JPH0449332B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a battery charging control circuit used in portable VTRs (video tape recorders) and the like.

(b) Prior art The conventional circuit shown in Fig. 8 is, for example, the video tuner VRF-500 manufactured by Sanyo Electric Co., Ltd. and its AC back.
It is also stated in the "SANYO service technical data" published in April 1981 regarding VAR-500. This circuit is a power supply circuit 1 that selectively generates a constant voltage output mode and a constant current output mode.
(The specific structure is detailed in Japanese Patent Application No. 59-165376), a battery 2, a connecting means 3 for connecting the battery 2 and the power supply circuit 1, and a selection signal based on an external operation. It consists of an input terminal 4 and a charging signal generation circuit 5, and is additionally provided with a first switch circuit 6 with an overvoltage protection function and a second switch circuit 7 with an overcurrent protection function. The battery 2 is, for example, an assembled battery in which a plurality of sealed nickel-cadmium storage batteries are connected in series, and in the illustrated case, six 1.2V single cells are placed in _E1 and six in E2.
Four of them are connected in series to give a voltage capacity of 12V. Note that 8 is a breaker, which functions to prevent overcurrent. 9 is a thermostat connected between negative terminal 11 and terminal 12, and battery 2
Information on the full charge of the battery is provided to the charging signal generation circuit 5 through the connection terminal 15 coupled to the terminal 12. That is, when rapid charging is performed with a constant current of 1.3 amperes applied from the power supply circuit 1 through the second switch circuit 7 and the connection terminal 13, the internal temperature of the battery 2 rises rapidly when it is fully charged, and the battery 2 becomes bimetallic. Open the contacts of thermostat 9, so
The terminal 12 of the battery 2 is cut off from the negative terminal 11. In addition, after fully charging,
When quick charging is stopped, the internal temperature of battery 2 decreases and thermostat 9 closes the contact, so terminal 12
becomes the same potential as the negative terminal again. By the way, the thermostat 9 opens and closes the contacts at 45℃±5℃,
Also, the breaker 8 opens and closes the contacts at 80℃±5℃.

The power supply circuit 1 constantly generates a voltage at the sixth terminal 22 when the outlet 16 is connected to a commercial AC power source. Furthermore, when a high level is applied to the fourth terminal 20, a constant voltage is output to the second terminal 18, and the fifth terminal 20 outputs a constant voltage.
When a high level is applied to 1, the second terminal 18
Outputs constant current.

In the first switch circuit 6, when a high level is applied to the input terminal 4, the transistor _Q1 is turned on, and the transistors _Q2 and _Q3 are also turned on. A constant voltage is led to the output terminal 29 through the transistor _Q3 . The output terminal 29 is connected to, for example, a deck section of a VTR and supplies a constant power supply voltage to the deck section. Zener diode of first switch circuit 6
Z ₁ and Z ₂ act to prevent a voltage exceeding a certain value determined by these Zener voltages from being applied to the output terminal 29 even if the voltage applied from the power supply circuit 1 to the terminal 31 becomes abnormally large. . When a low level is applied to the input terminal 4 of the first switch circuit 6, the transistors Q ₁ , Q ₂ , and Q ₃ are all turned off, and no power is supplied to the output terminal 29 .

In the second switch circuit 7, when a low level is applied to the input terminal 4, a high level is applied from the ninth terminal 25 of the charging signal generation circuit 5 to the base of the transistor _Q4 through the terminal ₃₆ . , Q ₅ , and Q ₆ are turned on, and the constant current generated at the second terminal 18 of the power supply circuit 1 is passed through the transistor.
Lead out to terminal 37 through Q ₆ . This constant current is further applied to the connection terminal 13 and the positive terminal 1 of the connection means 3.
0 to the battery 2 as a charging current. Diode D ₁ of the second switch circuit 7,
D ₂ together with resistor R ₇ prevents overcurrent. That is, the base current of transistor Q ₆ is the same as that of diodes D ₁ and D ₂
(e.g. 1.2V) to the emitter-base voltage of transistor _Q5 (e.g.
0.6V) minus the voltage value 1.2V - 0.6V = 0.6V with resistance
Since it is determined by the value divided by _R7 , the excessive current input to terminal 34 passes through transistor _Q6 to terminal 3.
7 will not be output.

