JPH11353061A - Power source controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power source controller for a universal serial bus(USB) capable of supplying power from host equipment when the power source of a printer is turned off and enabling power supply to equipment as well even in an off-state of the printer. SOLUTION: When the power source of a printer 6 is turned on, power is supplied from a printer power source part 8, a driving current flows to relays RL1 and RL2, the contact of the relay RL2 is turned on, and power on the side of the printer 6 is supplied through transistors Q1-Q3 to connected equipment. When the power source of the printer 6 is turned off, power supply from the printer power source part 8 is cut off, the supply of the current to the relays RL1 and RL2 is stopped, and power is supplied from the side of a USB cable to the connected equipment by turning on the contact of the relay RL1. Through such control, while the printer 6 is driven, power is supplied from the side of the printer 6 to the equipment but while the printer 6 is not driven, power can be supplied from the side of the USB cable.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a USB (Universa)
l Serial Bus).

[0002]

2. Description of the Related Art USB (Universal Serial Bus) is an interface standard for personal computers developed by a number of international companies, and includes a mouse, a keyboard, a printer, a modem, a speaker, a joystick, and the like. Is to be able to connect.

Conventionally, it has been necessary to connect to a separate interface for each of the above peripheral devices, and to restart the personal computer after the connection. However, the USB (Un
According to iversal Serial Bus), up to 127 layers of peripheral devices can be connected through a hub (HUB / concentrator), and if a device is connected to an empty connector while the computer is turned on, it can be used immediately Is what you can do.

The above-mentioned six layers means that, for example, there are five star-connected hubs from a computer, and FIG. 5 shows a five-layer USB (Universal Serial Bus).
Here is an example using. In addition, a plurality of terminal devices can be connected to one hub, and some peripheral devices have a hub function. For example, a printer device is one example, and some printer devices have a hub function.

FIG. 6 is a system configuration diagram for explaining an example of a printer device equipped with a hub function and using the USB interface. In FIG. 1, reference numeral 1 denotes a printer power supply unit, and 2 denotes a printer control unit. In normal print processing, the printer control unit 2 is driven by the +5 V and +24 V power supplies supplied from the printer power supply unit 1, and performs print processing according to print data supplied from a host device (not shown).

On the other hand, USB control is performed by a USB control unit 3. That is, the printer device shown in the figure has a hub function, and has a connector HT connected to a host device (for example, a personal computer) and three connectors PT1 to PT3 connected to peripheral devices. Each of the above connectors H
T and PT1 to PT3 each have four terminals of + 5V, GND (ground), and D +, D- (data), and transmit and receive data.

In the above printer, when the power of the printer is turned on, a high signal is supplied to the base (B), so that the three transistors Q1 to Q3 are turned on, and the transistors Q1 to Q3 are supplied from the printer power supply unit 1. Power is supplied to the connectors PT1 to PT3 via the. Further, data supplied from the host device includes terminals D + of the connector HT,
The print data is supplied to the USB control unit 3 via D-, and the print data is sent to the printer control unit 2 under the control of the USB control unit 3 to perform a printing process. Further, the peripheral devices connected to the connectors PT1 to PT3 perform each drive using the power supplied through the corresponding connector.

[0008]

The following problems occur in the power supply control in the above-mentioned conventional USB. (B) First, the peripheral devices connected to the connectors PT1 to PT3 cannot be driven unless the power of the printer device is turned on. That is, if power is not supplied to the printer device, the host device cannot recognize the peripheral device and cannot drive the peripheral device. Therefore, even when only the devices connected to the connectors PT1 to PT3 are used, the power of the printer device must be turned on.

(B) On the other hand, it is also possible to directly supply power to devices connected to the hub from a USB cable.
However, in this case, the supply current is limited. For example, the current that can be supplied to the hub is 0.1 A, and is the current supplied to one hub.
If the total current of all devices connected to 1 to 3 exceeds 0.1 A, it cannot be supplied directly from the USB cable. Therefore, it is practically impossible to connect and use a plurality of devices.

