JP2011083116A - Mobile terminal and control method of the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mobile terminal which charges a secondary battery with higher efficiency, and to provide a control method of the mobile terminal. <P>SOLUTION: The mobile terminal 1 includes: a current measuring part 13 measuring current to be consumed Ia supplied to an inner circuit 11 and charging current Ib supplied to the secondary battery 14 when the secondary battery is charged; and a determining part 12 determining full charge of the secondary battery 14 when a level of the charging current Ib measured by the current measuring part 13 matches a full charge threshold Ith. The full charge threshold Ith is a value for determining full charge of the secondary battery 14, and corresponds to a first value showing the level of the current to be consumed Ia when constant voltage charging of the secondary battery 14 is started. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a portable terminal and a control method thereof, and more particularly to a portable terminal that charges a secondary battery more efficiently and a control method thereof.

  A method for charging a secondary battery is described in Patent Document 1. The technology described in Patent Document 1 detects a charging current when charging a secondary battery at a constant voltage, and after the charging current becomes equal to or lower than a set value, interrupts the constant voltage charging and reduces the open voltage of the secondary battery. Detection is performed to detect the difference between the release voltage and the charging voltage, and charging is terminated. Alternatively, the recharge time is detected from the detected open voltage, and the secondary battery is charged until it is fully charged.

FIG. 8 is a diagram showing the mobile terminal 100. The inflow current _{I A} from the charger 101 through the charging circuit 102 branches to the consumption current _{I C} to be supplied to the internal circuit 103 of the mobile terminal 100 the charging current _{I B} supplied to the secondary battery 104, I _A = I _B + I _C. Since the inflow current I _A from the charger 101 is a constant magnitude, the magnitude of the charging current I _B is in accordance with the magnitude of the consumption current I _C, when the consumption current I _C is greater charging current I _B is small will, when the consumption current _{I C} is small charging current _{I B} increases.

The secondary battery 104 is initially charged with a constant current and then charged with a constant voltage. Thus the charging current I _B is according to the magnitude of the consumption current I _C, gradually decreases after taking a constant value with respect to time. The voltage V of the secondary battery 104 increases after the start of charging, and gradually increases gradually as the secondary battery 104 approaches full charge. Time for the secondary battery 104 is fully charged is increased as the charging current I _B is reduced.

Figure 9 is a graph showing the voltage V charging current I _B and the secondary battery 104. When the consumption current I _C is small, the charging current I _B and the voltage V of the secondary battery 104 are indicated by the charging current I ₂₀₁ and the voltage V ₂₀₁ , and when the consumption current I _C is large, they are indicated by the charging current I ₂₀₂ and the voltage V ₂₀₂ . .

If the consumption current _{I C} is smaller, the time voltage _{V 201} at t106 rises to the full charge voltage, the charging current _{I 201} decreases until the charge completion current threshold. The secondary battery 104 measures the charging current I ₂₀₁ , detects the full charge of the secondary battery 104, and ends the charging.

JP 7-235332 A

When the consumption current I _C is large, the value of the charging current I ₂₀₂ charged in the secondary battery 104 is smaller than when the consumption current I _C is small. Further, as compared with the charging current I ₂₀₁ in the case consumed current I _C is small, the time from the start of charging until the charging current I ₂₀₂ equal to or less than the charge completion threshold becomes shorter. In this case, since the value of the charging current I ₂₀₂ is small and the time until full charge is detected is shortened, the secondary battery 104 is not fully charged at the timing t105, and the battery voltage battery voltage V ₂₀₂ is It has not risen to full charge voltage. However, in the technique described in Patent Document 1, as in the case where the consumption current I _C is small, when the charging current I ₂₀₂ becomes equal to or lower than the charging completion current threshold, full charging is detected, and the secondary battery 104 is fully charged. There was a problem that it could not be detected accurately.

  The present invention has been made to solve such problems, and more accurately determines the full charge of the secondary battery by measuring the current value of the current supplied to the internal circuit of the mobile terminal. An object of the present invention is to provide a portable terminal and a control method thereof.

  The present invention has been made to solve such problems, and more accurately determines the full charge of the secondary battery by measuring the current value of the current supplied to the internal circuit of the mobile terminal. An object of the present invention is to provide a portable terminal and a control method thereof.

