JP2604275B2 - Electronic device charge control method - Google Patents

Description

The present invention relates to a charge control system for rapidly charging a secondary battery such as a nickel-cadmium (Ni-cd) battery in an electronic device such as a personal computer.

(B) Conventional technology Since electronic devices such as laptop computers and notebook computers are intended to be carried around, most of them are equipped with rechargeable secondary batteries such as nickel cadmium batteries as power supplies. It is.

Conventionally, in this type of device, as disclosed in Japanese Patent Application Laid-Open Nos. 63-124731 and 1-166441, the usage status of the electronic device main body is determined, and when the device is not in use, a rapid response is made. It was controlled to charge. Specifically, the on / off state of the power switch is detected, and when the switch is turned off from on, quick charging is started.

(C) Problems to be Solved by the Invention In the prior art, quick charging is always started when the power switch is turned on from off, so even if a fully charged battery that has already been charged is mounted, Charging is performed, which causes a problem that the battery is overcharged and the deterioration of the battery is accelerated.

(D) Means for Solving the Problems The present invention provides a power switch provided on an electronic device main body, a secondary battery detachably mounted on the electronic device main body,
A charging circuit for rapidly charging the secondary battery based on an external power supply; a first detecting unit for detecting an on / off state of the power switch; a second detecting unit for detecting a mounting state of the secondary battery; A flag control means for setting a prohibition flag in response to the end of the quick charge and resetting in response to the removal of the secondary battery; and an output of the first and second detection means and a state of the charge prohibition flag. Charge control means for controlling the charging circuit, when the secondary battery is in the mounted state, and when the power switch is off and the charging prohibition flag is in the reset state, to start rapid charging,
This is to solve the above-mentioned problem.

Further, the present invention provides a power switch provided on the electronic device main body, a secondary battery detachably attached to the electronic device main body, an adapter for supplying power from an external power supply to the electronic device main body, A charging circuit for rapidly charging the secondary battery; first detecting means for detecting an on / off state of the power switch; second detecting means for detecting a mounting state of the secondary battery; A third detecting means for detecting a connection state with the device main body, and a charging prohibition flag are set according to the end of the rapid charging, and the secondary battery is removed and the connection between the adapter and the electronic device main body is released. Flag control means for resetting, and charge control means for controlling the charging circuit in accordance with the outputs of the first to third detection means and the charging of the charging prohibition flag. Rutotomoni adapter and the electronic apparatus main body and is connected, and, when the power switch is in the charging prohibition flag is reset off, so as to initiate a rapid charge is intended to solve the above problems.

(E) Operation According to the present invention, once the battery is charged, the charging prohibition flag is set, so that even when a fully charged battery is mounted when the power switch is turned off, the battery is re-charged. There is no rapid charging, and overcharging can be prevented.

Further, since the charging prohibition flag is reset in accordance with the removal of the battery, the quick charging is always performed automatically when the battery is replaced.

Also, after charging the battery, the adapter is disconnected from the main body and the main body is used by driving the battery. Then, when the adapter is connected to the main body, rapid charging is automatically started.

(F) Embodiment FIG. 2 is a block diagram showing a schematic configuration of an embodiment of the present invention, where 1 is a secondary battery such as a nickel cadmium (Ni-cd) battery or a nickel hydride battery (Ni-MH) battery. One end of an information device body 3 such as a personal computer to which a battery pack 2 is detachably attached is connected to the AC plug 4 at one end and the other end is connected to the main body 1 via a cable 5, and converts AC voltage to DC voltage. It is an AC adapter and charger having an AC adapter function for supplying to the main body and a function for charging the battery pack 2.

The main body 1 has a DC plug 6 for connecting a cable 5,
A main body power supply circuit 8 for converting the supplied power supply voltage into a DC-DC voltage and supplying the load 7 to the load 7, a power supply switch 9 inserted in the power supply line, and a quick charge for detecting on / off of the power supply switch in conjunction with the power supply switch 9. A detection switch 10, a battery type detection switch 11, a diode 12 inserted in a forward direction from the terminal HP2 of the DC plug 6 toward the input / output terminal of the battery pack 2, and a connection of the DC plug 6 from the input / output terminal of the battery pack 2. It has a diode 13 inserted in the forward direction toward the terminal HP1.

