KR20000047151A - Device for electric power reduction of portable electronic equipment - Google Patents

Abstract

PURPOSE: A device for electric power reduction of portable electronic equipment is disclosed to extend useful life of battery by blocking majority of supply of power when there are no keyboard inputs in a preset time period even if power is on. CONSTITUTION: A device for electric power reduction of portable electronic equipment is composed of clearance, determination, and output. An internal timer's time count value(CNT) is cleared and high level signal is output from a control output port(S10). A CPU scans key input department and determines if voluntary key input has been made(S12). If yes, an execute proper function of the key(S14), clear the CNT that is saved upto the present(S16), and return to S10. If there were no key inputs, increase the CNT(S18) and determine if it has reached the preset time(S20). If less than the preset time, return to S12. If it has reached the preset time, output low level signal from control output port(S22). Step 22 turns off the second transistor, charges the condenser, and when condenser reaches the cutoff point, the third transistor is turned on and the first transistor is turned off.

Description

Power saving device for portable electronic devices

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power saving device of a portable electronic device. In particular, in a portable electronic device using a battery, when there is no key input for a predetermined time, even if the power switch is turned on, the power supply from the battery is cut off. The present invention relates to a power saving device of a portable electronic device.

In recent years, with the development of the secondary battery industry, various portable electronic devices such as notebook computers and portable cash registers have been actively used in real life. In such portable electronic devices, due to the limitation of the battery's charge capacity, most of the internal components are designed to be low power consumption type, and in particular, when the battery is left unused while the power switch is turned on, various measures for power saving are sought. It is becoming.

An example of such a power saving device of a conventional portable electronic device is a combination of both hardware and software. According to this, the central processing unit inside the device has various key inputs and no key inputs. The duration is checked and the power supply is controlled accordingly. That is, when the duration of the no-input state of the key reaches a predetermined reference value, an appropriate control signal is output to cut off the power provided to a large power consumption part, for example, a display unit, and the like. If this exists, the power supply to the component is immediately resumed.

However, in order to enable the control as described above, at least the central processing unit and its peripheral circuits must be continuously supplied with power, and thus there is a problem in that the power saving capability is somewhat reduced.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems. In the case where there is no key input for a predetermined time in a portable electronic device, even if the power switch is turned on, the battery life is cut off by cutting off most of the power supply from the battery. It is an object of the present invention to provide a power saving device of a portable electronic device that can be extended.

In order to achieve the above object, a power saving device of a portable electronic device of the present invention processes battery power and supplies power to a logic power source and a driving power source in an on state, and cuts off the supplied logic power source and a driving power source in an off state. A first switching unit; Operated by the logic power supply, different levels are determined depending on whether the various keys provided in the device are input and whether the non-input state duration of the key is greater than a preset reference value. A central processing unit for outputting a logic signal of the; A second switching unit which is turned on or off by the logic signal output from the central processing unit, and a third switching unit which is turned on or off according to an on / off state of the second switching unit to turn on or off the first switching unit; Is done.

1 is a block diagram of a portable cash register to which the power saving device of the present invention can be applied;

2 is a detailed circuit diagram of a power supply unit of FIG. 1;

3 is an output waveform diagram of each part in FIG.

4 is a flowchart for explaining the operation of the power saving device of the portable electronic device of the present invention.

*** Explanation of symbols for the main parts of the drawing ***

10, BATT: battery, 11: power supply,

12: CPU, 13: ROM,

14: ram, 15: clock part,

16: key input, 17: printer,

18: other driving unit, 19: display unit,

R1-R4: resistor, CE1, CE2: capacitor,

TR1-TR3: transistor, ZD1: zener diode,

SW1: power switch

Hereinafter, a power saving device of a portable electronic device according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram of a portable cash register to which the power saving device of the present invention can be applied. As shown in FIG. 1, the portable cash register to which the present invention can be applied includes a battery 10 as an independent power source, a key input unit 16 for generating various key codes for mode designation, and money registration, and a key input unit 16. The central processing unit 12 for specifying the mode of the cash register according to the input key code and performing various functions in the designated mode, RAM for storing various data generated during a program or a transaction set by the user 14) under the control of the ROM 13 storing the system operation program, the printer 17 and the central processing unit 12, which issue documents for customer receipts and various processing results under the control of the central processing unit 12; Display unit 19 for visually displaying various information related to the power supply unit 11 and other necessary parts to process and supply the output voltage of the battery 10 to the size required for each unit The same consists of the other drive unit 18.

FIG. 2 is a detailed circuit diagram of the power supply unit of FIG. 1. As shown in FIG. 2, the power saving device of the portable cash register according to the present invention includes a power supply unit 11 composed of hardware components and a central processing unit 12 that executes a system program residing in the ROM 13. . First, the power supply unit 11 includes voltages provided by the first to third switching units 11a, 11b, 11c and the first switching unit 11a, each of which includes at least one transistor. Is converted into a logic power supply (Vcc) necessary to drive the central processing unit 12, the ROM 13, the RAM 14, and the like. 17) and a driving power supply 11e for converting and supplying the voltage Vpp (approximately about 20 [V], which will also be referred to as a driving power supply as required below) required to drive the display portion 19 and the like. The first switching unit 11a includes a first transistor TR1 having a collector connected to a battery Batt, two resistors R2, R3 connected in series between the collector and the base of the first transistor TR1, and The Zener diode ZD1 is connected between the connection point C of the resistors R2 and R3 and the ground terminal. The logic power supply 11d and the driving power supply 11e are connected in parallel to the output terminal of the first switching unit 11a, that is, the emitter.