  When the secondary battery is charged, the portable terminal according to the present invention measures the consumption current supplied to the internal circuit and the charging current supplied to the secondary battery, and the current measurement unit measures And a determination unit that determines whether the secondary battery is fully charged when the magnitude of the charging current matches the full charge threshold, and the full charge threshold is a value for determining the full charge of the secondary battery, This is a value corresponding to the first value indicating the magnitude of current consumption when starting constant voltage charging of the secondary battery.

  The portable terminal and the control method thereof according to the present invention measure the current consumption flowing in the internal circuit when the secondary battery is charged, periodically measure the value of the charging current for charging the secondary battery, and measure it. The value according to the first value indicating the magnitude of the consumption current when the magnitude of the charging current is a value for determining whether the secondary battery is fully charged, and starting the constant voltage charging of the secondary battery When the full charge threshold value is coincident, the full charge of the secondary battery is determined.

  ADVANTAGE OF THE INVENTION According to this invention, the portable terminal which determines full charge more correctly by measuring the electric current value of the electric current supplied to the internal circuit of a portable terminal, and its control method can be provided.

1 is a block diagram showing a mobile terminal according to a first exemplary embodiment; 1 is a block diagram showing a mobile terminal according to a first exemplary embodiment; 3 is a graph showing current consumption, charging current, charging threshold, and battery voltage according to the first exemplary embodiment. 3 is a table showing charging currents according to current consumption according to the first exemplary embodiment. 3 is a table showing charging currents according to operating conditions of the internal circuit according to the first embodiment. 3 is a flowchart illustrating an operation of the mobile terminal according to the first exemplary embodiment. 10 is a flowchart illustrating an operation of the mobile terminal according to the second exemplary embodiment. It is a figure which shows the conventional portable terminal. It is a graph which shows the charging current supplied to the conventional secondary battery, and the voltage of a secondary battery.

Embodiment 1
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a portable terminal 1 according to the first embodiment of the present invention. The mobile terminal 1 according to the first embodiment of the present invention includes a current measurement unit 13 and a determination unit 12. When the secondary battery is charged, the current measuring unit 13 measures the consumption current Ia supplied to the internal circuit and the charging current Ib supplied to the secondary battery. The determination unit 12 determines the full charge of the secondary battery when the magnitude of the charging current Ib measured by the current measurement unit 13 matches the full charge threshold value Ith. This threshold value Ith is a value for determining whether the secondary battery is fully charged, and is a value corresponding to a first value indicating the magnitude of the consumption current Ia when starting constant voltage charging of the secondary battery. is there.

  As will be described in detail later, when the inflow current Ic supplied to the mobile terminal 1 is constant, the charging current Ib decreases as the consumption current Ia increases. Therefore, when constant voltage charging of the secondary battery is started, if the consumption current Ib is large, the charging current Ib is small. When the charging current Ib at the start is small, the value of the charging current Ib at the time when the secondary battery reaches full charge is also small. On the other hand, when the charging current Ib at the start of constant voltage charging is large, the value of the charging current Ib when the secondary battery reaches full charge also increases.

  In the present embodiment, paying attention to the value of the charging current Ib at the time of full charging, the value of the charging current Ib for detecting full charging (charging threshold Ith) is set to the consumption current Ia at the start of constant voltage charging. By appropriately changing the setting according to the value of the charging current Ib or the value of the charging current Ib, even if the mobile terminal 1 performs different processing in the internal circuit, the full charge is accurately detected.

  The current measuring unit 13 measures the value of the consumption current Ia when starting constant voltage charging, periodically measures the value of the charging current Ib, and outputs it to the determination unit 12. The determination unit 12 uses the full charge threshold value Ith corresponding to the current consumption Ia value (Ia1) when starting constant voltage charging, and fully charges when the measured charge current Ib value is equal to or less than the threshold value Ith. Is detected.

  Next, the mobile terminal 1 will be specifically described. Specifically, the portable terminal 1 can be configured as shown in FIG. FIG. 2 is a block diagram showing details of the portable terminal 1 according to the present embodiment. The charging control unit 10 is connected to the internal circuit 11 and the secondary battery 14 and controls the consumption current Ia and the charging current Ib supplied to each. The charging control unit 10 controls the charging current Ib, performs constant current charging that charges the secondary battery 14 at a constant current value, and then performs constant voltage charging that charges at a constant voltage value. Accordingly, the value of the charging current Ib gradually decreases as the battery voltage of the secondary battery 14 approaches in constant voltage charging after taking a constant value in constant current charging.

