JP2008187796A - Electronic equipment and charge control method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide electronic equipment and a charge control method therefor wherein temperature rise is suppressed when a non-genuine charging adapter is used. <P>SOLUTION: Even when the electronic equipment is connected to a non-genuine charging adapter, it is charged by an appropriate charging method by a monitoring means and a controlling means. Therefore, temperature rise can be suppressed when a non-genuine charging adapter is used. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electronic device incorporating a secondary battery and a charge control method thereof.

In general, there is a charging method using a constant current circuit provided in a charging adapter in an electronic device that has a rechargeable battery inside and charges the secondary battery with an external charging adapter. A charging method (for example, refer to Patent Documents 1 and 2) using a constant current circuit provided in an electronic device has been developed.
Japanese Patent Laid-Open No. 2004-173408 Japanese Patent Laid-Open No. 11-069674

  However, the charging method using the constant current circuit provided in the charging adapter is a charging circuit that expects the output voltage to have a drooping characteristic. Therefore, the charging current does not have a constant current circuit inside the charging adapter. When a charging adapter with a high supply capacity is connected, the potential difference between the supply voltage and the battery voltage is larger than that of a charging adapter with drooping characteristics, so the amount of heat loss generated inside the electronic device is large. There was a problem that would become.

In addition, in the charging method using the constant current circuit included in the charging adapter, taking into account the possibility of failure, it is necessary to take measures when a nonstandard charging adapter is connected to the electronic device.
This is because a genuine charging adapter is generally expensive, and many users charge electronic devices using a general-purpose charging adapter or a non-standard charging adapter.

  The above-described invention described in Patent Document 1 assumes a case where an electronic device is charged with a genuine charging adapter, and the invention described in Patent Document 2 is intended to improve charging efficiency. Problems due to temperature rise of electronic equipment are not considered.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an electronic device and a charging control method for the electronic device that suppress a temperature rise when a non-genuine charging adapter is used.

  In order to solve the above-mentioned problem, the invention according to claim 1 is an electronic device for charging a built-in secondary battery using an external charging adapter; and monitoring means for monitoring an input voltage to the secondary battery; And a control means for switching a charging method according to a charging adapter connected to the secondary battery.

  According to the first aspect of the present invention, the monitoring means for monitoring the input voltage to the secondary battery, and the control means for switching the charging method according to the charging adapter connected to the secondary battery, Even if it is connected to a non-genuine charging adapter, it is charged by an appropriate charging method, so that an increase in temperature when a non-genuine charging adapter is used can be suppressed.

  The invention according to claim 2 is characterized in that, in the invention according to claim 1, the control means stops the charging operation when the supply capacity of the charging adapter is higher than a predetermined value.

  According to the first aspect of the present invention, when the supply capacity of the charging adapter is higher than a predetermined value, the charging operation is stopped, so that the secondary battery is not supplied with energy from the outside. Temperature rise when using can be suppressed.

  The invention according to claim 3 is the invention according to claim 1, wherein the control means performs intermittent charging at a constant period when the supply capacity of the charging adapter is higher than a predetermined value. To do.

  According to the third aspect of the present invention, when the supply capacity of the charging adapter is higher than a predetermined value, intermittent cooling is performed at a constant cycle so that natural cooling is performed during the charging stop period. Temperature rise when using an adapter can be suppressed.

  According to a fourth aspect of the present invention, in the invention of the third aspect, the intermittent charging cycle is performed a predetermined number of times with a charging time of n minutes and a charging stop time of m minutes.

According to the fourth aspect of the present invention, the intermittent charging cycle is not genuine because the charging time is n minutes, the charging stop time is m minutes, and natural cooling is performed in the charge stop period by performing a predetermined number of times. Temperature rise when using a charging adapter can be suppressed.
Here, for example, n is 1 and m is 3. The predetermined number of times includes, for example, 9 times. However, n, m, and the predetermined number of times can be changed according to the type and rating of the secondary battery used in the electronic device. The change includes, for example, changing a numerical value of a non-volatile table built in the electronic device.

