Programmable logic controller
First Claim
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1. 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, whereinthe 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.
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Accused Products
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.
18 Citations
4 Claims
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1. A programmable logic controller, comprising:
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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. - View Dependent Claims (2, 3)
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4. A programmable logic controller, comprising:
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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.
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Specification