The present invention has been made in view of such circumstances, and in a printer having a hub function, power is supplied from the printer when the power of the printer is turned on, and connected devices are turned off when the power of the printer is turned off. When the current capacity is below a certain value, power is supplied to the device via a USB cable, and even if the printer device is in an off state,
An object of the present invention is to provide a power supply control device capable of supplying power to a device.

[0011]

According to a first aspect of the present invention, there is provided a power supply control device including a device having a hub function using a USB cable, wherein a power supply on the USB cable is connected to the device. First switching means for disconnecting when the power of the apparatus is on and connecting when the power of the apparatus is off; and connecting the power of the apparatus when the power of the apparatus is on and when the power of the apparatus is off. By providing a power supply control device having a second switching means for disconnecting, and a supply means for supplying power by the first and second switching means to a power supply of a device connected to the device via a hub. Can be achieved.

Here, the USB cable is the USB cable described above.
(Universal Serial Bus) A cable created in accordance with the standard, for example, a printer device, a mouse, a keyboard, a scanner, and the like can be connected to the cable. The hub is an interface for connecting the printer device or the like to a USB cable. The above device may be a device other than the printer device, for example, a peripheral device such as a scanner device, and any device having a hub function.

The first switching means is, for example, a switch which is turned on and off when supplying power to the device from the USB cable, and the second switching means supplies power to the device from the device. For example, a switch that is turned on and off is used.

With this configuration, when a device such as a printer device having a hub function is powered on,
For example, power is supplied from the device to the device via the second switching means. On the other hand, when the device is not turned on (when the device is not in use), power is supplied to the device from the USB cable via the first switching means, for example.

Therefore, while a device having a hub function, such as a printer device, is powered on, power is supplied from the device to the device, so that sufficient power can be supplied to the device. On the other hand, even when the device is not powered on, power can be supplied from the USB cable.

The devices having a hub function as described above include a printer device, a scanner device, a speaker device,
And the like can be applied. According to a second aspect of the present invention, in a power supply control device using a USB cable and including a printer having a hub function, the power supply on the USB cable is disconnected when the power of the printer is turned on. First switching means for connecting when the power of the printer is off, and second switching means for connecting the power of the printer when the power of the printer is on and disconnecting when the power of the printer is off. Can be achieved by providing a power supply control device comprising: a switching unit for supplying power to a device connected to the printer device via a hub through the first and second switching units. .

Here, the fact that the USB cable and the device have the function of a hub is the same as the first aspect of the present invention.
This example shows a printer device as an example of a device having a hub function. Further, the first and second switching means are the same as those in the above invention, and the first switching means is, for example, a switch which is turned on and off when power is supplied from the USB cable to the device. The switching means is, for example, a switch that is turned on and off when power is supplied from the printer device to the device.

With this configuration, when the printer is used and the power of the printer is turned on, power is supplied from the printer to the above-described device via, for example, the second switching means. On the other hand, when the printer device is not used (when the power of the printer device is not turned on), power is supplied to the device from the USB cable via the first switching means, for example.

Therefore, while power is supplied to the printer connected to the USB cable, power is supplied from the printer to the device, so that sufficient power can be supplied to the device. On the other hand, even when the power of the printer device is not turned on, power can be supplied from the USB cable.

According to a third aspect of the present invention, in the second aspect of the present invention, when the power of the printer is turned on, the second
The switching means is driven to supply the power of the printer to the device, and when the power of the printer is off, the first switching means is driven to supply the power on the USB cable to the device. It is a configuration to supply.

This embodiment shows a specific example of driving the first and second switching means. The second switching means is driven when the power supply of the printer is turned on, and the apparatus is connected to the device. Supply power to the printer. The first switching means is driven when the power of the printer is off, and supplies the power of the printer to the device.

