JP2001119861A - Power unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control and verify the mode of an AC/DC switching power circuit and the state of a switch circuit. SOLUTION: An AC/DC switching power circuit 11 is supplied with a commercial power source via a terminal Ti. The power circuit 11 is controlled by a microcomputer 12. The output of the power circuit 11 is supplied to one hand of a terminal To via a switch circuit Sa, and also is supplied to the positive side of a secondary battery BT via a switch circuit Sb. The other side of the terminal To and the negative side of the secondary battery BT are grounded. The microcomputer 12 properly selects either the charge mode for outputting the power voltage for charging the secondary battery BT or the supply mode for outputting the power voltage to an external portable electronic apparatus, and the power circuit 11 is controlled. Moreover, the microcomputer 12 detects the states of switching circuits Sa and Sb, and also controls the switching circuits Sa and Sb.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a switching power supply for outputting a power supply voltage and a power supply unit capable of preventing a malfunction of a switch circuit.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 12, a role of a so-called AC adapter for supplying power to a portable electronic device 111, a main body having a secondary battery, and a portable power source using the secondary battery as a power source. Power supply unit 11 for supplying power to electronic equipment
There are two. The power supply unit 112 is provided with a connector to which a power cable 113 for obtaining commercial power and a cable 114 for supplying power to the portable electronic device 111 can be connected.

[0003] The electrical characteristics of the power supply unit differ between when it is used as a charger for charging a secondary battery and when it is used as an AC adapter. That is, when the power supply voltage is supplied to the portable electronic terminal,
The voltage and the current when charging the secondary battery are different. further,
Since the battery temperature characteristics are different, they cannot be used with the same electrical characteristics.

At this time, if a malfunction occurs, for example, when the power supply unit is operating in a charging mode for charging an internal secondary battery and the power supply voltage is supplied to an external portable electronic device, Or, when the power supply voltage is supplied to the internal secondary battery while the power supply unit is operating in the supply mode for supplying the power supply voltage to the external portable electronic device, the external portable electronic device or the internal This has a bad effect on secondary batteries. In particular, when the voltage difference or the current difference between the charging mode and the supply mode is large, the external portable electronic device and the internal secondary battery are adversely affected.

[0005]

However, in the prior art, a circuit which controls only the mode of the AC / DC switching power supply circuit by the control circuit and confirms which mode is operating to prevent malfunction is provided. There was no problem.

Accordingly, it is an object of the present invention to check the mode of a voltage conversion means such as an AC / DC switching power supply circuit, and also to check the state of a switch circuit, thereby preventing a malfunction. A power supply unit is provided.

[0007]

According to a first aspect of the present invention, there is provided a power supply unit for outputting a predetermined power from a commercial power supply, a power supply mode for supplying power to a load, and a power supply to a secondary battery. And a switch connected between the voltage converter and the load and the secondary battery, the state of which is switched according to the supply mode or the charging mode. Means for comparing the result of detecting the mode of the voltage conversion means with the result of detecting the state of the switch means, and confirming whether or not they match, and according to the result of detecting the state of the switch means. And a control means for controlling the state of the voltage conversion means.

According to a third aspect of the present invention, in a power supply unit for outputting a predetermined power from a commercial power supply, a supply mode for supplying power to a load and a charging mode for supplying power to a secondary battery are provided. Mode, and a voltage conversion unit that can be switched between a precharge mode that supplies a low-voltage low-current power supply, and a voltage conversion unit that is connected between the voltage conversion unit and the load and the secondary battery, and that is connected to the mode of the voltage conversion unit. A switch means for switching the state of the switch means, a result of detecting the mode of the voltage conversion means and a result of detecting the state of the switch means, and a confirmation means for confirming whether or not they match, And control means for controlling the state of the voltage conversion means in accordance with the result of detecting the state of the switch means, when the state of the switch means is not in either the supply mode or the charge mode. Or when the state of the switch means does not match the mode of the voltage conversion means, a power supply unit, characterized in that as the pre-charging mode is outputted from the voltage conversion means.