  According to a fifth aspect of the present invention, in the first aspect of the invention, the monitoring means monitors the input voltage at regular intervals, continuously measures a predetermined number of times during one measurement, The average value is a measured value.

  According to the fifth aspect of the present invention, the input voltage is monitored at regular intervals, continuously measured a predetermined number of times during one measurement, and the average value thereof is used as a measurement value. Therefore, it is possible to suppress the temperature rise when using a non-genuine charging adapter.

  The invention according to claim 6 is the invention according to claim 1, wherein the monitoring means monitors the input voltage at regular intervals, and the input voltage exceeds a predetermined value twice in succession. The charging adapter is determined to be a charging adapter having a high charging current supply capability without a constant current circuit.

  According to the sixth aspect of the present invention, the input voltage is monitored at regular intervals, and when the input voltage exceeds a predetermined value twice in succession, the charging adapter does not have a constant current circuit. By determining that the charging adapter is high, the charging control corresponding to the charging adapter having a high charging current supply capability is performed, so that an increase in temperature when a non-genuine charging adapter is used can be suppressed.

  According to a seventh aspect of the present invention, in the invention of the sixth aspect, the control means determines that the charge adapter is a charge adapter having a high charge current supply capability that does not have a constant current circuit, and performs intermittent charge control. Charging is forcibly stopped when the continuous intermittent charge control becomes longer than the set time when the transition is made.

  According to the seventh aspect of the present invention, when the charging adapter is determined to be a charging adapter having a high charging current supply capability that does not have a constant current circuit, and the transition to the intermittent charging control is performed, the continuous intermittent charging control is set. By forcibly stopping the charging when it becomes longer, no energy is supplied to the secondary battery, so that an increase in temperature when using a non-genuine charging adapter can be suppressed.

  According to an eighth aspect of the present invention, in the first aspect of the present invention, the control means is capable of reading the charge current value detected by the charge current monitoring circuit that monitors the charge current from the charge control IC. Yes, calculate the amount of heat loss based on the potential difference detected by the external voltage monitoring circuit that monitors the input voltage and the battery voltage monitoring circuit that monitors the voltage of the secondary battery, and the charging current value detected by the charging current monitoring circuit When the amount of heat loss exceeds a threshold, it is determined that the charge adapter is a charge adapter having a high charge current supply capability that does not have a constant current circuit.

  According to the eighth aspect of the present invention, the potential difference detected by the external voltage monitoring circuit that monitors the input voltage and the battery voltage monitoring circuit that monitors the voltage of the secondary battery, and the charging current value detected by the charging current monitoring circuit. If the heat loss amount exceeds the threshold, it is determined that the charge adapter is a charge adapter with a high charge current supply capability that does not have a constant current circuit. Since it is not supplied to the battery, it is possible to suppress an increase in temperature when a non-genuine charging adapter is used.

  According to a ninth aspect of the present invention, in the charging control method for an electronic device that charges a built-in secondary battery using an external charging adapter, an input voltage to the secondary battery is monitored, and the secondary battery is connected to the secondary battery. The charging method is switched according to the connected charging adapter.

  According to the ninth aspect of the present invention, even when connected to a non-genuine charging adapter, the battery is charged by an appropriate charging method, so that an increase in temperature when a non-genuine charging adapter is used can be suppressed.

  According to the present invention, even if connected to a non-genuine charging adapter, charging is performed by an appropriate charging method by the monitoring unit and the control unit, so that an increase in temperature when a non-genuine charging adapter is used can be suppressed.

An electronic device according to the present invention includes a rechargeable battery inside, and an electronic device that charges the secondary battery with an external charging adapter, periodically monitors the input voltage and is connected According to the adapter, the charging method is switched.
That is, according to the present invention, when a charging adapter that does not have a constant current circuit and has a high charging current supply capability is connected, this is detected and the charging is stopped forcibly or intermittent charging is performed in which charging is performed at a constant cycle. By switching, the amount of heat loss generated inside the electronic device is reduced.

Embodiments of the present invention will be described.
[Embodiment 1]
This embodiment will be described with reference to the drawings, taking a mobile phone as an example.
FIG. 1 is a block diagram relating to the power supply of a mobile phone as an electronic device to which the electronic device control method according to the present invention is applied. In order to simplify the explanation, the radio frequency unit, the baseband unit, the memory (including the non-volatile table), the speaker, the microphone, the key, the image processing unit, the camera, the CCD, and the like are omitted in FIG.