On the other hand, the AC adapter & charger 3 includes, on the primary side of the power transformer 14, a line filter 15, a rectifier circuit 16, a smoothing circuit 17, a primary coil 18, a switching element 19, a PWM control circuit 20 for controlling on / off of the switching element, The phototransistor 21 includes a phototransistor 211 as a light receiving unit.

The secondary side of the transformer is provided with first and second two coils 22, 23, each of which has a rectifier circuit 24, 25 and a smoothing circuit.
26 and 27 are connected. The output of the smoothing circuit 26 is connected to a terminal P1 of a DC plug 29 via a diode 28 having a first contact S1 inserted in a forward direction, and a second contact S2 is connected to a DC plug.
It is connected to a relay 30 connected to the terminal P2 of the 29.

Further, on the output side of the smoothing circuit 26, a constant voltage circuit 31, a current detection circuit 32, a constant current circuit 33, and a photodiode 210 of the photocoupler 21 are provided in order to realize constant voltage and constant current of the power supply. ing. Control of these constant voltage circuit and constant current circuit is performed by the microcomputer 34,
This microcomputer 34 has a terminal P of the DC plug 29
From P3, the switch output of the quick charge detection switch 10 and the battery type detection switch 11 on the main body side, and the detection signals from the open battery & -ΔV detection circuit 35 and the short battery detection circuit 36 are input. The drivers 38 and 39 of the relay 30 and the LED 37 are also controlled by the microcomputer 34.

On the output side of the other smoothing circuit 27 on the secondary side, a trickle charge control resistor 40 is inserted to supply a trickle charge current to the battery pack 2 via the terminal P2 of the DC plug 29.

In the present embodiment, the trickle charge current Ir is 0.1 m or less and 150 m
It is set to A, and the voltage of the supply line 42 is set to 23 V when the battery is not mounted and the battery is open. In the adapter mode, the contact of the relay 30 is set to S1
Is connected to the supply line 41, a constant voltage of 16V is supplied to the supply line 41, and in the rapid charging mode, the contact of the relay 30 is connected to S2, and the supply line 42 is supplied with a constant voltage of 23V, and The constant current value is controlled so as to gradually increase with time, as described later.

Next, a specific configuration of the AC adapter & charger 3 is shown in FIG. 3 and will be described in more detail.

First, the microcomputer 34 is an AD converter that converts an analog voltage input from the terminal COMP into a digital voltage.
50, a ROM 51 for storing a program and a ΔV value for each of a Ni-cd battery and a Ni-MH battery, an input voltage BV from the AD converter 50, its peak voltage PEEK, and various flags used for charge control described later. RAM52 for storing INF, SHORTF, BATF, DELTA
And safety timer, short timer, charge timer,
Various timers 53 such as a -ΔV timer are incorporated.

The open battery & -ΔV detection circuit 35 receives the pulse signal PWM from the microcomputer 34 and outputs the sawtooth reference voltage V
A sawtooth voltage generating circuit 60 comprising a transistor 600 for outputting 1 and a capacitor 601;
The comparator 61 compares the resistance divided voltage Vs of 42 with the output of the comparator 61.
It comprises a transistor 62 for input to the COPM, and inputs an analog voltage corresponding to the voltage of the line 42 to the COPM terminal.

Here, the voltage Vs is set to be substantially the same potential as the highest value of the reference voltage V1 when the voltage of the line 42 is 22V, and the lowest value of V1 is 0V. Therefore, when the DC plug 29 is not connected to the DC plug 5 or when the battery is not mounted, the voltage of the line 42 is always higher than 23 V and 22 V. While the input is continued, while the DC plug is connected and the battery is installed, the voltage of the line 42 decreases to the battery voltage.
34 can determine whether or not the DC plug 29 is connected and whether or not the battery is in an open battery state.

The short battery detection circuit 36 compares the resistance divided voltage of the line 42 with the reference voltage from the constant voltage regulator 63, and detects that the voltage of the line 42 is 10 V or less. The transistor 65 is connected to the relay driver 38, and the transistor 66 is connected to the comparator 61.
Are connected to the-terminal.

Next, the constant voltage circuit 31 and the constant current circuit 33 will be described.

