JP2524258B2 - Power adapter with charging and discharging functions - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to, for example, a camera-integrated portable VTR.
A power adapter (so-called AC that has a function of charging a secondary battery used for a (bite tape recorder) and that converts a stepped-down AC from a commercial AC power source into a direct current and supplies this to the VTR as an operating power source current. The present invention also relates to an adapter), and also has a discharge function of discharging the secondary battery deeper than usual in order to refresh the secondary battery having a reduced capacity due to a memory effect.

[Prior Art] Generally, a nickel cadmium battery is used as a secondary battery in the above-mentioned VTR. This battery does not require maintenance, so it is easy to use, but be careful because it has the memory effect described later. The memory effect mentioned above occurs when the battery is discharged a little and charged, and then charged and discharged a little.
It means that a part of the capacity is gradually deactivated, and as a result, the capacity of the battery decreases.

In order to prevent this memory effect, it is desirable to discharge the battery to an ideal final voltage commensurate with the number of cells in the battery.

However, in the VTR (including the integrated camera), when the battery drops to the ideal end voltage, the VTR will shoot and
Since it does not perform sufficient operation for recording, the operation of the VTR is stopped before the ideal final voltage is lowered to prompt the charging of the battery. Therefore, a memory effect occurs.

Also, due to the nature of being portable, in order to avoid that the voltage of the battery drops during use and the VTR does not operate, it will be charged with caution with a little use, resulting in repeated shallow charge and discharge. Therefore, it is unavoidable that the memory effect is generated for this reason.

It is known that in order to restore (refresh) the battery in which the memory effect has occurred in this way, it is sufficient to discharge the battery to an ideal final voltage deeper than usual and then charge it.

Further, in order to refresh the memory effect, a charger having a discharging function for discharging a battery to an ideal final voltage is also commercially available.

[Problems to be Solved by the Invention] In the commercially available charger, the discharge current is relatively small in order to suppress heat generation due to discharge to a predetermined value or less,
Therefore, there is a drawback that the discharge time is long.

The present invention eliminates the above-mentioned drawbacks and provides a power supply adapter with a charging function and a discharging function that has a relatively short discharge time.

[Means for Solving the Problems] In order to solve the above problems, the present invention includes a secondary battery mounting portion, a DC power supply circuit, a load resistor, and an external load connection terminal, and the DC power supply circuit From the DC power supply circuit to a power supply circuit for supplying an operating current to an external load connected to the external load connection terminal from the DC power supply circuit mounted on the secondary battery mounting portion. Is a power adapter with a charging function and a discharging function, in which a charging circuit for supplying a charging current and a discharging circuit for flowing a discharging current from the secondary battery mounted in the secondary battery mounting portion to the load resistance are formed. In the power adapter with a charging function and a discharging function, the external load connected to the external load connection terminal is connected in parallel with the load resistor when the discharging circuit is formed. is there.

[Operation] In the power supply adapter with the charging function and the discharging function configured as described above, when the discharge circuit of the secondary battery is formed, the discharge current flows to the external load as well as the load resistance. The discharge time is shorter than the conventional one.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of a main part of a power adapter with a charging function and a discharging function and a VTR (including an integrated camera) as an external load connected to the power adapter, and FIG. 2 is a charging function and a discharging function. FIG. 3 is a perspective view of the power adapter and the VTR as an external load connected to the power adapter and a secondary battery to be mounted on the power adapter, and FIG. 3 is a perspective view of the power adapter with a charging function and a discharging function.

In FIG. 2, reference numeral 1 is a power adapter body with a charging function and a discharging function, 2 is an AC (alternating current) cord for connecting the adapter body to a commercial power source, 3 is a secondary battery (nickel cadmium battery pack), 4 is the adapter body 1
A DC (direct current) cord connecting a VTR, which will be described later, 5 is a portable VTR integrated with the camera described above, 6 is a VTR camera lens, and 7 is a VTR5 operation unit. Reference numeral 8 is a discharge operation start switch (normally open) of the adapter body 1, 9 is a power supply display lamp, 10 is a discharge operation start display lamp, and 11 is a secondary battery mounting portion of the adapter body 1 in which the secondary battery 3 is mounted. It is a switch that detects that. In FIG. 3, the same symbols as those in FIG. 2 indicate the same items.

