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.

An all-MOSFET voltage reference circuit includes a first cascaded branch configured to generate a bias current and composed of a first current source and a diode-connected first N-type transistor connected at a first interconnected node; a second cascaded branch composed of a second current source, a diode-connected second N-type transistor and a third N-type transistor connected with the second N-type transistor disposed in between, wherein the second N-type transistor and the third N-type transistor are connected at a second interconnected node; a third cascaded branch composed of a third current source and a diode-connected fourth N-type transistor connected at an output node that provides a reference voltage; and an amplifier with a non-inverting node coupled to the first interconnected node and an inverting node coupled to the second interconnected node. A threshold voltage of the third N-type transistor is larger than a threshold voltage of the second N-type transistor.

An all-MOSFET voltage reference circuit includes a first cascaded branch configured to generate a bias current and composed of a first current source and a diode-connected first N-type transistor connected at a first interconnected node; a second cascaded branch composed of a second current source, a diode-connected second N-type transistor and a third N-type transistor connected with the second N-type transistor disposed in between, wherein the second N-type transistor and the third N-type transistor are connected at a second interconnected node; a third cascaded branch composed of a third current source and a diode-connected fourth N-type transistor connected at an output node that provides a reference voltage; and an amplifier with a non-inverting node coupled to the first interconnected node and an inverting node coupled to the second interconnected node. A threshold voltage of the third N-type transistor is larger than a threshold voltage of the second N-type transistor.

A voltage generation circuit includes an amplifier configured to detect a difference between a reference voltage and a feedback voltage according to a control signal and a bias current, and configured to generate a driving signal. The voltage generation circuit also includes a driver configured to generate an internal voltage by driving an external voltage according to the driving signal. The amount of the bias current may be forcibly adjusted by the control signal.

A voltage generation circuit includes an amplifier configured to detect a difference between a reference voltage and a feedback voltage according to a control signal and a bias current, and configured to generate a driving signal. The voltage generation circuit also includes a driver configured to generate an internal voltage by driving an external voltage according to the driving signal. The amount of the bias current may be forcibly adjusted by the control signal.

A constant voltage generator circuit is provided with an operational amplifier including a feedback circuit having a first resistor, and an output transistor. The operational amplifier generates a feedback voltage generated by dividing an output voltage between an output terminal and a substrate voltage potential of the constant voltage generator circuit by the first resistor and a second resistor. Then, the operational amplifier is configured to amplify a voltage potential difference between a predetermined reference voltage and the feedback voltage and to output a control voltage. The output transistor controls an output voltage based on the control voltage from the operational amplifier, and the feedback circuit is further configured to superimpose high-frequency noise components from the substrate voltage potential onto the feedback voltage.

A constant voltage generator circuit is provided with an operational amplifier including a feedback circuit having a first resistor, and an output transistor. The operational amplifier generates a feedback voltage generated by dividing an output voltage between an output terminal and a substrate voltage potential of the constant voltage generator circuit by the first resistor and a second resistor. Then, the operational amplifier is configured to amplify a voltage potential difference between a predetermined reference voltage and the feedback voltage and to output a control voltage. The output transistor controls an output voltage based on the control voltage from the operational amplifier, and the feedback circuit is further configured to superimpose high-frequency noise components from the substrate voltage potential onto the feedback voltage.

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.

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.

An apparatus is provided, which includes energy storage circuitry to store energy and to supply some of the energy to the apparatus. Discharge circuitry discharges the energy storage circuitry in response to the energy being supplied to the apparatus. Power supply circuitry recharges the energy storage circuitry. The discharge circuitry retains a non-zero residual energy in the energy storage circuitry when the energy storage circuitry is discharged by the discharge circuitry.