JPH11143559A - Power unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control the start order of plural power output circuits. SOLUTION: A DC-CD converter 3 and an AC-DC adapter 2 which are plural power output circuits when they are seen externally are provided, the converter 3 is also driven by the adapter 2, also, a sequence circuit 6 makes the power of the adapter 2 output through a power MOSFET transistor 15 after the output voltage of the converter 3 rises, and therefore, it is possible to surely control the start order of respective power output circuits which are externally seen. Because current flows through the FET transistor 15 gradually at the time of start, it is also possible to make a rush current small. Also, it is possible to control disconnection order by providing contact circuit 10a and 10b in a power supply switch 10 with them divided into an input side and an output side of respective power output circuits.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a power supply device,
In particular, the present invention relates to a power supply device having a plurality of power supply output circuits.

[0002]

2. Description of the Related Art Conventionally, power supply devices for controlling the activation of a single power supply output circuit are disclosed in Japanese Patent Application Laid-Open Nos. 1-1970, 3-89375 and 4-17.
The invention disclosed in Japanese Patent No. 2921 is known.

[0003]

In the above-described conventional power supply device, only a single DC-DC converter circuit or the like performs the start control of slow start, and a plurality of power supply output circuits are provided. In this case, the starting order cannot be controlled.
In addition, although it is not impossible to control the startup sequence by adjusting each slow start time, the startup sequence is not controlled in principle, so the order may be reversed due to aging etc. possible.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a power supply device capable of reliably controlling the start-up sequence when a plurality of power supply output circuits are provided.

[0005]

In order to achieve the above object, the invention according to claim 1 comprises a plurality of power supply output circuits,
A startup sequence control circuit for controlling the startup sequence of the plurality of power supply output circuits is provided.

In the invention according to claim 1 configured as described above, a plurality of power supply output circuits are provided, respectively, and a start-up sequence control circuit controls a start-up order of the plurality of power supply output circuits. Thereby, the power supply output circuits are activated in a desired order.

In this case, the power supply output circuits need only be externally controlled in the activation order, and the physical power supply output circuits do not necessarily have to be activated sequentially. For example, a plurality of output terminals may be provided as a power supply device, and the output power may appear at each output terminal in a predetermined order. In this case, a plurality of power supply circuits exist inside, and they may be activated in the respective order.

As an example of this, according to a second aspect of the present invention, in the power supply device according to the first aspect, the power supply output circuit includes a first power supply output circuit activated first and a second power supply output activated later. And the first power supply output circuit is driven by an output power supply of the second power supply output circuit, and the control circuit is interposed in an output path of the second power supply output circuit. A switch circuit that is normally in a cutoff state when conducting and blocking an output path, and a switch drive circuit that drives the switch circuit from a cutoff state to a conduction state using an output of the first power supply output circuit. There is a configuration to have.

According to the second aspect of the present invention, the first power supply output circuit is activated first, and the second power supply output circuit is activated later. The first power supply output circuit is driven by the output power supply. Therefore, although the first power supply output circuit will be started later if this state is maintained, the switch circuit of the control circuit is interposed in the output path of the second power supply output circuit and is normally in the cutoff state. Therefore, the output of the first power supply output circuit is supplied to the outside first. The switch driving circuit uses the output of the first power supply output circuit to drive the switch circuit from the cut-off state to the conduction state, so that the output of the first power supply output circuit is supplied to the outside. Thus, the output of the second power supply output circuit is also supplied to the outside.

As a specific example, the invention according to claim 3 is the charging circuit according to claim 2, wherein the switch driving circuit is charged by using an output of the first power output circuit. And the switch circuit is configured to include a switching element that changes from a cut-off state to a conductive state when the charging voltage of the charging circuit becomes a predetermined value or more.

In the invention according to claim 3 configured as described above, the charging circuit as the switch driving circuit is charged by using the output of the first power supply output circuit. It is gradually charged after the first power supply output circuit starts to output. On the other hand, the switching element as the switch circuit monitors the charging voltage of the charging circuit, and changes from a cutoff state to a conduction state when the charging voltage exceeds a predetermined value. Therefore, the switching element is turned on after a lapse of a predetermined time from the output of the first power supply output circuit, and the output of the second power supply output circuit is supplied to the outside.

