JP2001275272A - Charging control circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To conduct charging current control to a secondary cell without providing an actual current consumption detector of a load in an electronic equipment capable of simultaneously supplying an output current output from an AC adapter to the cell and the load. SOLUTION: A charging control circuit charges the secondary cell 3 connected in parallel with the loads 5 to 8 to a power source means 1. The control circuit comprises a control circuit 4 for outputting control signals for controlling drives of the loads 5 to 8 to the loads 5 to 8, and means 2, 12 for controlling the charging current to the cell 3 based on the control signals.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a charge control circuit.

[0002]

2. Description of the Related Art A portable electronic device employs a so-called multi-drive power supply system capable of at least AC drive and built-in battery drive, and uses a rechargeable secondary battery as the built-in battery. At the time of AC driving, charging of the secondary battery is enabled together with driving of a load in the device.

[0003] For example, Japanese Patent Application Laid-Open No. 4-35939 (H
02J7 / 34), the output current from the AC adapter is controlled so that the charging current supplied to the secondary battery is constant, regardless of the current value consumed by the load, so that the charging of the secondary battery is always constant. And US Pat.
No. 363031 describes a configuration for controlling charging control of a secondary battery in accordance with a current value consumed by a load when a constant current is output from an AC adapter.

[0004]

However, in the former configuration, if the current consumed by the load of the device increases with the advancement of functions, the size of the AC adapter must be increased accordingly. It is not suitable for portable electronic devices. In the latter configuration, a circuit configuration for constantly checking the current value consumed by the load of the device is indispensable.
In addition, the circuit must be increased in size to cope with a high current with an increase in the current consumption by the load of the device, and it is still unsuitable for a portable electronic device that requires miniaturization.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has a feature in a charge control circuit for charging a secondary battery connected in parallel with a load to power supply means. There is provided a control circuit for outputting a control signal for controlling the driving of the load to the load, and means for controlling a charging current to the secondary battery based on the control signal.

[0006]

FIG. 1 is a block diagram showing a main circuit of an electronic apparatus to which the present invention is applied.

In the present embodiment, a commercial AC voltage supplied from a commercial power supply (not shown) is converted into a constant current DC voltage by an AC adapter 1 and then supplied to a secondary battery 3 via a charging circuit 2. The drive voltage VC is also applied to each part described later.
It is supplied in parallel as C.

The main control unit 4 is composed of, for example, a microprocessor and has a CD-ROM based on a built-in control program.
It controls the drive 5, HDD drive 6, and FDD drive 7. The LED display circuit 8 is provided for each of the drives 5 to 7 described above.
And first to third display elements 9 to 11 made of, for example, light emitting diodes. The display circuit 8 turns on / off / blinks / turns off the corresponding first to third display elements 9 to 11 based on a control signal output from the main control unit 4 and indicating the drive state of each of the drives 5 to 7. And each state. For example, when the drives 5 to 7 are operating, the first to third display elements 9 to 11 are turned on, and when the drives 5 to 7 are not operating, the first to third display elements 9 to 11 are turned off. .

The detection circuit 12 detects the driving state of each of the drives 5 to 7 according to the control signal output from the main control unit 4 to the LED display circuit 8. When it is determined that none of the drives 5 to 7 has been driven for a predetermined time (for example, 1 to 2 seconds) based on the detection of the drive state, the charging circuit 2 is charged with the maximum current. A signal for instructing charging at the lowest current is output otherwise. Note that the maximum current charging means charging with the remaining current obtained by subtracting the maximum current consumed by the circuits other than the drives 5 to 7 from the current output from the AC adapter 1, and the minimum current charging. The current charging means charging with the remaining current obtained by subtracting the maximum current consumed by the circuits including the drives 5 to 7 from the current output from the AC adapter 1. For this reason, the minimum current may be substantially zero depending on the device.

The charging circuit 2 incorporates, for example, a one-chip microcomputer, and switches and supplies the charging current of the secondary battery 3 to the maximum current or the minimum current according to an instruction signal supplied from the detection circuit 12.

In the present embodiment, the detection circuit 12 supplies the LED display circuit 8 with a secondary battery 3 according to a control signal output from the main control unit 4 to indicate the driving state of each of the drives 5 to 7.
The main control unit 4 outputs an instruction signal for controlling the charging current of the drive 5 to the drive circuit 5 to 7 directly.
The instruction signal is supplied to the charging circuit 2 according to the control signal output to the
May be output.

In the present embodiment, the instruction signal to the charging circuit 2 is selected based on only the driving states of the drives 5 to 7, but the driving states of other peripheral devices such as a display may be referred to. .

Further, in the present embodiment, the instruction signal has two stages, but it may be configured to have multiple stages. For example,
Only one of the drives 5 to 7 is in a driving state,
When the other drive has not been driven for a predetermined time, the secondary battery 3 can be charged with a current value between the maximum current and the minimum current.

[0014]

According to the present invention, the driving state of the peripheral device can be program-controlled for the charging current of the secondary battery based on the control signal output from the main control unit. This eliminates the need for a dedicated circuit, and as a result, there is no problem that the size of the device is increased due to an increase in current consumption at the load of the device.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a main circuit of an electronic apparatus according to an embodiment of the invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 AC adapter 2 Charging circuit 3 Secondary battery 4 Main control circuit 5 CD-ROM drive 6 HDD drive 7 FDD drive 8 LED display circuit 12 Detection circuit

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5G003 AA01 BA01 CB09 CC07 DA15 DA17 EA04 GC05 5H030 AA03 AS20 BB03 DD06 FF41 FF42 FF67

Claims (4)

[Claims] 1. A charge control circuit for charging a secondary battery connected in parallel with a load to a power supply means, the control circuit outputting a control signal for controlling the driving of the load to the load. Means for controlling the charging current to the secondary battery based on the control signal. 2. A power supply means, a secondary battery, a means for supplying a current output from the power supply means to the secondary battery as a charging current, and a power supply means connected to the power supply means in parallel with the supply means. A load to which an output current of the power supply is supplied as a drive current; and a control circuit for outputting a control signal for controlling the driving of the load to the load, wherein the supply means is configured to supply the secondary battery based on the control signal. A charge control circuit for controlling a charge current supplied to a battery. 3. A power supply means, a secondary battery, a means for supplying a current output from the power supply means to the secondary battery as a charging current, and a power supply means connected to the power supply means in parallel with the supply means. A load to which an output current of the power supply is supplied as a drive current, and a unit for displaying an operation state of the load;
A control circuit for controlling the driving of the load and outputting a control signal for displaying the driving state of the load on the display means to the display means, wherein the supply means performs the secondary control based on the control signal. A charge control circuit for controlling a charge current supplied to a battery. 4. A charge control circuit according to claim 1, wherein said power supply means supplies a constant current DC voltage.