With this configuration, the second switching unit supplies power to the above-described device while the power to the printer connected to the USB cable is on, and the second switching unit can supply enough power to the device. Power supply can be performed. Further, when the power of the printer device is not turned on, power can be supplied to the device from the USB cable by the first switching unit.

According to a fourth aspect of the present invention, when the power supply of the printer is switched from on to off, the power supply from the printer to the device is changed, and the power supply to the device is changed. In this configuration, the power supply is changed to the power supply to the device.

With this configuration, even if the power of the printer functioning as a hub is turned off, the power supply to the device connected to the printer (hub) is controlled by the US.
This is a configuration for maintaining via a B cable.

According to a fifth aspect of the present invention, in the third or fourth aspect, when power supply from the power supply on the USB cable to the device requires a current supply of a predetermined current or more, the device is connected to the device. Is stopped.

With this configuration, when the power supply to the device is changed from the printer device to the USB cable, it is possible to prevent the occurrence of a trouble when the power is immediately supplied from the USB cable. For example, current supply that can be supplied by a USB cable or more can be prevented.

[0027] Claim 6 describes claim 1, 2, 3,
In the invention described in Item 4 or 4, the first and second switching means are, for example, relays. Here, the first and second
The switching means is, for example, a relay, but the present invention is not limited to the above-mentioned relay, and may be constituted by another solid state element such as a transistor.

[0028]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 2 is a system configuration diagram of a power supply control device using a USB cable for explaining the embodiment. In the figure, a personal computer (personal computer) 5 as a host device and a printer device 6
Print data is supplied from the personal computer 5 to the printer device 6 via an SB cable. The printer device 6 is a printing device having a hub function, and has a hub function in addition to the printing process based on the above-described print data, and is connected to three USB devices 7a to 7c via connectors PT1 to PT3. I have.

Here, the above-mentioned USB device is a computer peripheral device such as a modem, a keyboard, and a speaker. A commercial power supply (100 V AC) is connected to the personal computer 5, used as a drive power supply for the personal computer 5, and supplied to the printer device 6 via a USB cable A. In addition, this US
The current that can be supplied via the B cable A is 0.1 A per hub.

On the other hand, a commercial power supply (AC
100V) is supplied, and is used as a drive power source for the printer device 6 and also as a drive power source for the aforementioned USB devices 7a to 7c.

FIG. 1 is a specific circuit configuration diagram of the printer 6 described above. The printer device 6 includes a printer power supply unit (D
C) 8, printer controller 9, USB controller 10, relays RL1, RL2, AND gate 11, connector H
T, PT1 to PT3, and transistors Q1 to Q3.

The printer power supply unit 8 is, for example, AC100V
+ 5V and + 24V
Output DC power supply. Here, the voltage conversion of the printer power supply unit 8 is an AC / DC voltage conversion circuit using, for example, a MOS transistor, a bipolar transistor, an IGBT (insulated gate bipolar transistor), or the like.

The printer control unit 9 receives +24 V power supply from the printer power supply unit 8 and performs a printing process according to the print data. That is, as described above, according to the print data output from the personal computer 5, the character code included in the print data is converted into pattern data, the print data is developed in the image memory, and the printing process on the recording paper (not shown) is performed. Do.

The above-described printer power supply unit 8 includes the first,
A drive current is supplied to relays RL1 and RL2 as second switching means. That is, when the power of the printer device 6 is turned on, the power of +24 V is also supplied to the printer control unit 9 so that the drive current flows through the coil 13 of the relay RL1 or the drive current flows through the coil 14 of the relay RL2.
The switch 15 of L1 and the switch 16 of relay RL2 are driven. The current flowing through the coil 14 of the relay RL2 is input to the USB control unit 10 as Vin.

