JP2727624B2 - Charging device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in the following order.

A Industrial application field B Outline of the invention C Conventional technology (Fig. 4) D Problems to be solved by the invention (Figs. 4 and 5) E Means for solving the problems (Fig. 1) F) Action G Example (FIGS. 1 to 3) (G1) First Example (FIGS. 1 and 2) (G2) Second Example (FIGS. 1 and 3) (G3) Other Embodiments H Effects of the Invention A Industrial Field of the Invention The present invention relates to a charging device, and in particular, automatically detects when a battery to be charged is attached or detached (this is referred to as battery detachment), and performs charging. It's something you can start with.

B. Summary of the Invention In the present invention, the charging / discharging state of a battery is detected on the basis of a detected current power supply obtained from a secondary winding of a switching transformer, so that the overall configuration is complicated and complicated. Battery charging can be started automatically with high detection sensitivity without increasing the size.

C. Prior Art In this type of charging device, a device has been devised to enhance the safety by making it possible to output a charging output only when a battery to be charged is connected to a battery connection terminal. Conventionally, a circuit having the configuration shown in FIGS. 4 and 5 has been used as a circuit for detecting battery attachment / detachment.

In the charging device 1 shown in FIG. 4, the battery 2 to be charged is connected to the ground terminal 3N (ground line LN) of the charging device main body 3.
Is connected to the battery connection terminal 3P, and the battery 2 is charged by flowing a charging current I _CHG from the battery connection terminal 3P to the ground terminal 3N through the battery 2 when the battery 2 is mounted. I do.

When the battery 2 is detached from this mounted state, the battery 2 is electrically disconnected from the terminals 3N and 3P, so that the terminals 3N and 3P are opened, so that the charging current I
_CHG is not supplied.

The charging device main body 3 is a switching regulator circuit unit 5
And a rectifying circuit 8 rectifies a commercial AC power supplied through a connector 6 through a filter 7, and controls a switching DC current I ₁ of the rectifying circuit 8 by a switching transistor 9. The switching transformer 9 is supplied to the primary winding N1 of the switching circuit 10 and the switching transistor 9 is controlled by a pulse width control circuit 11 to control the switching.
10 supplies a switching-output current I ₂ generated in the secondary winding N2 to the diode 12 and the main current output circuit 14 of the rectifier circuit arrangement consisting of a capacitor 13.

As a result, two ends of the capacitor 13 of the main current output circuit 14
Main circuit power supply having a power supply voltages V ₁ to the voltage across V ₀ formed by averaging the winding N2 is formed, the main current I ₃ from the main circuit power supply
To the battery connection terminal 3P through the battery mounting detection circuit 15.
As charging current I _CHG .

In the case of FIG. 4, the battery mounting detection circuit 15 has a comparison circuit 16 in the form of an operational amplifier circuit, and the voltage dividing resistors 17, 1 connected in series between the output terminal of the main current output circuit 14 and the ground line LN.
Together provide the non-inverting input of the comparator circuit 16 a divided voltage obtained at the connection midpoint P1 between the resistor 18 and 19 of 8 and 19 as a reference potential V _2, the connection point P2 between the resistor 17 and 18 Series resistance
At the same time as connecting to the inverting input terminal 21 via 20 and 21,
The connection point P3 between the resistors 20 and 21 is connected to the battery connection terminal 3P.

Identification output signals S ₁ of the comparator circuit 16 is given as on-off control signal to the main current switch circuit 22 provided at both ends of the resistor 17 to the side passage.

In the configuration of FIG. 4, the resistor 20 while operating as Batsuteri attachment detection element by flowing detected current I ₄ to be part of the mounting when the charging current I _CHG in response to the mounting or desorption state of Batsuteri 2 Thus, no current flows when the battery 2 is detached, so that the potential at the inverting input terminal of the comparison circuit 16 changes according to the state of attachment or detachment of the battery 2.

That is, when the battery 2 is detached, the detection current I ₄
By does not flow, sends an identification output signals S ₁ such as the potential of the non-inverting input terminal and inverting input terminal is off operation of the main current switch circuit 22 as an identification output signals S ₁ by approximately equal comparison circuit 16 You are in a state to do.

