JPH04145840A - Charging controller - Google Patents

Abstract

PURPOSE:To perform appropriate charging control and, at the same time, to expand the applicable scope of a used battery by reading out different prescribed voltages in accordance with the kind of mounted batteries and detecting whether or not voltages drops front peak values become lower than the prescribed values. CONSTITUTION:When a DC plug is connected and, at the same time, a battery is mounted, whether or not the power switch 9 of a main body 1 has been turned on is discriminated through a rapid charging detecting switch input from a terminal P3 and, when the switch 9 has been turned on, whether or not an internal flag INF is '0' is checked. When the INF is '0', a rapid charging mode is set. A microcomputer 34 turns on a transistor by changing the level of a signal from a high level to a low level and raises the value of a constant-current when the time of a charging timer exceeds 20 seconds after the charging is started. The microcomputer 34 successively changes the value of the constant-current by successively changing the level of the signal from the high level to the low level.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a charging control device for rapidly charging secondary batteries such as nickel-cadmium (Ni-cd) batteries and nickel-metal hydride (Ni-MH) batteries.

(b) Conventional technology In general, secondary batteries are of the A type, in which the terminal voltage of the battery decreases significantly after reaching its peak value at the end of charging.
There are several types with different charging characteristics, such as type B, which causes the battery temperature to rise by 1.

Conventionally, as disclosed in JP-A-1-190226, a ΔV charging control means detects the voltage drop (-ΔV) to control charging, and a ΔV charging control means detects the temperature rise (ΔT) to control charging. By providing a △T charge control means and selecting which control means according to the type of battery,
It was designed to be compatible with multiple types of batteries with significantly different charging characteristics.

(c) Problems to be Solved by the Invention The conventional technology can certainly adequately cope with a plurality of batteries having greatly different charging characteristics as in A and B above.

However, there are also batteries among secondary batteries that have substantially the same charging characteristics but different specific values. For example, both nickel-cadmium batteries and nickel-metal hydride batteries have the above-mentioned type A charging characteristics, in which the terminal voltage gradually increases from the start of charging and then drops significantly after reaching the peak voltage. ■ to the drop voltage value is different,
Nickel metal hydride batteries are usually smaller than nickel cadmium batteries.

Even if the above-mentioned conventional technology is applied, it is not possible to deal with multiple types of batteries with similar charging characteristics, and therefore it is necessary to limit the number of batteries that can be installed to such batteries to only one type. I didn't get it.

(d) Means for Solving the Problems The present invention provides a mounting section that can selectively mount a plurality of types of secondary batteries, a charging circuit that supplies charging current for rapid charging to the secondary battery, and a charging circuit that supplies charging current for rapid charging to the secondary battery. charging control means for controlling the charging circuit and terminating the rapid charging in response to the detection; , storage means for storing the predetermined voltage which is different for each type of battery; identification means for identifying the type of battery mounted on the mounting section; and a corresponding predetermined voltage from the storage means according to the identification result of the identification means. This invention solves the problem in item 1 by having a readout means for reading out the voltage and using the read predetermined voltage for the detection in 11Xj.

(E) Effect In the present invention, a predetermined voltage that differs depending on the type of battery installed is read out, and it is detected whether or not the voltage drop from the peak value has fallen below this predetermined voltage. With the addition of , it becomes possible to support different types of batteries with similar charging characteristics.

(F) Embodiment FIG. 2 is a block diagram showing a schematic configuration of an embodiment of the present invention, and 1 is a block diagram showing a schematic configuration of an embodiment of the present invention. The main body of an information device such as a personal computer has a detachable battery pack 2;
This is an AC adapter and charger that has an AC adapter function that converts voltage into DC voltage and supplies it to the main body, and a function that charges the battery pack 2.

The main body 1 includes an I)C plug 6 for connecting the cable 5, a main power supply circuit 8 that converts the supplied power supply voltage from DC to DC and supplies it to the load 7, a power switch 9 inserted into the power supply line, A quick charge detection switch 10 works in conjunction with the power switch 9 to detect whether the power switch is on or off.
, a switch 11 for battery type detection, a diode 12 inserted in the forward direction from terminal HP2 of the DC plug 6 toward the input/output terminal of the battery pack 2, and a switch 11 inserted from the input/output terminal of the battery pack 2 to the terminal HP1 of the DC plug 6. It has a diode 13 inserted in the forward direction.

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

Further, the secondary side of the transformer is provided with two coils 22, 2.3, a first and a second, and rectifier circuits 24, 25, respectively.
, smoothing circuit 2'6.27 are connected. Smoothing circuit 2
The output of 6 is a relay 30 whose first contact S1 is connected to the terminal P1 of the DC plug 29 via the diode 28 inserted in the forward direction, and whose second contact S2 is connected to the terminal P2 of the DC plug 29. It is connected to the.