The constant voltage circuit 31 connects the resistor R1, the photodiode 210, and the shunt regulator 70 in series between the line 42 and the ground, and connects the voltage dividing point A of the series resistors R2, R4, and R5 to the Vref terminal of the shunt regulator 70. Connected and configured. The shunt regulator 70 has its Vref voltage always constant,
R3 and C3 are elements for preventing oscillation.

A transistor Q1 is connected in parallel to the resistor R5, and a signal T0 from the microcomputer 34 is input to the base of the transistor Q1 via the resistor R7.

Therefore, when the voltage V0 of the line 42 is going to rise or fall, the current flowing through the photodiode 210 increases or decreases, and this current is
The switching element is fed back to the control circuit 20, and the switching element is turned on and off so as to decrease or increase the voltage V0.
It works to keep V0 constant. V0 = ｛1 + R2 / (R4 + R
5) Since refVref, when transistor Q1 turns on (R
4 + R5) becomes only R4, and the voltage V0 increases. Here, it changes from 16V to 25V.

On the other hand, the constant current circuit 33 includes one end C of the current detection resistor 32 and the series resistors R13 and R1 connected to the output of the constant voltage regulator 63.
2, R11, R10, R9, the voltage at the voltage dividing point D is input to the + terminal, and the voltage at the other end B of the current detection resistor 32 is input to the-terminal via the resistor R8; twenty one
A diode 72 inserted in a forward direction from the connection point E between the zero and the cathode of the shunt regulator 70 toward the output of the comparator 71, and series-connected resistors R13, R12, and R11 are connected in parallel to each other. It comprises transistors Q1, Q2, and Q3 that input T1, T2, and T3 to their respective bases.

In this circuit, when the battery pack 2 is mounted, the line
A current flows in the direction indicated by an arrow from the current detection resistor 41 through the battery pack 2 to the current detection resistor 32. If the current increases or decreases, the output of the comparator 71 decreases or increases. The current flowing through the diode 210 increases or decreases, and this current is fed back to serve to reduce or increase the current flowing through the current detection resistor 32, thereby keeping the current constant.

Further, when the signals T1, T2, T3 change from H to L, the transistors Q2, Q3, Q4 are respectively turned on and the resistors R13, R12, R11 are short-circuited, whereby the reference voltage at the point D increases. Therefore, at this time, the value of the constant current flowing through the current detection resistor 32 increases. Here, the constant current value is 1 A according to the signals T1, T2, and T3.
= 0.6C, 1.7A = 1C, 2.5A = 1.5C. In addition, T0 ~
The constant current value when T3 is all H is set to 0.3A = 0.2C.

By the way, in this embodiment, two types of batteries, Ni-cd and Ni-MH, can be used, and the battery types are identified by the configuration shown in FIG.

That is, a micro switch 91 as a battery type switch is provided in the insertion portion of the battery pack, and the Ni-cd battery
In FIG. 5A, the position corresponding to the switch 91 is flat as shown in FIG.
In FIG. 5, as shown in FIG. 5B, a convex portion 202 is formed at a portion corresponding to the switch.

Therefore, according to the arrow, when the Ni-cd battery 200 is inserted, the switch does not come into contact with the battery, and the switch remains off. Is pushed in, and the switch turns on. And the output of this on / off switch is the DC plug terminal HP4
And input to the microcomputer via P4.

Returning to FIG. 3, the LED 37 is composed of an LED 370 and a section 371 of two colors, red and green, and the LED driver 39 is also composed of two transistors 390 and 391.

Hereinafter, the operation of the embodiment will be described in detail with reference to the flowchart of FIG. 1 and the waveform diagram of FIG.

When the AC plug 4 is plugged into an outlet, the AC adapter & charger 3 is power-on reset, the internal state is cleared, and the relay 30 contacts the contact S1 side.
An adapter mode for supplying a constant voltage of 16 V from the line 41 to the plug terminal P1 is set. In this mode, a torque charging current of 0.1 C or less is supplied to the battery pack 2 from the line 42 via the terminal P2 when the battery is mounted.

