KR20100115642A - Wireless modem - Google Patents

Abstract

PURPOSE: A wireless modem is provided to stably turn off power of the wireless modem in case of abnormal power off. CONSTITUTION: If supply of main power is disconnected, a sub power supply unit(20) supplies sub power by charged power. If power supply is stopped, a blackout sensing unit(10) outputs a power down signal. A power on/off unit(30) outputs a power on/off signal by a control signal of an external controller. A wireless communication unit(50) turns off power according to a preset power down process of tasks according to the power down signal or the power on/off signal.

Description

Wireless Modem {Wireless modem}

The present invention relates to a wireless modem. More particularly, the present invention relates to a wireless modem, and more specifically, to detect a disconnection of an operating power supply from a main power supply, to terminate a software task being executed normally, and to power a predetermined management server and / or a mobile network. It's about a wireless modem that automatically registers down.

In order to establish a ubiquitous environment, it is essential to establish various wireless communication environments between wireless terminals (local devices) installed in facilities near or far away and a central management server that manages them collectively.

In the M2M (Machine to Machine) communication industry, cellular mobile communication networks such as GSM / CDMA / WCDMA are widely used for long-distance wireless communication. In particular, a wireless modem using a cellular network plays a key role in the fields of automatic vehicle location (AVL), remote meter reading, and remote monitoring.

Most of these wireless modems operate by receiving DC power from an external power source such as a cigar jack power of a vehicle or a general adapter.

However, the conventional wireless modem has a problem that the external power is cut off immediately. In this case, it is like removing a battery without turning off the mobile phone by pressing the power button. As a result, the wireless modem does not perform the necessary procedure when powering down and suddenly turns off, causing various side effects. In particular, in the case of a terminal using a flash memory, if the power is suddenly disconnected without completing a write operation, an error that is difficult to recover may occur.

In order to solve the problem caused by abnormal power disconnection, an uninterruptible power supply (UPS) is conventionally used. However, since the uninterruptible power supply uses a large capacity battery and requires a complicated circuit for charging and discharging, There is a problem that is expensive and not suitable for small terminals. In addition, when using a battery, it is difficult to use in a high temperature environment, such as a car.

Moreover, in the case of a conventional wireless modem, if the power is suddenly disconnected, the operator of the device can quickly take a follow-up action such as failover because the power supply does not notify the mobile management network or the central management server that remotely manages the wireless modem. There is a problem that the abnormal state lasts for a long time. In particular, the terminal installed at a remote location or a place where people are not easily accessible (for example, a terminal installed in a mountain to monitor the forest environment, a terminal installed at a corner of a building for remote meter reading, or a flood or river level in a river) In the case of a power failure in a wireless modem used for a terminal installed for monitoring, etc., the above-described problem may be more serious.

In addition, even in a mobile communication network that does not know that the power is disconnected, there is a problem in that it wastes network resources because it continuously tries to deliver a paging message when an incoming call is generated to a corresponding terminal.

The present invention is to improve the structure of the wireless modem to perform a normal power down procedure even in the event of an abnormal power failure to be able to turn off the power stably.

In addition, the present invention is intended to prevent unnecessary waste of network resources and prompt follow-up by registering the power down to the mobile communication network and reporting the fact to the management server when an abnormal power failure occurs.

The wireless modem of the present invention charges the power when the main power supply is in a normal state, and if the main power supply is disconnected, an auxiliary power supply unit supplying auxiliary power by using the charged power, and whether the main power is disconnected. Power failure detection unit for detecting and outputting a power down signal when the power supply is disconnected, a power on / off unit for outputting a power on / off signal according to a control signal applied from an external controller and the main power or The wireless communication unit may be configured to perform wireless communication using the auxiliary power source. The wireless communication unit may be configured to turn off the power according to a preset power down procedure after normally terminating the tasks in progress when the power down signal or the power on / off signal occurs.