Next, with the connection terminals 13, 14, 15 of the connection means 3 connected to the terminals 10, 11, 12,
The charging signal generation circuit 5 operates when a high level or low level selection signal is given to the input terminal 4.
The explanation will focus on the function of

First, when a high level is applied to the input terminal 4, a high level is applied to the base of the transistor _Q7 through the 10th terminal 26, and the transistor
_Q7 turns on and transistor _Q8 turns off, so
The +12V power supply voltage applied from the sixth terminal 22 to the eighth terminal 24 of the power supply circuit 1 is connected to the transistor _Q8.
is not derived to the emitter side. Therefore, the ninth terminal 25 becomes low level and the transistor _Q4 is not driven, so the second switch circuit 7 is turned off and the battery 2 is not charged. At this time, by applying the high level of the input terminal 4 to the fourth terminal 20, a constant voltage is generated from the power supply circuit 1 to the second terminal 18, and this constant voltage is turned on by applying the high level from the input terminal 4. The signal is led out to the output terminal 29 through the first switch circuit 6 connected thereto. The constant voltage derived from this output terminal 29 is supplied to the VTR deck section connected to the output terminal 29.

Next, when a low level is applied to the input terminal 4, the transistor _Q7 of the charging signal generating circuit 5 is cut off, making the transistor _Q8 conductive. If you press the charging start button 38 in this state,
The seventh terminal 23 becomes the ground potential, and the eighth terminal 24
→ Transistor Q ₈ → Resistor R ₉ → Resistor R ₁₀ → Diode D When current flows through the path of ₃ , transistor Q ₈ is turned on, and transistor Q ₉ is turned on.
is also turned on. When the transistor Q ₉ is turned on, the transistor Q ₁₀ connected to the transistor Q ₉ by a thyristor is also turned on, so even if the charging start button 38 is released, the transistors Q ₈ , Q ₉ ,
The on state of Q ₁₀ is sustained. In this state, a high level is output from the collector of the transistor _Q9 to the ninth terminal 25. This high level is applied to the fifth terminal 21 of the power supply circuit 1, and as a result, a constant current is output from the second terminal 18. On the other hand, the high level of the ninth terminal 25 is also supplied to the second switch circuit 7, turning the second switch circuit 7 on, so that the constant current from the second terminal 18 passes through the second switch circuit 7. It will be supplied to battery 2. At this time, the first switch circuit 6 is turned off by the low level applied from the input terminal 4, and no power supply voltage is derived from the output terminal 29. The battery 2 is rapidly charged by supplying the constant current. When the battery 2 is fully charged, the thermostat 9 opens its contacts and the terminal 12 is disconnected from the negative potential (earth potential). For this reason,
The current flowing from the collector of transistor Q ₉ to resistor R ₁₄ → 12th terminal 28 → terminals 15, 12 → thermostat 9 → terminals 11, 14 → ground is cut off, and the current flowing from the collector of transistor Q ₉ to resistor R ₁₄ → diode _D5 → Current flows between the base and emitter of transistor _Q11 , turning on transistor _Q11 . By turning on this transistor _Q11 , the transistor
Q ₁₀ is turned off, and subsequently transistors Q ₈ and Q ₉ are also turned off, and the collector of transistor Q ₉ , and therefore the ninth terminal 25, becomes low level, turning off the second switch circuit 7. Therefore, charging of the battery 2 is stopped. Thereafter, even if the internal temperature of the battery 2 decreases, the thermostat 9 closes, and the terminal 12 returns to the ground potential again, the battery 2 will not be charged unless the charging start button 38 is pressed again.

During the charging operation described above, transistor Q ₁₄ is turned on and LEDD ₇ lights up to indicate that the charging operation is in progress.

If the charging voltage becomes abnormally high for some reason while charging the battery 2 mentioned above, the abnormally high voltage causes the Zener diode Z ₃ → diode D ₈ → resistor R ₁₇ → transistor to pass through the 11th terminal 27.
Current flows through the base and emitter of _Q11 , turning on transistor _Q11 , which turns on the transistor.
Q ₁₀ , Q ₉ , and Q ₈ are set to off and charging stops.
This protects the battery 2 from overvoltage.