The second switching unit 11b has a base connected to the control output terminal P1.0 of the central processing unit 12 and the emitter is grounded with the base of the second transistor TR2 and the second transistor TR2 and the logic power supply unit ( 11e) is made up of a current limiting resistor R4.

The third switching unit 11c has a collector connected to the connection point C, and the emitter is connected in series with the grounded third transistor TR3 and the battery Batt, and the connection point B is connected to the third transistor TR3. It consists of a resistor (R1) and a capacitor (CE1) connected to the base of the. The connection point B of the resistor R1 and the capacitor CE1 is also connected to the collector of the second transistor TR2. Meanwhile, it is preferable to increase the time constants of the resistor R1 and the capacitor CE1 so that the second transistor TR2 can be driven before the third transistor TR3. Reference numeral SW1 denotes a power switch.

Hereinafter, the operation of the power saving device of the portable electronic device of the present invention will be described in detail.

3 is an output waveform diagram of each unit in FIG. 2, and FIG. 4 is a flowchart for describing an operation of a power saving device of a portable electronic device according to the present disclosure.

First, when the user turns on the power switch SW1, a predetermined voltage, for example, a battery voltage of 24 [V], is applied to the point A. However, since the time constants of the resistor R1 and the capacitor CE1 are sufficiently large, even after the power switch SW1 is turned on, the base voltage of the third transistor TR3, that is, the voltage of the point B, is cut-off. It takes time for the voltage to be about 0.7 [V] or more, and as a result, the first transistor TR1 is turned on before the third transistor TR3. At this time, since the reference voltage of the zener diode ZD1, that is, the voltage of the point C is approximately 24 [V], the voltage of the point D which is the output terminal of the first transistor TR1 is about 23 [V]. Becomes The voltage thus output is then the Vpp voltage required for driving the printer 17 or the display unit 19 via the driving power supply unit 11d of 20 [V], and the logic power supply unit 11e of 5 [V] is replaced. Through this, it becomes the Vcc voltage required for the operation of the central processing unit 12 and the like.

As a result, a reset pulse as shown in FIG. 3 is applied to the reset terminal of the central processing unit 12. As a result, a system program stored from the start address of the ROM 13 is operated. An initialization step S10 of 4 is performed. In this initialization step S10, the time count value CNT of the internal timer is cleared, and a high level signal is output from the control output port P1.0. When the high level signal is output from the control output port P1.0, the second transistor TR2 is turned on, and accordingly, the base terminal of the third transistor TR3 is kept below the cutoff voltage. Transistor TR3 remains in an off state.

During this operation, the central processing unit 12 scans the key input unit 16 in step S12 to determine whether any key has been input. As a result of the determination in step S12, if even a key is input, the process proceeds to step S14 to perform the function of the corresponding key, and the process proceeds to step S16 again to clear the count value CNT to date. Return to step S10.

On the other hand, if there is no key input in step S12, the process proceeds to step S18 to increase the count value CNT, and the process proceeds to step S20 again to determine the count value CNT up to now. It is determined whether the reference value T _R has been reached, for example 5 minutes. As a result of the determination in step S20, when the current count value CNT falls below the reference value T _R , the process returns to step S12, and when the reference value T _R is reached, the process goes to step S22. The controller outputs a low level signal from the control output port P1.0. When a low level signal is output through the control output port P1.0 in step S22, the second transistor TR2 is immediately turned off. As described above, when the second transistor TR2 is turned off, the capacitor CE1 is charged. At the time T1 when the voltage of the capacitor CE1, that is, the voltage at the point B reaches the cutoff voltage, the third transistor TR3 is charged. The first transistor TR1 is turned off accordingly. As a result, the power supplied to both the logic power supply 11e and the driving power supply 11d is cut off, and after that, the power Vcc supplied to the central processing unit 12 is also cut off to control the output of the central processing unit 12. The port P1.0 continues to be in a low level state, and as a result, almost all circuits except the second transistor TR2 remain in a blocking state.

In order to release this state, for example, when the user turns off the power switch SW1 at the time T2, the power supplied to all electric circuits including the second transistor TR2 is cut off, and in this state, the power switch ( When SW1) is turned on again, the power supply resumes as it was.

The power saving device of the portable electronic device of the present invention is not limited to the above-described embodiments, and can be modified in various ways within the scope of the technical idea of the present invention.

According to the power saving device of the portable electronic device of the present invention as described above, when there is no key input for a predetermined time, even if the power switch is turned on, the use time of the battery is cut off by cutting off most of the power supply from the battery. There is an effect that can be extended.

Claims (1)

A first switching unit which processes the battery power in the on state and supplies the logic power and the driving power, and cuts off the supplied logic power and the driving power in the off state; Operated by the logic power supply, logic signals of different levels are checked depending on whether the various keys provided in the device are input and the non-input time of the keys, depending on whether the non-input time of the keys is greater than a preset reference time. Central processing unit for outputting; A second switching unit turned on or off by the logic signal output from the central processing unit; And a third switching unit which is turned on or off according to the on / off state of the second switching unit to turn on or off the first switching unit.