The relay RL1 is connected to the connector HT and the connector P
It is connected between T1 and PT3 and is turned on and off by the drive current supplied from the printer power supply unit 8 as described above.
For example, the drive current from the printer power supply 8
RL1 is turned off and the connector H
The + 5V power of T is supplied to the connectors PT1 to PT3.
However, specifically, since the terminal RL1 "of the relay RL1 is connected to the collectors (C) of the transistors Q1 to Q3 and the +5 V power of the connector HT is supplied to one input of the AND gate 11, When a base current is supplied to the bases (B) of the transistors Q1 to Q3, the + 5V power supply of the connector HT is connected to the connectors PT1 to PT3.
Supply 3

On the other hand, the relay RL2 is connected between the + 5V power supply of the printer power supply 8 and the connectors PT1 to PT3, and this relay RL2 is also turned on and off by the drive current supplied from the printer power supply 8 as described above. For example, when a drive current is supplied from the printer power supply 8 to the coil 14, the relay RL2 is turned on, and the + 5V power of the printer power supply 8 is supplied to the connectors PT1 to PT3. still,
Similarly to the above, the terminal RL2 ″ of the relay RL2 is connected to the collectors (C) of the transistors Q1 to Q3, and the + 5V power of the connector HT is supplied to one input of the AND gate 11, so that the transistor Q
When a base current is supplied to bases (B) of 1 to Q3,
Connect the + 5V power supply of the printer power supply section 8 to the connectors PT1 to PT
Supply 3

The USB control unit 10 performs the USB control of the present embodiment, and comprises a CPU 10a, a RAM 10b, and an I / O unit 10c. The CPU 10a is a central processing unit that controls the power supply control device of the present example including the printer device 6, and performs processing according to a program stored in a ROM (not shown).
The RAM 10b functions as a work area when the CPU 10a performs the above-described processing, and also has a function as buffering of print data supplied to the printer control unit 9 described above.

The I / O unit 10c is connected to the USB control unit 10
And the printer control unit 9, the connector HT, and the connectors PT1 to PT1.
Input / output control between PT3 and the like is performed. The resistor R1 is connected to the coil 13 of the relay RL1, and the resistor R2 is connected to the coil 14 of the relay RL2.

On the other hand, USB has two power supply lines (+ 5V line,
GND line) and two data lines (D + line and D− line). Therefore, the connectors HT and PT1 to PT1
The PT3 also includes four connection parts for connecting the above-described lines, and has + 5V, GND, D +, and D- connection parts. Four connection parts (+ 5V, GND, D
+, D-) are connected to a USB cable (not shown), and +5 V (+5 V line) is connected to the terminal RL1 'of the relay RL1 and the AND gate 11 inside the printer device 6.
D + and D- (D + line and D-
Line) is connected to the input side of the USB control unit 10.

In the connectors PT1 to PT3, +5
V (+ 5V line) and the corresponding transistors Q1 to Q1.
The emitter (E) of Q3 is connected, and D + and D- (D +
Line and D- line) are connected to the output side of the USB control unit 10. GND (GND line) is grounded.

Ven is supplied from the USB control unit 10 to the other input of the AND gate 11, and the drive of the transistors Q1 to Q3 can be stopped by the input / output control of Ven. The function of this Ven will be described later. The control operation of the power supply control device having the above configuration will be described below.

First, the power of the printer device 6 is turned on, and a +5 V voltage is supplied from the printer power supply unit 8 to the two relays RL1 and RL2.
RL 2 and the printer control unit 9. The printer device 6 is driven by this power supply. At this time, the coil 13 of the relay RL1 and the coil 14 of the relay RL2
Are supplied with current, and the switch 16 of the relay RL2 is
Is driven in the direction of the arrow to turn on the relay RL2 and supply a voltage of +5 V to the collectors (C) of the transistors Q1 to Q3. At this time, the switch 15 of the relay RL1 is also driven in the direction of the arrow, so that the contacts RL1 'and RL1 of the relay RL1 are connected.
It is off during 1 ".