  The determination unit 12 includes a storage unit 15, and the storage unit 15 includes information on the current threshold value Ith. Here, the current threshold value Ith is a value for detecting the full charge of the secondary battery 14. However, the value of the charging current Ib indicating full charge differs depending on the magnitude Ib1 of the charging current Ib at the start of constant voltage charging or the magnitude Ia1 of the consumption current Ia at the start of constant voltage charging. Accordingly, the storage unit 15 has information on the threshold value Ith corresponding to Ia1 or Ib1. The current measuring unit 13 measures the value Ib1 of the charging current Ib or the value Ia1 of the consumption current Ia at the start of constant voltage charging, and when the value of the charging current Ib is equal to or less than the current threshold Ith corresponding to the Ib1, The determination unit 12 detects that the secondary battery 14 has reached full charge.

FIG. 3 is a graph showing the consumption current Ia, the charging current value Ib, the current threshold Ith, and the voltage Vd. The vertical axis indicates the magnitude of current or voltage, and the horizontal axis indicates time. Referring to FIG. 3, for current consumption Ia supplied to the internal circuit, values at the start of constant voltage charging are 111 to 114 (111 <112 <113 <114), and charging current Ib at that time is 101 to 104, respectively. (101>102>103> 104), the current threshold Ith is Ith ₁ to Ith ₄ , and the voltage Vd of the secondary battery 14 is 131 to 134 (131>132>133> 134). .

  The value of the consumption current Ia varies depending on the operation state of the internal circuit and the user's operation. Here, it is assumed that the consumption current Ia takes individual values and is a constant value from the start to the end of charging for simplicity.

  The relationship between the consumption current Ia and the charging current Ib will be described. The inflow current Ic supplied from the external charger is divided into a consumption current Ia supplied to the internal circuit 11 and a charging current Ib supplied to the secondary battery. Here, assuming that the current supplied from the charger is constant, the charging current Ib decreases as the current consumption Ia increases. Therefore, if the value of the consumption current Ia at the start of constant voltage charging is 111 <112 <113 <114, the value of the charging current Ib has a relationship of 101> 102> 103> 104.

  The secondary battery 14 is charged with a constant current until a certain time, and then becomes a constant voltage charge. Therefore, the value of the charging current Ib in FIG. 3 is constant until the voltage of the rechargeable battery reaches a certain value (constant current charging), and then gradually decreases as the voltage of the secondary battery increases (constant voltage). charging).

  The battery voltage Vd of the secondary battery 14 increases after the start of charging, and then gradually increases gradually as the secondary battery 14 approaches full charge. The battery voltage Vd increases to the full charge voltage value earlier as the value (Ib1) of the charging current Ib at the start of constant voltage charging is larger or as the value (Ia1) of the consumption current Ia at the start of constant voltage charging is smaller.

Timings t1 to t4 indicate times when the battery voltage Vd (131 to 134) reaches the full charge voltage value according to the magnitude (111 to 114) of the consumption current Ia. As shown in FIG. 3, the full charge is reached earlier as the charging current Ib (= Ib1) at the start of constant voltage charging is larger. Therefore, when the consumption current Ia is 111 <112 <113 <114, t1 <t2 < t3 <t4. The value of the charging current Ib decreases as the battery voltage Vd increases. When the battery voltage Vd reaches full charge, the value of the charging current Ib increases as the charging current Ib (= Ib1) at the start of constant voltage charging increases or the current consumption Ia (= Ia1 at the start of constant voltage charging). ) Is smaller, the larger it is. The value of the charging current Ib indicating the full charge is the current threshold Ith, and the current threshold Ith corresponding to the charging current 101>102>103> 104 is Ith ₁ > Ith ₂ > Ith ₃ > Ith ₄ .

  From the above, the current threshold Ith increases as the value of the consumption current Ia at the start of constant voltage charging (Ia1) decreases or as the value of the charging current Ib at the start of constant voltage charging (= Ib1) increases. Therefore, the current threshold Ith depends on the magnitude of the current consumption Ia value Ia1 or the charging current value Ib1 at the start of constant voltage charging. Therefore, the current threshold Ith can be determined by measuring the current value of the consumption current Ia. Here, in the present embodiment, it is assumed that information on the current consumption Ia and the threshold value Ith at the start of constant voltage charging is stored in the storage unit 15. Of course, information on the value (= Ib1) of the charging current Ib at the start of constant voltage charging and the threshold value Ith may be held. In that case, the current measuring unit 13 may measure the value of the charging current Ib at the start of constant voltage charging.

