JPH087787Y2 - Battery charging circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a battery charging circuit incorporated in a liquid crystal television receiver.

(Prior Art) Conventionally, a liquid crystal television receiver (hereinafter referred to as a liquid crystal TV)
Generally has a built-in battery charging circuit. In such an LCD TV, the power switch and the charging switch are shared. Further, when the liquid crystal panel is colorized, light is normally emitted from the back side of the liquid crystal panel by a backlight.

FIG. 2 is a block diagram showing a battery charging circuit used in a conventional liquid crystal TV.

The housing 1 of the liquid crystal TV is provided with a DC jack 2 and a battery case 3. The DC jack 2 has a male terminal 4 on the positive electrode side and a contact spring 5 on the negative electrode side, to which a plug such as an AC adapter (not shown) or a car battery cord is connected. That is, a plug such as an AC adapter and a car battery cord is composed of a female terminal on the positive electrode side and an outer conductor on the negative electrode side. At the time of connection, the male terminal 4 and the female terminal are fitted together, and the outer conductor is the convex portion of the contact spring 5. It comes in contact with 6. The male terminal 4 and the contact spring 5 are connected to the input terminals 7 and 8, respectively, and the input terminal 8 is connected to the reference potential point.

The battery case 3 is provided with N batteries 9 connected in series, the positive terminal of the battery 9 at one end of the series connection is connected to the input terminal 10, and the negative electrode of the battery 9 at the other end of the series connection. The side terminal is connected to the input terminal 11. Input terminal 11
It is connected to a terminal 12 on the DC jack 2 side, and the terminal 12 can come into contact with the contact spring 5 via a contact 13. When a plug such as an AC adapter is connected to the DC jack 2, the contact 13
The contact spring 5 and the contact spring 5 are not in contact with each other.

Input terminal 7 main power circuit 1 through the diode D ₁
4, the inverter circuit 15, the audio power supply circuit 16 and the input terminal P ₁ of the slide switch 17.

The slide switch 17 has terminals P _{1 to} P ₆ and is adapted to slide the contact portion to the position A or B. When the contact portion is selected to the position B, the terminals P ₂ and P ₅ are , respectively connected to the terminal P _3, P _6, when the contact portion is selected to the position a, the terminal P _2, P ₅ is adapted respectively connected to the terminals P _1, P _4. The terminal P ₂ is connected to the on / off circuit 18, the terminals P ₃ and P ₅ are connected to the reference potential point, and the terminal P ₆ is a resistor.
It is connected to the input terminals 11 and 12 via R ₁ . The terminal P ₄ is an empty terminal.

The on / off circuit 18 is a circuit that controls on / off of the main power supply circuit 14, the inverter circuit 15, and the audio power supply circuit 16, and when the contact portion of the switch 17 is at the position A, outputs an on signal to turn on the main signal. When the power supply circuit 14, the inverter circuit 15, and the audio power supply circuit 16 are turned on, and the contact portion is at the position B,
Send off signal, main power supply circuit 14, inverter circuit
15. Turn off the audio power supply circuit 16.

The main power supply circuit 14 supplies the DC voltage from the input terminal 7 or the input terminal 10 to the channel selecting section, the image receiving section, the image processing section, and the liquid crystal panel. The inverter circuit 15 has an input terminal 7
Alternatively, the DC voltage from the input terminal 10 is converted into an AC voltage and supplied to the backlight drive device. Further, the audio power supply circuit 16 outputs the DC voltage from the input terminal 7 or the input terminal 10
It is supplied to the audio receiving unit, the audio processing unit, and the speaker.

 The operation of such a conventional liquid crystal TV will be described.

When the liquid crystal TV is set in the receiving state, the contact portion of the slide switch 17 is selected at the position A. As a result, the terminals P ₁ and P ₂ are connected. Now, it is assumed that an input voltage is obtained from the battery 9 without connecting a plug such as an AC adapter or a car battery to the DC jack 2. Since the plug is not connected, the contact 13 and the contact spring 5 are in contact with each other. For this reason,
The negative terminal of the battery 9 is connected to the reference potential point and supplies a DC voltage to the main power supply circuit 14, the inverter circuit 15, the audio power supply circuit 16 and the slide switch 17. At this time, the control signal from the on / off circuit 18 becomes high level, and the main power supply 14, the inverter circuit 15, the audio power supply circuit 1
6, the channel selection unit, the image receiving unit, the image processing unit, the liquid crystal panel, the backlight driving device, the audio receiving unit, the audio processing unit, and the speaker are started to operate, and the liquid crystal TV enters the receiving state.

