Abstract: This application relates to analog-to-digital converter (ADC) circuitry (200). A time-encoding modulator (TEM 201) has a comparator (104) and a loop filter (105) configured to generate a pulse-width-modulated (PWM) signal (SPWM) in response to an input signal (SIN) and a feedback signal (SFB). A controlled oscillator, such as a VCO (202) receives the PWM signal and generates an output oscillation signal (SOSC) with a frequency that varies based on a drive signal at a drive node (109), e.g. a drive node of a ring oscillator (107). The controlled oscillator (202) comprises at least one control switch (112) controlled by a switch control signal (S1) generated from the received PWM signal so as to control the drive strength of the drive signal applied to the drive node (109). The feedback signal (SFB) for the TEM (201) is derived from the controlled oscillator (202) so as to include any timing error between the PWM signal and the switch control signal (S1) applied to said control switch.

Abstract: Methods and apparatus provide multiple input voltage regulation in which one regulator is selected for operation based on input power conditions. In one example, a dual input voltage regulator system in a combination smart card selects between contact and contactless (e.g., RF) operation based on which power source provides the highest available voltage level. A single transistor drop architecture provides low drop-out voltage regulation capability without substantially increased transistor size. In some implementations, multiplexed control of the regulators for each of a number independent power source inputs may be arranged to substantially reduce or prevent reverse current flow through regulators connected to inactive power inputs.

Abstract: Methods and apparatus may provide for multiple input voltage regulation in which a current supplied to an output node divides among voltage regulators according to their respective input voltages when the difference in input voltages falls within a voltage range. When the difference in input voltages falls outside of the voltage range, then the current to the output node is supplied substantially through the voltage regulator with the highest input voltage. In some implementations, the voltage range may be determined, at least in part, by a transistor gate-to-source threshold voltage characteristic. In one example, a dual input voltage regulator system in a combination smart card supplies current from contact and/or contactless (e.g., inductively coupled) power sources based on a relative voltage between the respective input voltages.

Abstract: A device can include one or more circuits that are configured to be powered by a supply voltage having a specified minimum operating value and a specified nominal operating value; and a reset circuit having a first voltage threshold and a second voltage threshold, the first voltage threshold having a value between the specified minimum operating value and the specified nominal operating value, the second voltage threshold having a value that is less than the specified minimum operating voltage. The reset circuit can be configured to a) reset the one or more circuits when the device is functioning in a first mode and the supply voltage drops below the first threshold and b) reset the one or more of circuits when the device is functioning in a second mode and the supply voltage drops below the second threshold.

Abstract: A device can include one or more circuits that are configured to be powered by a supply voltage having a specified minimum operating value and a specified nominal operating value; and a reset circuit having a first voltage threshold and a second voltage threshold, the first voltage threshold having a value between the specified minimum operating value and the specified nominal operating value, the second voltage threshold having a value that is less than the specified minimum operating voltage. The reset circuit can be configured to a) reset the one or more circuits when the device is functioning in a first mode and the supply voltage drops below the first threshold and b) reset the one or more of circuits when the device is functioning in a second mode and the supply voltage drops below the second threshold.

Abstract: Methods and apparatus may provide for multiple input voltage regulation in which a current supplied to an output node divides among voltage regulators according to their respective input voltages when the difference in input voltages falls within a voltage range. When the difference in input voltages falls outside of the voltage range, then the current to the output node is supplied substantially through the voltage regulator with the highest input voltage. In some implementations, the voltage range may be determined, at least in part, by a transistor gate-to-source threshold voltage characteristic. In one example, a dual input voltage regulator system in a combination smart card supplies current from contact and/or contactless (e.g., inductively coupled) power sources based on a relative voltage between the respective input voltages.

Abstract: Methods and apparatus provide multiple input voltage regulation in which one regulator is selected for operation based on input power conditions. In one example, a dual input voltage regulator system in a combination smart card selects between contact and contactless (e.g., RF) operation based on which power source provides the highest available voltage level. A single transistor drop architecture provides low drop-out voltage regulation capability without substantially increased transistor size. In some implementations, multiplexed control of the regulators for each of a number independent power source inputs may be arranged to substantially reduce or prevent reverse current flow through regulators connected to inactive power inputs.