Abstract: A low voltage crystal oscillator (XTAL) driver with feedback controlled duty cycling for ultra low power biases an amplifier for an XTAL in the sub-threshold operating regime. A feedback control scheme can be used to bias the amplifier for an XTAL biased in the sub-threshold operating regime. The amplifier of a XTAL oscillator can be duty cycled to save power, e.g., the XTAL driver can be turned off to save power when the amplitude of the XTAL oscillation reaches a maximum value in range; but be turned back on when the amplitude of the XTAL oscillation starts to decay, to maintain the oscillation before it stops. In addition or alternatively, a feedback control scheme to duty cycle the amplifier of a XTAL oscillator can be used to monitor the amplitude of the oscillation.

Abstract: In some embodiments, an apparatus includes a bandgap reference circuit having a first bipolar junction transistor (BJT) that can receive a current from a node having a terminal voltage and can output a base emitter voltage. The apparatus also includes a second bipolar junction transistor (BJT) having a device width greater than a device width of the first BJT. The second BJT can receive a current from a node having a terminal voltage and output a base emitter voltage. In such embodiments, the apparatus also includes a reference generation circuit operatively coupled to the first BJT and the second BJT, where the reference generation circuit can generate a bandgap reference voltage based on the base emitter voltage of the first BJT and the base emitter voltage of the second BJT.

Abstract: In some embodiments, an apparatus includes a single-inductor multiple-output (SIMO) direct current (DC-DC) converter circuit, with the SIMO DC-DC converter circuit having a set of output nodes. The apparatus also includes a panoptic dynamic voltage scaling (PDVS) circuit operatively coupled to the SIMO DC-DC converter circuit, where the PDVS circuit has a set of operational blocks with each operational block from the set of operational blocks drawing power from one supply voltage rail from a set of supply voltage rails. Additionally, each output node from the set of output nodes is uniquely associated with a supply voltage rail from the set of supply voltage rails.

Abstract: The low input voltage boost converter with peak inductor current control and offset compensated zero detection provide a boost converter scheme to harvest energy from sources with small output voltages. Some embodiments described herein includes a thermoelectric boost converter that combines an IPEAK control scheme with offset compensation and duty cycled comparators to enable energy harvesting from TEG inputs as low as 5 mV to 10 mV, and the peak inductor current is independent to first order of the input voltage and output voltage. A control circuit can be configured to sample the input voltage (VIN) and then generate a pulse with a duration inversely proportional to VIN so as to control the boost converter switches such that a substantially constant peak inductor current is generated.

Abstract: A system comprising an ambient energy source, a power supply, and a power storage device. The ambient energy source is coupled to a first terminal end of an inductor. The power supply is also coupled to the first terminal end of the inductor. The power storage device is coupled to a second terminal end of the inductor. The ambient energy source provides power through the inductor in a first direction to the power storage device. The power storage device provides power through the inductor to the power supply in a second direction opposite the first direction.

Abstract: In some embodiments, an apparatus includes a single-inductor multiple-output (SIMO) direct current (DC-DC) converter circuit, with the SIMO DC-DC converter circuit having a set of output nodes. The apparatus also includes a panoptic dynamic voltage scaling (PDVS) circuit operatively coupled to the SIMO DC-DC converter circuit, where the PDVS circuit has a set of operational blocks with each operational block from the set of operational blocks drawing power from one supply voltage rail from a set of supply voltage rails. Additionally, each output node from the set of output nodes is uniquely associated with a supply voltage rail from the set of supply voltage rails.

Abstract: An ultra-low power clock source includes a compensated oscillator and an uncompensated oscillator coupled by a comparator circuit. In an example, the compensated oscillator is more stable than the uncompensated oscillator with respect to changes in one or more of temperature, voltage, age, or other environmental parameters. The uncompensated oscillator includes a configuration input configured to adjust an operating characteristic of the uncompensated oscillator. In an example, the uncompensated oscillator is adjusted using information from the comparator circuit about a comparison of output signals from the compensated oscillator and the uncompensated oscillator.