When an input voltage is obtained from a plug such as an AC adapter or a car battery to bring the liquid crystal TV into a receiving state, the contact portion of the slide switch 17 is selected at position A, and the plug is connected to the DC jack 2. Then, the contact 13 and the contact spring 5 are not in contact with each other, and the terminal voltage of the battery 9 is not supplied to the main power supply circuit 14, the inverter circuit 15, and the audio power supply circuit 16. In this case, a DC voltage is supplied from the plug to the main power supply circuit 14, the inverter circuit 15, and the audio power supply circuit 16 via the diode D ₁ , and the liquid crystal TV is in the receiving state.

When charging the liquid crystal TV, a plug such as an AC adapter or car battery is connected to the DC jack 2 and the contact portion of the slide switch 17 is selected at the position B. As a result, the terminals P ₅ and P ₆ are connected. Then, the negative terminal of the battery 9 is connected to the reference potential point via the resistor R ₁ , and a DC voltage is supplied to the battery 9 from the plug via the diode D ₁ to charge the battery 9. To be done. In this case, since the terminals P ₂ and P ₃ are connected, the control signal VI from the on / off circuit 18 becomes low level, and the main power supply
13, the power supply to the inverter circuit 15 and the audio power supply circuit 16 is turned off, and the liquid crystal TV is stopped.

When the liquid crystal TV is completely stopped without being charged, the contact portion of the slide switch 17 may be selected at the position B without connecting the AC adapter or the car battery plug to the DC jack 2.

Such a conventional portable LCD TV has the following problems.

First, it cannot be used as a TV because it is dedicated to charging during charging. Also, if charging is possible while using a TV, it is necessary to increase the capacity of the AC adapter.
The size of the AC adapter becomes large and the merit as a portable device diminishes.

Secondly, since the power-off and the charging mode are shared, it is difficult to identify which mode is being used. Further, since the rechargeable battery is built in the set or stored in the battery case, it cannot be judged from the appearance of the set. If the rechargeable battery is left in the off mode with the built-in rechargeable battery, it will be overcharged and the rechargeable battery will deteriorate.

Thirdly, since it is a two-circuit, two-contact switch, a slide type is generally used, and since the initial charging current flows several hundred mA, it becomes a large current type, so that the selection range of the switch is limited.

Fourthly, in TV broadcasting where a news program or the like can be heard without looking at the screen, the battery life can be extended by providing a sound mode in which only the sound is output from the portable liquid crystal TV. However, if a voice mode is added to this switch, the number of contacts is increased, resulting in a very complicated switch configuration.

(Problems to be solved by the invention) As described above, the conventional liquid crystal television receiver cannot be used as a television receiver during charging, it is difficult to distinguish between power-off and charging, and switch selection There are problems that the range is limited and that adding a sound mode complicates the switch configuration.

This device is to eliminate the above problems,
An object of the present invention is to provide a liquid crystal television receiver capable of adding various additional functions with a simple switch configuration.

[Structure of the Invention] (Means for Solving the Problem) The present invention is a battery charging circuit built in a liquid crystal television receiver, which includes a first power input unit using a battery,
A second power source input section using a power source other than the battery, and a first direct current voltage to the first power source input section when the second direct current voltage is supplied from the second power source input section. And a first direct-current voltage or a second direct-current voltage
Main power supply circuit for supplying power to the channel selection section, the image reception section, the image processing section and the liquid crystal panel by generating the first power supply voltage by the DC voltage of the first DC voltage or the second DC voltage. Is provided to generate a second power supply voltage and supplies power to the audio processing unit and the audio device;
Power supply circuit for a backlight which supplies a direct-current voltage or a second direct-current voltage to generate a third power-supply voltage and supplies the third power-supply voltage to the drive device for the backlight, A standby power supply circuit that generates a voltage, and a constant voltage from the standby power supply circuit is input as a power supply to a first input terminal and also as a control signal to a second input terminal, and a control signal is supplied to the second input terminal. Is not input, the main power supply circuit, the voice power supply circuit,
The backlight power supply circuit is turned on, and when a control signal is input to the second input terminal, the control circuit that turns off only the backlight power supply circuit and the supply of the DC voltage to the standby power supply circuit are turned on. A first switch for turning on / off, a second switch for turning on / off the supply of the control signal to the second input terminal of the control circuit, and a collector-emitter path between one end of the battery and a reference potential point. Connect
A path from which the voltage from the standby power supply circuit can be supplied to the base via the second switch, and when the second switch is turned on, the collector-emitter is turned on to charge the battery. And a transistor that forms a transistor.