In the wireless modem of the present invention, the auxiliary power supply unit includes a large capacity capacitor. The power failure detecting unit divides the voltage of the main power supply at a predetermined ratio, and when the level of the divided voltage is lower than a predetermined level, the power down signal generator and the auxiliary power supply outputting the power down signal. It includes a diode to block the flow into the voltage divider. In this case, the power down signal generator includes a PNP type transistor connected between a power down signal input terminal of the wireless communication unit and a ground power source and receiving an output voltage of the voltage divider as a base terminal.

In the wireless modem of the present invention, the wireless communication unit may include a terminal to which the power down signal is applied and a terminal to which the power on / off signal is applied.

The wireless modem of the present invention compensates the voltage difference between the main voltage and the base input voltage of the main power supply and the PNP type transistor to compensate for the voltage difference between the charging voltage of the main power supply and the auxiliary power supply. It may further include a second voltage regulator.

In addition, the wireless modem of the present invention further comprises a third voltage regulator for simultaneously compensating the voltage difference between the charging voltage of the main power supply and the auxiliary power supply and the voltage difference between the main power supply and the base input voltage of the PNP type transistor. It may include.

In the wireless modem of the present invention, the wireless communication unit may transmit a report message for notifying the power down when the power down signal is generated to a predetermined central management server or register the power down fact in a mobile communication network.

The present invention enables stable operation of the wireless modem by steadily turning off the power of the wireless modem even in the event of an abnormal power cut, preventing unnecessary waste of network resources and enabling quicker follow-up when the power is cut off. Do it.

In addition, the present invention does not require a separate charging and discharging circuit by using a capacitor as an auxiliary power supply means, and can be applied to a small size wireless modem.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the present invention.

1 is a block diagram showing the configuration of a wireless modem according to an embodiment of the present invention.

The wireless modem of the present invention includes a power failure detecting unit 10, an auxiliary power supply unit 20, a power on / off unit 30, a pull-up unit 40 and a wireless communication unit 50.

The power failure detection unit 10 detects whether the main power supply MP _DC is normally supplied and generates a power down signal when the main power supply MP _DC is disconnected to turn on / off the signal of the wireless communication unit 50. Pull down the input terminal (MODEM_ON / OFF) to ground voltage level. In this case, the main power source MP _DC may be an external power source supplied from the outside through a vehicle cigar jack or an adapter. The power failure detection unit 10 is a voltage divider 12 for distributing the voltage of the main power supply MP _DC at a predetermined ratio, and generates a power down signal for outputting a power down signal when the level of the divided voltage is lower than a predetermined level. And a diode D1 which prevents the unit 14 and the auxiliary power from being applied to the voltage divider 12. The voltage divider 12 includes resistors R1 and R2 connected in series between a power input terminal POWER of the wireless communication unit 50 and a ground power source. In addition, the power down signal generator 14 is connected between the ON / OFF signal input terminal MODEM_ON / OFF of the wireless communication unit 50 and the ground power source, and is connected to the output voltage of the voltage divider 12, that is, across the resistor R2. And a PNP type transistor Q1 that receives the voltage V _R2 (when the voltage of the main power supply MP _DC is V _DC , V _R2 = R2 / (R1 + R2) × V _DC ) as the base terminal. At this time, the size of the resistors R1 and R2 and the size of the resistor R3 to be described later are the voltage (voltage V _R2 across the resistor R2) applied to the base terminal of the PNP transistor Q1 when the main power supply MP _DC is normally supplied. It is determined to be greater than the voltage applied to the emitter terminal of the PNP transistor Q1 through, so that the PNP transistor Q1 is kept turned off when the main power supply MP _DC is normally supplied. The diode D1 causes the PNP transistor Q1 to be turned on by blocking the application of the auxiliary power supply to the voltage divider 12 when the main power supply MP _DC is disconnected and the power supply is switched to the auxiliary power supply. The operation of the power failure detection unit 10 is described in detail in the operation description of the wireless modem of the present invention described later.

