JPH0491620A - Dc power supply - Google Patents

Abstract

PURPOSE:To protect external machine block with high safety by applying power supply voltage on the external machine block, comparing the applying voltage of each battery block with a reference voltage thereby detecting low voltage state of power supply block reliably with high safety. CONSTITUTION:Supply voltage from a power supply block 1A is applied or interrupted onto/from an electronic machine block 7A by turning a switch block S1 ON, OFF. In a low voltage detecting circuit 2A, a voltage comparing means 3 is applied with voltages from respective battery blocks 1a-1c while furthermore provided with a reference voltage from a reference voltage block 4A. The voltage comparing means 3 compares the applying voltages from respective battery blocks 1a-1c with the reference voltage and transmits a detection signal P1 representing the low voltage state of the battery blocks 1a-1c when the applying voltage drops below the reference voltage.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a DC power supply device having a power supply section composed of a battery pack, that is, a battery array, composed of a plurality of batteries connected in series.

(Prior Art) Conventionally, this type of DC power supply device has been mainly used to apply a DC power supply voltage to small portable or portable electronic devices.

FIG. 7 shows the basic configuration of such a DC power supply device. 1 The illustrated DC power supply device has an electronic device section 7C and a power supply section consisting of a battery array in which four batteries 13a to 13d are connected in series. IC and electronic device section 7 from this power supply section 1C
A switch section S3 for turning on and off the application of the power supply voltage to C is provided. And this switch part S3
By turning on and off, the application of the power supply voltage to the electronic device section 7C can be turned on and off.

Normally, the power supply section of such a DC power supply device has a specified power supply voltage for external equipment, so it cannot be charged or applied voltage from a special power source such as a commercial power source used outdoors or a car battery. The only thing I can do is make it happen.

Furthermore, there are many types of batteries used in such power supply units; for boat fishing, there are primary batteries for obtaining relatively small current consumption, and secondary batteries for obtaining large current consumption. It can be broadly classified. For example, secondary batteries include manganese batteries, alkaline manganese batteries, mercury batteries, oxidation batteries, and zinc-air batteries.

There are lithium batteries, etc.

On the other hand, secondary batteries include lead batteries, nickel-cadmium batteries (Ni-Cd batteries), lithium batteries, and the like. Regardless of which type these are, the electromotive voltage of the single battery cell is specified to be 3V or less. Specifically, it is 1.5 V for a negative manganese battery, and 2.5 V for a secondary lead battery. OV,
3° for a lithium battery and 1.0° for a 0V Ni-Cd battery.
It is 2V.

Note that many secondary batteries can be used repeatedly by being charged.

By the way, in the DC power supply devices installed in recent electronic devices, various batteries are not only selected to form the power supply section of the battery array, but also the state of the power supply voltage applied to the power supply section is monitored and the power supply is adjusted as necessary. Some devices have a protection function to cut off the application of power supply voltage.

FIG. 6 shows an example of a DC power supply device having such a protection function. Here, as shown in FIG. 1, a DC power supply device that can be opened and closed is constructed by connecting a battery array power supply section 1B and a switch section S2 to an electronic device section 7B. Furthermore, a low voltage detection circuit section 5 for detecting a low voltage state of the voltage applied to the battery array is connected between both poles of the battery array. The low voltage detection circuit section 5 detects the low voltage state of the power supply section IB by outputting a detection signal when the power supply voltage of the power supply section IB falls below a predetermined reference voltage. Further, an alarm circuit section 6B is connected to the low voltage detection circuit section 5 shown in Figure 1, and generates an alarm when a detection signal indicating that the voltage has become low is provided from the low voltage detection circuit section 5. This alarm circuit section 6B is actually provided as necessary.

On the other hand, the switch section S2 connected to the low voltage detection circuit section 5
is closed when the detection signal is not transmitted, and is opened when the detection signal is transmitted to cut off the application of power supply voltage to the electronic device 7B. Therefore, the DC power supply device equipped with the low voltage detection circuit section 5 can protect the external device section 7B by cutting off the application of the power supply voltage as necessary.

Generally, for a DC power supply device equipped with a power supply section using such a battery, in addition to the protection function of the power supply section, efforts are made to reduce the power consumption of the power supply section itself.

However, actual DC power supplies are often used at voltages of about 3V to 12V, which are relatively higher than the nominal voltage of various electronic devices.

In the case of such a DC power supply, the power supply voltage is insufficient if only multiple batteries are connected in series, so by connecting multiple battery arrays in series, the power supply section is made up of a group of battery arrays. many.