(Operation) According to such a configuration, by turning on the first switch for standby and the second switch for both the surround mode and charging, the power supply circuit for backlight is turned off and the backlight is forcibly forced. Can be turned off and only the sound can be output. At the same time, the transistor is turned on, so that the battery can be charged. Further, the power-off and the charging mode are different modes, and the charging mode can be identified by checking whether or not the second switch is on, so that the rechargeable battery is not left overcharged. Since the electric contacts of the first and second switches can be realized by one push switch, the switch selection range is expanded.

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

FIG. 1 is a block diagram showing an embodiment of a battery charging circuit according to the present invention, showing a state of being incorporated in a liquid crystal TV.

As in the conventional example shown in FIG.
The battery case 23, which is the power input section 51, and the DC jack 22, which is the second power input section 52, are provided. The DC jack 22 has a male terminal 24 on the positive electrode side and a contact spring 25 on the negative electrode side, and is adapted to be connected to a plug such as an AC adapter (not shown) or a car battery cord.
That is, at the time of connection, the male terminal 24 and the female terminal of the plug are fitted so that the outer conductor of the plug comes into contact with the convex portion 26 of the contact spring 25. The male terminal 24 and the contact spring 25 are connected to the input terminals 27 and 28, respectively, and the input terminal 28 is connected to the reference potential point.

The battery case 23 is provided with N batteries 29 connected in series, the positive terminal of the battery 29 at one end of the series connection is connected to the input terminal 30, and the negative electrode of the battery 29 at the other end of the series connection. The side terminal is connected to the input terminal 31. The input terminal 31 is connected to the terminal 32 on the DC jack side, and the terminal 32 can come into contact with the contact spring 25 via the contact 33. When the plug is connected to the DC jack 22, the contact spring 25 is curved and the contact 33 is not in contact with the contact spring 25.

Input terminal 27 is connected to main power supply circuit 3 via diode D _11.
4, inverter circuit 35, audio power supply circuit 36 and switch 41
It is connected to the input terminal of. The output terminal of the switch 41 is connected to the input terminal of the standby power supply 42.

The standby power supply 42 outputs a constant voltage VS and supplies it to the first input terminal of the microcomputer 43 when a high level voltage is supplied to its input terminal. The output terminal of the standby power supply 42 is connected to the input terminal of the switch 44, the output terminal of the switch 44 is connected to the second input terminal of the microcomputer 43, and is also connected to the base of the transistor Q ₁ via the resistor R _12. ing. The transistor Q ₁ has its emitter connected to the reference potential point and its collector connected to the input terminal 31 via the resistor R ₁₁ . Transistor Q ₁ is turned on by the presence of the base voltage, so as to turn off.

When the constant voltage VS is supplied to the first input terminal a of the microcomputer 43, the microcomputer 43 outputs high level output V from the output terminals d and e, respectively.
P, VI main power on / off circuit 45, inverter on /
The power is supplied to the off circuit 46 to turn on the main power supply circuit 34 and the inverter circuit 35. When a high level signal is supplied to the second input terminal b, the microcomputer 43 inverts the output VI to low level and turns off the inverter circuit.

Outputs from the key switches such as power on / off, channel up / down, and audio up / down are supplied to the third input terminal c of the microcomputer 43. Corresponding to these outputs, the main power supply Controls on / off, channel up / down, audio up / down.