[0009] A voltage conversion means, for example, a switching mode of an AC / DC switching power supply circuit is controlled to appropriately switch between a charging mode for charging an internal secondary battery and a supply mode for supplying a power supply voltage to an external electronic device. . At this time, the mode in which the AC / DC switching power supply circuit is operating is detected, and the state of the switch circuit suitable for the detected mode is controlled. Further, the state of the switch circuit is detected, and the mode of the AC / DC switching power supply circuit is controlled in a mode suitable for the detected state of the switch circuit.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a schematic configuration of an embodiment to which the present invention is applied. Commercial power is supplied to the AC / DC switching power supply circuit 11 via the terminal Ti. The AC / DC switching power supply circuit 11 is controlled by a microcomputer (microcomputer) 12. The output of the AC / DC switching power supply circuit 11 is supplied to one of the terminals To via the switch circuit Sa and to the + side of the secondary battery BT via the switch circuit Sb. The other terminal To and the negative side of the secondary battery BT are grounded.

The microcomputer 12 includes, for example, a charging mode for outputting a power supply voltage for charging the secondary battery BT, a terminal T
The switching operation of the AC / DC switching power supply circuit 11 is controlled by appropriately selecting one of the supply modes in which the power supply voltage is output from o to the portable electronic device. Further, the microcomputer 12 controls on / off of the switch circuits Sa and Sb and detects the states of the switch circuits Sa and Sb.

A first embodiment of the present invention will be described with reference to a block diagram shown in FIG. Hereinafter, the same blocks as those in FIG. 1 described above are denoted by the same reference numerals, and description thereof will be omitted. The output of the AC / DC switching power supply circuit 11 is
It is supplied to the detection control circuit 21. The detection control circuit 21 detects a voltage and a current output from the AC / DC switching power supply circuit 11. The AC / DC switching power supply circuit 11 is controlled such that the detected voltage and current match the reference voltage and reference current in the charging mode or the supply mode.

The detection control circuit 21 includes a switch circuit 24
, The reference voltage and the reference current in the charging mode are supplied from the charging mode setting unit 22. Similarly, a reference voltage and a reference current in the supply mode are supplied from the supply mode setting unit 23 to the detection control circuit 21 via the switch circuit 24.

The switch circuit 24 is controlled by a control circuit 25. The state of the controlled switch circuit 24 is
The confirmation is performed by the confirmation circuit 28. The confirmed state of the switch circuit 24 is supplied from the confirmation circuit 28 to the control circuit 25.

An ON signal from an ON signal section 26 is supplied via a switch circuit 27, and is supplied to a switch circuit Sa or S.
b is turned on. The switch circuit 27 is controlled by the control circuit 25. The state of the controlled switch circuit 27 is confirmed by the confirmation circuit 28. The state of the confirmed switch circuit 27 is transmitted from the confirmation circuit 28 to the control circuit 25.
Supplied to

The check circuit 28 checks whether the state of the switch circuit 24 and the state of the switch circuit 27 match. When the check circuit 28 determines that the state of the switch circuit 24 does not match the state of the switch circuit 27, the control circuit 25 checks the state of the switch circuit 24 and then controls the state of the switch circuit 27. You may do it. When the check circuit 28 determines that the state of the switch circuit 24 does not match the state of the switch circuit 27, the control circuit 25 checks the state of the switch circuit 27 and then controls the state of the switch circuit 24. You may do it.

FIG. 3 shows a circuit configuration corresponding to the first embodiment of the present invention. AC / DC switching power supply circuit 1
Reference numeral 1 includes an input rectification unit, a switching unit, a control unit, and an output rectification unit.

The input rectifier comprises a diode bridge 31 and a capacitor 32. In the input rectifier, the commercial power supplied from the terminal Ti is rectified. The switching unit is an n-channel type MOSFET 35,
It comprises a parasitic diode 35a, a resistor 36 and a transformer 37. In this switching section, MOSFET
By turning on / off (switching) the switch 35, a voltage and a current corresponding to the duty ratio of the switching signal supplied to the gate of the MOSFET 35 are output to the secondary side of the transformer 37.

The control section comprises a resistor 33, a PWM (pulse width modulation) circuit 34, and a photocoupler 38.
This control unit, according to the voltage and current generated on the secondary side,
The switching unit is switched at a duty ratio such that a desired output voltage / output current is generated. The output rectifier includes a diode 41 and a capacitor 42. The output rectifier is provided on the output side of the switching unit, and rectifies the voltage and current output by switching.