(Problems to be Solved by the Invention) In the case of a DC power supply device in which the power supply section is configured using a battery row or a group of battery rows as described above, there is a problem in which the individual batteries constituting the battery row have different usage times (described later). In some cases, batteries may include batteries with relative variations in voltage discharge characteristics, or other types of batteries with different capacitances may be mixed together. When batteries with different voltage discharge characteristics are mixed together in this way, reverse charging and related over-discharging often occur within the battery row, making the state of power supply voltage application unstable. If the power supply unit continues to be used in a state where reverse charging or overdischarging occurs in this way, there is a risk of damaging the parts of the electronic device.

Now, it is assumed that reverse charging occurs in the power supply IC shown in FIG. 7. In this case, reverse charging as shown in FIG. 5 occurs. FIG. 5 shows the relationship between the voltage drop V and the starting time T of the battery array, ie, the voltage discharge characteristics of the power supply IC. However, here, the batteries 138 to 13d each have a local voltage V equivalent to a unit battery compared to the total voltage V of the power supply IC.

/4 will be explained. Assume that the voltage discharge line V (13d) of the battery 13d falls 61 hours in advance of the voltage discharge lines V (13a, 13b, 13c) of the other three batteries 13a to 13c. This means that the battery 13d has been used for ΔT hours before the other three batteries 13a to 13c.

When the switch section S3 is closed to turn on the application of the power supply voltage to the electronic device 7C equipped with such a power supply section IC,
The battery 13d has a voltage v as shown in the voltage discharge line V (13d).
After maintaining L/4, the voltage begins to drop and the discharge is completed at time T1.

On the other hand, each of the batteries 13a to 13c has a voltage discharge line V
After maintaining vL/4 as shown in (13a, 13b, 13c), the voltage starts to drop and discharge continues until time T2, which is 61 hours added to time T1. Therefore, the total voltage of the power supply section 1C is maintained by the voltage discharge line V.
As shown in (IC), the total voltage of this power supply IC drops to 3/4VL at time T1, and after maintaining the 3/4VL state for a while, the voltage starts to drop suddenly. At time T2, the discharge is completed. During the time difference of 61 hours from point T1 to point T2, even if the battery 13d is completely discharged, the other three
Since the two batteries 13a to 13c are discharged and not fully discharged,
Until the discharge of batteries 13a to 13C is completed, battery 1
A potential difference occurs between the two poles of 3d in opposite directions, positive and negative. At this time.

The battery 13d enters a reverse charge V (13d') state, and at the same time, the batteries 13a to 13c enter an overdischarge state.

Such reverse charging that occurs within the battery imposes a greater load than when discharging in the forward direction, causing a large amount of heat to be generated inside the battery and a large amount of gas to be produced. When a large amount of gas is generated inside the battery.

This can have a variety of side effects, such as the pressure increasing and causing the battery to swell, or sometimes breaking the safety valve of the battery and releasing the generated gas and electrolyte to the outside. In particular, when reverse charging occurs in a secondary battery, the electrical capacity of the battery remains reduced, so even if a battery array is formed with other normal batteries, reverse charging will only occur in the same battery. , the life of the entire battery array may be shorter than that of a single battery.

In addition, in a DC power supply device that has a power supply section that includes a battery that can cause such reverse charging, even if the low voltage detection circuit section described above is used, the low voltage state of the power supply section cannot be detected by the electronic device section. It has become difficult to protect electronic devices with high safety by detecting them before the power supply voltage is applied to them.

Furthermore, in the case of the conventional DC power supply device, the low voltage state of the power supply section is not detected in a timely manner, so that malfunctions of electronic equipment cannot be sufficiently prevented in practice.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a DC power supply device in which a power supply unit having a relatively large power supply voltage is constructed of a battery, and is capable of accurately detecting a low voltage state of the power supply unit. By doing this, in addition to starting the power supply section,
To provide a DC power supply device that can protect external equipment with high safety even if a power supply part becomes a low voltage state during application of power supply voltage.

(Means for Solving the Problems) The present invention relates to a DC power supply device that uses a battery in a power supply section and applies a power supply voltage to an external device. A power supply unit that connects a plurality of battery arrays to form a battery array group, and a power supply unit that connects a plurality of battery arrays in series to constitute a battery array group; a low voltage detection circuit that manually compares the applied voltage with a reference voltage and outputs a detection signal indicating a low voltage state of the power supply section when the applied voltage drops below the reference voltage; This is achieved by configuring a DC power supply device including a switch circuit section for turning off the application of power supply voltage to the external device when the detection signal is transmitted.