Also in FIG. 1, the same reference numerals as those in FIG. 2 indicate the same things. In FIG. 1, reference numeral 12 is a relay, and 12a to 12d.
Is the contact of the relay. 13 is an external load connection terminal
A DC output connector, 14 is a load resistance (cement resistance) for discharging, 15 is a voltage detection circuit, and 16 is a transistor. 17
Is a DC power supply circuit, which steps down the AC from the commercial power supply and converts this AC into DC. The direct current from the DC power supply circuit 17 is supplied to the VTR 5 as an operating current when the power supply adapter with the charging function and the discharging function operates as a power adapter, and when operating as a charger,
It is supplied to the secondary battery 3 as a charging current. Also, reference numeral 18
Numerals 21 to 21 are power diodes, and 22 is a VTR power source section including a regulator for supplying power source currents to the mechanical section, video circuit, audio circuit, CCD and the like of the VTR 5. The power supply section 22 supplies the power supply current supplied to the terminal IN to the mechanical section or the like. The power supply current supplied to the mechanical section or the like is such that the voltage applied to the terminal CTL is "H" or "L". Controlled by or. That is, when the voltage is "H", the power supply current flows and the VTR5 can operate, and when the voltage is "L", the power supply current is cut off and the VTR5 does not operate. Reference numeral 23 is a power supply voltage detection circuit, 24 is a power switch (slide switch) for the VTR 5, 25 to 27 are small signal diodes, 28 is a power diode, and 29 is an AND gate.

Next, the operation of the power adapter with the charging function and the discharging function will be described.

First, when the power adapter with the charging function and the discharging function is used as a power adapter, the secondary battery 3 is removed from the adapter body 1, so the switch 11 is connected to the A side. Since the relay 12 is not excited, the contacts 12a to 12d are connected to the A side. In this state, a power supply voltage is applied from the DC power supply circuit 17 to the terminal IN of the power supply unit 22 of the VTR 5 through the diode 28, the DC output connector 13, the DC cord 4, and the diode 18 on the VTR 5 side.
This power supply voltage is also applied to the power supply voltage detection circuit 23, and the detection circuit outputs a voltage of "H". This "H"
Is applied to one input terminal of the AND gate 29 via the diode 25.

If you turn on the power switch 24 of the VTR5,
The voltage applied to the terminal IN of 22 is applied to the other input terminal of the AND gate 29 as the voltage of "H", and the output of the AND gate becomes "H" and applied to the terminal CTL. As a result, the power supply current supplied from the DC power supply circuit 17 to the terminal IN is supplied to the mechanical unit and the like via the power supply unit 22, and the VTR 5 operates according to the operation of the operation unit 7.

This operable state can be continued until the output of the power supply voltage detection circuit 23 becomes “L” when the level of the power supply voltage applied to the power supply voltage detection circuit 23 becomes a predetermined value or less, for example. The level of the power supply voltage at which this output becomes "L" differs depending on whether or not the voltage of "H" is applied to the detection circuit 23 via the diode 26. As in the above case, since the voltage of "H" is not applied through the diode 26 when used as the power supply adapter, when the power supply voltage applied to the detection circuit 23 drops to the first voltage, the detection circuit The output of 23 becomes “L”. As will be described later, when the “H” voltage is applied to the detection circuit 23 via the diode 26, the output of the detection circuit 23 is output when the power supply voltage drops to the second voltage which is lower than the first voltage. Becomes "L".

Here, the first voltage refers to the lowest voltage that can be operated with satisfactory performance suitable for shooting / recording, such as when the VTR5 operates in a sufficient state, that is, in a state in which S / N does not deteriorate.

By the way, the second voltage means the lowest voltage at which the VTR can operate, although the S / N of the VTR5 becomes worse and is not suitable for shooting and recording.

Next, the operation of the case where the power adapter with the charging function and the discharging function is used as a discharger for the forced discharge of the secondary battery 3 will be described.

When the power adapter is used as a discharger, the secondary battery 3 is mounted on the secondary battery mounting portion of the adapter body 1. By this mounting, the switch 11 is switched to the B side. continue,
Turn on the discharge operation start switch 8. When this is turned on, an exciting current flows from the secondary battery 3 to the relay 12, and its contact 12a
~ 12d is switched to B side, and discharge operation start display lamp 1
A current for light emission flows through the light emitting diode which becomes 0. Contact 1
When 2d is switched to the B side, the voltage of the secondary battery 3 is applied to the voltage detection circuit 15 via the contact, and when this voltage is higher than the above-mentioned ideal end voltage, the transistor 16 is turned on. By turning on the transistor, the excited state of the relay 12 is maintained even if the switch 8 is opened. In this state, a discharge current flows from the secondary battery 3 to the load resistor 14 via the contact 12d, and the secondary battery 3 is forcibly discharged.