When turned on, the main power supply circuit 34 supplies the DC voltage from the input terminal 27 or the input terminal 30 to the channel selection section, the image reception section, the image processing section, and the liquid crystal panel. The audio power supply circuit 36 is turned on by the high level DC voltage from the main power supply circuit 34. Audio power circuit 36
When turned on, supplies the DC voltage from the terminal 27 or the input terminal 30 to the audio processing unit and the speaker. When the inverter circuit 35 is turned on, the inverter circuit 35 converts the DC voltage from the input terminal 27 or the input terminal 30 into an AC voltage and supplies the AC voltage to the backlight drive device.

 The operation of such a battery charging circuit will be described.

When the liquid crystal TV is to receive both audio and video from the battery 29 by the power source, the switch 41 is turned on and the switch 44 is turned off without connecting the AC adapter or the car battery plug to the DC jack 2. Leave. As a result, the microcomputer 43 is supplied with the constant voltage VS from the standby power supply circuit 42 to the first input terminal a, and the high level signals VP, V
I is output and supplied to the main power supply on / off circuit 45 and the inverter on / off circuit 46 to turn on the main power supply circuit 34 and the inverter circuit 35. When the main power supply circuit 34 is turned on, the audio power supply circuit 36 is turned on by the high level output of the main power supply circuit 34. As a result, the channel selecting unit, the image receiving unit, the image processing unit, the liquid crystal panel, the backlight driving device, the audio receiving unit, the audio processing unit, and the speaker start their operations, and the liquid crystal TV enters the receiving state.

When an input voltage is obtained from a plug such as an AC adapter or a car battery to bring the liquid crystal TV into a receiving state for both audio and video, switch 41 is turned on and switch 44 is turned off. This enables the standby power supply 42 and the microcomputer 4
3, the main power on / off circuit 45 and the inverter on / off circuit 46 perform the same operation as in the case of obtaining power from the battery 29 by the DC voltage from the plug, and bring the liquid crystal TV into the receiving state. In this case, the contact 33 and the contact spring 25 are not in contact with each other, and the terminal voltage of the battery 29 is not supplied to the main power supply circuit 34, the inverter circuit 35, and the audio power supply circuit 36.

When the liquid crystal TV is in the receiving state while receiving the sound while the liquid crystal TV is in the charging state, the plug is connected to the DC jack 22 and the switches 41 and 44 are turned on. This causes the microcomputer 43 to connect the standby power supply circuit 42 to the first input terminal a.
From the constant voltage VS, the second input terminal b is supplied with a high level voltage, and the first output terminal d outputs a high level signal VP to the main power supply ON / OFF circuit 45, The main power supply circuit 34 is turned on, the second output terminal e outputs the low level signal VI, and the inverter on / off circuit
46, and the inverter circuit 35 is turned off. When the main power supply circuit 34 is turned on, the audio power supply circuit 36 is turned on by the high level output of the main power supply circuit 34. In this case, since the main power supply circuit 34 and the audio power supply circuit 36 are in the ON state, the channel selection unit, the video reception unit, the video processing unit, the liquid crystal panel, the audio reception unit, the audio processing unit, and the speaker start operating. , The LCD TV receives audio. Here, the liquid crystal panel is also starting to operate, but the inverter circuit 35 is not operating, so the backlight is off and no image is displayed. Further, since the switch 44 is turned on, the transistor Q ₁ is turned on, and the negative terminal of the battery 29 is connected to the reference potential point via the resistor R ₁ .
A DC voltage is supplied to the battery 29 from the plug via the diode D ₁₁ , and the battery 29 is charged.

If you want to charge the LCD TV without receiving both video and audio, connect the plug to the DC jack 22 and switch 41, 4
Turn on 4 and turn off the power on / off key switch. As a result, in the microcomputer 43, the constant voltage VS is supplied from the standby power supply circuit 42 to the first input terminal a and the voltage supplied to the second input terminal b becomes high level. Since the output of OFF is supplied from the switch, low level signals VP and VI are output and supplied to the main power supply ON / OFF circuit 45 and the inverter ON / OFF circuit 46, and the main power supply circuit 34 and the inverter circuit 35 are turned OFF. To do.
Also, since the switch 44 is turned on, the transistor
Q ₁ is turned on, a DC voltage is supplied from the plug to the battery 29 via the diode D ₁₁ , and the battery 29 is charged. As a result, the LCD TV is only charged.

When the liquid crystal TV is stopped, the switches 41 and 44 may be turned off.