  The determination unit 12 refers to the storage unit 15 and compares the current value of the charging current Ib with the threshold value Ith corresponding to the value Ib1 of the consumption current Ia measured by the current measuring unit 13 at the start of constant voltage charging. Thus, it is determined whether the battery is fully charged. When the measured current value Ib is equal to or less than the current threshold value Ith, the determination unit 12 determines that the battery is fully charged, and outputs the result to the charge control unit 10. FIG. 4 is a table showing the current threshold Ith according to the current value of the consumption current Ia when the determination unit 12 determines that the secondary battery 14 is fully charged.

  Whether the storage unit 15 has the information about the current threshold Ith based on the value (Ia1) of the current consumption Ia at the start of constant voltage charging when detecting the full charge of the secondary battery 14, whether the battery is fully charged The value of the charging current Ib for determining can be changed according to the current consumption value Ia1.

  Here, the value of the consumption current Ia at the start of constant voltage charging changes according to the operating state of the internal circuit 11. In this case, the storage unit 15 may have information on the current threshold value Ith of the charging current Ib according to the operation state of the internal circuit 11 when the secondary battery 14 is fully charged. The determination unit 12 compares the current threshold value Ith of the charging current Ib according to the operation state of the internal circuit 11 and the measured charging current Ib, and when the measured charging current Ib is small, It is determined that the secondary battery 14 is fully charged. FIG. 5 is a table showing the current threshold Ith according to the operation state of the internal circuit 11 when the determination unit 12 determines whether the secondary battery 14 is fully charged.

  Thus, when the full charge of the secondary battery 14 is detected, the storage unit 15 has information on the current threshold value Ith based on the operation state of the internal circuit 11 at the start of constant voltage charging, so that the internal circuit 11 Depending on the operation, it is possible to appropriately set the current value of the charging current Ib when determining whether or not the battery is fully charged. Further, in this embodiment, since charging can be continued until the battery is fully charged, as in the conventional case, when full charge is detected with a certain current value, the voltage of the secondary rechargeable battery is measured and really charged. It is unnecessary to perform processing such as determining whether or not charging has been reached and charging again if not reached.

  The internal circuit 11 has an LED 20 and a display unit 21 for notifying completion of charging to the outside and notifying the result of the internal operation. The internal circuit 11 includes a control unit 22 for controlling the internal circuit 11 and a program storage unit 23 having information on a program for operating the internal circuit 11.

  The full charge determination operation according to the present embodiment will be described in detail. FIG. 6 is a flowchart showing the operation of the mobile terminal 1 according to the present embodiment. When the voltage of the secondary battery 14 falls by a predetermined value from the full charge voltage value, charging is started (step S600). The charging in this case is constant current charging. When the secondary battery 14 is charged to a predetermined voltage, the process proceeds to constant voltage charging (step S601). At this time, the current measuring unit 13 measures the value Ia1 of the consumption current Ia (step S602). The determination unit 12 refers to the storage unit 15 and reads the current threshold Ith corresponding to the value Ia1 of the consumption current Ia at the start of constant voltage, which is measured in step S602 (step S603). Thereafter, the current measuring unit 13 measures the value of the charging current Ib at every predetermined time (step S604). The determination unit 12 compares the current threshold Ith read in step S603 with the value of the charging current Ib measured in step S604 (step S605). When the value of the charging current Ib is larger than the current threshold value Ith (step S605: No), charging is continued. The portable terminal 1 repeats the process from step S603 every predetermined time.

  In step S604, when the value of the charging current Ib is smaller than the current threshold Ith (step S605: Yes), the determination unit 12 determines that the battery is fully charged, and outputs the result to the charge control unit 10 (step S606). . When receiving the full charge determination result from the determination unit 12, the charge control unit 10 stops supplying the charging current Ib to the secondary battery 14. Then, the internal circuit 11 notifies the charging completion to the outside using the LED 20 and the display unit 21 (step S607).

  Next, an operation of reading the current threshold value Ith corresponding to the operation state of the internal circuit 11 and charging until full charge will be described. FIG. 7 shows a flowchart of the operation according to the present embodiment. FIG. 7 is different from FIG. 6 in that, instead of measuring the current consumption Ia at the start of constant voltage charging, the internal circuit 11 is inquired about the operation status. Portions overlapping the description of the flowchart of FIG. 6 are omitted.