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 circuits and constant current circuits is performed by a microcomputer 34, and this microcomputer 34 has DC
Terminal P3 of plug 29. From P4, press the quick charge detection switch 10 on the main body side. The switch output of the battery type detection switch 11 and the detection signals from the open battery &-Δ■ detection circuit 35 and the short battery detection circuit 36 are input. In addition, each driver 38.3 of the relay 30 and LED 37
9 is also controlled by the microcomputer 34.

A trickle charging current is supplied to the output side of the other smoothing circuit 27 on the secondary side through the terminal P2 of the DC plug 29 to the battery pack 2.
A trickle charge control resistor 40 is inserted to supply the voltage.

In this embodiment, the trickle charging current Ir is 0. The voltage of the supply line 42 is set to 150 mA, which is lower than the IC, and the voltage of the supply line 42 is set to 23 V when the battery is not installed. In addition, in the adapter mode, the contact of the relay 30 is connected to 81, and the supply line 41 has one
A constant voltage of 6V is supplied, and in the fast charging mode, the contacts of the relay 30 are connected to 82, and the supply line 42 has two
A constant voltage of 3V is supplied and 1. Moreover, the constant current value is controlled to increase stepwise with time, as will be explained later.

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

First, the microcomputer 34 converts the analog voltage input from the terminal COMP into a digital voltage.
Converter 50, program, N1-cd battery, and Ni
- a ROM 51 that stores each Δ■ value for the MH battery;
Input voltage BV from AD converter 50, its peak voltage P
EEK, various flags INF used for charging control described later,
It has a built-in RAM 52 for storing 5HORTF, BATF, and DELTA, and various timers 53 such as a safety timer, short timer, charging timer, and -Δ■ timer.

The open battery & -ΔV detection circuit 35 includes a wave suppression voltage generation circuit 60 comprising a transistor 600 and a capacitor 601 which inputs the pulse signal PWM from the microcomputer 34 and outputs the side wave reference voltage 1, and this harmonic reference. It consists of a comparator 61 that compares the voltage V1 with the resistor-divided voltage Vs of the line 42, and a transistor 62 that is turned on and off by the output of the comparator 61 and inputs the output to the terminal COPM, and converts an analog voltage according to the voltage of the line 42 to COMP. input to the terminal.

Here, the voltage Vs is set to be approximately the same potential as the highest value of the reference voltage (1) when the voltage of the line 42 is 22V, and the lowest value of (1) is O (2). Therefore, in an open battery state where the DC plug 29 is not connected to the DC plug 5 or the battery is not installed, the line 42
Since the voltage of COM is always higher than 23V and 22V,
The H signal continues to be input to the P terminal, and on the other hand, when the DC plug is connected and the battery is installed, the voltage on the line 42 drops to the battery voltage, so the input signal to the COMP terminal causes the micro The computer 34 can determine whether the DC plug 29 is connected and whether there is an open battery condition.

The short battery detection circuit 36 includes a comparator 64 that compares the resistance divided voltage of the line 42 with a reference voltage from the constant voltage regulator 63 and detects that the voltage of the line 42 is below IOV, and is turned on and off by the output of the comparator 64. The transistor 65 is connected to the relay driver 38 and the transistor 66 is connected to one terminal of the comparator 61.

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

The constant voltage circuit 31 has a resistor R1,
Photodiode 210. The shunt regulator 70 is connected in series, and the voltage dividing point A of the series resistors R2, R4, and R5 is connected to the Vref terminal of the shunt regulator 70. The shunt regulator 70
The ef voltage is always constant, and R3 and C3 are elements for preventing oscillation.

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

Therefore, when the voltage vO on the line 42 attempts to rise or fall, the current flowing through the photodiode 210 increases or decreases, and this current is fed back to the PWM control circuit 20 by the phototransistor 211, causing the voltage
The switching element is turned on and off to lower or raise O, and works to keep the voltage VO constant. Also, V.O.
= 110R2/(R4+R5)l Vr e f, so when transistor Q1 is turned on, (R4+R5
) becomes only R4, and the voltage vO becomes high. Here, the voltage changes from 16V to 25V.

On the other hand, the constant current circuit 33 includes a series resistor' connected to one end C of the current detection resistor 32 and the output of the constant voltage regulator 63.
R13, R12, R11, RIO.

R9, a comparator 71 which inputs the voltage at its voltage division point to its child terminal, and inputs the voltage at the other end B of the current detection resistor 32 to one terminal via the resistor R8, and a photodiode 210.
A diode 72 inserted in the forward direction from the connection point E between the terminal and the cathode of the shunt regulator 70 toward the output of the comparator 71, and series resistors R13, R12, R11.
are connected in parallel to the signals TI, T2 . Transistors Q1 . T3 are input to each base, respectively. ．． Q2. Q3 and more.