Next, as shown in the flowchart of FIG. 1, the microcomputer 34 connects the DC plug 29 of the AC adapter & charger 3 to the DC
It is determined whether the battery is connected to the plug 6 and whether the battery is in an open battery state. If the DC plug is connected and a battery is installed, it is further determined whether the power switch 9 of the main body 1 is turned on by a quick charge detection switch input from the terminal P3. Is checked whether the prohibition flag INF is 0. Then, when INF is 0, the operation enters the quick charge mode.

In the rapid charging mode, the microcomputer 34 sets the signal T0 to H, drives the relay driver 38 to switch the contact of the relay 30 from S1 to S2, and turns on the transistor Q1 of the constant voltage circuit 31 to turn on the line 41. The supply voltage when the battery is opened is increased to 25 V, and the signals T2 to T4 are set to H to turn off the transistors Q2 to Q4, thereby starting the rapid charging of 0.2C. And with the start, safety timer 530
And the charging timer 531 is started. Line 42
Of course is the same as the voltage of the battery 2.

After the start of 0.2C charging, the microcomputer 34
The battery type detection switch input from P4 is read and the battery type is determined.If the battery type is a Ni-cd battery, the flag BATF is set to 0, the driver 390 is driven, the red LED 370 is turned on, and the Ni-MH battery is used. If there is, the flag BATF is set to 1 and the drivers 390 and 391 are driven to turn on the LEDs 370 and 371 and turn on the LED 37 in orange.

Next, the microcomputer 34 determines whether or not 20 seconds have elapsed since the start of the 0.2 C charging by the charging timer, and if so, changes the signal T1 from H to L, turns on the transistor Q2, and sets the constant current value to 0.6. Raise to C. After that, the signal T2 and T3 are sequentially changed from H to L every 20 seconds by the charging timer.
Then, as shown in FIG. 4A, the constant current value is sequentially increased by 1 C and 1.5 C.
Change to C. Along with this, the battery voltage BV gradually increases as shown in the figure, and a pseudo peak voltage caused by suddenly applying a large current at the beginning of charging as in the conventional example shown in FIG. 6A does not occur. This effect is more effective as the number of steps for changing the constant current value is reduced.

In each quick charge cycle of 0.1C to 1.5C, STEP-
As shown in A, B, and D, the connection state of the DC plug, the open battery state, and the body switch state are always detected, and the DC plug is disconnected, the battery is removed, or the body switch 9 is turned on. Then, quick charge is stopped and LED37
Also goes out.

Also, the microcomputer 34 samples the battery voltage BV at a constant cycle based on the output of the AD converter 50, constantly compares the previous sampling value with the latest sampling value, and uses the larger value as the PEEK in the RAM 52. To be remembered. And the latest sampling value is
When it becomes lower than PEEK, it is determined that a peak voltage has occurred.

After the occurrence of the peak voltage, it is determined whether or not the difference between the peak value and the latest sampling battery voltage BV has exceeded the ΔV value stored in the ROM 51 in advance. I do. If this state continues for one minute by the ΔV timer, it is determined that the battery is fully charged, the prohibition flag INF is set to 1, and the rapid charging is terminated as shown in FIG. 4A. In other words, the signal T0 is set to L, T1 to T3 to H, and the contact of the relay 30 to S1,
Returning to the adapter mode, the battery 2 enters trickle charge of 0.1 C or less.

If no peak voltage or -ΔV is detected even after 80 minutes from the start of the quick charge, the safety timer 530 stops the quick charge.

By the way, after the occurrence of the peak voltage, in the present embodiment, a different ΔV value is read from the ROM 51 according to the type of the battery by the determination of the flag BATF. ing.

In each charge cycle of 0.2C to 1.5C,
As shown in -C, it is determined whether or not the battery is in an abnormal state in which the battery is short-circuited by determining whether or not the battery voltage BV is 10 V or less.

That is, it is checked whether the state in which the battery voltage BV is 10 V or less continues for 30 seconds or more by a short timer. In the case of a Ni-cd battery, the LED 37 flashes red, and in the case of a Ni-MH battery, the LED 37 flashes orange.

