Programmable logic controller
AssigneeOMRON Corporation
InventorsHiroaki Ueda, Hideki Harada, Daisuke Wakabayashi
Life of this patent
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Abstract
A power supply circuit in a PLC includes a first node that receives a DC voltage with a first level, a second node that outputs a voltage for driving a control unit, wiring connecting the first and second nodes, a first rectifier on the wiring having a forward direction from the first node to the second node, a charger for charging and discharging, a first converter that converts a discharging voltage from the charger into a DC voltage with a second level lower than the first level and outputs the voltage, and a second rectifier connected between an output of the first converter and the second node to have a forward direction from the first converter to the second node.
Claims4
A programmable logic controller, comprising:
- a control unit configured to control a target device;
- and
- a power supply circuit comprising:
- a first node configured to receive a first DC voltage;
- a second node configured to output a voltage for driving the control unit;
- a first rectifier connecting the first node and the second node, the first rectifier having a forward direction from the first node to the second node;
- a charger configured to perform charging and discharging;
- a first converter configured to convert a discharging voltage output from the charger into a second DC voltage that is lower than the first DC voltage, and output the second DC voltage;
- a second rectifier connecting an output of the first converter and the second node, the second rectifier having a forward direction from the first converter to the second node;
- and
- a second converter that converts the first DC voltage into a third DC voltage that is higher than the first DC voltage, and outputs the third DC voltage to the charger, wherein
- the second converter comprises:
- a second converter circuit comprising a second switching element and configured to generate and output a DC voltage determined in accordance with a conduction ratio of the second switching element;
- a second voltage detection unit configured to detect the third DC voltage;
- and
- a second control circuit configured to:
- operate on the first DC voltage, and control a switching operation of the second switching element;
- stop the switching operation of the second switching element in response to the third DC voltage reaching a first predetermined level;
- and
- start the switching operation of the second switching element in response to the third DC voltage decreasing below the first predetermined level.
A programmable logic controller, comprising:
- a control unit configured to control a target device;
- and
- a power supply circuit comprising:
- a first node configured to receive a first DC voltage;
- a second node configured to output a voltage for driving the control unit;
- a first rectifier connecting the first node and the second node, the first rectifier having a forward direction from the first node to the second node;
- a charger configured to perform charging and discharging;
- a first converter configured to convert a discharging voltage output from the charger into a second DC voltage that is lower than the first DC voltage, and output the second DC voltage;
- and
- a second rectifier connecting an output of the first converter and the second node, the second rectifier having a forward direction from the first converter to the second node, wherein
- the first converter comprises:
- a first converter circuit comprising a first switching element and configured to generate and output a DC voltage determined in accordance with a conduction ratio of the first switching element;
- a first voltage detection unit configured to detect the second DC voltage;
- and
- a first control circuit configured to:
- operate on the discharging voltage output from the charger, and control a switching operation of the first switching element;
- stop the switching operation of the first switching element in response to the second DC voltage reaching a second predetermined level;
- and
- start the switching operation of the first switching element in response to the second DC voltage decreasing below the second predetermined level.
Dependencies are inferred from the claim text.