In this circuit, when battery pack 2 is installed, line 4
A current flows in the direction of the arrow from 1 to the current detection resistor 32 via the battery pack 2, and when this current attempts to increase or decrease, the output of the comparator 71 decreases or increases, and accordingly, a photovoltaic signal flows through the diode 72. diode 2
The current flowing through 10 increases or decreases, and this current is fed back to act to decrease or increase the current flowing through current sensing resistor 32, thus keeping the current constant.

Additionally, signals TI, T2 . When T3 goes from H to L, transistor Q2. Q3. Q4 turns on and resistor R
13, R12, and R11 are short-circuited, thereby increasing the reference voltage at point D.

Therefore, at this time, the value of the constant current flowing through the current output resistor 32 becomes high. Here, the signals TI, T2 . Depending on T3,
Constant current Ih is IA=0.6C, 1, 7A=IC, 2
, 5A=1.5C.

Note that the constant current value when TO to T3 are all H is 0.
It is set to 3A'=0.2C.

By the way, in this embodiment, two types of batteries, N1-cd and NiMH, can be used, and the battery types are identified by the configuration shown in FIG. 5.

That is, the insertion part of the battery pack is provided with a microswitch 91 for battery type Swiss/Sochi, and N1-c
In the d battery 200, as shown in FIG. 5A, the position corresponding to this switch 91 is flat, but the Ni
In the -MH battery 201, as shown in FIG. 5B, a convex portion 202 is formed at a portion corresponding to the switch.

Therefore, when the N1-CD battery 200 is inserted according to the arrow, the switch and the battery do not come into contact and the switch remains off, but when the Ni-MH is inserted, the convex part closes the switch. is pushed in and the switch turns on. This on/off switch output is input to the microcomputer via DC plug terminals HP4 and R4.

Returning to Figure 3, the LED 37 is a two-color LED of red and green.
The LED driver 39 also includes 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. 4.

When the AC plug 4 is inserted into the outlet, the AC adapter & charger 3 is power-on reset, the internal state is cleared, and the relay 30 contacts the contact SL side, and a constant voltage of 16V is applied from the line 41 to the plug terminal P1. It becomes the supply adapter mode. In this mode, with the battery installed, a trickle charging current of less than 0, IC is supplied to the battery pack 2 from the line 42 via the terminal P2.

Next, as shown in the flowchart of FIG. 1, the microcomputer 34 receives the A
It is determined whether the DC plug 29 of the C adapter & charger 3 is connected to the DC plug 6 on the main body l side, and whether the battery is in an open battery state. If the DC plug is connected and the battery is installed, it is determined whether the power switch 9 of the main unit 1 is turned on based on the quick charge detection switch input from the terminal P3, and if it is turned on, the internal Check whether the inhibition flag INF is O. Then, when INF is 0, the rapid charging mode is entered.

In the quick charging mode, the microcomputer 34 sets the signal To to H, drives the relay driver 38 to switch the contact point of the relay 30 from 81 to 82, turns on the transistor Q1 of the constant voltage circuit 31, and disconnects the signal from the line 41. The supply voltage when the battery is open is increased to 25V, and the signals T2 to T4 are set to H, and the transistors Q2 to Q
4 and start 0.2C quick charging. Then, at the start, the safety timer 530 and the charging timer 5
Start 31. Note that the potential of the line 42 is, of course, the same potential as the voltage of the battery 2.

0.20 After the start of charging, the microcomputer 34
Read the battery type detection switch input from terminal P4 to determine the battery type, and if it is an N1-cd battery, flag B is set.
Set the ATF to 0 and drive the driver 390 to turn on the red LED 370. If there is a Ni-MH main battery, set the flag BATF to 1 and drive the drivers 390 and 390.
1, lights up LEDs 370 and 371, and
Light up D37 in orange.

Next, the microcomputer 34 uses a charging timer to determine whether 20 seconds have elapsed since the start of 0.2C charging, and if it has, the microcomputer 34 changes the signal T1 from I to ■ to turn on the transistor Q2 to provide a constant current. Increase the value to 0.60. Thereafter, every 20 seconds due to the charging timer, the signal T2. T3 is sequentially changed from H to L, and the constant current value is sequentially changed to IC, 1, and 5C, as shown in FIG. 4A.

Along with this, the battery voltage BV gradually increases as shown in the figure.
1, and the pseudo peak voltage that occurs when a large current is suddenly applied at the beginning of charging, as in the conventional example shown in FIG. 6A, no longer occurs. This effect becomes more effective as the number of steps for changing the constant current value becomes smaller.

In each quick charge cycle from 0, IC to 1.50,
5TEP-As shown in A, B, and D, DC plug connection status and open battery status.

The state of the main body switch is constantly detected, and when the DC plug is removed, the battery is removed, or the main body switch 9 is turned on, quick charging is stopped and the LED 37 is also turned off.