On the other hand, if the charging voltage becomes abnormally low for some reason, when the charging voltage is normal, the current flows from the 11th terminal 27 to the Zener diode Z ₄ → resistor R ₂₂ → base-emitter of the transistor Q ₁₂ . The current flows from the collector of transistor Q ₉ to resistor R ₁₆ → diode _{D 6 →} base and emitter of transistor Q ₁₁ , and the transistor Q 12 is cut off.
Q ₁₀ , Q ₉ , and Q ₈ are cut off and charging stops. Therefore, the battery 2 is damaged and the positive terminal 10
This prevents charging from occurring when the negative terminal 11 is in the short state, when a metal box with the same shape as the battery 2 is connected to the battery connection terminal, or when the battery is intentionally short connected. do.

(c) Problems to be Solved by the Invention The conventional charging control circuit described above has the following drawbacks. First, when starting charging, the charging start button 38 must be pressed after the battery 2 is connected by the connecting means 3.
Second, if a high level is applied to the input terminal 4 during battery charging to cause the power supply circuit 1 to operate as a constant voltage power supply, the charging state is canceled, but then the input terminal 4
Even if the high level is removed from the battery and the battery is changed to a low level, charging will not occur and the charging start button 38 must be pressed again. In this way, the first
In either of the second cases, there is a drawback that a charging start button must be pressed when charging is to be started. The present invention overcomes these drawbacks.

(d) Measures to solve the problem: The structure of the connection means for connecting the battery to the power source is such that it can distinguish between incomplete connection and complete connection, and only when this connection means is a complete connection. means for creating a standby state for charging signal formation;
The configuration includes means for determining whether to remain in a standby state or to generate a charging signal based on a signal from an input terminal.

(E) Effect By completely connecting the battery with the connecting means, the charging signal generation circuit enters the standby state, and if a signal from a separate input terminal instructs charging, the standby state changes to the charging signal generation state. to move to. If the selection signal is not a charging instruction, the standby state remains.

(li) Embodiment In FIG. 1, in which the present invention is implemented, the same parts as in FIG. 8 are denoted by the same reference numerals, and redundant explanation will be omitted.

In Figure 1, negative terminal 1 of battery 2
The connecting terminals 14a and 14b are shorter than the other terminals 13 and 15, respectively. and the longer terminal 14
The terminal a is connected to the ground, and the shorter terminal 14b is connected to the standby forming means 40 via the thirteenth terminal 39 of the charging signal generating circuit 5. The standby forming means 40 is composed of transistors Q ₁₅ and Q ₁₆ which are turned on when the thirteenth terminal 39 is at ground potential, an N-gate thyristor S ₁ and transistors Q ₁₉ and Q ₂₀ . When the connecting means 3 is completely connected to the battery 2, the 13th terminal 39 becomes ground potential, and a current flows through the path of the 8th terminal 24 → resistor R ₂₄ → resistor R ₂₅ → 13th terminal 39, biasing the transistor Q ₁₅ . , so the transistor _Q15 becomes conductive. At this time, the capacitor C ₁ is charged with a time constant determined by its own capacitance and the value of the resistor R ₃₀ , so that the transistor Q ₁₆ becomes conductive in a triggered manner. The discharge path of capacitor C ₁ is capacitor C ₁ → → resistor R ₂₈ → diode
D ₁₁ → capacitor C ₁ . N gate thyristor
_S1 turns on when the gate potential is lower than the anode potential and the gate current is extracted from the gate.
Even if the gate current is subsequently cut off, the on state is maintained as long as the anode and cathode are forward biased. Turn-on of N-gate thyristor _S1 is (A)
Since the point is set to high level, transistor Q ₁₉ becomes conductive and current flows through the path from the 8th terminal 24 → resistor R ₄₁ → resistor R ₄₂ → collector-emitter of transistor Q ₁₉ , and transistor Q ₂₀ turns on and enters standby state. . At this time, when a low level (charging instruction signal) is applied to the input terminal 4, the transistor Q ₂₁ whose base is connected to the 10th terminal 26 is turned off, and both the transistor Q ₂₂ and the transistor Q ₂₃ are turned on. A high level is generated at the 9 terminal 25. When the ninth terminal 25 becomes high level, the battery 2 is charged as described in connection with FIG. At this time, as transistor Q ₂₂ turns on, LEDD ₇ also turns on to display charging.
When a high level is applied to the input terminal 4, the transistor Q ₂₁ is turned on, and therefore the transistors Q ₂₂ and Q ₂₃ are turned off. Therefore, the ninth terminal 25 becomes low level, and charging is not performed. The transistor _Q21 constitutes a determining means 41 that determines whether to remain in a standby state for generating a charging signal or to proceed to generating a charging signal depending on whether the selection signal applied to the input terminal 4 is at a high level or a low level.