First, charging control using a constant current circuit of the charging adapter (111) in a general mobile phone will be described.
In charging by the charging adapter (111) having a constant current circuit, the output voltage of the charging adapter (111) has a drooping characteristic, and the input terminal and the output terminal of the charging control FET (104) are in an open state. The potential difference between the voltage at point A and the point B in FIG. 1 is a minimum value.
This is an operation during constant current charging, but switches to constant voltage charging when it is nearly fully charged. During constant voltage charging, the charging current is controlled by the charging control FET (104), so the voltage at point A is approximately 5.5V to 6V, which is almost the same as the no-load voltage of the charging adapter (111). It becomes.

  Assuming that the voltage when the battery (101) is fully charged is about 4.2V to 4.3V, the potential difference between the points A and B is about 1.2V to 1.8V.

Here, in the cellular phone (100) according to the present invention, the external voltage monitoring circuit (110) and the battery voltage monitoring circuit (107) as the monitoring means during charging are controlled by the CPU (106) as the control means. The voltage at point B and point B are monitored, the CPU (106) calculates the potential difference between point A and point B, and compares it with the threshold values in Table 1.
Table 1 shows data for setting a threshold value for detecting an adapter with a high supply capability that does not incorporate a constant current circuit, and is a potential difference between points A and B in FIG. (100) is stored in a non-illustrated non-volatile table.

When charging the mobile phone (100) during constant current charging, it is confirmed from the threshold values in Table 1 that the voltage is 0.5 V or less, and during constant voltage charging, it is confirmed that it is 2.0 V or less.
If a voltage exceeding the threshold is detected, the CPU (106) controls the charging control IC (105) to forcibly stop charging.

〔Constitution〕
FIG. 1 shows an external I / O connector (102) for connecting a charging adapter, a charging current detecting resistor (103), and a charging control FET for controlling the charging current in a mobile phone (100) as an electronic apparatus according to the present invention. (104) The charge control IC (105) that controls the overall charge control and the charge current supply capability of the external power supply adapter (111) are detected. When it is detected that the supply capability is high, the charge is forcibly stopped, or It is comprised by CPU (106) which performs judgment, such as switching to intermittent charge control.

  The charging control IC (105) includes a battery voltage start circuit (107) for monitoring the voltage of the battery (101), a charging control circuit (108) for controlling the charging control FET (104), and a charging current detection. A charging current monitoring circuit (109) for monitoring a voltage drop due to the resistor (103) and monitoring the charging current, and an external voltage monitoring circuit (110) for monitoring the voltage on the charging adapter (111) side are provided.

  That is, the charging adapter (111) is connected to the input end (left end in the figure) of the external I / O connector (102) of the mobile phone (100) shown in FIG. The output end (in this case, the right end) of the external I / O connector (102) is connected to one end (in this case, the left end) of the resistor (103) and the external voltage monitoring circuit (110) of the charge control IC (105). A connection point of the external I / O connector (102), the resistor (103), and the external voltage monitoring circuit (110) is defined as a point A.

  The other end (right end in this case) of the resistor 103 is connected to the input end (left end: drain) of the charge control FET (field effect transistor: 104) and the charge current monitoring circuit (109) of the charge control IC (105). . A connection point of the resistor (103), the charge control FET (104), and the charge current monitoring circuit 109 is a point C.

The output terminal (in this case, right end: source) of the charge control FET 104 is connected to the battery (101) and the battery voltage start circuit (107) of the charge control IC (107). A connection point of the charge control FET (104), the battery (101), and the battery voltage monitoring circuit (107) is a point B.
The charge control IC (105) is connected to the CPU (106) and is controlled by the CPU (106).
As the battery (101), for example, a lithium ion battery (nominal capacity 830 mAh, rated voltage 3.8 V)

  Table 2 shows data for setting the charging ON time and OFF time during the intermittent charging of the mobile phone as the electronic apparatus according to the present invention, and these data are stored in a non-illustrated non-volatile table.

