JPH06253465A - Trickle battery charger - Google Patents

Abstract

PURPOSE:To provide a trickle battery charger capable of setting a voltage automatically suitable for the type of batteries to be charged selectively. CONSTITUTION:A battery charger comprises a charging circuit 2 for generating a trickle charging current to supplement a shortage after a full-charge state for a battery 1 set in a fitting unit, a battery charging controller 3 for detecting the type of the battery 1 and generating a control signal for making the trickle charging current suitable for each type of the battery 1. Then, the trickle charging current is adjusted on this basis of the control signal. The type of the battery 1 can be discernible by an ID in the battery 1 or by using the battery temperature, which is ordinarily used for detecting the full-charge state of the battery 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a trickle charging device for various batteries such as nickel-cadmium batteries, nickel-hydrogen batteries, nickel-manganese batteries, lithium batteries, etc. ) It relates to a trickle charging device which adjusts a trickle charging current for compensating for the shortage based on the type of the battery.

In general, when a battery is charged, the full charge state is correctly detected to automatically reduce or stop the charge current, and the trickle charge is used to compensate for the shortage that occurs thereafter. The trickle charging method is used.

In such a trickle charging system, it is required to adjust the supply amount of the trickle current to prevent the battery from being overcharged or undercharged, and the present invention responds to this request. It is a thing.

"Trickle charge" used in this specification
Is charging to compensate for the shortage due to self-discharge after full charge or use, etc. Normally, the battery and load connected in parallel to the charging circuit are usually separated and the charging circuit is exclusively used. This means not only compensating charging by a method in which the load is not applied on the side, and the battery is connected to the load only when an abnormality occurs, but also compensating charging by a method in which the load is constantly connected to the battery.

[0005]

2. Description of the Related Art FIG. 5 is an explanatory view showing a conventional trickle charging device, 11 is an AC adapter, 12 is a battery mounting portion,
13 is a battery, 14 is a DC-DC converter, 15 is a battery charge controller, 16 is a charge switch, 17 is a discharge switch, and 18 and 19 are diodes.

Here, a signal s ₁₀ indicating whether or not the battery 13 is set in the battery mounting portion 12 and a signal s ₂₀ indicating the charge state of the battery 13 are sent from the battery side to the battery charge controller 15. ing.

Then, the battery charge controller 15 is
Based on these input signals, the normal charge is started, the full charge state is detected, and the control signal c ₁₀ for setting the trickle charge mode to the DC-DC converter 14 after the detection is generated.

That is, the battery charge controller 15
Starts the normal charging by first turning on the charging switch 16 and connecting the battery 13 to the output side of the DC-DC converter 14, and then the signal s obtained from the battery 13
The full charge of the battery is recognized based on ₂₀ and the control signal c ₁₀ is sent to the DC-DC converter 14, and a part of the hardware is switched to reduce the charging current I to a predetermined value to set the trickle charging mode. .

As the signal s ₂₀ indicating the state of charge of the battery 13, the terminal voltage and temperature information (at the pole portion) are used, and the control signal c ₁₀ for setting the trickle charge mode is: -Detection of voltage drop (-delta V) that occurs after the terminal voltage reaches its peak-It is generated based on the detection of temperature rise at the pole when fully charged (see Fig. 6).

[0010]

As described above, in the conventional trickle charging device, the full charge state of the battery 13 is detected and automatically set to the trickle charge mode. The charging current I is determined to a specific value, that is, a single current value corresponding to the type of a specific battery set in this trickle charging device.

This is based on the property that the optimum value of the charging current I in the trickle charge mode differs depending on the battery, for example, the optimum value of the nickel-cadmium battery is larger than that of the nickel-hydrogen battery.

Therefore, in various electronic devices such as a notebook computer and a video camera having a trickle charging device, batteries of different types, for example, nickel-cadmium batteries and nickel-hydrogen batteries are selectively set under the recent circumstances. There is a problem that when a battery whose charge current in the trickle charge mode does not match the set value is used, overcharge occurs or sufficient trickle charge is not performed.

Therefore, in the present invention, the battery charge controller has a function of recognizing the type of the attached battery and controlling the trickle charge current based on the recognition result, so that the trickle charge state corresponding to the used battery is obtained. It aims at automatic setting of.

