Hybrid comparator and method

A method of measuring an input voltage using a first half-cell comparator and a second half-cell comparator, wherein each half-cell comparator includes a first amplification stage, a second amplification stage, at least one first coupling component for coupling voltage to the input of the first amplification stage, and at least one second coupling component for coupling an output of the first amplification stage to an input of the second amplification stage, wherein the first coupling component and the second coupling components have capacitance, the method comprising:

• deactivating a first analog switch to remove, during a first time period, a reference voltage from the first coupling component of the first half-cell comparator;
• activating a second analog switch to apply, during the first time period, the input voltage to the first coupling component of the first half-cell comparator;
• deactivating a third analog switch to remove, during the first time period, the input voltage from the first coupling component of the second half-cell comparator;
• activating a fourth analog switch to apply, during the first time period, the reference voltage to the first coupling component of the second half-cell comparator;
• deactivating the second analog switch to remove, during a second time period, the input voltage from the first coupling component of the first half-cell comparator;
• coupling, during the first time period, the outputs of the first amplification stage of the first and second half-cell comparators to their respective inputs;
• activating the first analog switch to apply, during the second time period, the reference voltage to the first coupling component of the first half-cell comparator;
• deactivating the fourth analog switch to remove, during the second time period, the reference voltage from the first coupling component of the second half-cell comparator;
• activating the third analog switch to apply, during the second time period, the input voltage to the first coupling component of the second half-cell comparator;
• decoupling the outputs of the first amplification stage of the first and second half-cell comparators from their respective inputs during at least the second time period
• coupling, during a third time period, the output of the second amplification stage of the first half-cell comparator to the input of the second amplification stage of the second half-cell comparator;
• and
• coupling, during the third time period, the output of the second amplification stage of the second half-cell comparator to the input of the second amplification stage of the first half-cell comparator.

A method of measuring an input voltage using a first half-cell comparator and a second half-cell comparator, wherein each half-cell comparator includes at least one amplification stage and at least one first coupling component for coupling voltage to the input of the at least one amplification stage, the method comprising:

• applying, during a first time period, the input voltage to the first coupling component of the first half-cell comparator;
• applying, during the first time period, a reference voltage to the first coupling component of the second half-cell comparator;
• applying, during a second time period, the reference voltage to the first coupling component of the first half-cell comparator;
• applying, during the second time period, the input voltage to the first coupling component of the second half-cell comparator;
• during a third time period, receiving, at a control circuit, complementary half-cell outputs from the first and second half-cell comparators, wherein one output is substantially equal to a maximum supply voltage and wherein the complementary output is substantially equal to a minimum supply voltage;
• during the third time period, outputting from the control circuit a maximum and a minimum control voltage, wherein the maximum and the minimum control voltage are substantially the same regardless of which half-cell comparator output is substantially equal to the maximum supply voltage and regardless of which half-cell comparator output is substantially equal to the minimum supply voltage;
• receiving, during the third time period, the maximum and minimum control voltages at the at least one amplification stage of each half-cell comparator;
• and
• disabling the at least one amplification stage of each half-cell comparator in response to the control voltages.

A method of measuring an input voltage using a first half-cell comparator and a second half-cell comparator, wherein each half-cell comparator includes a first amplification stage, a second amplification stage, at least one first coupling component for coupling voltage to the input of the first amplification stage, and at least one second coupling component for coupling an output of the first amplification stage to an input of the second amplification stage, the method comprising:

• applying, during a first time period, the input voltage to the first coupling component of the first half-cell comparator;
• applying, during the first time period, a reference voltage to the first coupling component of the second half-cell comparator;
• applying, during a second time period, the reference voltage to the first coupling component of the first half-cell comparator;
• applying, during the second time period, the input voltage to the first coupling component of the second half-cell comparator;
• and
• coupling, during a third time period, a bias voltage to the output of the first amplification stage of each half-cell comparator.

A method of measuring an input voltage using a first half-cell comparator and a second half-cell comparator, wherein each half-cell comparator includes a first amplification stage, a second amplification stage, at least one first coupling component for coupling voltage to the input of the first amplification stage, and at least one second coupling component for coupling an output of the first amplification stage to an input of the second amplification stage, the method comprising:

• during a first time period:
• applying the input voltage to the first coupling component of the first half-cell comparator;
• applying a reference voltage to the first coupling component of the second half-cell comparator;
• during a second time period:
• applying the reference voltage to the first coupling component of the first half-cell comparator;
• applying, during the second time period, the input voltage to the first coupling component of the second half-cell comparator;
• during a third time period:
• coupling the output of the second amplification stage of the first half-cell comparator to the input of the second amplification stage of the second half-cell comparator;
• coupling the output of the second amplification stage of the second half-cell comparator to the input of the second amplification stage of the first half-cell comparator;
• receiving, at a control circuit, complementary half-cell outputs from the first and second half-cell comparators, wherein one output is substantially equal to a maximum supply voltage and wherein the complementary output is substantially equal to a minimum supply voltage;
• outputting from the control circuit a maximum and a minimum control voltage, wherein the maximum and the minimum control voltage are substantially the same regardless of which half-cell comparator output is substantially equal to the maximum supply voltage and regardless of which half-cell comparator output is substantially equal to the minimum supply voltage;
• receiving the maximum and minimum control voltages at the first amplification stage of each half-cell comparator;
• and
• disabling the first amplification stage of each half-cell comparator in response to the control voltages, wherein disabling the first amplification stages reduces power consumption;
• and
• coupling a bias voltage to the output of the first amplification stage of each half-cell comparator.

A voltage measuring circuit comprising a first half-cell comparator and a second half-cell comparator, wherein each half-cell comparator comprises:

• a first amplification stage;
• at least one first coupling component for coupling voltage to the input of the first amplification stage;
• a first pair of complementary clocked analog switches for applying either a reference voltage or an input voltage to the at least one first coupling component;
• a second amplification stage;
• at least one second coupling component for coupling an output of the first amplification stage to an input of the second amplification stage;
• and
• a cross-coupling clocked analog switch for connecting an output of the second amplification stage of a half-cell to the input of the second amplification stage of the other half-cell;
• wherein the first pair of complementary clocked analog switches are connected so that when the input voltage is applied to the first half-cell, the reference voltage is applied to the second half-cell, and when the reference voltage is applied to the first half-cell, the input voltage is applied to the second half-cell;
• wherein the first amplification stage of the first and second half-cells generate a first output voltage and a complementary second output voltage, respectively;
• and
• wherein the cross-coupling clocked analog switches latch the outputs of each second amplifier stage.