  Table 3 shows data for setting an intermittent charging time timer for a mobile phone as an electronic apparatus according to the present invention, and these data are stored in a non-illustrated non-volatile table.

  2A is a battery voltage monitoring timing diagram of the mobile phone shown in FIG. 1, FIG. 2B is an external voltage monitoring timing diagram of the mobile phone shown in FIG. 1, and FIG. ) Is a timing diagram in which the timing diagram of FIG. 2A and the timing diagram of FIG. 2A to 2C, the horizontal axis is the time axis, but in FIGS. 2A and 2B, the unit is seconds, and in FIG. 2C, the unit is minutes.

[Explanation of effects]
In the above, even when charging is started by a charging adapter that is not originally designed, or an adapter with a high charging current supply capability that does not have a constant current circuit inside the charging adapter, this is detected and the charging operation is performed. By forcibly stopping or intermittently charging at a constant cycle, it is possible to reduce the amount of heat loss generated inside the electronic device and to suppress the temperature rise of the electronic device.

  The above-described embodiment shows an example of a preferred embodiment of the present invention, and the present invention is not limited thereto, and various modifications can be made without departing from the scope of the invention. is there. For example, in the above description, the case of a mobile phone has been described. However, the present invention is not limited to this, and an electronic device having a built-in secondary battery such as a notebook computer, a video camera, a digital camera, or a radio control (registered trademark) toy. It is also applicable to the power supply of equipment. In the above-described embodiment, the case where the FET is used has been described. However, the present invention is not limited to this, and can be applied to a bipolar transistor.

Next, another embodiment of the electronic device to which the electronic device control method according to the present invention is applied will be described.
[Embodiment 2]
Another embodiment will be described with reference to FIG. 1, Table 1, and Table 2.
When the potential difference between the points A and B in FIG. 1 exceeds the threshold shown in Table 1 during charging, intermittent charging is performed in which charging is repeated at a constant period.
Here, as shown in Table 2, the period of intermittent charging is, for example, n minutes as a charging time, 1 minute, m minutes as a charging stop time, and a predetermined number of charging / stop repetition times. When the number of times is nine, the temperature rise due to charging can be suppressed to about one-fourth as compared with the original charging (see FIGS. 3 and 4). However, n, m, and the predetermined number of times can be changed according to the type and rating of the secondary battery used in the electronic device. The change includes, for example, changing a numerical value of a non-volatile table built in the electronic device.

FIG. 3 is a diagram showing the relationship between the charging current and the temperature change when intermittent charging is performed in the mobile phone shown in FIG. FIG. 4 is a diagram showing a relationship between a charging current and a temperature change when intermittent charging is not performed in the mobile phone shown in FIG. 3 and 4, the horizontal axis represents the time axis, the left vertical axis represents the temperature axis, and the right vertical axis represents the current axis.
As the charging adapter conditions, for example, the voltage was set to +6 V, the current limit was set to 1 A (using a stabilized power supply), and a videophone was used (15 dBm).

[Embodiment 3]
The voltage monitoring timing will be described with reference to FIG. 1, Table 1, and FIGS.
When the respective voltages are detected by the external voltage monitoring circuit (109) and the battery voltage monitoring circuit (107), as shown in FIGS. 2 (a) to (c), for example, voltage monitoring is performed once every minute. By measuring four times every second at the time of measurement, and using the average value as the measurement value, it is possible to reduce the influence of malfunction due to ambient noise or the like.

[Embodiment 4]
Charging with high charging current supply capability without a constant current circuit when the threshold value shown in Table 1 is exceeded twice in succession, instead of making a determination every 4 minutes or once per minute Judged as adapter connection.
Even in this case, it is possible to suppress an increase in temperature when a non-genuine charging adapter is used.

[Embodiment 5]
The intermittent charge timer will be described with reference to FIG. 1 and Table 3.
When the mobile phone (100) determines that the CPU (106) is connected to an adapter having a high charging current supply capacity without a constant current circuit in the charging adapter and shifts to intermittent charging control, continuous intermittent charging control is performed. When it becomes longer than the time set by the non-volatile table data shown in Table 3, the CPU (106) controls the charging control IC (105) to forcibly stop charging. As a result, it is possible to avoid a state in which the battery (101) is continuously charged for a long time, and to further improve the reliability.