In such a portable liquid crystal TV, it is possible to charge while listening to only the sound of the TV broadcast when receiving the TV broadcast without having to see the screen such as news. That is, by turning off the backlight and receiving only sound, the amount of power of the backlight can be used for charging. Therefore, a large capacity AC adapter is not required.

Also, unlike the conventional case, the power-off and charge modes are not shared, and it is easy to see that the mode is the charge mode by checking whether the switch 44 is on, so the rechargeable battery is left overcharged. It is possible to prevent deterioration of the rechargeable battery.

Furthermore, since the switches 41 and 44 use only two contacts and the switches 41 and 44 may be ordinary push switches, the switch configuration is simple and the switch selection range is expanded. Further, since the charging current flows through the transistor Q1 and the charging current does not flow through the switches 41 and 44, the switches 41 and
44 may be a small current type.

In the embodiment of FIG. 1, only the sound cannot be received except during charging (that is, the sound mode is also used), but a circuit for independently turning on / off the sound power supply circuit is provided. The circuit may be controlled by a microcomputer so that only sound can be received (that is, a sound mode can be provided in addition to the surround mode + charging mode. A radio can be added to the LCD TV, You may be able to listen to the sound of the radio.

[Effects of the Invention] As described above, according to the present invention, it is possible to charge while listening only to the sound of the television receiver, it is easy to distinguish between power off and charging, the switch selection range is expanded, and The switch configuration does not become complicated even if modes are added.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a battery charging circuit according to the present invention, and FIG. 2 is a block diagram showing a conventional battery charging circuit. 21 …… Case, 22 …… DC jack, 23 …… Battery case, 24
...... Male terminal, 25 ...... Contact spring, 27,28,30,31 ...... Input terminal, 29 ...... Battery, 32 ...... Terminal, 33 ...... Contact, 34 ...... Main power circuit, 35 ...... Inverter circuit , 36 …… Voice power supply circuit, 41,44 …… Switch, 42 …… Standby power supply, 43…
… Microcomputer, 45 …… Main power on / off circuit, 46 ……
Inverter on / off circuit, 51 ... first power input section,
52 …… Second power input section.

Claims (1)

[Scope of utility model registration request] 1. A battery charging circuit incorporated in a liquid crystal television receiver, comprising first and second power supply input parts, wherein the first power supply input part has a first DC voltage from the battery. And a second DC voltage from a power source other than the battery can be supplied to the second power input unit, and the first DC voltage is supplied from the second power input unit when the second DC voltage is supplied. Power supply means configured to block the supply of the first DC voltage to the power supply input section of the first power supply, and the first power supply to which the first DC voltage or the second DC voltage is applied from the power supply means. A main power supply circuit that generates a voltage and supplies power to the channel selection unit, the image reception unit, the image processing unit, and the liquid crystal panel; and a first DC voltage or a second DC voltage from the power supply unit, Generates a power supply voltage of 2 and supplies power to the audio processor and audio device. A voice power supply circuit, and a backlight power supply circuit which is supplied with the first DC voltage or the second DC voltage from the power supply means to generate a third power supply voltage and supplies the third power supply voltage to a backlight drive device. ON / OFF control of a standby power supply circuit that receives a first DC voltage or a second DC voltage from the power supply means to generate a constant voltage, and the main power supply circuit, the audio power supply circuit, and the backlight power supply circuit The constant voltage from the standby power supply circuit is input to the first input terminal as a power supply and to the second input terminal as a control signal, and the control signal is not input to the second input terminal. Sometimes, the main power supply circuit, the audio power supply circuit, and the backlight power supply circuit are turned on, and when a control signal is input to the second input terminal, the backlight power supply circuit A control circuit that turns off only the circuit; a first switch that is provided in a path that supplies a DC voltage to the standby power supply circuit and that turns on / off the supply of the DC voltage; and a second input terminal of the control circuit. A second switch, which is provided in a path for supplying a constant voltage from the standby power supply circuit and which turns on / off the supply of the control signal, and when power is supplied to the second power input section,
A switch for forming a path for charging the battery of the first power supply input section, wherein a collector-emitter path is connected between one end of the battery and a reference potential point, and the base has the standby power supply circuit. And a transistor forming a path for charging the battery by turning on the collector-emitter when the second switch is turned on. A battery charging circuit characterized in that