In this state, when the printer device 6 is connected to the personal computer 5 as a host device,
Hereinafter, processing according to the flowchart shown in FIG. 3 is performed. First, connect the connector HT to the USB of the personal computer 5.
When the USB controller 10 is connected to the cable A, the USB controller 10 performs an initial process, and temporarily shuts off the power of the device that functions as a hub, that is, the printer device 6 (step (hereinafter, referred to as S) 1). In this case, the USB control unit 10
Is set to “L (low level)”, and the power is shut off by shutting off the AND gate 11.

Next, it is determined whether or not there is an instruction to supply power to the hub from the personal computer 5 (S2). If there is no instruction to supply power (hub power is off), the process returns to the above-described processing (S1). On the other hand, if there is a power supply instruction from the personal computer 5 (hub power is on), power is supplied. With this power supply, the transistors Q1 to Q3
Is supplied with a high signal (the output Ven is set to “H (high level)”), and the transistors Q1 to Q3
Is turned on to supply + 5V power to the connectors PT1 to PT3 (S3).

In this state, for example, the printer 6
Is a personal computer 5 via a USB cable A
And the printer device 6 is in a driving state. When print data is supplied from the personal computer 5, the print data is supplied to the USB control unit 10 via the connector HT. As described above, this print data is supplied to the printer control unit 9 via the USB control unit 10, and is subjected to command analysis by a circuit (not shown), and, for example, print data corresponding to a character code is developed. The print data is printed on recording paper by the printer control unit 9.

During this time, the relay RL2 is on as described above, and the connector P is connected from the printer power supply unit 8 of the printer device 6 via the relay RL2 and the transistors Q1 to Q3.
Power is supplied to T1 to PT3. Therefore,
Power is supplied to the devices 7a to 7c connected to the connectors PT1 to PT3, and these devices 7a to 7c receive a sufficient power supply from the power supply of the printer device 6 and drive the respective devices.

During this time, the CPU 10a determines whether or not the power of the printer device 6 is turned off (N in S4), and the above-described processing (S2 to S4) while the power of the printer device 6 is not turned off.
repeat.

Thereafter, the printing process by the printer device 6 is completed, and the power of the printer device 6 is turned off (Y in S4). In this case, the relay RL1,
Since the drive current supplied to RL2 stops, the switches 15, 16 of the relays RL1, RL2 return in the direction of the dotted arrow. Therefore, the contacts RL2 'and RL of the relay RL2 are
2 "is turned off and the contact RL of the relay RL1 is turned off.
1 'and RL1 "are turned on. Therefore, the connector P
A voltage of +5 V on a USB cable supplied from the personal computer 5 is supplied to T1 to PT3.

However, when the personal computer 5 supplies a + 5V voltage to each device via the connectors PT1 to PT3, the supply current becomes a predetermined value (for example, 0.1 A in this example).
Is determined (S5). Here, if the supply current exceeds a predetermined value, it is determined that the current supply by the USB cable A is impossible (Y in S5), and the output of Ven by the USB control unit 10 of the printer device 6 is set to “L”. "Level. In this case, the AND gate 11 is turned off, the transistors Q1 to Q3 are turned off, and the connector PT1 is turned off.
Stop power supply to PT3.

On the other hand, if the supply current is within the predetermined value range, the current supplied from the personal computer 5 via the USB cable A is used. As described above, when a current supply of a predetermined value (for example, 0.1 A) or more is required, U
In order to prevent an overcurrent from flowing through the SB cable, the supply of current to each device is stopped, and when the value is equal to or less than a predetermined value, the current is supplied to the device.

In the above-described embodiment, the printer device is described as an example of a device connected to the personal computer 5 and having a hub function. However, another device may be used. For example, peripheral devices such as a scanner device and a speaker device may be used.

In the above-described embodiment, the connectors PT1 to PT1 are supplied by the Ven output supplied to the AND gate 11.
Power supply to PT3 is cut off, but individual connectors PT3
The power supply may be cut off every 1 to PT3.

Although the relays RL1 and RL2 are used as the first and second switching means, the present invention is not limited to the relay RL,
Other switching means such as an S transistor and a bipolar transistor may be used.