Since the forward voltage drop of the N-gate thyristor _S1 is sufficiently large compared to the conduction voltage between the collector and emitter of the transistor, the N-gate thyristor _S1
can be turned off by turning on transistor _Q17 . transistor
_Q17 is turned on in various cases.

The first case is when the terminal 12 of the battery 2 is disconnected from the ground potential. That is, in this case, resistor R ₄₀ → diode D ₁₄ → resistor R ₃₉ → transistor
Current flows through the base-emitter path of _Q17 , turning on transistor _Q17 . This means that when battery 2 is rapidly charged and reaches full charge, thermostat 9 opens its contacts and transistor Q ₁₇
This means turning on and stopping charging.
Transistor Q ₁₇ is turned on by N-gate thyristor S ₁
This is because it turns off and prevents the creation of a charging signal. At this time, even if the terminal 12 returns to the ground potential again, the charging will continue to stop unless the battery is inserted and removed from the connecting means 3 again and a trigger-like gate current is applied to the gate of the N-gate thyristor _S1 .

Second, when the short connecting terminal 14b of the connecting means 3 is disconnected from the negative terminal 11, the thirteenth terminal 39 floats, so that the transistor _Q15 is turned off. The connection point B between resistors R ₂₆ and R ₂₇ is a transistor
The transistor is connected to the base of _Q18
As Q ₁₅ turns off, transistor Q ₁₈ also turns off, and resistor R ₃₇ → diode D ₁₂ → transistor Q ₁₇
Current flows through the base-emitter path of Q17, turning on transistor _Q17 and stopping charging.

The circuit composed of C ₂ , D ₈ , and Z ₃ is exactly the same as the circuit shown in FIG. 8, and stops charging the battery 2 when the charging voltage becomes abnormally high.

The operation of the circuit consisting of Z ₄ , D ₁₀ , C ₃ , R ₂₂ , R ₂₁ , Q ₁₂ , R ₃₈ and D ₁₃ is the same as in Figure 8, and when the charging voltage becomes abnormally low, Stop charging.

However, in order to reliably start charging a fully discharged battery, the resistor R ₄₀ → diode
Charging is enabled by charging the capacitor C ₃ along the path D ₁₅ → capacitor C ₃ and turning on the transistor Q ₁₂ to set the anode of the diode D ₁₃ to approximately 0V. That is, in this state, the connecting means 3 is connected to the fully discharged battery, and the transistors Q ₁₅ ,
With Q ₁₈ on, if capacitor C ₃
If there is no charge or if it is not charged, the abnormally low voltage at the 11th terminal 27 will turn off the transistor Q12, and the transistor _Q12 will be turned off.
Q ₁₇ turns on (charge blocking state).
By charging capacitor C ₃ in advance as described above, transistor Q ₁₇ is ensured to be turned off (and therefore on standby for charging). Note that this requires that a low level is applied to the input terminal 4 at the beginning of the standby state to quickly create a charging signal, but generally the input terminal 4 is normally set to a low level. So no problem.

