JP2001128389A - Power supply unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress power consumption and over discharge of a secondary battery by stopping the operation of a AC/DC switching power supply circuit, when the circuit of power supply unit except for the AC/DC switching power supply circuit does not operate. SOLUTION: An AC/DC switching power supply circuit Ra outputs the prescribed power supply voltage from the commercial power supply supplied via a terminal Ti. The prescribed output power supply voltage is outputted to the outside from a terminal To via a switch circuit Sa. A switching circuit Sb and a secondary battery BT are inserted in series between the output terminal of the power supply circuit Ra and the ground. Moreover, a DC/DC switching power supply circuit Rd is inserted between the output terminal of the power supply circuit Ra and the ground. In a stop signal generating circuit 12, when both switch circuits Sa, Sb are off in the operation detecting circuit 11 and the stop condition of the power supply circuit Rd is detected, the stop signal for suspending the operation of the power supply circuit Ra is supplied to the power supply circuit Ra.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply unit capable of controlling a switching power supply circuit in a stop mode to reduce power consumption.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 10, there is a power supply unit 112 for converting a commercial power supply to a predetermined power supply and supplying power to a portable electronic device 111. This power supply unit 1
12 is provided with a connector capable of connecting a power cable 113 for obtaining commercial power and a cable 114 for supplying power to the portable electronic device 111. Further, the power supply unit 112 is provided with an AC / DC switching power supply circuit for converting a commercial power supply to a predetermined power supply. This power supply unit 112
Supplies a predetermined power from a commercial power supply to the portable electronic device 111, has a function of an AC adapter, and has a secondary battery in the main body, and supplies a predetermined power from the secondary battery to the portable electronic device 111. , A so-called battery function.

In the power supply unit 112, a state in which the portable electronic device 111 is not connected, that is, a no-load state is detected, and a low-voltage low-current power supply is output from the AC / DC switching power supply circuit.

[0004]

However, even if circuits other than the AC / DC switching power supply circuit in the power supply unit 112 are not operating, the power consumption is reduced to zero because the AC / DC switching power supply circuit is operating. And couldn't. Further, the secondary battery used in the power supply unit 112 has a usable voltage / current range, and it is necessary to prevent the voltage / current from falling below the range (overdischarge).

Accordingly, an object of the present invention is to suppress power consumption by stopping the AC / DC switching power supply circuit when the circuits other than the AC / DC switching power supply circuit in the power supply unit 112 are not operating. It is another object of the present invention to provide a power supply unit capable of suppressing overdischarge of a secondary battery.

[0006]

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 for supplying power to a secondary battery. A voltage conversion unit that is switchable between a charging mode for supplying power, a switch unit that is connected between the voltage conversion unit and the load and the secondary battery, and that switches the state, and a capacity of the secondary battery. Capacitance detection means for detecting, and control means for controlling the state of the voltage conversion means according to the result of detecting the state of the switch means,
The control unit is a power supply unit characterized in that when the switch unit is off and the capacity of the secondary battery is determined to be equal to or more than a predetermined capacity, the operation of the voltage conversion unit is stopped.

When the AC / DC switching power supply circuit operates and the circuits other than the AC / DC switching power supply circuit do not operate within a range in which the secondary battery can be used,
/ Stop the operation of the DC switching power supply circuit.

[0008]

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 a first embodiment to which the present invention is applied. Commercial power is supplied from the terminal Ti. The supplied commercial power is AC
/ DC switching power supply circuit Ra. AC /
In the DC switching power supply circuit Ra, a predetermined power supply voltage is output from the supplied commercial power supply. The output predetermined power supply voltage is output to the outside from the terminal To via the switch circuit Sa.

A switch circuit Sb and a secondary battery BT are inserted in series between the output terminal of the AC / DC switching power supply circuit Ra and the ground. Further, a DC / DC switching power supply circuit Rd is inserted between the output terminal of the AC / DC switching power supply circuit Ra and the ground.

The ON / OFF states of the switch circuits Sa and Sb and the operation state of the DC / DC switching power supply circuit Rd are detected by an operation detection circuit 11. In the operation detection circuit 11, for example, the switch circuits Sa and Sb
Are both off and the DC / DC switching power supply circuit R
When d is stopped, a signal is output to the stop signal generation circuit 12. In the stop signal generation circuit 12, AC /
The stop signal for stopping the operation of the DC switching power supply circuit Ra is generated by the AC / DC switching power supply circuit Ra.
Supplied to The AC / DC switching power supply circuit Ra supplied with the stop signal stops the switching operation.

