-inverted input of the amplifier from the first switch input when switched off;
- and
- a second switch configured to receive a second switch input, provide the second switch input to the inverted input of the amplifier when switched on, and to electrically isolate the inverted input of the amplifier from the second switch input when switched off;
- and
- a pair of dummy circuit elements cross coupled between the inputs of the pair of amplifier input switches and the inputs of the amplifier, each dummy circuit element of the pair of dummy circuit elements having substantially the same capacitance as the first switch when the first switch is switched off;
- wherein the pair of amplifier input switches of one of the plurality of channels is configured to provide charge to the non-inverted and the inverted inputs of the amplifier, when the pair of amplifier input switches of the other of the plurality of channels are switched off.
An electronically-implemented method of reducing differential change, the method comprising:
- biasing a first switch to electrically isolate a non-inverting node from an input of the first switch;
- and
- while the first switch is biased to electrically isolate the non-inverting node from the input of the first switch, coupling charge on an inverting node to at least partially cancel charge injected on the non-inverting node by the first switch;
- wherein the non-inverting node and the inverting node comprise nodes of a differential pair.
Dependencies are inferred from the claim text.