JPH1011183A - Live plug inserting method and electronic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control a rush current at the time of inserting a live plug correspondingly to each electronic circuit unit. SOLUTION: An electronic circuit unit 3 is loaded to a mother board 1 through a connector 11 and power is supplied from a power source 4 to the unit 3. A rush current preventing circuit 2 consisting of plural feeding routes is formed on the mother board 1. At the time of inserting a live plug to the unit 3, the pins 3b, 3c, 3d of the unit 3 are connected to the pins 11b, 11c, 11d of the connector 11, and after a slight delay, a pin 3a is connected to a pin 11a. At the time of sensing the insertion of the live plug to the unit 3 through an input line 12-1 by the connection between the pin 3d and the pin 11d, the circuit 2 controls the open/close of a feeding route optimally to the unit 3 and gradually increases a rush current into the unit 3 through an output line 13. When the pin 3a is connected to the pin 11a, power is supplied from the power source 4 to the unit 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a configuration in which a plurality of operating electronic circuit units are present in an operating system, and a part of the unit is replaced or added while the system is operating. / Regarding insertion / extraction technology,
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stopcock insertion method and an electronic device suitable for reducing inrush current when a stopcock is inserted.

[0002]

2. Description of the Related Art When a plurality of electronic circuit units such as packages (printed circuit boards) are mounted on a motherboard and supplied with the same power supply, when a stopcock is inserted for replacement or addition of some units, the electronic circuit unit may be replaced. Excessive rush current flows due to a power supply noise prevention bypass capacitor between the power supply and the ground. As a result, there is a problem that the power supply voltage of the motherboard is reduced and other operating electronic circuit units malfunction.

Conventionally, as a measure to prevent this, as described in, for example, Japanese Patent Application Laid-Open No. 1-2395995, an inrush current power supply pin and a main power supply pin are provided in each unit (package), and the length of the inrush current power supply pin is reduced. In addition to making the power longer than the main power supply pin, a limiting resistor is provided between the inrush current power supply pin and the main power supply, and when a stopcock is inserted, the inrush current power supply pin is first connected and power is supplied while limiting the inrush current with the limiting resistor. Then, a method is known in which a main power supply pin is connected to prevent a power supply voltage drop due to an inrush current. Further, as described in Japanese Patent Application Laid-Open No. 5-327244, for example, a plurality of limiting resistors are provided between a rush current power supply pin and a main power supply via a switch so that a charging voltage of a capacitor reaches a predetermined switching voltage. Then, a method of distributing the peak value of the inrush current by switching the limiting resistance so as to decrease the resistance value is known.

[0004]

In the prior art, when there is only one limiting resistor, the sum of the rush current limited by the limiting resistor and the current of the other unit (package) in operation causes the power supply potential to drop. There is no problem if it is within the allowable range. However, when an inrush current is added, the current cannot be applied if the current falls outside the allowable range. If the electrical resistance is increased to reduce the inrush current, the power supply potential between the inrush current power supply pin (long pin) and the main power supply pin (short pin) connection of the unit is determined by the ratio of electrical resistance to internal resistance. As the potential decreases and the difference from the original power supply potential increases, the inrush current flowing from the main power supply pin when the main power supply pin is connected increases, resulting in a decrease in the power supply potential. Further, in the case where a normal operation of the power reset circuit of the package and a high impedance state of the output signal are expected until the main power supply pin is connected, a malfunction occurs when the power supply potential is low.
And so on.

[0005] These problems can be solved to some extent by providing a plurality of limiting resistors and switching according to the rise of the charging voltage. However, in the prior art, it is necessary to provide each package with a limiting resistor group and switching control means. There is a problem that the physical quantity of the package increases. Also,
When there are a plurality of types of packages having different operating conditions and internal resistances, it is necessary to mount a limiting resistor group having a different resistance value and a switching limiting means having a different control condition for each package. Uneconomical,
In addition, there is a problem that errors easily occur.

SUMMARY OF THE INVENTION It is an object of the present invention to eliminate the above problems in the prior art and to provide a stopcock insertion method and an electronic device in which the system does not malfunction.