Further, by switching the contacts 12b and 12c to the B side, the DC output connector 13 is applied with a voltage having a polarity opposite to that of the secondary battery 3 when used as the power supply adapter as described above. The voltage from the secondary battery via the DC code 4 is applied to the terminal IN of the power supply unit 22 of the VTR via the diode 21. The voltage via the DC code 4 is also applied to the power supply voltage detection circuit 23, and is ANDed via the diode 27.
The voltage is applied to the power supply voltage detection circuit 23 via the other input terminal of the gate 29 and the diode 26. When the voltage from the secondary battery 3 is higher than the second voltage described above, the output of the power supply voltage detection circuit 23 becomes "H", and the voltage of "H" is applied to the other input terminal as described above. One input terminal of the applied AND gate 29 also becomes “H”, and the output of the AND gate 29 which becomes “H” is applied to the terminal CTL of the power supply unit 22, so that the power supply unit described above. The power supply current is supplied to the mechanical parts and the like.

The secondary battery 3 is forcibly discharged by such a power supply current to the mechanical section and the like. When the voltage of the secondary battery 3 becomes lower than the second voltage due to this discharge, the output of the power supply voltage detection circuit 23 via the diode 25 becomes "L", and the output of the AND gate, that is, the power supply unit 22. The input of the terminal CTL of is "L", and the power supply current from the power supply unit 22 to the mechanical unit and the like is cut off.

As a result, the discharge of the secondary battery 3 due to the power consumption of the VTR 5 is stopped, but the discharge current of the secondary battery 3 flows through the load resistor 14. When the voltage of the secondary battery 3 drops to the ideal final voltage due to the discharge by the load resistor 14, the output of the voltage detection circuit 15 is stopped, the transistor 16 is turned off, and the relay 1
2 is in a non-excited state, and its contacts 12a to 12d are switched to the A side.

When the contact 12a is switched to the A side, a charging current flows from the DC power supply circuit 17 to the secondary battery 3, and the secondary battery is charged.

As described above, in order to charge the secondary battery 3 without forcibly discharging it, it is only necessary to mount the secondary battery 3 on the adapter body 1 and not turn on the switch 8.

In the above embodiment, the diode 27 is provided and the secondary battery 3 is provided.
Although the power supply current is automatically supplied from the power supply unit 22 to the mechanical unit etc. during the forced discharge of, the diode 27 is not provided and the switch 24 is manually turned on even during the forced discharge. Good. Further, at the time of forced discharge, the voltage of "H" is applied to the power supply voltage detection circuit 23 via the diode 26 to switch the detection level. However, without providing the diode 26, the detection level is described above. It may be the first voltage. When the diodes 26 and 27 are not provided, it is not necessary to reverse the voltage applied to the DC output connector 13 during forced discharge.

Further, in the above embodiment, the external load is used even during forced discharge.
Although VTR5 is used, a load resistor connectable to the DC connector 13 may be used as an external load at the time of forced discharge.

[Advantages of the Invention] As described above, the present invention provides load resistance during forced discharge.
Since the external load is connected in parallel with 14, the discharge time of the secondary battery 3 is shortened without generating a large amount of heat. Incidentally, in a commercially available charger with a discharge function, the discharge current due to the load resistance is about 0.3 to 0.5 A, but when VTR5 is used as the external load, the discharge current flowing to the VTR becomes about 1 A.

[Brief description of drawings]

1 to 3 show an embodiment of the present invention. FIG. 1 is a block diagram, FIG. 2 and FIG. 3 are perspective views. 1: Power adapter body, 3: Secondary battery, 5: VTR, 13: DC output connector, 14: Load resistance, 17: DC power supply.

Claims (3)

(57) [Claims] 1. A secondary battery mounting section, a DC power supply circuit, a load resistor, and an external load connection terminal, wherein an operating current is supplied from the DC power supply circuit to an external load connected to the external load connection terminal. And a charging circuit that supplies a charging current from the DC power supply circuit to the secondary battery that is mounted on the secondary battery mounting portion and that is used for the external load, and that is mounted on the secondary battery mounting portion. A power supply adapter with a charging function and a discharging function configured to form a discharge circuit that causes a discharge current to flow from the secondary battery to the load resistor, wherein the discharge resistor is formed in parallel with the load resistor when the discharge circuit is formed. A power adapter with a charging function and a discharging function, wherein an external load connected to the external load connection terminal is connected. 2. The voltage applied to the external load connection terminal when the discharge circuit is formed is opposite to the polarity of the voltage applied to the external load connection terminal when the power supply circuit is formed. The charging function according to claim 1, wherein the external load connected to the external load connection terminal is automatically brought into an operating state when the voltage having the opposite polarity is applied. Power adapter with discharge function. 3. The voltage applied to the external load connection terminal when the discharge circuit is formed is opposite to the polarity of the voltage applied to the external load connection terminal when the power supply circuit is formed. There is no polarity, and the set level that automatically stops the operation when the power supply voltage of the external load connected to the external load connection terminal when the voltage of the opposite polarity is applied falls below the set level. The power adapter with a charging function and a discharging function according to claim 1, wherein the power adapter has a lower voltage.