(Function) The DC power supply device of the present invention is for applying a power supply voltage to external equipment using a power supply unit using a battery having a relatively high power supply voltage. For this reason.

Rather than constructing a power supply section with a single battery string by connecting multiple batteries in series, the power supply section is constructed from a group of battery rows in which multiple battery rows are connected in series. There is. In one aspect of the present invention, the applied voltage applied to the signal line connected to each battery row of the power supply section is compared with a reference voltage set to a voltage equal to or lower than the voltage corresponding to each battery row,
The low voltage detection circuit section is configured to output a detection signal indicating a low voltage state of the power supply section when the applied voltage drops below the reference voltage. In other words, even if a particular battery row is in a low voltage state due to reverse charging or overdischarge, this low voltage detection circuit can accurately determine the voltage drop in the applied voltage of that battery row by comparing it with the reference voltage. can be detected. In this way, the low voltage state of the battery row is inputted to the switch section as a detection signal.

The DC power supply device is configured to be able to cut off the application of power supply voltage to external equipment by opening the switch.

(Example) Hereinafter, a DC power supply device of the present invention will be described in detail with reference to an example.

FIG. 1 shows the basic configuration of the DC power supply device of the present invention,
Here, a state in which the DC power supply device is connected to the electronic device section 7A is shown. As shown in Figure 1, the DC power supply device includes a power supply section IA and a switch section S1 connected to one end of the power supply section IA, and an electronic device section 7A is connected between the switch section S1 and the other end of the power supply section IA. has been done.

Here, the power supply section IA has a battery array group configured by mutually connecting battery arrays 1a, lb, and lc each having a predetermined number of batteries connected in series. The power supply voltage from the power supply section IA is supplied by turning on and off the switch section S1.

The voltage is applied to the electronic device section 7A or cut off. The DC power supply device further includes a low voltage detection circuit section 2A that compares the voltage applied to each of the battery rows 1a to IC with a reference voltage and detects a drop in the voltage of each battery row. Specifically, the low voltage detection circuit section 2A, together with the voltage comparison means 3 connected between the poles of each of the three battery arrays 13 to 1C constituting the power supply section IA, has a circuit for supplying the above-mentioned reference voltage. It has a reference voltage section 4A. An output terminal C is provided on the output side of the two low voltage detection circuit sections, and the signal line α from this output terminal C is connected to the switch section Sl at an intersection on the way, and is also connected to the alarm circuit section 6A. has been done.

In the low voltage detection circuit 2A, the voltage comparison means 3 is supplied with the applied voltages from each of the battery rows 1a to 1c, and is also manually supplied with a reference voltage from the reference voltage section 4A. The voltage comparison means 3 compares the applied voltage from each of the battery rows 1a to 1c of the power supply unit IA with a reference voltage, and when the applied voltage drops below the reference voltage, the voltage of each battery row] a to 1 is determined.
A detection signal P1 representing the low voltage state of c is output to the signal line α. In this way, each battery row 1a constituting the power supply section IA
The low voltage state of ~1c can be determined by sending out the detection signal P1. Therefore.

An alarm is obtained by transmitting this detection signal P1 to the alarm circuit section 6A, or by transmitting it to the switch 151, the switch section S1 is opened.

Application of the power supply voltage to the electronic device section 7A can be interrupted.

The DC power supply device having such a configuration shuts off the switch S1 when the applied voltage is in a low voltage state based on the state of the applied voltage from each of the battery rows 1a to 1C of the power supply section 1A composed of a group of battery rows. However, application of the power supply voltage to the electronic device section 7A can be cut off.

Therefore, the electronic device section 7A can be protected from the adverse effects caused by the application of low voltage.

Next, as the low voltage detection circuit section 2A equipped with the voltage comparison means 3 and the reference voltage section 4A, each battery row 1 of the power supply section IA is
By selecting the relationship between the applied voltages from a to 1c and the reference voltage, several different circuit configurations are possible.

For example, FIGS. 2 and 3 specifically show examples of different low voltage detection circuit sections 2B and 2C, and both can be replaced with the two low voltage detection circuit sections shown in Diagram N1. .

First, the low voltage detection circuit section 2B shown in FIG.

Voltage comparison elements 12a to 12c are provided corresponding to each of the battery rows 1a to IC.
The reference voltage section 4B is connected to the input side of 12c, and on the other hand,
A multi-input OR circuit section 9 is connected to the output side. In the low voltage detection circuit 2B having such a configuration, a reference voltage is applied from the reference voltage unit 4B to each voltage comparison element 12a to 12 (by a dedicated battery), and from each signal line, a reference voltage is applied from each battery row 1a to the IC. Voltage is input here.