[0012] In this case, as an example of ensuring that the charging of the charging circuit is performed later than the output of the first power supply output circuit, the invention according to claim 4 is the invention according to claim 2 or 3. Wherein the switch drive circuit charges the charging circuit when the output of the first power supply output circuit becomes equal to or higher than a predetermined voltage.

[0013] In the invention according to claim 4 configured as described above, the switch driving circuit charges the charging circuit when the output of the first power supply output circuit exceeds a predetermined voltage. Even when the output of the first power supply output circuit gradually rises, the output to the charging circuit for starting the second power supply output circuit is started after the output can be reliably obtained. Is done.

As an example of the switch circuit, the invention according to claim 5 is the power supply device according to any one of claims 2 to 4, wherein the switch circuit is a power MOSF.
It is configured to include ET. In the invention according to claim 5 configured as described above, since the power MOSFET is interposed in the second power supply output circuit, the output of the power MOSFET is effectively cut off and opened effectively.

As an application example of the plurality of power supply output circuits whose start is controlled in this way, the invention according to claim 6 is the power supply device according to any one of claims 1 to 5,
The power supply output circuit activated first supplies power to the control circuit, and the power supply output circuit activated later supplies power to the drive mechanism.

According to the sixth aspect of the present invention, the power output circuit which is activated first supplies power to the control circuit, and after the power can be reliably controlled, the drive mechanism is activated later. Since the power supply output circuit supplies power, the drive mechanism is not driven even if an unstable control state occurs initially in the control circuit.

As a specific example, the invention according to claim 7 is the power supply device according to claim 6, wherein the control circuit is a printer logic circuit, and the driving mechanism is a printer head. In the invention according to claim 7 configured as described above, since the printer logic circuit in the printing apparatus is normally started and then the power is supplied to the printer head, an inadvertent printer head drive current is supplied. Nothing.

Further, according to an eighth aspect of the present invention, in the power supply device according to any one of the first to seventh aspects, the control circuit controls the disconnection order of each power supply output circuit. .

In the invention according to claim 8 configured as described above, the control circuit controls not only the starting order of the power supply output circuits but also the disconnection order. In the case of a printing apparatus, for example, the driving current to the printer head is not supplied first, and then the driving current to the logic circuit is cut off. Of course, also in this case, it is possible to prevent the logic circuit from stopping first and an inadvertent drive current being supplied to the printer head.

According to a ninth aspect of the present invention, in the power supply device according to the eighth aspect, a switch element having a plurality of independent contact circuits is provided, and the contact circuit is provided in an output path of the power supply output circuit that needs to be disconnected quickly. And a contact circuit is interposed in the input path of the power supply output circuit for cutting off slowly.

According to the ninth aspect of the present invention, there is provided a switch element having a plurality of independent contact circuits, and the power is turned on and off by operating the switch element. In this case, a contact circuit is interposed in the output path of the power supply output circuit that needs to be disconnected earlier, and a contact circuit is interposed in the input path of the power supply output circuit that needs to be disconnected later. If a contact circuit is interposed in the output path, the power is instantaneously shut off by performing an operation of cutting with a switch element. On the other hand, in the case where a contact circuit is interposed in the input path, the input is cut off instantaneously, but the power is usually stored in the power supply output circuit, so the output continues for a short time. , Gradually decay. Therefore, the power supply output circuit in which the contact circuit is interposed in the input path is disconnected later.

According to a tenth aspect of the present invention, in the power supply device according to any one of the first to ninth aspects,
The power supply output circuit is configured to execute slow start. In the invention according to claim 10 configured as described above, the power supply output circuit is configured to start slowly, so that the power supply output circuit is activated in a predetermined order and the output is gradually supplied at the time of activation. become.

[0023]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a circuit diagram showing a power supply device according to a first embodiment of the present invention, and FIG. 2 is a timing chart showing its operation.

In FIG. 1, an AC 1
An AC-DC adapter 2 as a second power supply output circuit for converting 00V to DC 24V is connected.
The DC 24 V output of the adapter 2 is supplied to a DC-DC converter 3 as a first power supply output circuit.
The converter 3 converts DC 24V to DC 5V and outputs it. The output of the DC-DC converter 3 is supplied to a logic circuit 4 in the printing apparatus, and the output of the AC-DC adapter 2 is supplied to a printer head 5 in the printing apparatus as a driving mechanism. It has become. However, a sequence circuit 6 is interposed between the AC-DC adapter 2 and the printer head 5, and the sequence circuit 6 gradually turns on the AC-D converter after the output of the DC-DC converter 3 normally rises.
The output of the C adapter 2 is output to the printer head 5.

