JP2903896B2 - Power supply with refresh request function - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply with a refresh request function, and more particularly to a power supply with a refresh request function that has a NiCd battery and is capable of charging and discharging and supplies DC power to other electronic devices.

[0002]

2. Description of the Related Art A conventional power supply having this type of nickel-cadmium (nickel-cadmium) battery supplies power to other electronic devices (discharge of the nickel-cadmium battery), and when the internal energy is reduced to some extent, the above-mentioned power supply is provided by a charger. The internal battery is charged, and charging is performed by supplying power from the outside until the battery is almost in the original state.

In addition, when the discharge and the charging are repeated with a shallow depth of discharge (the amount of discharged energy of the NiCd battery is sufficiently smaller than the amount of energy held when the NiCd battery is sufficiently charged), Since the NiCd battery causes a phenomenon called a memory effect, which will be described later, it is estimated that the depth of discharge during the current charge from the previous charge state is shallow prior to charging so that such a memory effect does not occur. When a power supply circuit is connected, a discharge circuit called a refresher is connected as a load of the power supply circuit, and the NiCd battery of the power supply to be charged is discharged until the depth of discharge is sufficiently low. When charging, no matter what the discharge amount of the target nickel-cadmium battery is, the discharge circuit is once used as a load as described above. Connect, discharge in the load, that is, performing a predetermined charge after performing refresh.

After charging a NiCd battery,
For the maximum amount of discharge that this nickel-cadmium battery has, charging is repeated a plurality of times after performing a relatively small amount of discharge, and then discharging to a region exceeding the amount of discharge up to then, The above-mentioned phenomenon in which the output voltage of the NiCd battery suddenly drops when the amount of discharge that has been performed by that time is exceeded is called the memory effect of the NiCd battery.

[0005]

In order to prevent the above-mentioned memory effect from occurring, the power supply having the above-mentioned conventional nickel-cadmium battery supplies power to other electronic devices or the like, that is, at the time of discharging. When performing charging, it is necessary to determine whether or not to perform the refresh as described above by grasping the progress of past charge / discharge, but it is possible to grasp the progress of such past charge / discharge. Because it is complicated, it is often omitted when it is necessary to perform the refresh, or refresh is performed when the refresh is unnecessary, which is inconvenient for such an operation when charging the power supply. In many cases.

SUMMARY OF THE INVENTION It is an object of the present invention to monitor the number of discharges that cause a memory effect in a power supply having a nickel-cadmium battery. It is an object of the present invention to provide a power supply with a refresh request function capable of outputting a signal for a refresh request without requiring a power supply.

[0007]

A power supply with a refresh request function according to the present invention comprises a nickel-cadmium battery, a first input / output unit connected to one electrode of the nickel-cadmium battery, and a second input / output unit of the nickel-cadmium battery. A resistor having one end connected thereto, a second input / output section connected to the other end of the resistor, and an output having one end connected to the second input / output section when the nickel-cadmium battery is sufficiently discharged; A reference voltage generator having an output level substantially equal to a voltage level, and the first input / output unit and the other end of the reference voltage generator, and a second input / output unit of the first input / output unit And a first comparator that outputs a reset signal when a voltage level of the resistor becomes equal to or lower than a voltage level of the reference voltage generator, and a terminal connected to the nickel-cadmium battery among terminals of the resistor. Input, and the second input / output And outputs a high-level count signal when the input level of the first input section is higher than the level of the second input section, and outputs a low-level count signal otherwise. A second comparator;
When the reset signal goes low, the output is reset, the output of the second comparator is counted, and when the count value reaches a predetermined value, a low level is output if a high level has been output until then. A first output unit that outputs a high level when a low level has been output until:
A counter having a second output unit that outputs a high level if it is a low level and outputs a low level if it is a high level when counting a count signal of an integral multiple of the first output unit; An AND gate to which the outputs from the first and second output units of the counter are input, and a warning circuit to which the output of the AND gate is input and which outputs a refresh request signal when the output of the AND gate is at a high level It is comprised including.

[0008]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a power supply with a refresh request function according to the present invention.
FIG. 3 is a waveform diagram for explaining the operation of the embodiment of FIG.

As shown in FIG. 1, a power supply with a refresh request function according to this embodiment includes a NiCd battery 1 and a NiCd battery 1.
An input / output unit 9 connected to the positive electrode side of the battery for supplying power to the NiCd battery 1 to the outside and for supplying power for charging the NiCd battery 1 from the outside, A resistor 2 having one end connected thereto, and an input / output unit connected to the other end of the resistor 2 for outputting power of the nickel battery 1 to the outside and for supplying power to the nickel battery 1 from outside when charging. 10 is provided. The input / output unit 10 is grounded to a power supply with a refresh request function.

Further, the power supply 8 with a refresh request function outputs a voltage of a preset level, and has a reference voltage generator 4 provided with one end, a positive electrode of the NiCd battery 1 and the aforementioned reference voltage generator 4. The other end of the comparator 3 is connected to the input side and outputs a reset signal; the two input sides are connected to both ends of the resistor 2 to output a count signal; The counter 6 counts the state, outputs two types of signals QA and QB separately, and resets the contents when the reset signal goes low, and an AND which receives the signals QA and QB as inputs. It includes a gate 11 and a warning circuit 7 which receives an output of the AND gate 11 as an input and outputs a refresh request signal.

