JP3814907B2 - Handy terminal - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a handy terminal used for inventory management of goods in a warehouse, ordering of goods at a storefront, ticketing services such as a ticket for transportation, and the like. More specifically, the handy terminal main body is provided. The present invention relates to a method for increasing the efficiency of a voltage stabilizing circuit and extending the life of a power source battery as a main power source of a handy terminal.
[0002]
[Prior art]
Conventionally, as a main power source for activating the handy terminal main body, a battery such as an alkaline primary battery, a nickel cadmium battery, or a lithium secondary battery has been used as a main power source battery. The characteristics of the battery used as the power supply battery for the handy terminal are as follows: the battery voltage at the start of using an unused power supply battery, A battery voltage drop of about 1 to 2V occurs. When the voltage of the power battery drops, the brightness of the liquid crystal display portion provided in the handy terminal main body changes, and the information displayed on the liquid crystal display portion (for example, numerical information relating to the inventory of the product) The phenomenon that it becomes difficult to see from the operator who operates the minal occurs. In order to prevent such a phenomenon from occurring, the conventional handy terminal has a built-in voltage stabilizing circuit comprising a DC / DC converter 50 as shown in FIG. Since the handy terminal emphasizes portability, it is necessary to reduce the size of the voltage stabilization circuit, so use a DC / DC converter IC that is advantageous in terms of the degree of component integration. In general, the power supply voltage is kept constant regardless of the remaining amount of the power battery.
[0003]
[Problems to be solved by the invention]
However, a standard DC / DC converter IC generally has a conversion efficiency of about 90%. However, when designing the power supply circuit of the handy terminal, the DC / DC converter IC must be designed safely so that there is a margin in the current consumption that is about 1.5 times the maximum current consumption of the handy terminal. There must be. Further, in the output characteristics of the DC / DC converter IC, the replacement efficiency of 90% is not maintained in the entire range from the minimum value to the maximum value of the driving capability, but a 500 mA DC / DC converter as shown in FIG. -When using a 1mA output current, the exchange efficiency is 30%. When there is a 100mA output current, the exchange efficiency increases to the maximum value of 90%. When the output current is 500mA, the exchange efficiency increases. The efficiency drops slightly to 80%. When the 100 mA DC / DC converter shown in FIG. 7 is used, the exchange efficiency is 30% when the output current is 0.1 mA, but the output is 10 mA. When there is a current, the exchange efficiency is increased to 90%, which is the maximum value, and when the output current is 100 mA, the exchange efficiency is slightly lowered and generally has such a performance as 80%.
[0004]
For this reason, when using a handy terminal, when the current consumption is low, the DC / DC converter IC replacement efficiency drops to 50% or less, and the power battery of the handy terminal itself is consumed wastefully over 40%. Will occur. In addition, while displaying information such as characters and numbers on the liquid crystal display device provided in the handy terminal main body, the operator inputs data such as goods using the input key provided in the handy terminal main body. In this state, the consumption current is about 3 mA, and the exchange efficiency of the DC / DC converter in this state is remarkably lowered, which is very inefficient.
[0005]
FIG. 6 shows the relationship between the operating state of the handy terminal main body (not shown) and the power consumption during each operation. (1) is an operating state in which characters, symbols, etc. are displayed on an LED (liquid crystal display device) provided in the handy terminal body, and the power consumption at this time is 50 mA. (2) is a state in which the backlight of the LED is turned on, and the current consumption at this time requires 100 mA. (3) communicates via RS-232C when transmitting and receiving data between the handy terminal main body and an external device. At this time, the current consumption of the power supply battery is 70 mA.
[0006]
Next, when the CPU provided in the handy terminal terminal (not shown) of (4) is operated for each function of the handy terminal terminal, the current consumption is 50 mA, and is provided inside the handy terminal terminal of (5). When a data file stored in a RAM (not shown) is searched by a command from the CPU, a current consumption of 50 mA is required. Further, item (6) is a bar code scanner attached to the handy terminal when the bar code attached to the product is scanned when collecting inventory data of the product. Is used, the power consumption of the power supply battery is 150 mA. If the LCD backlight is turned on simultaneously with the bar code scanning of (7), a current consumption of 250 mA is required. Since the current consumption in (1) to (7) is 50 mA to 250 mA, the current consumption in the handy terminal is operated in the normal operation mode.