The reference voltage given from the reference voltage section 4B is applied to each battery row 1a.
~The voltage is set to be slightly lower than the voltage generated by the IC. Therefore, each voltage comparison element 12a to 12c is
The applied voltage and the reference voltage are compared for each battery row 1a-c, and when the applied voltage falls below the reference voltage, a detection signal P2 indicating a low voltage state is output for each battery row 1a-IC. At this time, the multi-input OR circuit section 9 connects each battery row 13 to
The detection signal P2 can be outputted to the terminal C even when the detection signal P2 is sent out from any of the voltage comparison elements 12a to 12C corresponding to the IC.

This configuration makes it possible to simplify the nine-signal system.

On the other hand, the low voltage detection circuit section 2C shown in FIG.

It is roughly configured by an input switching section 10 connected to each signal line and a voltage comparator 8 connected to this input switching section 10. Of these, the input switching unit 10 includes three input changeover switch units 54 inserted between the voltage comparator 8 and each signal line drawn out from one end of each battery row 1a to IC.
a-S4c and.

In order to sequentially turn on and off the input selector switches 54a to 54c in a time-sharing manner by transmitting a synchronization signal,
The synchronous circuit section 11 is connected to each of the manual changeover switch sections 84a-S4C. In addition, the voltage comparator 8 is set to a voltage equal to or lower than the applied voltage from the battery row selected from each of the battery rows 1a to IC and the voltage equivalent to the battery row unit transmitted from the reference voltage section 4B equipped with a dedicated battery. When the applied voltage drops below the reference voltage, the low voltage state of the selected battery row is detected by outputting a detection signal P3.

That is, the low voltage detection circuit 2C having such a configuration selects the battery row to be detected from among the battery rows 1a to 1c based on the synchronization signal from the synchronization circuit section 11, and then detects the low voltage state of the battery row. It can be detected in a time-division manner.

In this way, in the DC power supply device equipped with the low voltage detection circuit 2B or 2C, after monitoring whether the applied voltage of each battery row 1a to IC of the power supply section IA is in a low voltage state, the electronic device section 7A Apply power supply voltage to. Therefore, it is possible to detect in advance the adverse effects on the electronic device section 7A due to reverse charging or overdischarging that may occur in each of the battery rows 1a to 1c, and to control the application of power supply voltage as necessary. The electronic device section 7A can be protected with high safety by shutting off the switch section Sl.

However, in the DC power supply device of the present invention, the reference voltage section 4B included in the low voltage detection circuit 2B or 2C can be used even if the total voltage of each battery array 1a to 1c obtained in the power supply section IA is used as the power supply voltage for the electronic device section 7A. The reference voltage of is not set based on its total voltage.

In other words, as described above, the reference voltage is set to be lower than the voltage corresponding to the battery array unit of the power supply section IA. This is to enable accurate detection of a low voltage state of the power supply unit caused by a combination of battery arrays made up of batteries with different voltage discharge characteristics.

In general, in DC power supplies that use batteries as the power supply, if there are variations in the voltage discharge characteristics of the batteries due to differences in usage time, the power supply voltage at the time of starting the power supply will drop suddenly during the specific usage time. It begins to occur. For this reason, it becomes difficult to accurately detect a low voltage state of a power supply section composed of a plurality of batteries.

Therefore, in the DC power supply device of the present invention, the power supply section IA shown in FIG.
As shown in the voltage discharge characteristics, the power supply voltage for the electronic device section 7A is the total voltage V of the power supply section IA shown by the voltage discharge line V (IA), and the reference voltage is the voltage V corresponding to the battery row unit regarding the power supply section 1A. It is set to V'/3, which is somewhat lower than V'/3. still.

The illustrated voltage V' is a voltage assumed to be lower than the total voltage V. By the way, it is easy to obtain the reference voltage v'/3 in the reference voltage section 4B, and the voltage V,/3 may be lowered using, for example, a resistor.

When such a reference voltage v'/3 is set in the reference voltage section 4B, the voltage discharge characteristics of each battery array 1a to IC are determined by voltage discharge lines V(la) and V(lb) shown in FIG.
), V C1c), it is possible to first detect the low voltage state of the battery row 1a with the shortest discharge at one point in time t1. That is, since the voltage discharge characteristic of the power supply section IA shows a correlation as a drop in the voltage level V with respect to the starting time T, the voltage level V/3 shown by the battery array 1a at the second time t1 should be set as the reference voltage. This makes it possible to first detect the low voltage state of the battery string with the shortest discharge time.

