A power supply circuit and techniques for voltage regulation are described. Certain aspects provide a method of supplying power by a power supply circuit. The method generally includes: generating an output voltage based on a voltage at a Vin node via a first transistor having a gate coupled to a gate of a second transistor, wherein a source of the second transistor is coupled to the Vin node and wherein a drain of the second transistor is coupled a drain of a third transistor; and sourcing a current to the third transistor, wherein during a light load condition of the power supply circuit, the current varies based on the voltage at a Vout node of the power supply circuit, and during a heavy load condition of the power supply circuit, the current is limited based on a current threshold.

A circuit configured to perform low-dropout regulation of an output voltage includes a first buffer, a second buffer, controller circuitry, and switching circuitry. The first buffer includes a first driving element configured to provide a first current into a first output node based on the output voltage. The first bias circuitry is configured to bias the first current. The second buffer includes a second driving element configured to provide a second current into a second output node based on a voltage at the first output node. The second bias circuitry is configured to bias the second current. The controller circuitry is configured to generate a control signal based on a current at the pass device and switching circuitry configured to electrically couple the first output node to the control node of the pass device based on the control signal.

A circuit configured to perform low-dropout regulation of an output voltage includes a first buffer, a second buffer, controller circuitry, and switching circuitry. The first buffer includes a first driving element configured to provide a first current into a first output node based on the output voltage. The first bias circuitry is configured to bias the first current. The second buffer includes a second driving element configured to provide a second current into a second output node based on a voltage at the first output node. The second bias circuitry is configured to bias the second current. The controller circuitry is configured to generate a control signal based on a current at the pass device and switching circuitry configured to electrically couple the first output node to the control node of the pass device based on the control signal.

In certain aspects, a voltage regulator includes a pass device coupled between an input of the voltage regulator and an output of the voltage regulator. The voltage regulator also includes an amplifying circuit having a first input, a second input, and an output, wherein the first input is configured to receive a reference voltage, the second input is coupled to the output of the voltage regulator via a feedback path, and the output of the amplifying circuit is coupled to a gate of the pass device. The voltage regulator further includes a first current source coupled between a supply rail and the amplifying circuit, and a capacitor coupled between the first current source and the output of the voltage regulator.

In certain aspects, a voltage regulator includes a pass device coupled between an input of the voltage regulator and an output of the voltage regulator. The voltage regulator also includes an amplifying circuit having a first input, a second input, and an output, wherein the first input is configured to receive a reference voltage, the second input is coupled to the output of the voltage regulator via a feedback path, and the output of the amplifying circuit is coupled to a gate of the pass device. The voltage regulator further includes a first current source coupled between a supply rail and the amplifying circuit, and a capacitor coupled between the first current source and the output of the voltage regulator.

A voltage reference circuit that can operate in a large supply voltage range with high PSRR, that dissipates low-power for a given output noise, and that has a low temperature-coefficient (TC) across a wide-temperature range. The voltage reference circuit does not require any calibration for low TC and high PSRR, occupies a relatively small circuit area, may be used without additional supply filtering in noisy or high-ripple supply environments, and is more robust against device mismatch effects particularly compared to designs based on sub-threshold operations. The voltage reference circuit is a special form of constant transconductance circuit that uses current mirror ratios that are chosen to achieve high PSSR and low noise properties. The device saturation voltage may be chosen so that flat temperature characteristics may be achieved.

A voltage reference circuit that can operate in a large supply voltage range with high PSRR, that dissipates low-power for a given output noise, and that has a low temperature-coefficient (TC) across a wide-temperature range. The voltage reference circuit does not require any calibration for low TC and high PSRR, occupies a relatively small circuit area, may be used without additional supply filtering in noisy or high-ripple supply environments, and is more robust against device mismatch effects particularly compared to designs based on sub-threshold operations. The voltage reference circuit is a special form of constant transconductance circuit that uses current mirror ratios that are chosen to achieve high PSSR and low noise properties. The device saturation voltage may be chosen so that flat temperature characteristics may be achieved.

A load coupled to a linear voltage regulator may create a load transient so that an output of the voltage regulator is temporarily raised to an elevated level above a regulated level. Without compensation, the linear voltage regulator may respond by turning a pass transistor completely OFF thereby losing regulation and allowing a compensation capacitor to become charged in a polarization opposite to one required for regulation. If a subsequent load transient (i.e., back-to-back load transient) is generated while the linear voltage regulator is in this condition, a large spike in the output may occur as the voltage regulator recharges the pass transistor turns back ON and as the compensation capacitor recharges. Disclosed herein is a linear voltage regulator with transient compensation circuitry to prevent the scenario described above and reduce the spike in the output.

A load coupled to a linear voltage regulator may create a load transient so that an output of the voltage regulator is temporarily raised to an elevated level above a regulated level. Without compensation, the linear voltage regulator may respond by turning a pass transistor completely OFF thereby losing regulation and allowing a compensation capacitor to become charged in a polarization opposite to one required for regulation. If a subsequent load transient (i.e., back-to-back load transient) is generated while the linear voltage regulator is in this condition, a large spike in the output may occur as the voltage regulator recharges the pass transistor turns back ON and as the compensation capacitor recharges. Disclosed herein is a linear voltage regulator with transient compensation circuitry to prevent the scenario described above and reduce the spike in the output.

An irrigation system comprises an irrigation controller that receives user input and provides a power signal and command and message data to an encoder. The encoder encodes the command and message data onto the power signal to provide a data encoded power waveform that is sent over a two-wire path. The irrigation system further comprises one or more decoders in communication with the two-wire path to receive the data encoded power waveform and one or more irrigation valves in communication with the one or more decoders. The data encoded power waveform provides power to the decoders and the decoders decode the command and message data from the data encoded power waveform to control the irrigation valves according to the user input.