FIG. 4 is a diagram for explaining a modification of the above-described embodiment. By using the circuit configuration shown in FIG. 4 to detect the power supply of the printer device, the power supply of the printer device 6 can be turned off earlier. Can be detected by

That is, in FIG. 1 described above, the +24 V output of the printer power supply unit 8 has the circuit configuration shown in FIG.
This is supplied to the control unit 10. Specifically, an operational amplifier is used as the comparator 20 and the comparator 2
A non-inverting input (+ input) of 0 inputs the voltage at the connection point between the above-mentioned resistors R3 and R4 connected between + 24V and ground, and a non-inverting input (-input) connects the resistor R connected between + 5V and ground.
Input the voltage at the connection point between R5 and R6. With this configuration, when the power of the printer device 6 is turned off, the +24 V voltage first drops to, for example, about 15 V, the output of the comparator 20 is inverted from “H” to “L”, and the You can know that the power is off. That is, after the + 24V voltage first decreases to about 7V,
Since the V voltage drops, the USB control unit 10 can know that the power of the printer device 6 is turned off before being adversely affected by the voltage drop.

[0056]

As described above, according to the present invention, even when the power supply of a device having a hub function such as a printer is turned off, sufficient power can be supplied to peripheral devices connected to the device. .

In addition, even if the power supply of the above-mentioned apparatus is off, if the current is less than a predetermined value, it can be supplied to peripheral devices, and the switching can be performed automatically.

[Brief description of the drawings]

FIG. 1 is a specific circuit configuration diagram of a printer device.

FIG. 2 is a system configuration diagram of a power control device using a USB cable for explaining the embodiment.

FIG. 3 is a flowchart illustrating an example of the embodiment.

FIG. 4 is a diagram illustrating a modification of the present embodiment.

FIG. 5 is a diagram illustrating an example in which a USB (Universal Serial Bus) of five layers is used.

FIG. 6 is a diagram illustrating a system configuration of a conventional power supply control device.

[Explanation of symbols]

 Reference Signs List 5 Personal computer 6 Printer device 7a to 7c USB device 8 DC control unit 9 Printer control unit 10 USB control unit 11 AND gate 13, 14 Coil 15, 16 Switch R1 to R6 Resistance HT, PT1 to PT3 Connector Q1 to Q3 Transistor RL1, RL2 relay

Claims (6)

[Claims] 1. A power supply control device using a USB cable and including a device having a hub function, wherein a power supply on the USB cable is disconnected when the power supply of the device is on, and connected when the power supply of the device is off. First
Switching means, and connecting the power supply of the device when the power supply of the device is on,
A second switching unit that disconnects when the power of the device is off; and a power supply connected by the first and second switching units.
A power supply unit for supplying power to a device connected to the device via a hub. 2. A power supply control device including a printer device having a hub function using a USB cable, wherein a power supply on the USB cable is disconnected when the power supply of the printer device is on, and the power supply of the printer device is off. First switching means for connecting when the power of the printer is turned on, and second switching means for disconnecting when the power of the printer is turned off, and disconnecting when the power of the printer is turned off; , The power supply connected by the second switching means,
Power supply means for supplying power to a device connected to the printer device via a hub. 3. When the power of the printer is turned on, the first switching unit is driven to supply the power of the printer to the device, and when the power of the printer is turned off, the USB cable is turned off. The power supply control device according to claim 2, wherein the power supply is supplied to the device. 4. When the power supply of the printer device is switched from on to off, the power supply from the printer device to the device is changed, and the power supply from the USB cable is supplied to the device. The power supply control device according to claim 2, wherein: 5. The apparatus according to claim 3, wherein, when power is supplied from the power supply on said USB cable to said device and a current supply of a predetermined current or more is required, current supply to said device is stopped. Or the power supply control device according to 4. 6. The power supply control device according to claim 1, wherein said first and second switching means are relays.