[0007]

According to the present invention, a rush current prevention circuit is provided in a motherboard or a common unit (herein collectively referred to as a motherboard) connected to the motherboard, and an output line thereof is connected via a connector. And a connection to the inrush current power supply pin of each electronic circuit unit.
The inrush current prevention circuit includes a plurality of power supply paths through which a current limited by an electric resistance or the like can flow, and a control unit that controls opening and closing of the power supply paths. Multiple power supply paths are opened sequentially for each, and the number of open power supply paths increases over time,
The rush current of the electronic circuit unit is gradually increased.

Further, the control unit is constituted by a one-chip microcomputer or the like, and a sequence of opening and closing the power supply path is programmed in advance for each electronic circuit unit. Optimally controls the opening and closing of multiple power supply paths for each unit.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an overall configuration diagram of an embodiment of the present invention. In the figure, reference numeral 1 denotes a motherboard, which is supplied with power from an external power supply 4 and supplies power to an electronic circuit unit (package) 3 via a connector 11. A plurality of connectors 11 are mounted on the motherboard 1 and are mutually connected. Therefore, the units 3 are mounted on the motherboard 1 by the number of the connectors 11 and are supplied with power from the power supply 4 in common. The motherboard 1 is provided with an inrush current prevention circuit 2, and the unit 3 is connected to the circuit 2 via a connector 11.

The pin group of the connector 11 includes a main power supply pin 11 a connected to the main power supply line 41 of the power supply 4 and a ground line 42.
Ground pin 11b connected to the rush current prevention circuit 2
And an input pin 11d connected to one of the input line groups 12-1 to 12-n of the inrush current prevention circuit 2. Of these, pin 11
Although a, 11b, and 11c are commonly connected to each other among the connectors, the pin 11d is individually connected to the corresponding input line (here, 12-1) of the inrush current prevention circuit 2 for each connector. Only the main power supply pin 11a is a short pin, and the other pins 11b, 11c and 11d are long pins.

The pin group of the unit 3 includes a main power supply pin 3a, a ground pin 3b corresponding to the main power supply pin 11a and a ground pin 11b of the connector 11, and a connector 1
The inrush current prevention circuit includes a rush current power supply pin 3c connected to the output pin 11c and a unit-side output pin 3d connected to the input pin 11d. Within unit 3,
The rush current power supply pin 3c is connected to the main power supply pin 3a via the diode D to become a power supply point 32, and power is supplied to the main circuit 31 of the unit 3. The main circuit 21 can be equivalently represented by a parallel circuit of an internal resistance r and a capacitance C,
The other end is connected to the ground pin 3b. When the output pin 3d is connected to the ground pin 3b and the unit 3 is hot-plugged into the connector 11, a signal at the same level as the ground pin 3b is transmitted to the inrush current prevention circuit 2 via the output pin 3d.

FIG. 2 is a detailed diagram of the inrush current prevention circuit 2.
A plurality of power supply paths 22-1 to 22 -m (a power supply path 22 -m
And a control unit 21 for controlling the opening and closing of the plurality of power supply paths. The control unit 21 includes, for example, 1
Each of the input lines 12-1 to 12-n corresponding to each unit is constituted by a chip microcomputer, and each of the power supply paths 22-1 to 22-n.
It is possible to program the 2-m opening / closing control sequence.

FIG. 3A shows the power supply paths 22-1 to 22-m by the control unit 21 for the input line 12-1.
Control time chart of the open / close signals 21-1 to 21-m,
(B) shows a power supply point 3 of the unit 3 when power is supplied to the unit 3 through the power supply paths 22-1 to 22-m according to (a).
2 is a potential change. The time axes of FIGS. 3A and 3B are the same.

Next, the operation of the electronic circuit unit (package) 3 when a stopcock is inserted will be described with reference to FIGS. 1, 2 and 3. FIG.

When several electronic circuit units are connected to the motherboard 1 and they are in operation, the power supply path opening / closing signals 211 to 21-m of the control unit 21 in FIG. ２２22-m MOS transistors Tr1 to Trm are turned off, and the power supply paths are all closed. In this case, each operating unit is supplied with power from the main power supply line 41 via the connector.