This AC / DC switching power supply circuit Ra
Can be operated by appropriately selecting a charging mode for charging the secondary battery BT and a supply mode for supplying a power supply voltage to an external electronic device. For example, the switch circuit S
a is turned off and the switch circuit Sb is turned on, the AC / DC switching power supply circuit Ra operates in the charging mode, and when the switch circuit Sa is turned on and the switch circuit Sb is turned off, the AC / DC The switching power supply circuit Ra operates in the supply mode.

A more detailed configuration of the first embodiment of the present invention will be described with reference to the block shown in FIG. The same blocks as those in FIG. 1 described above are denoted by the same reference numerals,
The description is omitted. One of the DC / DC switching power supply circuits Rd is connected to the output terminal of the AC / DC switching power supply circuit Ra, and the other is connected to the switch circuit 21. Then, when the switch circuit 21 is turned on, the power supply voltage of the secondary battery BT is supplied to the DC / DC switching power supply circuit Rd. The state of the switch circuit 21 is
The operation is detected by the operation detection circuit 24. The states of the switch circuits Sa and Sb are also detected by the operation detection circuit 24.

The secondary battery BT is connected to a switch circuit 23 and a capacity detection circuit 22. The capacity detection circuit 22 detects the current capacity of the secondary battery BT, and supplies the detected capacity to the operation detection circuit 24. In the operation detection circuit 24, a signal is supplied to the stop signal generation circuit 25 according to the state of the supplied switch circuits Sa, Sb, 21 and the capacity of the secondary battery BT from the capacity detection circuit 22. In the stop signal generation circuit 25, a stop mode signal is supplied to the AC / DC switching power supply circuit Ra according to the supplied signal. The operation of the AC / DC switching power supply circuit Ra is stopped in response to the supplied stop mode signal.

As described above, the AC / DC switching power supply circuit Ra is operating and the capacity of the secondary battery BT is within the usable range. At this time, if circuits other than the AC / DC switching power supply circuit Ra are not operating, the AC / DC
The operation of the DC switching power supply circuit Ra is stopped.

A first embodiment of the present invention will be described with reference to a flowchart shown in FIG. In step S11, the AC / DC switching power supply circuit Ra operates.
In step S12, the operation of the circuit of the present device is detected. In step S13, it is determined whether or not the circuits of the present apparatus other than the AC / DC switching power supply circuit Ra are operating based on the detection result. If it is determined that the operation is stopped, the control proceeds to step S14. If it is determined that it is operating, control returns to step S12.

In step S14, the capacity of the secondary battery BT is detected. In step S15, it is determined whether or not the detected capacity of the secondary battery BT is within the usable range. If it is determined that the capacity of the secondary battery BT is within the usable range, the process proceeds to step S16. When it is determined that the value is not within the usable range, the control returns to step S14. In step S16, a stop mode signal is generated, and the stop mode signal is supplied to the AC / DC switching power supply circuit Ra. In step S17,
The operation of the AC / DC switching power supply circuit Ra is stopped. Then, the control moves to steps S18 and S21.

In step S18, the operation of the circuit of the present apparatus except the AC / DC switching power supply circuit Ra is detected. In step S19, it is determined whether or not a part of the circuit of the present apparatus except the AC / DC switching power supply circuit Ra is operating based on the detection result. If it is determined that a part is operating, the process proceeds to step S11. When the control is returned and it is determined that it is not operating, the control returns to step S18.

In step S21, the capacity of the secondary battery BT is detected. In step S22, it is determined whether or not the capacity of the secondary battery BT is below the usable range from the detection result. If it is determined that the capacity of the secondary battery BT is below the usable range, the control returns to step S11. If it is determined that it is not below the usable range, the control returns to step S21.

Here, an example of detecting the capacity of the secondary battery BT will be described. The capacity of the secondary battery BT and its output voltage are
It is almost proportional. Therefore, in this embodiment, the terminal voltage of the secondary battery BT is detected, and the capacity of the secondary battery BT is determined based on the detected voltage.

A second embodiment of the present invention will be described with reference to a block diagram shown in FIG. The second embodiment is an example in which the capacity of the secondary battery BT is always kept constant. That is, the power consumed by the secondary battery BT is
By operating and charging the AC / DC switching power supply circuit Ra, the capacity of the secondary battery BT is kept constant.