Abstract: A low voltage crystal oscillator (XTAL) driver with feedback controlled duty cycling for ultra low power biases an amplifier for an XTAL in the sub-threshold operating regime. A feedback control scheme can be used to bias the amplifier for an XTAL biased in the sub-threshold operating regime. The amplifier of a XTAL oscillator can be duty cycled to save power, e.g., the XTAL driver can be turned off to save power when the amplitude of the XTAL oscillation reaches a maximum value in range; but be turned back on when the amplitude of the XTAL oscillation starts to decay, to maintain the oscillation before it stops. In addition or alternatively, a feedback control scheme to duty cycle the amplifier of a XTAL oscillator can be used to monitor the amplitude of the oscillation.

Abstract: The low input voltage boost converter with peak inductor current control and offset compensated zero detection provide a boost converter scheme to harvest energy from sources with small output voltages. Some embodiments described herein includes a thermoelectric boost converter that combines an IPEAK control scheme with offset compensation and duty cycled comparators to enable energy harvesting from TEG inputs as low as 5 mV to 10 mV, and the peak inductor current is independent to first order of the input voltage and output voltage. A control circuit can be configured to sample the input voltage (VIN) and then generate a pulse with a duration inversely proportional to VIN so as to control the boost converter switches such that a substantially constant peak inductor current is generated.

Abstract: An ultra-low power clock source includes a compensated oscillator and an uncompensated oscillator coupled by a comparator circuit. In an example, the compensated oscillator is more stable than the uncompensated oscillator with respect to changes in one or more of temperature, voltage, age, or other environmental parameters. The uncompensated oscillator includes a configuration input configured to adjust an operating characteristic of the uncompensated oscillator. In an example, the uncompensated oscillator is adjusted using information from the comparator circuit about a comparison of output signals from the compensated oscillator and the uncompensated oscillator.

Abstract: A low voltage crystal oscillator (XTAL) driver with feedback controlled duty cycling for ultra low power biases an amplifier for an XTAL in the sub-threshold operating regime. A feedback control scheme can be used to bias the amplifier for an XTAL biased in the sub-threshold operating regime. The amplifier of a XTAL oscillator can be duty cycled to save power, e.g., the XTAL driver can be turned off to save power when the amplitude of the XTAL oscillation reaches a maximum value in range; but be turned back on when the amplitude of the XTAL oscillation starts to decay, to maintain the oscillation before it stops. In addition or alternatively, a feedback control scheme to duty cycle the amplifier of a XTAL oscillator can be used to monitor the amplitude of the oscillation.

Abstract: The low input voltage boost converter with peak inductor current control and offset compensated zero detection provide a boost converter scheme to harvest energy from sources with small output voltages. Some embodiments described herein includes a thermoelectric boost converter that combines an IPEAK control scheme with offset compensation and duty cycled comparators to enable energy harvesting from TEG inputs as low as 5 mV to 10 mV, and the peak inductor current is independent to first order of the input voltage and output voltage. A control circuit can be configured to sample the input voltage (VIN) and then generate a pulse with a duration inversely proportional to VIN so as to control the boost converter switches such that a substantially constant peak inductor current is generated.

Abstract: The low input voltage boost converter with peak inductor current control and offset compensated zero detection provide a boost converter scheme to harvest energy from sources with small output voltages. Some embodiments described herein includes a thermoelectric boost converter that combines an IPEAK control scheme with offset compensation and duty cycled comparators to enable energy harvesting from TEG inputs as low as 5 mV to 10 mV, and the peak inductor current is independent to first order of the input voltage and output voltage. A control circuit can be configured to sample the input voltage (VIN) and then generate a pulse with a duration inversely proportional to VIN so as to control the boost converter switches such that a substantially constant peak inductor current is generated.

Abstract: The low input voltage boost converter with peak inductor current control and offset compensated zero detection provide a boost converter scheme to harvest energy from sources with small output voltages. Some embodiments described herein includes a thermoelectric boost converter that combines an IPEAK control scheme with offset compensation and duty cycled comparators to enable energy harvesting from TEG inputs as low as 5 mV to 10 mV, and the peak inductor current is independent to first order of the input voltage and output voltage. A control circuit can be configured to sample the input voltage (VIN) and then generate a pulse with a duration inversely proportional to VIN so as to control the boost converter switches such that a substantially constant peak inductor current is generated.