The output level of the above-described reference voltage generator 4 is such that the NiCd battery 1 has a sufficiently large energy amount close to its maximum charging energy amount, for example, 95% of the maximum charging amount.
Is set in advance so as to output a voltage equal to the output voltage when the is discharged. The comparator 3 compares the level of the output voltage VA of the nickel-cadmium battery 1 with the level of the voltage VC of the reference voltage generator 4, and the level of the output voltage VA of the nickel-cadmium battery 1 is higher than the output voltage of the reference voltage generator 4. When the level is higher than the level of VC, as shown in FIG. 3, a high-level reset signal is output, and when the level of the output voltage VA of the NiCd battery 1 becomes lower than the level of the output voltage VC of the reference voltage generator 4. , So that a low-level reset signal is output.

The input of the comparator 5 outputs a high-level count signal when the NiCd battery 1 is in a charged state, that is, when a current flows from the NiCd battery 1 through the resistor 2 to the input / output unit 10. In addition, when the battery 1 is in a discharging state, that is, when a current flows from the input / output unit 10 through the resistor 2 to the negative electrode side of the battery 1, it is adjusted in advance to output a low-level count signal. Keep it.

Each time the count signal changes from the low level to the high level, the level of the OA changes alternately between the high level and the low level, and the level of the QA changes twice. At this time, the state of QB is adjusted to change from a high level to a low level or vice versa, and when the reset signal changes from a high level to a low level, The counter 6 is adjusted so that the level of QB is reset to a low level.

Further, the warning circuit 7 outputs a high-level refresh request signal when the output from the AND gate 11 goes high, and outputs a low-level refresh signal when the other level is output from the AND gate 11. Output a signal.

In the waveform diagram of FIG. 2, the NiCd battery 1 is initially charged to a shallow discharge state, that is, the comparator 3
, The voltage level VB on the nickel battery side of the resistor 2 shifts from the high level to the low level with respect to the ground potential. Each time the state changes, the comparator 5 outputs a count signal having a high level during charging and a low level during discharging according to the level change of the input voltage VB.

When such a count signal is input,
The counter 6 outputs a high level as the signal QA until immediately before the input count signal changes from the high level to the low level. When the count signal further changes to the high level, the signal QA changes to the low level, When the count signal changes from a low level to a higher level, the signal Q
A again becomes a high-level output, and thereafter makes a similar change according to a change in the level of the count signal. Therefore, if three shallow discharges are performed so that a low-level reset signal is not output from the comparator 3, both the outputs QA and QB of the counter 6 become high level. The output goes high and the warning circuit 7
Outputs a refresh request signal having a preset level.

If a lamp or a buzzer which is turned on by the output of the refresh signal is connected to the output side of the refresh signal, it is possible to know that the refresh request signal has been output.
In contrast, a load is connected between the input / output units 9 and 10 to discharge the NiCd battery 1 (that is, cause the refresh to be performed) until the comparator 3 operates and outputs a low-level reset signal. ), The outputs QA and QB of the counter 6 are reset to a low level, and the refresh request signal from the warning circuit 7 is turned off.

Therefore, when a refresh request signal is output using such a power supply with a refresh request function, a discharge having a sufficiently large depth of discharge is performed to cut off the refresh request signal. The NiCd battery 1 can be discharged for refreshing.

In the embodiment shown in FIG. 1 and FIG. 2, when the charging and the accompanying discharge with a shallow discharge progress are performed three times in succession, the levels of the two outputs QA and QB of the counter 6 are changed. Although the level is set to a high level, if necessary, such charge / discharge is repeated an arbitrary number of times.
It is clear that the output levels of both the outputs QA and QB may be set to high levels.

[0021]

As described above, the power supply with a refresh request function of the present invention outputs a refresh request signal when a discharge having a shallow depth of discharge, which may cause a memory effect, is repeatedly performed. When a request signal is output, a load circuit is externally connected, and the power of this power supply is discharged until the above-mentioned refresh signal is cut off, thereby preventing the appearance of a memory effect and refreshing without waste whenever necessary. Can be performed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of a power supply with a refresh request function of the present invention.

FIG. 2 is a waveform diagram illustrating the operation of the embodiment of FIG.

FIG. 3 is an explanatory diagram illustrating an operation of a comparator 3 in the embodiment of FIG.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 NiCd battery 2 Resistor 3 Comparator 4 Reference voltage generator 5 Comparator 6 Counter 7 Warning circuit 9-10 Input / output unit 11 AND gate

Claims (1)

(57) [Claims] 1. A nickel-cadmium battery, a first input / output unit connected to one electrode of the nickel-cadmium battery, a resistor having one end connected to the other electrode of the nickel-cadmium battery, and A second input / output unit connected to an end, a reference voltage generating unit having one end connected to the second input / output unit and having an output level substantially equal to an output voltage level when the nickel-cadmium battery is sufficiently discharged; The first input / output unit and the other end of the reference voltage generation unit are input, and the voltage level of the first input / output unit with respect to the second input / output unit is equal to or lower than the voltage level of the reference voltage generation unit. A first comparator that outputs a reset signal when the signal becomes negative, and a terminal connected to the NiCd battery among terminals of the resistor as a first input;
Are connected to the second input unit, and when the input level of the first input unit is higher than the level of the second input unit, a high-level count signal is output; otherwise, the count signal is low. A second comparator for outputting a count signal of a level; and resetting the output when the reset signal goes low, counting the output of the second comparator, and keeping the high level until the count value reaches a predetermined value. When a level has been output, a low level is output. When a low level has been output, a first output section that outputs a high level and a count signal that is an integral multiple of the first output section are counted. And a counter having a second output section that outputs a high level if it is at a low level and outputs a low level if it is at a high level, and a first output section and a second output section of the counter. output An AND gate for receiving as input, the A
A warning circuit that receives an output of the ND gate as an input and outputs a refresh request signal when the output of the AND gate is at a high level.