A hybrid SAR-ADC that uses a combination of voltage-based signal processing and time-based signal processing to convert an analog input signal to a digital output signal is disclosed. In some embodiments, the hybrid SAR-ADC has a voltage-based signal processing element configured to convert an analog input signal to a first digital signal having a plurality of MSBs and to generate a residue voltage from an input voltage and the first digital signal. A voltage-to-time conversion element is configured to convert the residue voltage to a time domain representation. A time-based signal processing element is configured to convert the time domain representation to a second digital signal comprising a plurality of LSBs. By determining the plurality of MSBs using voltage-based signal processing and determining the plurality of LSBs using time-based signal processing, the hybrid SAR-ADC is able to achieve low power and compact area.

A method for indirect conversion of a voltage value to a digital word consisting in sampling an input voltage through a parallel connection of a sampling capacitor to a source of the input voltage, and next in mapping a sample value of the input voltage to a time interval, and in assignment of a corresponding value of n-bit output digital word by the use a control module characterized in that the time interval is mapped to a difference of a length of a reference time and a length of a signal time, while the reference time is generated from an instant when the beginning of the time interval is detected by the use the control module, and the signal time is generated from an instant when the end of the time interval is detected by the use the control module, whereas generation of the reference time and the signal time is terminated at the same instant.

Certain aspects of the present disclosure generally relate to a voltage-to-time-to-voltage amplifier (VTVA). The VTVA may include: a first input capacitive element selectively coupled to a first input node of the VTVA; a first amplifier having an input coupled to the first input capacitive element; a first current source configured to sink a first discharge current from the first input capacitive element during a first phase through a first switch; and a first output capacitive element coupled to a first output node of the VTVA. In some aspects, the first current source is further configured to sink a second discharge current from the first output capacitive element during a second phase through a second switch, the second switch comprising a control input coupled to an output of the first amplifier; and the first phase is non-overlapping with the second phase.

An ADC (50) is disclosed. It has two VTCs (110a, 110b) for converting a first and a second input voltage, respectively, to pulses with delays corresponding to the magnitudes of these voltages. It further has a pulse-detector circuit (120) coupled to outputs (114a, 114b) of the two VTCs (110a, 110b). The pulse-detector circuit (120) is configured to make a transition from a first logic state (0) to a second logic state (F) at a first output (124a) of the pulse-detector circuit (120) in response to the start of the pulse from one of the VTCs (110a) and to make a transition from the first logic state (0) to the second logic state (F) at a second output (124b) of the pulse-detector circuit (120) in response to the start of the pulse from the other VTC. Furthermore, the pulse-detector circuit (120) is configured to reset both the first and the second output (124a, 124b) to the first logic state (0) in response to both the first output (124a) and the second output (124b) of the pulse-detector circuit (120) being set in the second logic state (1). The ADC (50) further has a first TDC (130a) coupled to the first output (124a) of the pulse-detector circuit (120) and a second TDC (130b) coupled to the second output (124b) of the pulse-detector circuit (120).

An ADC (50) is disclosed. It has two VTCs (110a, 110b) for converting a first and a second input voltage, respectively, to pulses with delays corresponding to the magnitudes of these voltages. It further has a pulse-detector circuit (120) coupled to outputs (114a, 114b) of the two VTCs (110a, 110b). The pulse-detector circuit (120) is configured to make a transition from a first logic state (0) to a second logic state (F) at a first output (124a) of the pulse-detector circuit (120) in response to the start of the pulse from one of the VTCs (110a) and to make a transition from the first logic state (0) to the second logic state (F) at a second output (124b) of the pulse-detector circuit (120) in response to the start of the pulse from the other VTC. Furthermore, the pulse-detector circuit (120) is configured to reset both the first and the second output (124a, 124b) to the first logic state (0) in response to both the first output (124a) and the second output (124b) of the pulse-detector circuit (120) being set in the second logic state (1). The ADC (50) further has a first TDC (130a) coupled to the first output (124a) of the pulse-detector circuit (120) and a second TDC (130b) coupled to the second output (124b) of the pulse-detector circuit (120).

A rail-to-rail potentiostat may require an offset current in order to support a bidirectional work electrode current at a work electrode. This offset current may improve measurements of the work electrode current made a dual-slope analog-to-digital converter, especially when the work electrode current is small, but can also lead to inaccuracies (e.g., due to a temperature coefficient) if it is not properly calibrated. Accordingly, bidirectional potentiostat is disclosed that can be configured in a normal configuration for measurement of a work electrode current or a calibration configuration for measurement (i.e., calibration) of an offset current. The reconfigurability allows calibrations to be taken as needed, on a schedule, or as specified by a user. The reconfigurability can also allow for maintaining a work electrode voltage and a work electrode current during calibration so that an electrochemical experiment using a cell coupled to the bidirectional potentiostat is unaffected by the calibration.