# US 9,819,346 B2 · PLC system

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- Number: US 9,819,346 B2
- Document ID: US9819346B2
- Status: Granted
- Kind: B2
- Application number: 15/293,210
- Filed: 2016-10-13
- Published: 2017-04-20
- Granted: 2017-11-14
- Earliest claimed: 2015-10-20
- Assignees: Lsis Co., Ltd.
- Applicants: Lsis Co., Ltd.
- Inventors: Ho-Kee Lee
- Web page: https://patentgrep.com/patent/US9819346B2

## CPC

- H03K 19/1776: for memories
- G05B 19/058: {Safety, monitoring}
- G06F 1/189: {Power distribution}
- G11C 5/14: Power supply arrangements {, e.g. power down, chip selection or deselection, layout of wirings or power grids, or multiple supply levels}
- G05B 2219/14053: Power failure, loss, abnormal battery
- G05B 2219/24137: Non volatile memory to store program on power loss
- H03K: PULSE TECHNIQUE (measuring pulse characteristics G01R; modulating sinusoidal oscillations with pulses H03C; transmission of digital information H04L; discriminator circuits detecting phase difference between two signals by counting or integrating cycles of oscillation H03D3/04; automatic control, starting, synchronisation or stabilisation of generators of electronic oscillations or pulses where the type of generator is irrelevant or unspecified H03L; coding, decoding or code conversion, in general H03M)
- G05B: CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS (systems for controlling or regulating non-electric variables G05D; systems for regulating electric or magnetic variables G05F; control devices or systems insofar as characterised by mechanical features only G05G)
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)
- G11C: STATIC STORES (semiconductor memory devices H10B)

## Abstract

In some embodiments, a PLC system includes a memory unit configured to back up user data stored in a MCU thereto when the power supply from the power module is interrupted, a capacitor configured to be charged by the power module and supply accumulated power to the memory unit when the power from the power module to the MCU is interrupted, a variable resistor unit configured to be coupled between the power module and the capacitor, and a switching unit configured to alternatively couple either the power module or the capacitor to the memory unit depending on a state of power being supplied from the power module. Some embodiments may provide advantages that a PLC system can supply much more power while reducing a charging period of time of an auxiliary power supply for supplying power with urgency when an abnormality occurs in a power module of the PLC system.

## Claims

### Claim 1

A Programmable Logic Controller (PLC) system configured to receive power from a power module, the PLC system comprising:
a memory unit configured to back up user data stored in a Micro Controller Unit (MCU) when a power supply from a power module is interrupted;
a capacitor configured to be charged by the power module and supply accumulated power to the memory unit when the power supply from the power module to the MCU is interrupted;
a variable resistor unit configured to be connected between the power module and the capacitor; and
a switching unit configured to alternatively connect either the power module or the capacitor to the memory unit depending on a state of power supplied from the power module,
wherein another operation of the PLC system, other than the charging of the capacitor, is restricted until the charging of the capacitor is completed.

### Claim 2 (depends on 1)

The PLC system according to claim 1, wherein a resistance of the variable resistor unit is determined based at least on a capacity of the power module.

### Claim 3 (depends on 1)

The PLC system according to claim 1, further comprising:
a voltage transform unit configured to be coupled between the capacitor and the switching unit and transform a voltage supplied from the capacitor to a voltage needed for the memory unit.

### Claim 4 (depends on 1)

The PLC system according to claim 1, wherein the switching unit is further configured to couple the power module and the memory unit only when the user data back-up is completed and wherein when the supply of power from the power module is resumed during user data back-up, the switching unit is further configured to continue coupling the capacitor to the memory unit.