  When the voltage of the secondary battery 14 falls by a predetermined value from the fully charged voltage value, charging is started (step S700). The charging in this case is constant current charging. When the secondary battery 14 is charged to a predetermined voltage, the process proceeds to constant voltage charging (step S701). At this time, the determination unit 12 inquires of the internal circuit 11 about the operation status of the internal circuit (step S702). The determination unit 12 refers to the storage unit 15 and reads the current threshold value Ith corresponding to the operation status of the internal circuit 11 (step S703). The current measuring unit 13 measures the value of the charging current Ib (step S704) and compares it with the value of the charging current Ib (step S605). The subsequent operation is the same as in FIG.

  In the present embodiment, paying attention to the fact that the value of the charging current for detecting the full charge of the secondary battery differs depending on the magnitude of the current consumption at the start of constant voltage charging, the current consumption at the start of constant voltage charging The current threshold Ith having a different value is set according to the magnitude of. As described above, the full charge of the secondary battery can be more accurately determined by setting the threshold value Ith according to the current consumed in the internal circuit, that is, the operation state of the internal circuit.

  Further, as described above, the threshold value of the charging current Ib indicating full charging differs depending on the magnitude of the charging current at the start of constant voltage charging. Therefore, even if the threshold value Ith is set according to the magnitude of the charging current Ib at the start of constant voltage charging, similarly, the full charge of the secondary battery can be determined more accurately.

  Further, in the present embodiment, the secondary battery is described as being charged from constant current to constant voltage, but is not limited thereto. If constant voltage charging is performed from the beginning, the threshold value Ith may be set according to the voltage value at that time.

  Note that the present invention is not limited to the above-described embodiment, and can be changed as appropriate without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 Portable terminal 10 Charge control part 11 Internal circuit 12 Judgment part 13 Current measurement part 14 Secondary battery 15 Memory | storage part 16 Voltage measurement part 20 LED
DESCRIPTION OF SYMBOLS 21 Display part 22 Control part 23 Program memory | storage part 100 Portable terminal 101 Charger 102 Charging circuit 103 Internal circuit 104 Secondary battery
I _A Inflow current
I _B charging current
I _C current consumption Ia consumed current Ib charging current Ic flowing current

Claims (8)

When the secondary battery is charged, a current measuring unit that measures the consumption current supplied to the internal circuit and the charging current supplied to the secondary battery;
A determination unit that determines the full charge of the secondary battery when the magnitude of the charging current measured by the current measurement unit matches a full charge threshold;
The full charge threshold is a value for determining whether the secondary battery is fully charged, and corresponds to a first value indicating the magnitude of the current consumption when starting constant voltage charging of the secondary battery. The mobile terminal that is the value.   The mobile terminal according to claim 1, wherein the full charge threshold is a value corresponding to a value of a charging current when starting constant voltage charging of the secondary battery. A storage unit that stores information on the full charge threshold that is associated with the first value and indicates that the secondary battery is fully charged;
The current measuring unit measures the value of the consumption current when starting constant voltage charging and periodically measures the value of the charging current,
The determination unit refers to the storage unit, reads the full charge threshold value according to the current consumption value when starting the constant voltage charging, and compares the measured charge current value with the full charge threshold value. The mobile terminal according to claim 1 for determination.   4. The mobile terminal according to claim 1, wherein a different value is set as the full charge threshold according to an operating state of the internal circuit at the time of charging. Measure the current consumption flowing in the internal circuit when starting constant voltage charging of the secondary battery,
Periodically measure the value of the charging current for charging the secondary battery,
The measured magnitude of the charging current is a value for determining whether the secondary battery is fully charged, and indicates the magnitude of the consumption current when starting the constant voltage charging of the secondary battery. A method for controlling a portable terminal, which determines whether the secondary battery is fully charged when a full charge threshold value corresponding to a value of 1 is reached.   The mobile terminal control method according to claim 5, wherein the full charge threshold is a value corresponding to a value of a charging current when starting constant voltage charging of the secondary battery.   In the determination step, when the constant voltage charging is started with reference to a storage unit that is associated with the first value and stores the information of the full charge threshold value indicating that the secondary battery is fully charged. The mobile terminal control method according to claim 5, wherein full charge is determined by reading the full charge threshold value corresponding to the current consumption value and comparing with the measured charge current value.   The mobile terminal control method according to claim 5, wherein a different value is set as the full charge threshold according to an operation state of the internal circuit at the time of charging.

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