Auxiliary power supply 20 when the state in which the main power MP _DC properly supplied to the charging by the main power MP _DC and main power MP _DC when the supply is cut off the auxiliary power source by using the charged power of the wireless communication unit of It is supplied to the power input terminal (50) of (50). The auxiliary power supply 20 includes a large capacity capacitor C1 connected between a power input terminal (POWER) and a ground power source. As such, by using a capacitor as an auxiliary power supply means, a separate charging and discharging circuit is not required, and it is applicable to a small size wireless modem.

The power on / off unit 30 generates a power on / off signal for controlling the on / off of the wireless communication unit 50 according to a control signal received from an external controller (not shown). . The power on / off unit 30 is connected between the on / off signal input terminal MODEM_ON / OFF of the wireless communication unit 50 and a ground power source, and receives a control signal received from an external controller as a base terminal to control the control signal. And an NPN type transistor Q2 which is selectively turned on according to the present invention. Since the present invention is for normally turning off the power of the wireless modem, the power on / off signal in the following description indicates a signal for turning off the power of the wireless modem.

When the power on / off signal or the power down signal is not generated, the pull-up unit 40 pulls up the on / off signal input terminal MODEM_ON / OFF of the wireless communication unit 50 to a high level. The pull-up unit 40 includes a resistor R3 connected between the power input terminal POWER and the ON / OFF signal input terminal MODEM_ON / OFF.

The wireless communication unit 50 is driven by the auxiliary power supplied from the main power source or the auxiliary power supply unit 20 to perform wireless communication according to a preset wireless protocol. When the wireless communication unit 50 receives a power on / off signal for powering off the terminal from the power on / off unit 30 or receives a power down signal from the power failure detection unit 10, the software tasks in progress are normal. After shutting down, turn off the wireless modem according to the preset power-down procedure. That is, the wireless communication unit 50 according to the present invention transmits a report message indicating a power down fact when a power on / off signal or a power down signal is received to a designated central management server, releases a call being accessed, and then powers down the fact. Register the mobile communication network. Then, the wireless communication unit 50 terminates the work being performed normally and then turns off the power of the wireless modem. In FIG. 1, the power on / off signal and the power down signal are both applied to the on / off signal input terminal MODEM_ON / OFF of the wireless communication unit 50. However, each signal may be applied to a separate terminal. It may be. That is, the wireless communication unit 50 receives the power down signal from the power failure detecting unit 10 and the power on / off signal from the power on / off unit 30 through different terminals, thereby preventing normal power disconnection (external Power supply by control signal from the controller) and abnormal power supply (main power supply MP _DC ) can be distinguished and report message is notified only when main power supply MP _DC is disconnected (power down signal is applied). Can be sent to a designated central management server.

2 is a flowchart illustrating the operation of the wireless modem of FIG. 1 when the main power supply MP _DC is disconnected.

Since the present invention relates to a method for coping with a wireless modem when the main power supply MP _DC is abnormally disconnected, the present embodiment describes the operation of the wireless modem focusing on the case where the main power supply MP _DC is abnormally disconnected.

When DC power is normally applied to the power input terminal (POWER) from the main power supply MP _DC , the wireless communication unit 50 performs a predetermined operation according to a predefined algorithm, and uses a mobile communication network such as GSM / CDMA / WCDMA. Performs communication with a wireless modem or a central management server (not shown).

At this time, the on / off signal input terminal MODEM_ON / OFF of the wireless communication unit 50 is pulled up to a high level by the pull-up unit 40, and the PNP-type transistor Q1 is divided by the main power supply MP _DC . The voltage applied to the resistor R2 of 12), that is, the base voltage of the PNP-type transistor Q1 is larger than the emitter voltage, and thus is turned off. The capacitor C1, which is the auxiliary power supply 20, receives the main power MP _DC and maintains a charging state.