This sequence circuit 6 has a constant voltage diode 19 and a resistor 20 interposed in series between the output side of the DC-DC converter 3 and the ground. To the base of the transistor 17. Therefore, when the output voltage of the DC-DC converter 3 becomes higher than the set voltage of the constant voltage diode 19, a current flows through the resistor 20, and the base current is supplied to the transistor 17.

The power MOSFET transistor 1 is connected between the AC-DC adapter 2 and the printer head 5.
5 is connected between the drain and source, and
A parallel circuit of a resistor 13 and a capacitor 14 is connected between the gate of the ET transistor 15 and the ET transistor 15. This parallel circuit is further connected to ground via the collector-emitter of the transistor 17 via a resistor 16. That is, when the transistor 17 is turned on, a current flows through the parallel circuit and the resistor 16, and the capacitor 14 is charged. In addition, about the resistance value, resistance 1
3 >> resistor 16, and the time constant in charging is the product of the capacitance of capacitor 14 and the resistance of resistor 16.

As described above, the transistor 17 is connected to DC-
Since the output of the DC converter 3 becomes conductive after the output becomes equal to or higher than the set voltage value of the constant voltage diode 19, the capacitor 14 starts to be charged gradually from that time. Initially, F
Since the ET transistor 15 is in an unsaturated state,
The output of the AC-DC adapter 2 is not immediately output to the printer head 5, but is output as the charging voltage of the capacitor 14 rises and the FET transistor 15 changes from an unsaturated state to a saturated state. Begin to.

Incidentally, a capacitor 11 and a resistor 12 are connected in parallel to the ground between the AC-DC adapter 2 and the printer head 5 in order to stabilize the driving current in the printer head 5. In order to stabilize the supply voltage, it is preferable that the capacity of the capacitor 11 is large. If only the existing technology is applied, as shown in FIG. 3, a capacitor 11 and a resistor 12 are simply connected in parallel between the AC-DC adapter 2 and the printer head 5 without the sequence circuit 6 or the like. It will be connected to ground.

However, in this state, when the power is turned on, the rush current flowing from the AC-DC adapter 2 to the capacitor 11 becomes too large, the output of the DC-DC converter 3 becomes unstable, and the operation of the logic circuit 4 becomes unstable. May be unstable. However, as shown in FIG.
With the interposition of the power supply 15, the impedance becomes large since the power supply is turned on to be in a non-saturated state at the beginning of power-on, and the initial rush current is suppressed.

A power switch 10 having contact circuits 10a and 10b is provided. The contact circuit 10b is interposed in an output path from the AC-DC adapter 2 to the printer head 5, and includes a contact circuit. 1
0a is interposed on the input side of the DC-DC converter 3.

When the power is turned on, the contact circuits 10a and 10b are simultaneously turned on. However, as described above, the output of the AC-DC adapter 2 is controlled by the FET 15, and is not output immediately, as shown in FIG. After the output of the DC-DC converter 3 rises, the output of the AC-DC adapter 2 is supplied. However, when the power switch 10 is turned off, the contact circuit 10b interposed in the output path of the printer head 5 is turned off, so that the drive current to the printer head 5 is immediately cut off. On the other hand, the contact circuit 10
Although a is also turned off immediately, it is interposed on the input side of the DC-DC converter 3, so that the output continues as much as is stored in the capacitor and the like provided inside, and gradually attenuates. This situation is shown in FIG.

Next, the operation of this embodiment having the above configuration will be described. Assuming that the AC-DC adapter 2 is connected to the AC power supply 1 and the power switch 10 is off,
No power is supplied to the DC-DC converter 3, no power is supplied to the logic circuit 4, no power is supplied to the sequence circuit 6, and no power is supplied to the printer head 5.

When the power switch 10 is turned on from this state, the contact circuit 10a is turned on, and the output of the AC-DC adapter 2 is supplied to the DC-DC converter 3, and
The output voltage of the C-DC converter 3 gradually increases and starts to be supplied to the logic circuit 4.