When the battery 2 is mounted in this state, the charging current I _CHG flows through the battery 2, and accordingly, the detection current I ₄ flows through the resistors 17 and 20 in response to the charging current I _CHG . When the potential difference between the non-inverting input terminal and the inverting input terminal increases, a potential difference exceeding the threshold of the comparison circuit 16 is applied. In this case the discrimination output signals S _1, such as to a main current switch circuit 22 on operation from the comparator circuit 16 is generated, the main current switch circuit 22
The main current I ₃ flows through the battery 2, whereby the charging current I _CHG is supplied to the battery 2.

In this case the detection current I ₄ flowing through the resistor 20 increases in the order of the main current I _3, the operating state of the slave connexion comparator circuit 16, a state slave connexion identification output signals S ₁ is obtained by the ON operation of the main current switch circuit 22 maintain.

Thus, according to the configuration of FIG. 4, it is possible to obtain the charging device 1 that automatically detects the battery 2 when the battery 2 is mounted and starts charging.

D Problem to be Solved by the Invention However, according to the configuration of FIG. 4, it is unavoidable to insert the resistor 20 as the battery mounting detection element into the main circuit for extracting the main current I ₃ as the charging current I _CHG. In addition, when the charging current I _CHG becomes small due to the charging characteristics of the battery 2, a malfunction may occur.

Incidentally, the charging current I _CHG to be actually supplied to the battery 2 is 1.
Since about 0 to 1.2 [A] is required, the resistance value of the resistor 20 can be increased from the viewpoint of sufficiently suppressing the heat generation of the resistor 20 for practical use and not increasing the voltage drop at the resistor 20 too much. Instead, it is practically selected to be about 0.05 [Ω].

In this case, the detection current corresponding to the threshold level of the comparison circuit 16 (that is, the detection current flowing through the resistor 20)
I ₄ ) is about 0.4 [A], and when the charging current I _CHG falls below the threshold current value due to the charging characteristics of the battery 2, the comparison circuit 16 determines that the battery 2 is attached even though the battery 2 is mounted. There is a possibility that it is erroneously detected as a non-attached state (ie, a detached state).

When the battery 2 to be charged is an old battery or when a battery in an overdischarged state or a fully charged state is attached, the value of the charging current I _CHG decreases to about 0.4 [A] or less. Can occur.

As a method of improving such erroneous detection, a method of winding the auxiliary winding N3 for a battery mounting detection circuit as a tertiary winding of the switching transformer 10 as shown in FIG.

In FIG. 5, in which parts corresponding to those in FIG. 4 are assigned the same reference numerals, one end of the auxiliary winding N3 is connected to the output end of the capacitor 13 of the main current output circuit 14, and the other end is connected to a diode.
Battery mounting detection power supply circuit consisting of 25 and capacitor 26
27, thereby supplying the charging voltage of the capacitor 26 to the battery mounting detection circuit 15 as a power output.

This power supply output is divided by the voltage dividing resistors 28 and 29,
Voltage of a connection point P4 of the resistors 28 and 29 is supplied as a reference voltage V ₂ to the non-inverting input of the comparator circuit 16.

In addition to this, the power output is connected to the battery connection terminal 3P of the charging device main body 3 sequentially through the resistor 30 as a mounting detection element and the coupling diode 31, and the connection midpoint P5 of the resistor 30 and the diode 31 is connected. Comparison circuit through resistor 32
Connected to 16 inverting inputs.

In this case, the main current obtained at the output terminal of the main current output circuit 14
I ₃ is the main current switch circuit 22 is connected to the Batsuteri connecting terminals 3P via coupling diode 33, thus when the main current switch circuit 22 identifies the output signal S ₁ is generated is turned on, the main current I ₃ is the charging current It is supplied to Battery 2 as I _CHG .

In the configuration of FIG. 5, the battery mounting detection power supply circuit 27 is used.
Batsuteri the power supply input voltage V _3, the value of piled voltage across V ₄ of the power supply voltages V ₁ to the auxiliary winding N3 of the output circuit 14 based on the earth line LN, thus the Batsuteri connecting terminals 3P and ground terminal 3N when wearing the 2, the even charging current I _CHG for Batsuteri 2 drops example to a level 0.4 [a], the current value of the detected current I ₅ flowing through the resistor 30 as a mounting detection device which the independently Can be selected. By the way,
In this case the resistor 30 is because not inserted the main current I ₃ in the main current circuit for supplying the Batsuteri 2.