In the operation detection circuit 31, the switch circuit Sa
And the state of Sb are detected. The stop mode setting unit 32 outputs a signal for stopping the AC / DC switching power supply circuit Ra. The timer circuit 33
As shown in FIG. 5, the switch circuit Sb is turned on for a predetermined time and at a predetermined interval. When the switch circuit Sb is turned on, a signal is output from the timer circuit 33 to the charging mode setting unit 34 in order to operate the AC / DC switching power supply circuit Ra in the charging mode.

In the charging mode setting section 34, when a signal is supplied from the timer circuit 33, a signal for operating the AC / DC switching power supply circuit Ra in the charging mode is A.
It is supplied to the C / DC switching power supply circuit Ra. For example, the switch circuit Sb is turned on for several tens of seconds, and during that time, the voltage / current in the charging mode is output from the AC / DC switching power supply circuit Ra.

A second embodiment of the present invention will be described with reference to a flowchart shown in FIG. In step S31, the operation of the AC / DC switching power supply circuit Ra stops. In step S32, the timer circuit 33 operates, and after Δta seconds, the AC / DC switching power supply circuit Ra
Is operated (step S33). In step S34, the operation of the AC / DC switching power supply circuit Ra is stopped after Δtb seconds. Then, the control moves to steps S32 and S35.

In step S35, the operation of the circuit of the present apparatus is detected. In step S36, the AC
It is determined whether or not the circuits of the present apparatus except for the / DC switching power supply circuit Ra are operating. If it is determined that the circuits are operating, the control proceeds to step S37, and if it is determined that they are not operating, Control returns to step S35. In step S37, the AC / DC switching power supply circuit Ra is operated. In step S38, the operation of the circuit of the present apparatus is detected. In step S39, the AC
It is determined whether or not the operation of the circuit of the present apparatus except the / DC switching power supply circuit Ra is stopped. If it is determined that the operation is stopped, the control returns to step S31, and it is determined that the operation is not stopped. Then, control returns to step S38.

FIG. 7 is a circuit diagram corresponding to the AC / DC switching power supply circuit Ra used in the first and second embodiments described above. Further, the example shown in FIG. 7 determines whether or not the supply of the commercial power is cut off, and when the supply of the commercial power is cut off, the stop mode signal supplied to the AC / DC switching power supply circuit Ra. Is to stop the output. That is, in this example, AC / D
Although the stop mode is used to stop the operation of the C switching power supply circuit Ra, power is also consumed to output the stop mode signal. Therefore, when the commercial power supply is cut off, the stop mode is used. In order to suppress the power consumption of the output of the signal of (1), the output of the stop mode signal is stopped, and the operation of the AC / DC switching power supply circuit Ra is stopped.

This AC / DC switching power supply circuit Ra
Is composed of an input rectifier, a switching unit, a controller, and an output rectifier. The input rectifier is a diode bridge 4
It is composed of 1. In the input rectifier, the commercial power supplied from the terminal Ti is rectified. The switching unit is n
Channel type MOSFET 44, parasitic diode 44
a and a transformer 45. In this switching section, when the MOSFET 44 is turned on / off (switching), a voltage current corresponding to the duty ratio of the switching signal supplied to the gate of the MOSFET 44 is output to the secondary side of the transformer 45.

The control section includes a resistor 42, a PWM (pulse width modulation) circuit 43, and a photocoupler 51.
The control unit switches the switching unit at a duty ratio such that a desired output voltage / output current is generated according to the voltage / current generated on the secondary side. The output rectifier includes a diode 47 and a capacitor 48. The output rectifier is provided on the output side of the switching unit, and rectifies the voltage and current output by the switching. Further, a diode 46 is provided on the secondary side of the transformer 45 so that a voltage current generated in a subsequent stage is not supplied to the operation detection circuit 49.

The operation detection circuit 49 is connected to the cathode of the diode 47. In the operation detection circuit 49, the transformer 4
5 is detected, and it is determined whether or not the AC / DC switching power supply circuit Ra is operating. When the operation detection circuit 49 determines that the AC / DC switching power supply circuit Ra is stopped, a signal is supplied to the microcomputer 50. In the microcomputer 50, when a signal indicating that the AC / DC switching power supply circuit Ra is stopped is supplied from the operation detection circuit 49, the microcomputer 50
, The output of the stop mode signal supplied to the photocoupler 51 is stopped.