On the other hand, until the output voltage of the DC-DC converter 3 exceeds the set voltage of the constant voltage diode 19, the transistor 17 is off. Since the transistor 17 serves as a charging path to the capacitor 14 via the resistor 16, the capacitor 14 is not charged while the transistor 17 is off. Therefore, FE
The T transistor 15 is in an unsaturated state and has high impedance.

Sequence circuit 6 via contact circuit 10a
The 24 V power supplied to the FET transistor 15 is applied to the FET transistor 15 but is in a non-saturated state and has a high impedance, so that no current flows. Therefore, power is not supplied to the printer head 5 either.

However, when the output voltage of the DC-DC converter 3 rises and exceeds the set voltage of the constant voltage diode 19, a current flows through the constant voltage diode 19 and the resistor 20, and the voltage drop by the resistor 20 Accordingly, a base current is supplied to the transistor 17 and the transistor 17 is turned on. Then, the capacitor 14 is charged based on a time constant determined by the capacitance of the capacitor 14 and the resistance value of the resistor 16, and the FET transistor 15 changes from a non-saturated state to a saturated state due to the charged voltage. Accordingly, the output voltage to the printer head 5 also increases.

The current in which the FET transistor 15 changes to the saturated state starts to flow, and the rush current for charging the capacitor 11 tends to increase.
The current is suppressed by an amount corresponding to the higher impedance of the ET transistor 15, and the rush current can be prevented from becoming excessive. Further, since the inrush current is small, the contact circuits 10a, 1
There is almost no arc at the time of chatter of 0b, and wear of the contacts of the power switch 10 can be prevented, and the life can be extended.

In the power-on process, power is supplied to the logic circuit 4 first, and then power is supplied to the printer head 5. That is, since the driving power of the printer head 5 is supplied after the logic circuit 4 can start the normal operation, an excessive current flows through the printer head 5 due to the malfunction of the logic circuit 4 and the malfunction occurs. I can't tell you anything.

When the power switch 10 is turned off,
Since the contact circuit 10b is turned off, the driving power for the printer head 5 is instantaneously cut off. On the other hand, the contact circuit 10
Even if a is turned off and power is no longer supplied to the DC-DC converter 3, the DC-DC converter 3 normally continues to operate due to the power remaining in the power supply output circuit. Then, when the accumulated power is running out after a very short time, its output gradually decreases. Immediately when the power supply to the logic circuit 4 is cut off, an erroneous operation which is hard to imagine may occur. However, at this point, the power supply to the printer head 5 has already been cut off. Will not leave.

Next, a second embodiment of the present invention will be described. FIG. 4 is a circuit diagram showing the power supply device according to the second embodiment, and FIG. 5 is a timing chart showing its operation. Note that components that are the same as or correspond to those in the first embodiment are denoted by the same reference numerals.

In the second embodiment, a DC power supply for supplying 35 V power to the LCD drive circuit 7 is provided.
The DC-DC converter 8 is provided, and the sequence circuit 6 controls the starting sequence so that the DC-DC converter 8 starts up last. That is, in the sequence circuit 6, when the output voltage of the DC-DC converter 3 rises, the first set of outputting the output voltage of 24V of the AC-DC adapter 2 to the printer head 5 and the printer head 5 A second set of transistors 17 and 15 is provided which is turned on when the output voltage rises. Therefore, the power supply startup sequence is 5V,
The order is 24V and 35V.

On the other hand, the power switch 10 has a third contact circuit 10c between the DC-DC converter 8 and the LCD drive circuit 7. Therefore, the power switch 10
When you turn off the printer head 5 and LCD
The drive power to the drive circuit 7 is cut off,
The power to the logic circuit 4 is cut off with a delay for a very short time.

Thus, when viewed from the output side, the DC-DC converter 3 and the AC-D
C-adapter 2 and the DC-DC converter 3 is driven by the AC-DC adapter 2, and the sequence circuit 6
Since the power of the AC-DC adapter 2 is output via the power MOSFET transistor 15 after the output voltage of the power supply circuit rises, the start-up sequence of each power supply output circuit can be reliably controlled when viewed from the outside. Since the current gradually flows through the FET transistor 15 at the time of startup, the rush current can be reduced. Also, contact circuits 10a, 10b in the power switch 10
Is provided on the input side and the output side of each power supply output circuit in a practical sense, so that the cutting order can be controlled.