Accordingly, the mounting detection element 30 can be selected to have a remarkably large value of, for example, about several hundred [Ω], and the resistance in the case of FIG.
20 can be selected about 10 ⁴ times the resistance value compared to 0.05 (Ω), and the detection current I ₅
Can be selected to be a small value.

Be lowered accordance connexion Batsuteri 2 during charging current I _CHG is extremely worn, it is possible to obtain a detection current I ₅ which may vary correspondingly while having practically sufficient margin accordance connexion comparator circuit 16 Can be effectively avoided.

However, according to the configuration of FIG. 5, the auxiliary winding N3 is connected to the switching transformer 10 of the switching regulator circuit unit 5.
It is necessary to provide a switching transformer
There is a problem that the configuration of 10 is large and complicated.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has been made by making it possible to obtain a battery mounting detection power supply output from a secondary winding of a switching transformer for supplying power to a main current circuit. It is an object of the present invention to propose a charging device which eliminates the need for providing an auxiliary winding in a switching transformer.

In the present invention for solving means above problems to solve E problems, rectifies the switching-output obtained from the secondary winding N2 of when to quenching transformer 10 to obtain the primary current I _3, the main current in the charging apparatus 1 for charging a Batsuteri 2 mounted on Yotsute Batsuteri connecting terminals 3P to I _3, to form a detection current power output S13 with a potential higher than the potential of the main current I ₃ from the secondary winding N2, Batsuteri and Batsuteri mounting detection circuit 35 for detecting the mounting or detaching of the detected current I ₁₁ I connexion Batsuteri 2 to whether flowing through the connection Batsuteri 2 attached to the terminal 3-Way, according to the detection output of the Batsuteri mounting detection circuit 35 to be provided a main current switch circuit 22 to deliver the main current I ₃ to Batsuteri connection terminal 3-way.

By the from F acts secondary winding N2 so as to form a sensing current source output S13 with a potential higher than the potential of the main current I _3,
Batsuteri the detection current I ₃ can practically sufficiently small to flow through 2, it is possible to detect the mounting or detaching of Batsuteri 2 with high accuracy without being affected by the charging characteristics of the resulting Batsuteri 2.

G Example Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

(G1) First Embodiment In FIG. 1, parts corresponding to those in FIG. 5 are denoted by the same reference numerals, and a switching transformer 10 of a switching regulator circuit unit 5 is used as a detection current power supply for a battery mounting detection circuit 35. Is used.

That is, the output signal S11 obtained at the non-earth side end of the secondary winding N2 is connected to the anode side to the earth line LN through the DC cut capacitor 36, and a clamping diode.
It is connected to the cathode of 37, thereby constituting a clamp circuit 38.

The clamp output signal S12 obtained at the output terminal of the clamping diode 37, that is, the cathode, is connected to the rectifying diode 39.
Is connected to the other end of the peak holding capacitor 40 having one end connected to the ground line LN, thus forming the peak rectifier circuit 41.

Thus, a detection current power supply output S13 is obtained at the output end of the peak holding capacitor 40, that is, the non-earth side end, and this is connected to the battery as a battery mounting detection constant voltage power supply output S14 through the constant voltage circuit 44 including the resistor 42 and the Zener diode 43. It is supplied to the detection resistor 50 and the transistor 51.

The transistor 51 is formed of a PNP type bipolar transistor, and receives the constant voltage power supply output S14 at its emitter, through a resistor 50 connected between the emitter and the base, further through a semi-fixed resistor 52, and a coupling diode 53 to a battery connection terminal 3P. It is made to supply.

Thus whereas Batsuteri bonding detection resistor 50 to detect current I ₁₁ is a transistor 51 when no flow is to detecting a state ,, Batsuteri 2 is not mounted by operating off detection resistor 50 transistor 51 when the current I ₁₁ flows is by turning on operation, thereby detecting a Batsuteri mounted state.

The collector of the transistor 51 is connected to the control output circuit 54, and sends an on-control signal S15 to the main current switch circuit 22 when the transistor 61 is turned on.

In the above configuration, the voltage V ₀ as when to quenching transistor 9 and the potential between the non-grounded end to the secondary winding N2 which are turned on increases of when to quenching the regulation Yoo regulator circuit 5 is generated (FIG. 2A), this charges the capacitor 13 via the diode 12 as the output signal S11, thereby generating the main circuit power supply output signal S0 of the main rectifier circuit 14.

