Loop powered process control instrument power supply
AssigneeMagnetrol International, Incorporated
InventorMichael D. Flasza
Life of this patent
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Abstract
A loop powered process instrument comprises a control circuit measuring a process variable and developing a control signal representing the process variable. An output circuit for connection to a two-wire process loop controls current on the loop in accordance with the control signal. A power supply circuit is connected to the output circuit and the control circuit for receiving power from the two-wire process loop and supplying power to the control circuit. The power supply comprises cascaded charge pump circuits.
Claims20
A loop powered process instrument comprising:
- a control circuit measuring a process variable and developing a control signal representing the process variable;
- an output circuit for connection to a two-wire process loop for controlling current on the loop in accordance with the control signal;
- and
- a power supply circuit connected to the output circuit and the control circuit for receiving power from the two-wire process loop and supplying power to the control circuit, comprising cascaded charge pump circuits.
A loop powered process instrument comprising:
- a control circuit measuring a process variable and developing a control signal representing the process variable;
- an output circuit for connection to a two-wire process loop for controlling current on the loop in accordance with the control signal;
- and
- a power supply circuit connected to the output circuit and the control circuit for receiving power from the two-wire process loop and supplying power to the control circuit, comprising a current source providing a select current to a plurality of cascaded switched capacitor voltage dividers.
In a loop powered process instrument including a control circuit measuring a process variable and developing a control signal representing the process variable and an output circuit for connection to a two-wire process loop for controlling current on the loop in accordance with the control signal, the improvement comprising:
- a power supply circuit connected to the output circuit and the control circuit for receiving power from the two-wire process loop and supplying power to the control circuit, comprising a plurality of cascaded switched capacitor voltage dividers.
Dependencies are inferred from the claim text.