[0014]

FIG. 1 is a diagram for explaining the principle of the present invention. In the figure, 1 is a battery, which is a nickel-cadmium battery, a nickel-hydrogen battery, a nickel
Various types of manganese batteries, lithium batteries, etc. are used to output the full charge detection signal s ₁ and the battery type signal s ₂ . A charging circuit 2 is composed of a DC-DC converter, a charging switch and the like, and supplies a normal charging current I ₀ until full charge detection and a trickle charging current I ₁ thereafter. A battery charge controller 3 generates a trickle charge mode setting control signal c ₁ based on the full charge detection signal s ₁ and the battery type signal s ₂ and sends the control signal c ₁ to the charging circuit 2.

The trickle supplied from the charging circuit 2 to the battery 1 by switching a part of the DC-DC converter or controlling the ON / OFF of the charging switch based on the control signal c _1. The magnitude of the charging current I ₁ and the supply time are adjusted.

[0016]

According to the present invention, the battery type signal s ₂ is recognized in addition to the full charge detection signal s _{1 and} the control signal c
_{Since the} battery charge controller 3 has a function of generating ₁ and controls the charging circuit 2 based on the control signal c ₁ , the battery 1 has a trickle charge current I ₁ corresponding to its type. Will be reliably supplied.

As the battery type signal s ₂ , a signal based on the battery temperature (see FIG. 6) and various IDs (positions of moving pieces, marks, electronic information, etc.) provided according to the type of each battery are used. Can be used.

Here, the battery temperature is generally used as the basis of the battery type signal s _{2 in} the type having a temperature sensor for detecting the temperature rise shown in FIG. 6 when fully charged. This is because it is possible to distinguish a typical battery (for example, a nickel-hydrogen battery) from a battery that does not, by the presence or absence of the output signal of the temperature sensor, and
This means that the battery temperature, which has been conventionally used for full charge detection, is also used for determining the battery type.

[0019]

Embodiments of the present invention will be described with reference to FIGS. FIG. 2 is an explanatory diagram showing an example of the entire configuration of the trickle charging device. In FIG. 2, a temperature sensor 21, a battery type setting circuit 22, an application program 23, and a priority setting circuit 24 for battery temperature detection are added to those shown in FIG. It is an added form, and c ₂ is a DC-DC converter 14
For the trickle charge current, c ₃ for the trickle charge current for the charge switch 16, and c ₄ for the discharge switch.

That is, this is an embodiment in which the output signal of the temperature sensor 21 is used for the battery type signal s ₂ in addition to the full charge detection signal s ₁ , and the battery charge controller 15
Is a battery equipped with the temperature sensor 21 when the output signal is obtained (for example, nickel-hydrogen battery), and a battery not equipped with the temperature sensor 21 when the output signal is not obtained (for example, nickel-cadmium battery). Are recognized as being set in the battery mounting portion 12, respectively.

It should be noted that the battery type setting circuit 22 and the application program 23 are battery type auxiliary signals s ₂ ′ which can be called secondary signals to indicate the type of the battery mainly used in the electronic equipment in which the trickle charging device is incorporated. The battery type auxiliary signal s ₂ ′ is set by the manufacturer of the trickle charging device.

Further, the priority setting circuit 24 is a temperature sensor.
Battery type signal s ₂ from 21 and battery type setting circuit
This is for instructing the priority order for the battery charge controller 15 with the battery type auxiliary signal s ₂ ′ designated by 22 or the like, and the manufacturer side also sets this priority order.

The need for such a secondary signal is that
For example, nickel / hydrogen batteries without the temperature sensor 21 and nickel / cadmium batteries with the temperature sensor 21 are produced and supplied, and the correspondence between the presence or absence of the temperature sensor 21 and the type of the battery 13 used is one-to-one. This is because the situation cannot be said.

The priority between the battery type signal s ₂ and the battery type auxiliary signal s ₂ ′ is determined by the battery type signal s ₂ and the actual type of the used battery 13 in the electronic device in which the trickle charging device is incorporated. Depending on the degree of correlation between the following: When the degree of correlation is high, the battery type signal s ₂ is given priority. When the degree of correlation is low, the battery type auxiliary signal s ₂ ′ is given priority.

When the ID assigned to each battery type is used as the battery type signal s ₂ , a one-to-one correspondence is ensured between this ID and the used battery type. There is no use of dynamic signals.

Next, as a method of setting the trickle charging current, it is possible to switch a part of the DC-DC converter 14 by the control signal c ₂ to adjust the output current, for example, the output current for a nickel-hydrogen battery. Is smaller than that for a nickel-cadmium battery.-The control signal c ₃ controls the on / off of the charging switch 16 to adjust the trickle charging time. For example, nickel-hydrogen battery is intermittently charged, -For Cadnium batteries, continuous charging (see Fig. 3) is used.