The detection control circuit 21 comprises a voltage detecting section and a current detecting section. The voltage detection unit includes resistors 43 and 4
4. It comprises a zener diode 45 and an operational amplifier circuit 46. The current detection unit includes resistors 47, 48, 49,
50 and 51 and an operational amplifier circuit 52. The output of the operational amplifier circuit 46 of the voltage detecting section and the output of the operational amplifier circuit 52 of the current detecting section are combined and supplied to the AC / DC switching power supply circuit 11 as a control signal.

The switch circuit 24 includes an npn transistor 54 and an npn transistor 56. The switch circuit 27 includes resistors 58 and 61, an npn transistor 59 and an npn transistor 62
Consists of The switch circuit Sa in FIG. 2 includes a p-channel MOSFET 60 and a parasitic diode 6.
0a, and the switch circuit Sb includes a pnp transistor 57. The control circuit 25 includes a control circuit 63.

A connection point between the resistances 43 and 44 of the voltage detection unit;
A resistor 53 is inserted between the transistor 54 and the collector. The emitter of transistor 54 is grounded, and its base is connected to control circuit 63. At this time, the control circuit 6 switches from the supply mode to the charging mode.
When a high-level signal is supplied to the base of transistor 54 from transistor 3, transistor 54 is turned on and resistor 4
The voltage at the junction of 3 and 44 drops. In the operational amplifier circuit 46, since the voltage at the non-inverting input terminal decreases, a signal that increases the voltage output from the AC / DC switching power supply circuit 11 is supplied to the LED 38a of the photocoupler 38.

On the other hand, when a low level signal is supplied from the control circuit 63 to the base of the transistor 54 to switch from the charging mode to the supply mode, the transistor 5
4 is turned off, and the voltage at the connection point between the resistors 43 and 44 increases. In the operational amplifier circuit 46, since the voltage at the non-inverting input terminal increases, a signal that decreases the voltage output from the AC / DC switching power supply circuit 11 is supplied to the LED 38a of the photocoupler 38.

A connection point between the resistances 48 and 49 of the current detection unit;
A resistor 55 is inserted between the transistor 55 and the collector of the transistor 56. The emitter of transistor 56 is grounded, and its base is connected to control circuit 63. At this time, as in the case of the voltage, when a high-level signal is supplied from the control circuit 63 to the base of the transistor 56 to switch from the supply mode to the charging mode, the transistor 56
Is turned on, and the current flowing to the non-inverting input terminal of the operational amplifier circuit 52 increases. Therefore, a signal that reduces the current output from the AC / DC switching power supply circuit 11 is supplied from the operational amplifier circuit 52 to the LED 38 a of the photocoupler 38.

On the other hand, when a low-level signal is supplied from the control circuit 63 to the base of the transistor 56 in order to switch from the charging mode to the supply mode, the transistor 5
6 is turned off, and the current flowing to the non-inverting input terminal of the operational amplifier circuit 52 decreases. Therefore, a signal that increases the current output from the AC / DC switching power supply circuit 11 is supplied from the operational amplifier circuit 52 to the LED 38 a of the photocoupler 38.

As described above, in the configuration of FIG. 3, in the charging mode, the transistors 54 and 56 are turned on, and the voltage and current in the charging mode shown in FIG. In the supply mode, the transistors 54 and 56 are turned off, and the voltage and current in the supply mode shown in FIG.
Output from the switching power supply circuit 11.

In the charging mode, a high-level signal is supplied from the control circuit 63 to the base of the transistor 59. Transistor 59 has its emitter grounded and its collector connected through a resistor 58 to transistor 5.
7 base. The transistor 59 supplied with the high-level signal is turned on, and the transistor 57 is turned on. At the same time, a low-level signal is supplied from the control circuit 63 to the base of the transistor 62. Transistor 62 has its emitter grounded and its collector connected to resistor 6
1 is connected to the gate of the MOSFET 60. The transistor 62 supplied with the low-level signal is turned off, and the MOSFET 60 is turned off.

In the supply mode, the control circuit 6
From 3, a low level signal is supplied to the base of the transistor 59. The transistor 59 to which the low-level signal is supplied is turned off, and the transistor 57 is turned off.
At the same time, a high-level signal is supplied from the control circuit 63 to the base of the transistor 62. The transistor 62 supplied with the high level is turned on, and the MOSFET 60 is turned on.