[Embodiment 6]
The CPU (106) can read out the charging current value detected by the charging current monitoring circuit (108) to the charging control IC (105). The external voltage monitoring circuit (110) and the battery voltage monitoring circuit ( 107) and the charge current value detected by the charge current monitoring circuit (108), the amount of heat loss is calculated. If the amount of heat loss exceeds the threshold, the charge current without the constant current circuit is calculated. It is determined that the adapter connection has a high supply capacity. Even in this case, it is possible to suppress an increase in temperature when a non-genuine charging adapter is used.

  INDUSTRIAL APPLICABILITY The present invention can be used for a power source of an electronic device having a built-in secondary battery such as a mobile phone, a notebook computer, a video camera, a digital camera, and a radio control (registered trademark) toy.

It is a block diagram about the power supply relationship of the mobile telephone as an electronic device to which the control method of the electronic device which concerns on this invention is applied. (A) is a battery voltage monitoring timing diagram of the mobile phone shown in FIG. 1, (b) is an external voltage monitoring timing diagram of the mobile phone shown in FIG. 1, (c) is (a) FIG. 4 is a timing diagram in which the timing diagram of FIG. It is a figure which shows the relationship between the charging current at the time of performing intermittent charge in the mobile telephone shown in FIG. 1, and a temperature change. It is a figure which shows the relationship between a charging current at the time of not performing intermittent charge in the mobile telephone shown in FIG. 1, and a temperature change.

Explanation of symbols

100 Mobile phone 101 Battery 102 External I / O connector 103 Resistor 104 Charge control FET
105 Charge control IC
106 CPU
107 battery voltage monitoring circuit 108 charge control circuit 109 charging current monitoring circuit 110 external voltage monitoring circuit 111 charging adapter

Claims (9)

  In an electronic device for charging a built-in secondary battery using an external charging adapter, a monitoring means for monitoring an input voltage to the secondary battery, and a charging method according to the charging adapter connected to the secondary battery An electronic device comprising a control means for switching between the electronic devices.   The electronic device according to claim 1, wherein the control unit stops the charging operation when the supply capacity of the charging adapter is higher than a predetermined value.   The electronic device according to claim 1, wherein the control unit performs intermittent charging at a constant cycle when the supply capacity of the charging adapter is higher than a predetermined value.   The electronic device according to claim 3, wherein the intermittent charging cycle is performed a predetermined number of times, with a charging time of n minutes and a charging stop time of m minutes.   The said monitoring means monitors the said input voltage for every fixed time, measures a predetermined number of times continuously at the time of one measurement, and makes the average value a measured value. Electronics.   The monitoring means monitors the input voltage at regular intervals, and when the input voltage exceeds a predetermined value twice in succession, the charging adapter does not have a constant current circuit and has a high charging current supply capability. The electronic device according to claim 1, wherein the electronic device is determined to be.   When the control means determines that the charging adapter is a charging adapter having a high charging current supply capability without a constant current circuit and shifts to intermittent charging control, the time when continuous intermittent charging control becomes longer than a set time The electronic device according to claim 6, wherein the charging is forcibly stopped.   The control means is capable of reading a charging current value detected by a charging current monitoring circuit that monitors a charging current to a charging control IC, and an external voltage monitoring circuit that monitors the input voltage and the secondary battery. Calculate the amount of heat loss based on the potential difference detected by the battery voltage monitoring circuit that monitors the voltage and the charging current value detected by the charging current monitoring circuit, and if the amount of heat loss exceeds the threshold, the charging adapter The electronic apparatus according to claim 1, wherein the electronic apparatus is determined to be a charging adapter having a high charging current supply capability without a circuit.   In a charging control method for an electronic device that charges an internal secondary battery using an external charging adapter, the input voltage to the secondary battery is monitored, and charging is performed according to the charging adapter connected to the secondary battery. A method for controlling charging of an electronic device, wherein the method is switched.

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