[0044]

As described above, according to the present invention, it is possible to provide a power supply device capable of reliably controlling the start-up sequence of a plurality of power supply output circuits. Further, according to the invention according to claim 2, the power supply output circuit that starts later supplies power to the power supply output circuit that starts first, and the power output circuit that starts up first uses the output power of the power supply output circuit that starts first. At first glance, control that controls the output path of the power supply output circuit on the activation side makes it possible to reliably control activation.

Further, according to the third aspect of the present invention,
It can be constituted by a simple charging circuit. Further, according to the fourth aspect of the invention, the operation is stabilized by strictly setting the condition for starting charging the charging circuit.

Further, according to the fifth aspect of the present invention,
By providing sufficient current resistance, current control can be performed reliably. Further, according to the invention of claim 6, it is possible to reliably supply power to the control circuit and the driving mechanism and to prevent unstable operation.

Further, according to the seventh aspect of the present invention,
The unstable operation of the printer head of the printing apparatus can be prevented. Furthermore, according to the invention of claim 8, it is possible to control not only the activation order but also the disconnection order.

Further, according to the ninth aspect of the present invention,
The cutting order can be controlled by a simple configuration such as arranging a contact circuit on the input path side or the output path side in each power supply output circuit.

Further, according to the tenth aspect of the present invention, the output of each power supply output circuit can be gradually increased according to the starting order.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a power supply device according to an embodiment of the present invention.

FIG. 2 is a timing chart of the power supply device.

FIG. 3 is a circuit diagram of a power supply device as a comparative example.

FIG. 4 is a circuit diagram of a power supply device according to a second embodiment.

FIG. 5 is a timing chart of the power supply device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Commercial AC power supply 2 AC-DC adapter 3 DC-DC converter 4 Logic circuit 5 Printer head 6 Sequence circuit 7 LCD drive circuit 8 Converter 10 Power switch 10a Contact circuit 10b Contact circuit 10c Contact circuit 11 Capacitor 12 Resistance 13 Resistance 14 Capacitor 15 Power MOSFET transistor 16 resistor 17 transistor 18 resistor 19 constant voltage diode 20 resistor

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FIG06F 1/00 334D

Claims (10)

[Claims] 1. A power supply device comprising: a plurality of power supply output circuits; and a start-up sequence control circuit that controls a start-up order of the plurality of power supply output circuits. 2. The power supply device according to claim 1, wherein the power supply output circuit includes a first power supply output circuit that starts first and a second power supply output circuit that starts later. The first power supply output circuit is driven by the output power supply of the second power supply output circuit, and the control circuit intervenes in the output path of the second power supply output circuit to conduct and cut off the output path. A power supply, comprising: a switch circuit that is normally in a cut-off state; and a switch drive circuit that drives the switch circuit from a cut-off state to a conductive state by using an output of the first power supply output circuit. apparatus. 3. The power supply device according to claim 2, wherein the switch driving circuit includes a charging circuit that is charged by using an output of the first power supply output circuit, and the switch circuit includes a charging circuit that charges the battery. A power supply device comprising: a switching element that changes from a cut-off state to a conductive state when a charging voltage of a circuit becomes a predetermined value or more. 4. The power supply device according to claim 2, wherein the switch drive circuit comprises:
A power supply device, wherein the charging circuit is charged when an output of the first power supply output circuit becomes a predetermined voltage or more. 5. The power supply device according to claim 2, wherein the switch circuit includes a power M
A power supply device comprising an OSFET. 6. The power supply device according to claim 1, wherein the power supply output circuit activated first supplies power to the control circuit, and the power supply output circuit activated later is connected to the power supply output circuit. A power supply device for supplying power to a driving mechanism. 7. The power supply device according to claim 6, wherein the control circuit is a printer logic circuit, and the driving mechanism is a printer head. 8. The power supply device according to claim 1, wherein the control circuit controls the disconnection order of each power supply output circuit. 9. The power supply device according to claim 8, further comprising: a switch element having a plurality of independent contact circuits, wherein the contact circuit is interposed in an output path of the power supply output circuit that needs to be disconnected quickly, and the power supply circuit is disconnected late. A power supply device comprising a contact circuit interposed in an input path of a power output circuit. 10. The power supply device according to claim 1, wherein the power supply output circuit executes a slow start.