Next, a second embodiment of the present invention will be described with reference to a block diagram shown in FIG. In the second embodiment, the AC / DC switching power supply circuit 11 can operate in a supply mode or a charge mode as a mode, and controls the switch circuits Sa and Sb based on control in this mode. It is.

The AC / DC switching power supply circuit 11 is switched between a supply mode and a charging mode in accordance with a control signal from the power supply control switching circuit 71. The power supply control switching circuit 71 is controlled by the control circuit 72. A control signal supplied from the control circuit 72 to the power supply control switching circuit 71 is detected by the detection circuit 73.

When the charging mode is detected by the detection circuit 73, a signal is supplied from the detection circuit 73 to the charging mode setting section 74. Then, a signal for turning off the switch circuit Sa is supplied from the charging mode setting unit 74 to the switch circuit Sa. At the same time, a signal for turning on the switch circuit Sb is sent from the charging mode setting unit 74 to the switch circuit Sb.
Supplied to

When the supply mode is detected by the detection circuit 73, a signal is supplied from the detection circuit 73 to the supply mode setting section 75. Then, a signal for turning on the switch circuit Sa is supplied from the supply mode setting unit 75 to the switch circuit S.
a. At the same time, a signal for turning off the switch circuit Sb is supplied from the supply mode setting unit 75 to the switch circuit Sb.

As described above, the control signal output from the control circuit 72 is detected, and the on / off control of the switch circuits Sa and Sb is performed according to the detected control signal.
Malfunction can be prevented.

The operation of the second embodiment will be described with reference to FIG.
This will be described with reference to the flowchart shown in FIG. Step S
In 1, the control signal is output from the control circuit 72 to the power supply control switching circuit 71. The power supply control switching circuit 71 supplies an AC / D signal according to the control signal supplied from the control circuit 72.
A signal is supplied to the C switching power supply circuit 11. In step S2, the control signal supplied from the control circuit 72 to the power supply control switching circuit 71 is detected by the detection circuit 73.

In step S3, it is determined whether or not the detected control signal is in the supply mode. If it is determined that the supply mode is set, the control moves to step S4, and the control mode is not the supply mode, that is, the charging mode. If determined, the control moves to step S6. In step S4, the switch circuit S
b is turned off. In step S5, the switch circuit S
a is turned on. In step S6, the switch circuit S
a is turned off. In step S7, the switch circuit S
b is turned on. When the control in steps S5 and S7 ends, the control returns to step S2. That is, a loop for confirmation is performed.

A third embodiment of the present invention will be described with reference to a block diagram shown in FIG. This third embodiment is:
Similarly to the second embodiment, the AC / DC switching power supply circuit 11 can operate the AC / DC switching power supply circuit 11 in the supply mode, the charging mode, or the pre-charge mode. Control the switch circuits Sa and Sb by detecting the states of the switch circuits Sa and Sb.
It controls the DC switching power supply circuit 11.
Although not shown in FIG. 8, the control circuit 72 and the power supply control switching circuit 7 shown in the second embodiment (FIG. 5) are used to control the switch circuits Sa and Sb.
1, a detection circuit 73, a charging mode setting unit 74, and a supply mode setting unit 75 are provided.

The ON / OFF detection circuit 85 detects the ON / OFF state of the switch circuit Sa. ON / OF
When the F detection circuit 85 detects that the switch circuit Sa is turned on, a signal is supplied to the coincidence detection circuit 82 and a signal is supplied to the supply mode setting section 87. Also,
When the OFF of the switch circuit Sa is detected, a signal is supplied to the coincidence detection circuit 83.

The ON / OFF detection circuit 84 detects the ON / OFF state of the switch circuit Sb. ON / OF
When the F detection circuit 84 detects that the switch circuit Sb is turned on, a signal is supplied to the coincidence detection circuit 82 and a signal is supplied to the charging mode setting unit 86. Also,
When the OFF state of the switch circuit Sb is detected, a signal is supplied to the coincidence detection circuit 83.

In the coincidence detection circuit 82, the switch circuit Sa
When Sb and Sb are turned on, a signal is supplied to the low-voltage low-current circuit 81. Similarly, in the coincidence detection circuit 83, when the switch circuits Sa and Sb are turned off, a signal is supplied to the low-voltage low-current circuit 81. Low voltage low current circuit 8
1, when both of the switch circuits Sa and Sb are on or off from the signals supplied from the coincidence detection circuits 82 and 83, the signal for operating the AC / DC switching power supply circuit 11 in the pre-charge mode is supplied to the AC / DC The power is supplied to the switching power supply circuit 11.