The trickle charging current setting method shown in FIG. 3 is based on the premise that the magnitude of the output current of the DC-DC converter 14 is associated with the nickel-cadmium battery by also using the control signal c _2. There is.

Further, the control signal c ₂ is not used, and only the control signal c ₃ is used to perform the intermittent charging of both the nickel-hydrogen battery and the nickel-cadmium battery, and the cycle of the intermittent charging is made different to each battery. You may make it obtain the trickle charge current corresponding to.

The control signal c ₃ is used to charge the charging switch.
By controlling ON / OFF of 16, DC-DC can be used regardless of whether control signal c ₂ is used or not.
The converter 14 does not need to form a new hardware part for outputting the trickle charging current corresponding to the battery having the small optimum value.

FIG. 4 is an explanatory diagram showing a processing procedure in the battery charge controller 15. That is, it is determined whether or not the battery 13 is attached by the signal s ₁₀ , and if “YES”, the process proceeds to the next step and “N
In the case of "O", this judgment is repeated. The full charge detection signal s ₁ is used to determine whether or not the battery 13 is fully charged. If “YES”, the process proceeds to the next step, and if “NO”, this determination is repeated. It is judged whether or not the battery type signal s ₂ has priority over the battery type auxiliary signal s ₂ ′, and “YES”
In case of, proceed to the next step, and in case of “NO”, proceed to step. The control signal c ₂ or c ₃ for setting the trickle charging current corresponding to the battery type signal s ₂ is generated,
Go to step. The control signal c ₂ or c ₃ for setting the trickle charging current corresponding to the battery type auxiliary signal s ₂ ′ is generated, and the process proceeds to the next step. Based on the control signal c ₂ or c ₃ , the magnitude of the output current of the DC-DC converter 14 and the on-time of the charging switch 16 are adjusted. The trickle charge current is set by such a procedure.

Although not shown, the battery charge controller 15 also performs charge control in the normal charge mode until the full charge is detected and the trickle charge mode is entered.

[0032]

As described above, the present invention uses the battery charge controller having the function of recognizing the type of the battery used based on the battery type signal sent from the battery side and setting the trickle charge current corresponding thereto. Therefore, even when batteries of different types are selectively used, it is possible to supply a trickle charging current having no excess or deficiency.

Further, since the battery temperature signal originally used in the detection of full charge is also used as the battery type signal, the trickle charge control corresponding to the battery type should be performed with the existing battery configuration. You can

Since the trickle charge current is controlled by the on / off control of the charge switch connected to the output side of the DC-DC converter, the trickle charge current corresponding to the battery having the smaller optimum value is output. The trickle charge mode of the battery can be set without newly providing a hardware part for the DC-DC converter.

Furthermore, as the information for recognizing the type of the battery, either the battery type signal obtained from the battery or the battery type auxiliary signal held by the battery charge controller is selected in a predetermined priority order. Since a battery type is used, it is possible to cope with a case where the degree of correlation between the battery type signal such as the battery temperature and the actual type of the used battery is low.

[Brief description of drawings]

FIG. 1 is a diagram illustrating the principle of the present invention.

FIG. 2 is an explanatory diagram showing an example of the overall configuration of a trickle charging device of the present invention.

FIG. 3 is an explanatory diagram showing a method for adjusting a trickle charging current by on / off control of a charging switch according to the present invention.

FIG. 4 is an explanatory diagram showing a processing procedure in a battery charge controller according to the present invention.

FIG. 5 is an explanatory diagram showing an example of the overall configuration of a conventional trickle charging device.

FIG. 6 is an explanatory diagram showing a general method for detecting a fully charged state.

[Explanation of symbols]

 In FIG. 1, 1 ... Battery 2 ... Charging circuit 3 ... Battery charge controller

Claims (4)

[Claims] 1. A charging circuit that outputs a trickle charging current for compensating for a shortage after full charging of a battery set in a mounting portion, and a type of the battery is recognized, and the trickle charging current is detected by the charging circuit. A trickle charging device, comprising: a battery charging controller that generates a control signal for setting a state corresponding to a type, and adjusting the trickle charging current based on the control signal. 2. The battery charge controller, when recognizing the type of the battery, selects either a battery type signal obtained from the battery or a battery type auxiliary signal held by itself according to a predetermined priority order. The trickle charging device according to claim 1, wherein the determination is performed based on the selection signal. 3. The battery charge controller uses the battery temperature originally used to detect the fully charged state of the battery as the information for recognizing the type of the battery. The trickle charging device described in 2. 4. The trickle charge according to claim 1, wherein the battery charge controller controls an on-time of a charge switch that is a component of the charging circuit when adjusting the trickle charge current. apparatus.