[0007]
(8) Information collected using the handy terminal input key using the handy terminal input data and data using a bar code scanner (not shown) (9) In the input waiting state, the current consumption of the power supply battery is 3 mA, and the current consumption in the handy terminal is classified in the low power mode. Since the maximum current consumption divided by this small power mode is about 3 mA, a 5 mA output DC / DC converter IC can be used to achieve a sufficient safety design. However, a 5 mA output DC / DC converter can be obtained. -Since there are few types of ICs and the cost is high, a 100 mA output DC / DC converter IC which is generally available is used in this embodiment.
[0008]
At first glance, this problem is because the handy terminal user is waiting for input of information while displaying information such as characters and numbers on the handy terminal main body's liquid crystal display device. It seems that there is no problem in power consumption, but if you look at the usage status of the handy terminal, the information remains displayed on the liquid crystal display device of the handy terminal as described above. The standby state in this state has a problem that it cannot be easily ignored in consideration of the usage pattern. The reason for this is that handheld terminal usage forms are overwhelmingly waiting for input of information using low current consumption.
[0009]
[Means for Solving the Problems]
The present invention has been made in view of the conventional problems, and is a handy terminal driven by a battery as a power source, and includes a ROM and a RAM for driving a CPU built in the handy terminal. A normal power DC / DC converter and a low power DC / DC converter that can be switched by a command from the CPU according to the usage state of the battery for operating the terminal, and the ROM includes a handy terminal. The operating state is registered separately in the normal operation mode and the low power mode. In the normal operation mode, the normal power DC / DC converter is used. In the low power mode, the low power DC / DC is used. A handy terminal characterized by using a converter.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to a handy terminal driven by an alkaline battery or a nickel cadmium battery. When a CPU or a bar code scanner built in the handy terminal main body is operating, an alkaline battery or nickel which is a power source is used. When driving a battery that is a relatively large load for a cadmium battery, a DC / DC converter IC for normal power is operated, and a key input waiting mode for inputting information such as letters and numbers is used. In the state where a small load is used for the power source as in the case of the power supply, a DC / DC converter IC for low power is used.
[0011]
【Example】
Hereinafter, details of the present invention will be described with reference to the accompanying drawings. The configuration of the handy terminal of this embodiment will be described with reference to FIG. Reference numeral 1 denotes a CPU, which sends out various commands in order to operate each function of the handy terminal. Reference numeral 2 is a ROM to which data necessary for operating the CPU 1 is input. Reference numeral 3 denotes a RAM, which stores data necessary for operating the CPU 1 in the same manner as the ROM 2 and stores product data collected in a warehouse or store. Reference numeral 4 denotes a key input portion. A numeric keypad and various function keys are arranged in a handy terminal main body (not shown), and the number of data is input by an operator. Reference numeral 5 denotes a DC / DC converter IC, which will be described later, and is composed of an IC with 500 mA output or more in consideration of the power margin.
[0012]
Reference numeral 6 denotes a liquid crystal display device provided in the handy terminal main body, which displays collected data. Reference numeral 7 denotes an RS-232C cable which is used when data collected on the handy terminal is transmitted to an external host computer (not shown). Reference numeral 8 denotes a bar code interface, which is a bar code scanner (not shown) attached to the handy terminal main body for taking the scanned information into the handy terminal main body. Reference numeral 9 is a DC / DC converter for low power described later. Reference numeral 10 denotes a battery for driving the handy terminal main body, and an alkaline battery or a nickel cadmium battery is used as described above.
[0013]
The information collected in (8) shown in FIG. 6 is waiting to be input using the handy terminal input key, and a bar code scanner (not shown) in (9) is used. In the data input waiting state, the current consumption of the power supply battery is 3 mA, and the current consumption in the handy terminal is classified in the low power mode. Since the maximum current consumption divided by this small power mode is about 3 mA, a 5 mA output DC / DC converter IC can be used to achieve a sufficient safety design. However, a 5 mA output DC / DC converter can be obtained. -Since there are few types of ICs and the cost is high, a 100 mA output DC / DC converter IC which is generally available is used in this embodiment.