If the power supplied from the main power supply MP _DC is suddenly disconnected while the wireless communication unit 50 performs a certain operation, the power failure detection unit 10 detects the disconnection of the main power supply MP _DC to wirelessly transmit a low level power down signal. The signal is transmitted to the on / off signal input terminal MODEM_ON / OFF of the communication unit 50 (step 210).

When the supply of the main power supply MP _DC is cut off, the auxiliary power is continuously supplied to the emitter terminal of the PNP transistor Q1 through the resistor R3, whereas the voltage distribution unit 12 is not supplied by the diode D1. The base terminal of the PNP transistor Q1 is brought down to the ground level. That is, the emitter voltage of the PNP-type transistor Q1 becomes larger than the base voltage, so that the PNP-type transistor Q1 is turned on, which causes the on / off signal input terminal MODEM_ON / OFF of the wireless communication unit 50 to ground level (low level). The low level power down signal is applied to the on / off signal input terminal MODEM_ON / OFF of the wireless communication unit 50.

At this time, even if the main power supply MP _DC is disconnected, the wireless communication unit 50 continuously receives the auxiliary power charged in the capacitor C1 to operate normally for a predetermined time when the supply of the auxiliary power is terminated.

When the power down signal is applied from the power failure detector 10, that is, when the on / off signal input terminal MODEM_ON / OFF is pulled down to the ground level, the wireless communication unit 50 transmits data using the current wireless communication. Check whether it was busy (step 220).

If data is being transmitted, the wireless communication unit 50 even transmits the data being transmitted to complete the data transmission (step 230).

When not transmitting data or when data transmission is completed in step 230, the wireless communication unit 50 transmits a report message indicating that the main power supply MP _DC is disconnected to a predetermined central management server (step 240).

As such, sending a report allows the operator to quickly recognize the power loss and to follow up more quickly. The report message may include a power down time and information on the corresponding terminal.

Next, the wireless communication unit 50 registers the fact that the mobile communication network enters the power-off state after releasing the connected call (step 250) (step 260).

As such, by registering the power down in the mobile communication network, the call connection attempt to the corresponding wireless modem is prevented from occurring, thereby preventing unnecessary waste of network resources.

Next, the wireless communication unit 50 terminates all the software tasks that are being performed normally according to a predetermined power down procedure, and then turns off the wireless modem (step 270).

The above-described operation sequence is in accordance with an embodiment of the present invention. Of the above-described operations, steps 240 to 260 may have a different order.

3 is a block diagram showing the configuration of a wireless modem according to another embodiment of the present invention.

3, the power down signal generated by the power failure detecting unit 10 and the power on / off signal generated by the power on / off unit 30 are included in the wireless communication unit 50. While applied to the same one terminal, that is, the on / off signal input terminal MODEM_ON / OFF, the wireless communication unit 60 of FIG. 3 has a power-down signal generated from the power failure detection unit 10 and a power on / off unit 30. A terminal to which the power on / off signal generated by the power supply is applied is separately provided.

That is, in the configuration of FIG. 1, since both the power down signal and the power on / off signal are applied to the on / off signal input terminal MODEM_ON / OFF, the wireless communication unit 50 pulls down the on / off signal input terminal MODEM_ON / OFF. In this case, it is not possible to distinguish whether the pulldown is caused by a power down signal or a power on / off signal. Accordingly, in this case, the report message is transmitted to the central management server not only when the main power supply MP _DC is disconnected but also when the power is down, but also in the case of normal power down by a control signal applied from an external controller.

However, since the terminal to which the power down signal is applied and the terminal to which the power on / off signal is applied are different from each other when configured as shown in FIG. 3, the wireless communication unit 60 determines whether the power down is caused by disconnection of the main power supply MP _DC . It is possible to selectively transmit the report message to the central management server only when the main power supply MP _DC is disconnected, that is, when the power down signal is generated. Alternatively, the wireless communication unit 60 may distinguish whether the power down is caused by disconnection of the main power supply MP _DC or by a control signal applied from an external controller, and transmit a different report message to the central management server.