Even when the AC / DC switching power supply circuit 11 is operating in the charging mode and the supply mode, if both the switch circuits Sa and Sb are turned on or off, the AC / DC switching power supply circuit 11 is operated in the pre-charging mode. Make it work. Then, the switch circuits Sa and S
b in the pre-charge mode until only one of
/ DC switching power supply circuit 11 is operated.

As described above, the switch circuits Sa and Sb
When the control circuit 72 in FIG. 5 for controlling the operation of the switch circuit malfunctions, both the switch circuits Sa and Sb may be turned on or off. If the AC / DC switching power supply circuit operates in the charging mode when both of the switch circuits Sa and Sb are turned on, it adversely affects external electronic devices, and the AC / DC switching power supply circuit operates in the supply mode. Adversely affects the secondary battery.

Here, the pre-charge mode will be described. In the pre-charge mode, as shown in FIG.
In this mode, a small current of about mA is output. When the AC / DC switching power supply circuit 11 is performing a switching operation in the pre-charge mode, the switch circuits Sa and Sb may be in either ON or OFF state. For example,
First, commercial power is supplied, and the switch circuits Sa and S
This mode is used for safety when the state of b is not known. Also, the pre-charge mode is the same as that of the secondary battery B.
T and a low-power mode that does not damage them even when supplied to an external portable electronic device.
It is also used at power-on when the state of Sb and Sb is unknown. The third embodiment can solve such a problem.

In the third embodiment, the coincidence detecting circuit 8
2 and 83, when both the switch circuits Sa and Sb are on or off, the AC / DC switching power supply circuit 11 is immediately operated in the pre-charge mode, but both the switch circuits Sa and Sb are on or off. In the case of OFF, the switching operation of the AC / DC switching power supply circuit 11 may be temporarily stopped, and then the AC / DC switching power supply circuit 11 may be operated in the pre-charge mode. When switching the mode of the AC / DC switching power supply circuit, the AC / DC
The switching operation of the switching power supply circuit may be temporarily stopped.

The operation of the third embodiment will be described with reference to the flowchart shown in FIG. Step S1
In 1, the ON / OFF detection circuit 85 detects the state of the switch circuit Sa, and the state of the switch circuit Sb is ON / O.
It is detected by the FF detection circuit 84. In step S12,
The coincidence detection circuits 82 and 83 detect coincidence of the states of the switch circuits Sa and Sb.

In step S13, as a result of the coincidence detection circuits 82 and 83, it is determined whether or not they match, and if it is determined that the states of the switch circuits Sa and Sb are in agreement, the control moves to step S14. If it is determined that they do not match, the control moves to step S15. Step S
14, in the pre-charge mode for outputting low power, AC / D
The C switching power supply circuit 11 is controlled.

In step S15, it is determined whether or not the switch circuit Sa is on. If the switch circuit Sa is on, the control proceeds to step S16, and if the switch circuit Sa is off, the control proceeds to step S17. Step S
At 16, the AC / DC switching power supply circuit 11 is controlled in a supply mode for outputting a power supply voltage to an external portable electronic device. In step S17, the AC / DC switching power supply circuit 11 is controlled in the charging mode for charging the secondary battery BT.

FIG. 10 shows a more detailed configuration of the third embodiment. The power supply voltage output from the AC / DC switching power supply circuit 11 is supplied to the switch circuit Sa via the resistor 94. Both ends of the resistor 94 are connected to the current detection circuit 93. Then, a voltage detection circuit 95 is inserted between the other end of the resistor 94 and the ground. The resistor 94, the current detection circuit 93 and the voltage detection circuit 95 determine the detection unit 91.
Is configured.

As an example, the detected voltage is compared with the reference voltage of the mode, and the error is supplied to the AC / DC switching power supply circuit 11 via the feedback circuit 92. A
In the C / DC switching power supply circuit 11, the switching operation is performed so that the power supply voltage output according to the error of the supplied voltage becomes the reference voltage. Similarly, the detected current is compared with the reference current of the mode, and the error thereof is output via the feedback circuit 92 to the AC / DC switching power supply circuit 1.
1 is supplied. AC / DC switching power supply circuit 11
In, the switching operation is performed so that the power supply voltage output according to the error of the supplied current becomes the reference current.