Abstract: A low voltage crystal oscillator (XTAL) driver with feedback controlled duty cycling for ultra low power biases an amplifier for an XTAL in the sub-threshold operating regime. A feedback control scheme can be used to bias the amplifier for an XTAL biased in the sub-threshold operating regime. The amplifier of a XTAL oscillator can be duty cycled to save power, e.g., the XTAL driver can be turned off to save power when the amplitude of the XTAL oscillation reaches a maximum value in range; but be turned back on when the amplitude of the XTAL oscillation starts to decay, to maintain the oscillation before it stops. In addition or alternatively, a feedback control scheme to duty cycle the amplifier of a XTAL oscillator can be used to monitor the amplitude of the oscillation.

Abstract: The low input voltage boost converter with peak inductor current control and offset compensated zero detection provide a boost converter scheme to harvest energy from sources with small output voltages. Some embodiments described herein includes a thermoelectric boost converter that combines an IPEAK control scheme with offset compensation and duty cycled comparators to enable energy harvesting from TEG inputs as low as 5 mV to 10 mV, and the peak inductor current is independent to first order of the input voltage and output voltage. A control circuit can be configured to sample the input voltage (VIN) and then generate a pulse with a duration inversely proportional to VIN so as to control the boost converter switches such that a substantially constant peak inductor current is generated.

Abstract: In some embodiments, an apparatus includes a bandgap reference circuit having a first bipolar junction transistor (BJT) that can receive a current from a node having a terminal voltage and can output a base emitter voltage. The apparatus also includes a second bipolar junction transistor (BJT) having a device width greater than a device width of the first BJT. The second BJT can receive a current from a node having a terminal voltage and output a base emitter voltage. In such embodiments, the apparatus also includes a reference generation circuit operatively coupled to the first BJT and the second BJT, where the reference generation circuit can generate a bandgap reference voltage based on the base emitter voltage of the first BJT and the base emitter voltage of the second BJT.

Abstract: Apparatus and method for controlling inductor current in a switch mode power supply. In one embodiment, a switch mode power supply includes an inductor, a high-side switch coupled to the inductor, a low-side switch coupled to the inductor, and a controller. The controller is coupled to at least one of the high-side switch and the low-side switch. The controller includes a first capacitor and a current source. The controller is configured to control timing of current switching to the inductor by enabling current flow through the at least one of the high-side switch and the low-side switch based on time to charge the first capacitor via the current source. The time is a function of voltage across the inductor.

Abstract: In some embodiments, an apparatus includes a bandgap reference circuit having a first bipolar junction transistor (BJT) that can receive a current from a node having a terminal voltage and can output a base emitter voltage. The apparatus also includes a second bipolar junction transistor (BJT) having a device width greater than a device width of the first BJT. The second BJT can receive a current from a node having a terminal voltage and output a base emitter voltage. In such embodiments, the apparatus also includes a reference generation circuit operatively coupled to the first BJT and the second BJT, where the reference generation circuit can generate a bandgap reference voltage based on the base emitter voltage of the first BJT and the base emitter voltage of the second BJT.

Abstract: A low voltage crystal oscillator (XTAL) driver with feedback controlled duty cycling for ultra low power biases an amplifier for an XTAL in the sub-threshold operating regime. A feedback control scheme can be used to bias the amplifier for an XTAL biased in the sub-threshold operating regime. The amplifier of a XTAL oscillator can be duty cycled to save power, e.g., the XTAL driver can be turned off to save power when the amplitude of the XTAL oscillation reaches a maximum value in range; but be turned back on when the amplitude of the XTAL oscillation starts to decay, to maintain the oscillation before it stops. In addition or alternatively, a feedback control scheme to duty cycle the amplifier of a XTAL oscillator can be used to monitor the amplitude of the oscillation.