An example of the operation of the circuit shown in FIG. 7 will be described with reference to the flowchart shown in FIG. Step S
At 41, the operation of the AC / DC switching power supply circuit Ra stops. In step S42, as shown in FIG.
During the period Δt1, the timer circuit operates to operate the AC / DC switching power supply circuit Ra. Step S
At 43, the stop mode of the AC / DC switching power supply circuit Ra is released for the period Δt1 after the period t2. That is, the AC / DC switching power supply circuit Ra is operated.

In step S44, AC /
The DC switching power supply circuit Ra is operated. In step S45, the operation detection circuit 49 detects an output voltage from the AC / DC switching power supply circuit Ra.
In step S46, it is determined whether or not there is an output voltage based on the detection result. If it is determined that there is no voltage, control proceeds to step S47. If it is determined that there is a voltage, control returns to step S41.

In step S47, the stop mode of the AC / DC switching power supply circuit Ra is released. In step S48, the operation detection circuit 49 causes the AC / D
An output voltage from the C switching power supply circuit Ra is detected. In step S49, it is determined whether or not there is an output voltage from the detection result. If it is determined that there is a voltage, the control returns to step S41. If it is determined that there is no voltage,
Control returns to step S47.

An AC / DC switching power supply circuit R
A photocoupler may be provided separately to notify the microcomputer that no power supply voltage is input to a. More specifically, the other output of the diode bridge 41 is connected to the anode of the LED of the photocoupler via a resistor. The cathode of the LED is grounded. The emitter of the phototransistor of the photocoupler is grounded, and its collector is connected to the detection circuit. By connecting the output of the detection circuit to the microcomputer, it is possible to detect that there is no power supply voltage input to the AC / DC switching power supply circuit Ra.

That is, when the power supply voltage is input, a signal is generated from the photocoupler, and the AC / D
When the switching power supply circuit Ra is stopped and the supply of the power supply voltage is cut off, no signal is generated from the photocoupler, and the stop mode of the AC / DC switching power supply circuit Ra is released.

[0034]

According to the present invention, when the circuits of the power supply unit except the AC / DC switching power supply circuit Ra are stopped, the operation of the AC / DC switching power supply circuit Ra is also stopped, and the internal circuit of the power supply unit is stopped. Since the AC / DC switching power supply circuit can be operated only when operates, power consumption can be suppressed.

Further, according to the present invention, since the capacity of the secondary battery is constantly monitored, overdischarge of the secondary battery can be suppressed.

[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 flowchart showing a first embodiment of the present invention.

FIG. 4 is a block diagram showing a second embodiment of the present invention.

FIG. 5 is a schematic diagram for explaining the present invention.

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

FIG. 7 is a circuit diagram of an example of an AC / DC switching power supply circuit of the present invention.

FIG. 8 is a flowchart for explaining an example of the operation of the AC / DC switching power supply circuit of the present invention.

FIG. 9 is a schematic diagram for explaining the present invention.

FIG. 10 is a schematic diagram for explaining how to use the power supply unit.

[Explanation of symbols]

Ti, To: terminal, Ra: AC / DC switching power supply circuit, Rb: DC / DC switching power supply circuit, Sa, Sb: switch circuit, 11: operation detection circuit, 12 ...・ Stop signal generation circuit

 ──────────────────────────────────────────────────続 き Continuing 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, Kita-Shinagawa, Shinagawa-ku, Tokyo Sony Corporation F term (reference) 5G003 AA01 BA01 CA06 CC02 DA07 DA18 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. Voltage converting means, switch means connected between the voltage converting means, the load, and the secondary battery, the state of which is switched, capacity detecting means for detecting the capacity of the secondary battery, and the switch Control means for controlling the state of the voltage conversion means in accordance with the result of detecting the state of the means, wherein the control means is such that the switch means is off and the capacity of the secondary battery is equal to or greater than a predetermined capacity. A power supply unit wherein the operation of the voltage conversion means is stopped when it is determined that there is a power supply unit. 2. The control device according to claim 1, wherein the control means operates the voltage conversion means in the charging mode when determining that the capacity of the secondary battery is equal to or less than a predetermined capacity. And power supply unit. 3. The power supply unit according to claim 2, wherein in the charging mode, the secondary battery is intermittently charged in order to keep the capacity of the secondary battery constant. 4. The power supply according to claim 1, wherein the presence or absence of a commercial power supply is determined, and when it is determined that the commercial power supply is not input, the operation of the voltage conversion means is stopped. unit.