Also, at the time t2 shown as a reference, the low voltage detection circuit 5 included in the conventional DC power supply shown in FIG.
This shows a case where a low voltage state of A is detected. According to this low voltage detection circuit 5.

Since the reference voltage is set based on the total voltage vL of the power supply unit IA, the power supply is first turned on at time t2 when the voltage of the battery row 1b drops, not at the time t1 when the voltage drops in the battery row 1a, which has the shortest discharge. This results in the detection of a low voltage state in section IA. That is, when the conventional low voltage detection circuit section 5 is used, there is a risk that reverse charging or overdischarging may occur in the battery array 1a due to the time difference from time t2 to time t1.

Therefore, the low voltage detection circuit section 2A included in the DC power supply device of the present invention in which the reference voltage V'/3 is set in the reference voltage section 4B.
It can be seen that the circuits 2C to 2C operate clearly different from the conventional low voltage detection circuit section 5.

Note that the number of battery arrays constituting the power supply section IA of the DC power supply device of the present invention and the number of voltage comparison elements and switch sections included in the low voltage detection circuit section 2B or 2C are not limited to those in the embodiment.

(Effect of the invention) According to the DC power supply device of the present invention as described above.

In the power supply section, multiple battery rows are connected in series to obtain a relatively large power supply voltage, which can be applied to external equipment, and the voltage applied to each battery row is set between the reference voltage and the reference voltage. The present invention is equipped with a low-voltage detection circuit section that can detect the low-voltage state of the power supply section accurately and with high stability. As a result, even if reverse charging or over-discharging occurs in the battery string, the low voltage state can be accurately detected, and the power supply voltage can be cut off before applying the power supply voltage to the external equipment section. This allows for highly secure protection. Since reverse charging and overdischarging are prevented, it is possible to avoid negative effects such as leakage, swelling, and heat generation that may occur in the batteries in the battery array.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing the basic configuration of the DC power supply device of the present invention including the electronic equipment section, Fig. 2 is a diagram specifically showing its low voltage detection circuit section, and Fig. 3 is a diagram showing another low voltage detection circuit section. FIG. 4 is a diagram showing the voltage detection circuit section, FIG. 4 is a diagram for explaining the setting of the reference voltage of the present invention based on the voltage discharge characteristics of the power supply section, and FIG. 5 is a diagram showing the reverse charging of the conventional DC power supply. FIG. 6 is a diagram showing an example of a DC power supply device including a conventional low voltage detection circuit. FIG. 7 is a diagram showing the basic configuration of a conventional DC power supply device. 1...Power supply section, 2.5...Low voltage detection circuit section, 3.
... Voltage comparison means, 4... Reference voltage section, 6... Alarm circuit section. 7... Electronic equipment section, 8... Voltage comparator, 10...
Input switching section, 11... Synchronous circuit section, 12... Voltage comparison element. Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7

Claims (3)

[Claims] (1) In a DC power supply device that applies power supply voltage to external equipment, a predetermined number of batteries are connected in series to form a battery array,
A power supply section in which a plurality of battery rows are connected in series to form a battery row group, and the applied voltage from the battery row that is applied to the signal line connected to each of the battery rows are inputted to create a reference voltage. a low voltage detection circuit unit that outputs a detection signal indicating a low voltage state of the power supply unit when the applied voltage drops below the reference voltage; A DC power supply device comprising: a switch circuit section for turning off application of power supply voltage to the external device. (2) The low voltage detection circuit section is provided corresponding to each battery row of the battery row group, and is provided corresponding to each battery row of the battery rows, and is configured to detect the applied voltage for each battery row. a plurality of voltage comparison elements that compare reference voltages that are lower than the voltage equivalent to the battery row unit and output a detection signal indicating a low voltage state of each battery row when the applied voltage drops below the reference voltage; The DC power supply device according to claim 1, further comprising: a multi-input OR circuit section for inputting the detection signal. (3) The low voltage detection circuit section includes an input switching section connected to each of the signal lines, and a voltage comparator connected to the input switching section, and the input switching section includes an input switching section connected to each of the signal lines and a voltage comparator connected to the input switching section. The voltage comparator is composed of a plurality of input changeover switches inserted between the voltage comparator and a synchronous circuit section for sequentially and dividedly turning on and off each of the input changeover switches, and the voltage comparator is connected to the battery row group. The applied voltage from each battery row selected by the synchronous circuit section and a reference voltage below the voltage equivalent to the battery row unit are compared, and when the applied voltage drops below the reference voltage, the battery row is determined. The DC power supply device according to claim 1, wherein the DC power supply device outputs a detection signal indicating a low voltage state.