The ON / OFF detection circuit 96 detects the state of the switch circuit Sb. ON / OFF detection circuit 9
6, when ON of the switch circuit Sb is detected, ON / O
A signal is supplied from the FF detection circuit 96 to the comparison detection circuit 98 and the charging mode setting unit 101. Also, ON / OF
When the OFF state of the switch circuit Sb is detected by the F detection circuit 96, a signal is supplied from the ON / OFF detection circuit 96 to the comparison detection circuit 99.

The ON / OFF detection circuit 97 detects the state of the switch circuit Sa. ON / OFF detection circuit 9
7, when ON of the switch circuit Sa is detected, ON / O
A signal is supplied from the FF detection circuit 97 to the comparison detection circuit 99 and the supply mode setting unit 102. Also, ON / OF
When the F detection circuit 97 detects that the switch circuit Sa is turned off, a signal is supplied from the ON / OFF detection circuit 97 to the comparison detection circuit 98.

In charging mode setting section 101, AC / DC
A signal for setting the output of the switching power supply circuit 11 to the charging mode is supplied to the switching circuit 103. In the supply mode setting unit 102, a signal for setting the output of the AC / DC switching power supply circuit 11 to the supply mode is supplied to the switching circuit 103.

In the comparison detection circuit 98, the switch circuit Sb
Is not detected, and a signal is supplied to the switching stop circuit 100 when the switch circuit Sa is not detected. In the comparison detection circuit 99, a signal is supplied to the switching stop circuit 100 when the off of the switch circuit Sb and the on of the switch circuit Sa are not detected.
In the switching stop circuit 100, when a signal is supplied from the comparison detection circuit 98 or 99, the switching circuit 103
The signal is supplied to.

In the switching circuit 103, a signal supplied from the charging mode setting unit 101 or the supply mode setting unit 102 is supplied to the detection unit 91 as a switching signal.
At the same time, a signal is supplied from the switching circuit 103 to the pre-charge mode stop circuit 104. When the switching circuit 103 receives the signal from the switching stop circuit 100, the switching circuit 103 stops outputting the switching signal supplied to the detection unit 91, and the precharge mode stop circuit 104
The supply of the stop signal to is stopped.

In the precharge mode stop circuit 104,
When a signal is supplied from the switching circuit 103, a stop signal is supplied to the pre-charge mode setting unit 105. The precharge mode setting unit 105 supplies the detection unit 91 with the reference voltage and the reference current in the precharge mode. However, when a stop signal is supplied from the precharge mode stop circuit 104, the supply of the reference voltage and the reference current is performed. Is stopped. That is, in the pre-charge mode setting unit 105, the supply of the reference voltage and the reference current to the detection unit 91 is stopped while the stop signal is supplied from the pre-charge mode stop circuit 104.

An example of the operation of the fourth embodiment is shown in FIG.
This will be described with reference to the flowchart shown in FIG. Step S
At 21, the on / off state of the switch circuits Sa and Sb is not known, so that the AC / DC switching power supply circuit 11 is operated in the precharge mode. Step S
At 22, the ON / OFF detection circuit 97 detects the state of the switch circuit Sa, and the ON / OFF detection circuit 9
At 6, the state of the switch circuit Sb is detected. In step S23, the comparison detection circuits 98 and 99 compare and detect the states of the switch circuits Sa and Sb. When the control in step S23 ends, the control moves to steps S24 and S28.

In step S24, as a result of the comparison and detection, it is determined whether or not there is a mismatch. If it is determined that there is no match, control is transferred to step S25.
Control returns to step S21. In step S25, the state of the switch circuit Sa is determined. If it is determined that the switch circuit Sa is on, the control proceeds to step S26. If it is determined that the switch circuit Sa is off, the control proceeds to step S30.

In step S26, the AC / DC switching power supply circuit 11 is operated in the supply mode. In step S30, the AC / DC switching power supply circuit 11 is operated in the charging mode. Next, in step S27, A
The pre-charge mode of the C / DC switching power supply circuit 11 is stopped.

In step S28, a switching stop signal is output from the switching stop circuit 100 to the switching circuit 103, and the signal output from the switching circuit 103 to the detection unit 91 is stopped. In step S29, the reference voltage and the reference current supplied to the detection unit 91 are switched. Thereafter, control returns to step S22.