In contrast when to quenching transistor 9 the voltage V _B of the reverse voltage V ₀ generated between secondary winding N2 of the current of the primary winding N1 by operating off decreases, the voltage
V _B is the main rectification by being by connexion blocked by the diode 12 of circuit 14 can not discharge the capacitor 13, thus the main rectifier circuit 14 a reference potential ground line LN to the output terminal of the (= 0 V) Main power supply of voltage V ₀ is maintained as
Which forms a main current source for flowing a main current I _3.

Clamp circuit 38 of Batsuteri mounting detection circuit 35 when the voltage V _B generated against which the clamp output signal S12 (FIG. 2 (B)) through the clamping diode 37 to ground potential. At the same time the voltage V _B is clamping diode
The DC cutting capacitor 36 is charged with a polarity such that the potential of the clamping diode 37 becomes higher through 37.

When switched to a state for generating a voltage V ₀ when to quenching transistor 9 from this state again and turned on, the potential of the output signal S11 of the secondary winding N2 is raised by potential V ₀ which, based on the earth line LN (FIG. 2 (a)), thereby the output signal S12 (FIG. 2 (B)) is the voltage V _B further potential V ₀ which had been charge DC Katsuhito capacitor 36 of the clamp circuit 38
It is raised to the potential V ₀ + V _B just pushed up.

In this state, the clamping diode 37 is off, and thus the grounding line is
An output signal S12 having a potential of V ₀ + V _{B based on} the potential of LN (= 0 [V]) is supplied to the peak rectifier circuit 41.

At this time, the peak rectifier circuit 41 holds the peak potential V ₀ + V _B in the capacitor 40 via the rectifying diode 39, thereby generating a DC output signal S13 having the potential (FIG. 2 (C)).
Is output.

In this way, the battery mounting detection circuit 35 outputs a voltage from the peak rectification circuit 41 to the voltage source having a potential (= V ₀ + V _B ) higher than the potential (= V ₀ ) of the main circuit power supply output signal S0 obtained from the main rectification circuit 14. can form, it can be supplied to the constant voltage signal S14 through the constant voltage circuit 44 from the voltage source having the high potential to the transistor 51 and the resistor R ₅₀ as Batsuteri mounting detection device.

Since the battery mounting detection transistor 51, which is a bipolar transistor, is a bipolar transistor, the emitter-to-base voltage must be equal to the forward voltage V _BE (= 0.7 V ])

The battery mounting detection resistor 50 must satisfy this condition.
The current I _{11 to} be applied to Can be expressed as Wherein R ₅₀ is represents the resistance value of Batsuteri mounting detection resistor 50.

In equation (1), the forward voltage V _BE is actually V _BE = 0.7
[V], and the resistance value of the battery mounting detection resistor 50
If R ₅₀ is selected to be R ₅₀ = 1 × 10 ³ [Ω], the limit value of the current I required for the battery mounting detection transistor 51 to perform the detection operation is almost the following equation. As shown in the above, only about 0.7 [mA] is required.

Therefore, the detection current I ₁₁ flowing in Batsuteri mounting detection resistor 50 when Batsuteri 2 is attached between terminals 3P and 3N,
Due to the charging characteristics of the battery 2, even if the potential of the main circuit power supply output signal S0 supplied from the main current circuit rises to near the potential (= V ₀ ), the current value of the detection current is sufficiently small for practical use. Therefore, it is possible to obtain a detection current that changes with a change width corresponding to the mounting or detaching state of the battery 2 while still having a sufficient margin, and thus a battery mounting detecting operation with high detection sensitivity can be realized.

In this way, since it is not necessary to add an auxiliary winding to the switching transformer 10, the overall configuration can be prevented from being complicated and large.

In addition, according to the configuration shown in FIG. 1, a power output for detecting battery mounting is obtained via the constant voltage circuit 44, so that a more stable battery mounting detection result can be obtained.

(G2) Second Embodiment FIG. 3 shows a configuration in which the charging device 1 is
This shows a second embodiment that can be used as a component device constituting one electronic device system.