When the above-described rapid charging cycle is completed, the processing of the microcomputer 34 returns to the top of FIG. 1, where the connection state of the DC plug and the open battery state are determined, and the connection of the DC plug is disconnected or the open state is established. When the battery enters the battery state, the prohibition flag INF is returned to 0, and the same determination is repeated again. Further, when the DC plug is connected and the battery is not in the open battery state, the main body switch state is determined, and then the prohibition flag INF is determined. When the main body switch 9 is turned on and the prohibition flag is set to 1, In this case, the process returns to the beginning without operating the INF, and shifts to the quick charge mode only when the INF is 0.

In other words, once the battery 2 is rapidly charged, even if the main body switch 9 is turned on and off, unless the DC plug is removed or the battery 2 is removed, the device is not inadvertently entered into the rapid charging mode. In other words, after fast charging, DC
If you remove the plug and use the main unit and then insert the DC plug or replace the battery with the DC plug connected, quick charging will always be performed.

FIG. 4B shows a fully charged battery by rapid charging.
It is a diagram showing an overcharged state of rapid charging again, in the present invention, in the initial state of rapid charging, as described above,
Since the charging current is gradually increased stepwise, the battery voltage also increases only gradually, and the temperature rise due to charging can be suppressed as much as possible as compared with the conventional example shown in FIG. 6B. Therefore, deterioration of the battery is prevented.

In addition, in the conventional example, for a few minutes determined by the −ΔV detection timer, the quick charge of 1.5 C must be continued even if the peak voltage has already been generated. If it waits, the charging can be terminated by detecting -ΔV according to the subsequent generation of the peak voltage, so that the charging time at the time of overcharging can be shortened, and the temperature rise can be further suppressed.

(G) Effects of the Invention According to the present invention, not only is rapid charging performed automatically in a device non-use state in which the power switch is off, but also overcharging of the battery can be prevented, and thus deterioration of the battery can be prevented. Can be suppressed. Furthermore, when the battery is replaced, quick charging can be automatically started.

Also, if a battery is installed, the battery can be quickly charged simply by connecting the adapter to the main body, which is very convenient.

[Brief description of the drawings]

FIG. 1 is a flowchart showing the processing contents of an embodiment of the present invention, FIG. 2 is a schematic block diagram of the present embodiment, FIG. 3 is a detailed circuit diagram of the present embodiment, and FIG. FIG. 5 is a diagram showing a main part structure of the present embodiment, and FIG. 6 is a diagram showing voltage and current waveforms in a conventional example. 1 ... body, 2 ... battery pack, 3 ... AC adapter & charger, 6, 29 ... DC plug, 9 ... power switch,
10: Quick charge switch, 11: Battery type detection switch, 14: Power transformer, 30: Relay, 31: Constant voltage circuit, 33: Constant current circuit, 34: Microcomputer, 35: Open Battery & -ΔV detection circuit, 36 ... Short battery detection circuit, 37 ... LED.

Claims (2)

(57) [Claims] A power switch provided on the electronic device main body; a secondary battery detachably mounted on the electronic device main body;
A charging circuit for rapidly charging the secondary battery based on an external power supply; a first detecting unit for detecting an on / off state of the power switch; a second detecting unit for detecting a mounting state of the secondary battery; A flag control means for setting a prohibition flag in response to the end of the quick charge and resetting in response to the removal of the secondary battery; and an output of the first and second detection means and a state of the charge prohibition flag. Charging control means for controlling the charging circuit, wherein when the secondary battery is in the mounted state, and the power switch is off and the charging prohibition flag is in the reset state, rapid charging is started. Charge control method for electronic equipment. 2. A power switch provided on an electronic device main body, a secondary battery detachably mounted on the electronic device main body,
An adapter for supplying power from an external power supply to the electronic device main body, a charging circuit for rapidly charging the secondary battery based on the supplied power; a first detecting means for detecting an on / off state of the power switch; A second detecting means for detecting a state of attachment of the secondary battery, a third detecting means for detecting a connection state between the adapter and the electronic device main body, and a charging prohibition flag set in accordance with the end of the rapid charging. Flag control means for resetting in response to removal of a battery and disconnection of the adapter from the electronic device main body;
A charging control means for controlling the charging circuit in accordance with the output of the detecting means and the charging of the charging prohibition flag, wherein the secondary battery is in the mounted state, the adapter is connected to the electronic device main body, and the power supply is A charge control method for an electronic device, wherein rapid charging is started when a switch is off and a charge prohibition flag is in a reset state.