When the terminal to which the power down signal is applied and the terminal to which the power on / off signal is applied are separately provided as shown in FIG. 3, the pull-up unit 70 may select each terminal when the power on / off signal and the power down signal are not generated. To pull up, it includes two resistors, R3 and R4, connected between each terminal and the power input (POWER).

4 and 5 is a block diagram showing the configuration of a wireless modem according to another embodiment of the present invention.

4 the wireless modem is a voltage regulator (82) to the main power MP _DC to the input of the auxiliary power supply unit (20) if the teeth difference in the charging voltage to the main power MP _DC auxiliary power supply 20 converts the terminal voltage of the and it may further include a voltage regulator 84 that the main power MP _DC for applying a base voltage of the transistor Q1 only if there is a significant difference between the base voltage and the main power MP _DC of the transistor Q1 converted to the base voltage of the transistor Q1.

At this time, if the sub power supply portion 20, the charging voltage and the transistor Q1 of, as is Fig. 4, if the base voltage is the same 2 without having the one voltage regulator (82, 84) respectively, the main power source as shown in Figure 5 MP _DC of A common voltage regulator 86 can be provided at the output terminal.

Preferred embodiments of the present invention described above are intended for purposes of illustration, and those skilled in the art will be able to make various modifications, changes, substitutions and additions through the spirit and scope of the appended claims, and such modifications may be made by the following patents. It should be regarded as belonging to the claims.

1 is a block diagram showing the configuration of a wireless modem according to an embodiment of the present invention.

2 is a flowchart illustrating the operation of the wireless modem of FIG. 1 when the main power is disconnected.

3 is a block diagram showing the configuration of a wireless modem according to another embodiment of the present invention.

4 and 5 is a block diagram showing the configuration of a wireless modem according to another embodiment of the present invention.

Claims (10)

An auxiliary power supply unit which charges power when the main power supply is in a normal state and supplies auxiliary power using the charged power when the main power supply is cut off; A power failure detector for detecting whether the main power is disconnected and outputting a power down signal when the power supply is disconnected; A power on / off unit for outputting a power on / off signal according to a control signal applied from an external controller; And The wireless communication unit performs wireless communication using the main power source or the auxiliary power source and turns off the power according to a preset power down procedure after normally terminating the tasks in progress when the power down signal or the power on / off signal is generated. Wireless modem comprising a. The method of claim 1, wherein the auxiliary power supply unit A wireless modem, characterized by a large capacity capacitor. The method of claim 2, wherein the power failure detection unit A voltage divider for distributing the voltage of the main power at a predetermined ratio; A power down signal generator for outputting the power down signal when the level of the divided voltage is lower than a preset level; And And a diode which blocks the auxiliary power from flowing into the voltage divider. The method of claim 3, wherein the power down signal generating unit And a PNP type transistor connected between a power down signal input terminal of the wireless communication unit and a ground power source and receiving an output voltage of the voltage divider as a base terminal. The method of claim 4, wherein And a first voltage regulator for compensating a voltage difference between the main voltage and the charging voltage of the sub power supply. The method of claim 5, And a second voltage regulator for compensating a voltage difference between the main power supply and a base input voltage of the PNP transistor. The method of claim 4, wherein And a third voltage regulator for simultaneously compensating a voltage difference between the charging voltage of the main power supply and the auxiliary power supply and a voltage difference between the main power supply and a base input voltage of the PNP transistor. . The method of claim 1 or 2, wherein the wireless communication unit And a terminal to which the power down signal is applied and a terminal to which the power on / off signal is applied, respectively. The method of claim 1 or 2, wherein the wireless communication unit When the power down signal is generated, the wireless modem, characterized in that for transmitting a report message indicating the power down to a predetermined central management server. The method of claim 1 or 2, wherein the wireless communication unit And registering the power down fact with the mobile communication network when the power down signal is generated.

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