[0014]
Next, a general application program in which the actual operation is used for the handy terminal turns on the power source of the A handy terminal main body by the operation of the operator. The work menu screen is displayed on the liquid crystal display device of the B handy terminal main body. On the C menu screen, an inventory management operation is selected by operating the input key. D Input a commodity item by a bar code scanner attached to the handy terminal. E The operator counts the number of products and inputs the number from the handy terminal input key. Repeat steps D through E until the F inventory management operation ends. Select the G operation end key to display the liquid crystal menu screen. Turn off the H power supply. The switching timing of the normal power DC / DC converter IC and the low power DC / DC converter IC will be described with reference to FIGS.
[0015]
The Schottky diode 13 shown in FIG. 3 is used for preventing short-circuiting when the DC / DC converter 5 for normal power and the DC / DC converter 6 for low power are simultaneously turned ON and for single activation. The DC / DC converter 5 for normal power or the DC / DC converter 6 for low power is used to prevent leakage current to the DC / DC converter 6. In the case of switching from the normal operation mode shown in FIG. 6 to the low power mode, the start signals 11 and 12 are also turned on in response to a command from the CPU 1 and the drive signal 11 is turned off by the control of the CPU 1 so As a single drive of the DC converter 6, a handy terminal main body (not shown) shifts to the low power mode.
[0016]
On the contrary, the handy terminal main body (not shown) is switched from the low power mode to the normal operation mode by turning on both the drive signal 11 and the drive signal 12 according to the command of the CPU 1 shown in FIG. In response to this command, the drive signal 12 is turned OFF and only the normal power DC / DC converter 5 is driven singly to shift to the normal operation mode. The switching procedure between the normal power DC / DC converter 5 and the low power DC / DC converter 6 and the operations when the handy terminal main body shown in FIG. The DC / DC converter is appropriately converted in the low power mode by synchronizing with the command of the CPU 1 provided.
[0017]
【The invention's effect】
Since the present invention is configured as described above, the operation state of the handy terminal is divided into the normal power mode section and the low power mode section, and the above described normal power mode to low power mode are divided. Or, before changing from the low power mode to the normal power mode, the DC / DC converter for normal power or the DC / DC converter for low power is connected according to the instructions of the CPU provided in the handy terminal main body. By selecting appropriately, the conversion efficiency of the DC / DC converter for normal power and the DC / DC converter for low power can be improved, and wasteful consumption of the power supply battery can be eliminated. Moreover, the battery can be used efficiently by making the conversion efficiency of normal power and low power correspond to each other.
[Brief description of the drawings]
[Fig. 1] Configuration diagram separating the normal power unit and the power consumption unit [Fig. 2] Transition of current consumption in the application program [Fig. 3] DC / DC converter switching circuit [Fig. -Minal configuration diagram [Fig. 5] Diagram explaining the conversion efficiency of the DC / DC converter [Fig. 6] Diagram showing the relationship between the operating state of the handy terminal and current consumption [Fig. 7] DC / DC converter Diagram explaining conversion efficiency of data [Explanation of symbols]
1 CPU
2 ROM
3 RAM
4 Key input portion 5 DC / DC converter for normal power 6 Liquid crystal display device 7 RS-232C cable 8 Bar code interface 9 DC / DC converter for low power 10 Battery
11 Start signal 1
12 Start signal 2
13 Schottky diode

Claims (1)

A handy terminal driven by a battery as a power source, having a ROM and a RAM for driving a CPU built in the handy terminal, and depending on a use state of the battery for operating the handy terminal, It has a DC / DC converter for normal power and a DC / DC converter for low power that can be switched by the command of the CPU. The ROM is divided into the normal operation mode and the low power mode in the handy terminal. A handy terminal which is registered and uses a DC / DC converter for normal power in the normal operation mode, and uses a DC / DC converter for low power in the low power mode.

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