Signal chopping switch circuit with shared bootstrap capacitor
AssigneeBAE Systems Information and Electronic Systems Integration Inc.
InventorsCameron Huang, Randall M. White
Life of this patent
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Abstract
An analog to digital converter is disclosed that is designed to receive a differential analog signal and includes a signal chopping circuit and a successive approximation register (SAR) coupled to the signal chopping circuit. The signal chopping circuit is designed to invert a polarity of the differential analog signal and includes a first switching circuit having a first transistor and a second switching circuit having a second transistor. A gate of the first transistor and a gate of the second transistor is each coupled to a same bootstrap capacitor. Coupling both switching circuits to the same bootstrap capacitor (as opposed to separate bootstrap capacitors) greatly frees up space on the die or chip.
Claims20
An analog-to-digital converter (ADC), comprising:
- a differential analog input configured to receive a differential analog signal;
- a signal chopping circuit coupled to the differential analog input and configured to invert a polarity of the differential analog signal, the signal chopping circuit including a first switching circuit, a second switching circuit, and a bootstrap capacitor, the first switching circuit having a first transistor and the second switching circuit having a second transistor, wherein a gate of the first transistor and a gate of the second transistor is each coupled to the bootstrap capacitor;
- and
- a successive approximation register (SAR) coupled to the signal chopping circuit.
A signal chopping circuit configured to receive an analog voltage at an analog input and switch between a first analog output and a second analog output, the signal chopping circuit comprising:
- a first switching circuit coupled to the analog input and the first analog output, the first switching circuit including a switch select input for changing switch position of the first switching circuit;
- a second switching circuit coupled to the analog input and the second analog output, the second switching circuit including a switch select input for changing switch position of the second switching circuit;
- a pull-up circuit including one or more transistors;
- a pull-down circuit including one or more transistors;
- and
- a bootstrap capacitor coupled to the pull-up circuit and to the pull-down circuit, and also coupled to the switch select input of the first switching circuit and the switch select input of the second switching circuit.
A communication device, comprising:
- a receiver comprising an antenna and configured to receive an RF signal;
- an analog-to-digital converter (ADC) coupled to the receiver, wherein the ADC comprises at least one signal chopping circuit configured to receive at least a portion of the RF signal, the signal chopping circuit comprising
- a first switching transistor coupled to an input of the signal chopping circuit and to a first output of the signal chopping circuit,
- a second switching transistor coupled to the input of the signal chopping circuit and to a second output of the signal chopping circuit, and
- a bootstrap capacitor coupled to a pull-up network of transistors and to a pull-down network of transistors and coupled to a gate of the first switching transistor and a gate of the second switching transistor;
- and
- a processor coupled to the ADC.
Dependencies are inferred from the claim text.