In FIG. 3 in which the same reference numerals are given to the parts corresponding to FIG. 1, a main current switch circuit 22 having a battery charge switching output terminal T1 and a related equipment switching output terminal T2 is used. While the main current switch circuit 22 is switched to the battery charge switching output terminal T1 when the control signal ST15 indicating the battery mounting state is obtained, the main current switch circuit 22 is detected when the battery output state is detected in the control output circuit 54. Is switched to the related equipment switching output terminal T2 side, so that the main circuit current output signal S0 obtained at the output terminal of the main rectifier circuit 14 is transmitted to the power output terminal 3W via the related equipment switching output terminal T2. I have.

In the case of this embodiment, for example, an external control signal S21 is supplied from the system controller of the electronic equipment system to the control output circuit 54.
The selection of the switching output terminal of the main current switch circuit 22, the switching operation timing and the like can be controlled by the external control signal S21.

In the configuration shown in FIG. 3, when the battery 2 is mounted, the control output circuit 54 switches the main current switch circuit 22 to the battery charge switching output terminal T1 side so that the main rectification circuit 14
Main circuit power supply output signal S0 is through Batsuteri charging switching output end T1 of, sent further via the coupling diode 32 to Batsuteri connection terminal 3-Way, thereby the Batsuteri 2 can be by connexion charging the main current I ₃ .

On the other hand, when the control output circuit 54 detects that the battery 2 is in the detached state, the main current switch circuit 22 is switched to the related equipment switching output terminal T2 side, so that the main circuit current output signal S0 is supplied to the power supply output terminal. Sent to 3W.

Actually, a power cable of an electronic device such as a video tape recorder is connected to the power output terminal 3W, and thus the charging device 1 operates as a power adapter for the video tape recorder.

According to the configuration of FIG. 3, in addition to being able to obtain the same effects as described above with reference to FIG.
When the battery is not in the battery charging operation state, it can be operated as a power adapter for the related equipment, and the function of the charging device can be multifunctional.

(G3) Other Embodiments (1) In the above-described embodiment, the case where the present invention is applied to the charging device configured to charge one battery has been described. However, the case where a plurality of batteries are simultaneously charged is described. The battery mounting detection circuit 15 may be connected to the secondary winding N2 of the switching transformer 10 for each battery.

(2) In the embodiment shown in FIG. 3, the operating condition at which the main current switch circuit 22 switches to the related equipment switching output terminal T2 side is determined by the external control signal S21 supplied to the control output circuit 54. However, in some cases, in addition to this, the control condition for switching to the battery charge switching output terminal T1 may be determined by the external control signal S21.

(3) In the above embodiment, the charging current I _CHG is obtained through the constant voltage circuit 44. However, the constant voltage circuit 44 may be omitted if necessary.

H Advantageous Effects of the Invention As described above, according to the present invention, a power supply output having a higher potential than the main circuit power supply output signal can be obtained as a power supply for the battery mounting detection circuit without winding a new auxiliary winding on the switching transformer. It is necessary to detect the battery installation or detachment state with high accuracy without being affected even if the battery voltage rises abnormally based on the battery's charging characteristics in practice. A charging device that can start charging in accordance with (1) can be easily obtained.

[Brief description of the drawings]

FIG. 1 is a connection diagram showing an embodiment of the charging device according to the present invention, FIG. 2 is a signal waveform diagram for explaining the operation thereof, FIG.
FIGS. 4A and 4B are connection diagrams showing a second embodiment of the present invention.
FIG. 1 is a connection diagram showing a conventional configuration. DESCRIPTION OF SYMBOLS 1 ... Charging device, 2 ... Battery, 3 ... Charging device main body, 5 ... Switching regulator circuit part, 22 ... Main current switch circuit, 35 ... Battery attachment detection circuit, 38 ...
... Clamp circuit, 41 ... Peak rectification circuit, 44 ... Constant voltage circuit, 50, 51 ... Battery mounting detection resistor, transistor.

Claims (1)

(57) [Claims] 1. A charging device for rectifying a switching output obtained from a secondary winding of a switching transformer to obtain a main current and charging a battery mounted on a battery connection terminal with the main current. A detection current power supply output having a potential higher than the potential of the main current is formed from the next winding, and the attachment or detachment of the battery is detected based on whether or not the detection current flows through the battery attached to the battery connection terminal. A battery charger comprising: a battery mounting detection circuit; and a main current switch circuit that sends the main current to the battery connection terminal according to a detection output of the battery mounting detection circuit.