In the embodiment described above, the AC / DC switching power supply circuit 11 is operated in the pre-charge mode,
After a lapse of a predetermined time, for example, one hour, it is detected whether or not the terminal voltage of the secondary battery BT is a predetermined value. If the terminal voltage is equal to or less than the predetermined value, the secondary battery BT may be short-circuited. The charging mode may be stopped.

The above-described embodiment may be controlled using both analog and digital signals. By using both analog and digital, it is possible to have analog accuracy and a large digital control range.

The above-described secondary battery BT may be a battery pack in which a charging circuit and one or more secondary batteries are simply combined in series and / or in parallel, or may have all the functions of the above-described embodiment. The battery pack may be provided.

[0062]

According to the present invention, the mode of the AC / DC switching power supply circuit and the state of the switch circuit are controlled, and the mode of the AC / DC switching power supply circuit and the state of the switch circuit are detected. Safety can be maintained and malfunction can be prevented. Therefore, it is possible to eliminate a bad influence on the secondary battery or the external portable electronic device.

[Brief description of the drawings]

FIG. 1 is a block diagram of a schematic configuration to which the present invention is applied.

FIG. 2 is a block diagram showing a first embodiment of the present invention.

FIG. 3 is a circuit diagram showing a first embodiment of the present invention.

FIG. 4 is a schematic diagram used for describing a charging mode and a supply mode according to the present invention.

FIG. 5 is a block diagram showing a second embodiment of the present invention.

FIG. 6 is a flowchart showing a second embodiment of the present invention.

FIG. 7 is a block diagram showing a third embodiment of the present invention.

FIG. 8 is a schematic diagram used for describing a charge mode, a supply mode, and a pre-charge mode of the present invention.

FIG. 9 is a flowchart showing a third embodiment of the present invention.

FIG. 10 is a block diagram showing a fourth embodiment of the present invention.

FIG. 11 is a flowchart showing a fourth embodiment of the present invention.

FIG. 12 is a schematic diagram for explaining a method of using the power supply unit.

[Explanation of symbols]

11 ... AC / DC switching power supply circuit, 12 ...
-Microcomputer, Ti, To ... terminals, Sa, Sb ...
Switch circuit, BT ... secondary battery

Continued on the front page (72) Inventor Akio Nakamura 6-7-35 Kita-Shinagawa, Shinagawa-ku, Tokyo Inside Sony Corporation (72) Inventor Tsutomu Suda 6-35-35 Kita-Shinagawa, Shinagawa-ku, Tokyo Sony Corporation In-house F-term (reference) 5G003 AA01 BA01 DA07 GA01 GA10 GB04 GC05

Claims (4)

[Claims] 1. A power supply unit for outputting a predetermined power from a commercial power supply, wherein a power supply mode for supplying power to a load and a charge mode for supplying power to a secondary battery can be switched. A voltage converting means, a switching means connected between the voltage converting means, the load and the secondary battery, the state of which is switched according to the supply mode or the charging mode; and Checking means for comparing the result of detecting the mode with the result of detecting the state of the switch means to confirm whether or not they match, and the voltage converting means according to the result of detecting the state of the switch means And a control means for controlling the state of the power supply. 2. The pre-charging device according to claim 1, wherein in the checking means, when a state of the switch means does not match a mode of the voltage converting means, a low-voltage low-current power is supplied from the voltage converting means. A power supply unit characterized by outputting a mode. 3. A power supply unit for outputting a predetermined power from a commercial power supply, comprising: a supply mode for supplying power to a load; a charging mode for supplying power to a secondary battery; A voltage conversion means capable of switching between a pre-charge mode for supplying power to the power supply, and a voltage conversion means connected between the voltage conversion means, the load and the secondary battery, and according to a mode of the voltage conversion means, Switch means for switching states, a detection means for comparing a result of detecting a mode of the voltage conversion means with a result of detecting a state of the switch means, and confirming whether or not they match; And control means for controlling the state of the voltage conversion means in accordance with the result of detecting the state of the switch. The precharge mode is output from the voltage conversion means when the mode is not any of the modes or when the state of the switch means does not match the mode of the voltage conversion means. Power supply unit. 4. The power supply unit according to claim 1, wherein the output of the voltage conversion means is temporarily stopped when the mode of the voltage conversion means is switched.