Next, to describe the embodiment for an 8m/m VTR, as shown in Fig. 2, the battery 2 can be attached to the deck part 42 of the VTR, and Fig. 2 a shows the installation in progress, and Fig. 2 b shows the installation complete state. . As shown in FIG. 3, the battery 2 is placed on the mounting table 44 together with the power supply section 43 while being integrated with the deck section 42.
At this time, the deck section 42 and the power supply section 43 are connected by an insertion/removal connection structure. AC outlet 16
When plugged into a power source, the input terminal 4 in Figure 1 goes to low level, charging starts, and the display shows that on the display 4.
It is done in 5. When the battery is fully charged, charging ends and the display disappears. When the operation button 46 of the deck part 42 is pressed, the first
Input terminal 4 in the figure becomes high level, and charging is not performed. Instead, a constant voltage power source is supplied from the output terminal 29 to the deck section 42, and the deck section is brought into operation. Note that the figure only shows the relevant operation buttons 46, and in reality, various buttons are provided according to the operational functions of the deck section 42. The power supply section 43 is usually equipped with a tuner, a timer, and the like. FIG. 4 shows a mode in which the battery 2 is charged alone, and shows the process of connecting the connecting means 3 to the battery 2. When connecting battery 2 alone as shown in Figure 4, input terminal 4 in Figure 1
is always at a low level.

FIG. 5 shows a side view of the connecting means 3 of FIG.

In Figure 6, the terminal on the battery 2 side is shaped like a plug,
The terminals on the connection terminal side are socket-shaped terminals 51, 52,
This indicates that it may be set to 53 or 54. In this case, the plug-shaped terminals 47 and 4 are attached to the deck portion 42.
8, 49, and 50, however, plug-shaped terminals may be provided directly on the battery 2. still,
The standby means 40 of FIG. 1 may be configured as shown in FIG. ₇ without using the N-gate thyristor S1.

Returning to the embodiment of FIG. 1, the battery 2 must be securely connected by the connecting means,
For example, if even one of the four terminals becomes disconnected, charging will stop. Furthermore, in order to start charging, connect the connecting terminals 13, 14a, 15 to the positive terminal 10, negative terminal 11, terminal 12 of the battery 2 securely, and then connect the connecting terminal 14b to the negative terminal 11 of the battery 2. There must be. If the connecting terminal 14b is long and contacts the negative terminal 11 first and the trigger is activated and the N-gate thyristor _S1 is turned on, the other connecting terminals 13, 14a, 15
If even one of them is disconnected, N gate thyristor S ₁
This is because it becomes a turn-off. Therefore, the connecting terminal 14b is formed to be the shortest.
Note that the length of the connection terminal 14b is determined in consideration of the tolerance of the battery connection angle.

(G) Effects of the Invention The present invention has the advantage that charging can be performed as long as the battery is completely connected by setting the input terminal to a charging instruction state, thereby eliminating the trouble of providing a separate charging start button and the like. can be resolved. Furthermore, even if the input terminal is configured to receive a signal that selects the charging instruction state and another state, the instruction signal for the other state may be applied to the input terminal during the charging operation, causing charging to occur. After stopping, if a charging instruction signal is applied to the input terminal again, charging can be restarted.

[Brief explanation of the drawing]

FIG. 1 is a specific circuit diagram of a charging control circuit embodying the present invention, FIGS. 2, 3, and 4 are explanatory diagrams thereof, FIG. 5 is a detailed diagram of a part thereof, and FIG. This figure is a diagram showing a different embodiment of a part of FIG. 1, and FIG. 7 is a circuit diagram showing a different embodiment of a part of FIG. 1. FIG. 8 is a specific circuit diagram of a conventional charging control circuit. 1...Power circuit, 2...Battery, 3...Connection means,
4... Input terminal, 5... Charging signal creation circuit, 40... Standby forming means, 41... Determining means.

Claims (1)

[Claims] 1. A power supply circuit that outputs constant current, a battery,
a connecting means for coupling the power supply circuit and the battery; an input terminal to which a charge instruction signal is applied; a charge signal generation circuit; and a charge generated from the charge signal generation circuit based on the charge instruction signal applied to the input terminal. In the charging control circuit that applies a constant current to the battery from the power supply circuit in response to a signal, the connection means has a plurality of connection terminals with different structures, and the connection terminals determine incomplete connection and complete connection. The charging signal generation circuit includes means for creating a standby state for forming a charging signal only when the connection terminal is fully connected, and a means for maintaining the standby state by a signal from the input terminal;
A charging control circuit comprising means for determining whether a charging signal is to be generated.