In addition, the microcomputer 34 samples the battery voltage BV at regular intervals using the output of the AD converter 850, constantly compares the previous sampling value and the latest sampling value, and selects the larger value as PEEK.
I am trying to store it in AM52. Then, when the latest sampled value becomes lower than PEEK, it is determined that a peak voltage has occurred.

After the peak voltage occurs, it is determined whether the difference between the peak value and the latest sampled battery voltage BV exceeds the V value stored in the ROM 51 in advance, and when it exceeds -Δ
It is determined that V has occurred.

Then, the △V timer allows this state to last for 1 minute! 'J continues, it is judged that the battery is fully charged and the prohibition flag INF is set to 1, and the fourth
As shown in Figure A, quick charging ends. In other words, the signal To is removed, Tl-T3 is set to N9sl/-, and the -30 contact is set to 81, returning to the adapter mode, and battery 2 is set to 0. I
Enter trickle charge below C.

If the peak voltage or -ΔV is not detected even after 80 minutes have passed after the start of quick charging, the safety timer 530
Quick charging will be stopped.

By the way, in this embodiment, after the peak voltage is generated, the ROM 51 is set depending on the type of battery based on the determination of the flag BATF.
By this process, it is possible to use two types of batteries.

In addition, in each charging cycle from 0.2C to 1.5C, the battery voltage BV
By determining whether or not the battery is below IOV, it is determined whether or not the battery is in an abnormal short-circuited state.

That is, the battery voltage BV is reduced to 10V by the short timer.
Check whether the following conditions continue for more than 30 seconds,
If it continues, it is determined that the battery is short and quick charging is stopped, and N is determined according to the battery type based on the flag BATF.
In case of 1-CD battery, blink LED 37 in red and press N.
In the case of the i-MH main battery, the LED 37 is made to blink in orange.

When the above-mentioned quick charging cycle is completed, the processing of the microcomputer 34 returns to the beginning of FIG.
The connection state of the plug and the open battery state are determined, and when the DC plug is disconnected or the open battery state is established, the inhibition flag INF is returned to 0 and the same determination is repeated again. Furthermore, when the DC plug is connected and there is no open battery state, the main body switch state is determined and the subsequent prohibition flag INF is determined. When the main body switch 9 is on and the prohibition flag is 1 In this case, the process returns to the beginning without operating INF, and moves to the quick charging mode only when INF is O.

In other words, once the battery 2 is rapidly charged, the system is configured so that even if the main body switch 9 is turned on and off, unless the DC plug is disconnected or the battery 2 is removed, the rapid charging mode will not be entered inadvertently. In other words, D after fast charging
If you use the main unit with the C plug removed, then insert the DC plug, or replace the battery with the DC plug connected, rapid charging will definitely occur.

FIG. 4B is a diagram showing an overcharged state in which a fully charged battery is quickly charged again. In the present invention, in the initial state of quick charging, the charging current is reduced as described above. Since the battery voltage is gradually increased in stages, the battery voltage also increases only gradually, and the temperature increase due to charging can be suppressed as much as possible compared to the conventional example shown in FIG. 6B.

Therefore, deterioration of the battery is prevented.

In addition, in the conventional example, the 1.50 quick charge must be continued for several minutes determined by the -ΔV detection timer even if a peak voltage has already occurred, but in the present invention, the 1.50 quick charge must be continued for 60 seconds in the step charge mode. If one waits for this, charging can be terminated by detecting -Δ■ in response to the occurrence of a subsequent peak voltage, thereby shortening the charging time during overcharging and further suppressing temperature rise.

(G) Effects of the Invention According to the present invention, it is possible to appropriately charge multiple types of batteries, such as nickel-cadmium batteries and nickel-metal hydride batteries, which differ only in voltage drop from the peak value and have almost the same charging characteristics. It becomes possible to perform control and expand the range of applications of batteries used.

[Brief explanation of drawings]

Fig. 1 is a flowchart showing the processing contents of the embodiment of the present invention, Fig. 2 is a schematic block diagram of the embodiment, Fig. 3 is a detailed circuit diagram of the embodiment, and Fig. 4 shows the voltage and FIG. 5 is a diagram showing the main structure of this embodiment, and FIG. 6 is a diagram of voltage and current waveforms in the 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...LEDo

Claims (1)

[Claims] (1) A mounting part that can selectively mount multiple types of secondary batteries, a charging circuit that supplies charging current for rapid charging to the secondary battery, and a battery terminal voltage that reaches a peak value during charging. charging control means for controlling the charging circuit and terminating the rapid charging in response to the detection; a storage means for storing, an identification means for identifying the type of battery mounted on the mounting section, and a reading means for reading out a corresponding predetermined voltage from the storage means according to the identification result of the identification means; A charging control device characterized in that the output predetermined voltage is used for the detection.