US 12,191,812 B2 · Low off-leakage current switch

Abstract

Low-leakage switch circuit techniques to reduce leakage current of an off-state switch, while maintaining a low on-resistance. The low-leakage switch circuit may allow measurement of low current signals in a transimpedance amplifier with improved accuracy without, the need for calibration. The low-leakage switch circuit may include a bootstrapping path connecting two or more terminals or voltage nodes of an off-state switch in the switch circuit. The bootstrapping path is configured to bootstrap major leakage current contributors in the switch circuit, such as the substrate diode leakage, the subthreshold leakage, or combinations thereof.

Claims20

Dependent claims

A low off-leakage switched gain trans-impedance amplifier (TIA) circuit having an input terminal to receive an input current, the switched gain TIA circuit comprising:

a first switch including a first transistor circuit coupled in series with a second transistor circuit via a first midpoint node, wherein a back-gate node of the second transistor circuit is coupled to the first midpoint node, and wherein the first switch has an ON state and an OFF state;
an amplifier circuit including an output node coupled to an input node of the first switch and an input node of a second switch;
and
a bootstrapping circuit configured to receive a voltage and generate an output signal selectively coupleable to the first midpoint node to bias the first midpoint node to a representation of the voltage based on whether the first switch is in the OFF state,
wherein an output of the first switch is coupled to a first resistor in a first feedback path of the TIA circuit.

2 more elements

A method of operating a low off-leakage switched gain amplifier circuit having an input terminal to receive an input current, the method comprising:

coupling a first switch including a first transistor circuit in series with a second transistor circuit via a first midpoint node, wherein a back-gate node of the second transistor circuit is coupled to the first midpoint node, and wherein the first switch has an ON state and an OFF state;
coupling a second switch including a third transistor circuit in series with a fourth transistor circuit via a second midpoint node, wherein a back-gate node of the fourth transistor circuit is coupled to the second midpoint node, wherein the second switch has an ON state and an OFF state, and wherein the second switch is configured to be in the ON state when the first switch is in the OFF state;
receiving, using a trans-impedance amplifier (TIA) circuit, the input current, wherein the TIA circuit has an output node coupled to an input node of the first switch and an input node of the second switch;
receiving, using a bootstrapping circuit, a voltage and generating an output signal selectively coupleable to the first midpoint node and the second midpoint node to bias the first midpoint node or the second midpoint node to a representation of the voltage based on whether the first switch is in the OFF state or the second switch is in the OFF state;
and
coupling an output of the first switch to a first resistor in a first feedback path of the TIA circuit, and coupling an output of the second switch to a second resistor in a second feedback path of the TIA circuit.

3 more elements

A low off-leakage switched gain trans-impedance amplifier (TIA) circuit having an input terminal to receive an input current, the switched gain TIA circuit comprising:

a first switch including a first transistor circuit coupled in series with a second transistor circuit via a first midpoint node, wherein a back-gate node of the second transistor circuit is coupled to the first midpoint node, and wherein the first switch has an ON state and an OFF state;
a second switch including a third transistor circuit coupled in series with a fourth transistor circuit via a second midpoint node, wherein a back-gate node of the fourth transistor circuit is coupled to the second midpoint node, wherein the second switch has an ON state and an OFF state, wherein the second switch is configured to be in the ON state when the first switch is in the OFF state;
an amplifier circuit including an output node coupled to an input node of the first switch and an input node of the second switch;
and
a bootstrapping circuit configured to receive a voltage and generate an output signal selectively coupleable to the first midpoint node and the second midpoint node to bias the first midpoint node or the second midpoint node to a representation of the voltage based on whether the first switch is in the OFF state or the second switch is in the OFF state,
wherein an output of the first switch is coupled to a first resistor in a first feedback path of the TIA circuit, and wherein an output of the second switch is coupled to a second resistor in a second feedback path of the TIA circuit.

3 more elements

Dependencies are inferred from the claim text.

Low off-leakage current switch

Life of this patent

Low off-leakage current switch

Life of this patent

Abstract

Claims20