Now, as shown in FIG.
Is inserted into the connector 11 by a stopcock, a power supply pin 3c, an output pin 3d, and a ground pin 3b for inrush current of the unit 3
However, almost at the same time, the long pins 11c, 11d,
The output line 13 and the input line 121 of the inrush current prevention circuit 2 and the ground line 42 of the power supply 4 are connected via the line 11b. Before the unit 3 is connected, the input line 121 is at a high level due to the resistor R1-1 connected to the main power supply line 41 shown in FIG. Grand Bell). Based on the signal change of the input line 121, the control unit 21 senses that the unit 3 is connected, starts opening / closing control of the power supply paths 22-1 to 22-m according to a sequence programmed in advance, and outputs The power is supplied to the unit 3 via the line 13, the output pin 11c, the inrush current power supply pin 3c, and the diode D. At this time, the main power supply pin (short pin) 11 of the connector 11
a and the main power supply pin 3a of the unit 3 are not connected.

As shown in FIG. 3A, when the input line 121 to the unit 3 changes to low level, first, the control unit 21 changes the power supply path switching signal 211 to low level.
The power supply path 22-1 is opened by turning on the MOS transistor Tr1. As a result, as shown in FIG. 3B, the potential of the power supply point 32 of the unit 3 rises and settles down to the internal resistance r of the unit 3 and the divided voltage value of the resistance R2-1 of the power supply path 22-1 (MOS The on-resistance of the transistor is negligibly small.) Hereinafter, the control unit 21
As shown in FIG.
1-m is sequentially set to a low level at an arbitrary time according to a predetermined sequence, so that the power supply path 22-2
~ 22-m. Thereby, as shown in FIG. 3B, the potential of the feeding point 32 of the unit 3 sequentially increases.
This is because the potential of the feeding point 32 of the unit 3 is equal to the internal resistance r
This is because it is determined by the divided voltage value of the combined resistance value of the plurality of power supply paths, and the combined resistance value decreases as the number of open power supply paths increases.
Finally, when the power supply path 22-m is opened, the potential of the power supply point 32 of the unit 3 is changed from the potential of the main power supply line 41 to the diode D of the unit 3 (the forward voltage is small) via the power supply path 22-m. Is used and rises to a reduced potential (from 0.3 V to about 0.5 V). Thereafter, the main power supply pin 3a of the unit 3 is connected to the main power supply pin 11a of the connector 11, and the power supply point 32 of the unit 3 becomes the main power supply potential.
The control unit 21 sends the power supply path open / close signal 21- at a time sufficiently after the time when the main power supply pin 3d of the unit 3 is connected.
1 to 21-m are set to a high level, and the power supply paths 22-1 to 22-2 are set.
2-m is closed.

For the sake of simplicity, in FIG. 3, the power supply paths 22-1 to 22-m are sequentially opened one by one. For example, when the unit 3 has an extremely small internal resistance r. By opening a plurality of power supply paths several times, the potential of the power supply point 32 of the unit 3 can be increased. If the unit 3 is expected to operate normally and establish a high impedance state of the output signal before the unit 3 is connected to the main power supply pin 3a, the power supply point 32 is connected immediately after the hot plug is inserted. It is necessary to increase the potential near the main power supply, but this is done by increasing the potential of the power supply point 32 of the unit 3 by narrowing the time interval in which the control unit 21 opens each of the power supply paths 22-1 to 22-m. Time can be hastened.

As described above, the electronic circuit unit 3 is connected to the connector 11
The control unit 21 of the inrush current prevention circuit 2 detects the insertion of a stopcock for each unit through the input lines 12-1 to 12-n, and can control each unit. It is. Also, in FIG.
Although the first main power supply pin 11a is a short pin, the same operation can be performed even when the main power supply pin 3a of the electronic circuit unit 3 is a short pin.

[0020]

As described above, according to the present invention, an inrush current prevention circuit comprising a plurality of power supply paths common to each electronic circuit unit is provided on a motherboard, and an inrush current is flowed little by little. The power supply potential can be prevented from dropping without providing a limiting resistor group and its switching control means in the unit (package), and the power supply potential of the unit is increased to near the main power supply potential before the main power supply pin of the unit is connected. As a result, the rush current when the main power supply pin is connected can be reduced.

If a control unit for controlling the opening and closing of a plurality of power supply paths is constituted by a one-chip microcomputer or the like, and the sequence of opening and closing the power supply paths is programmed for each unit in advance, there is flexibility for each unit. Inrush current control is possible.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of an embodiment of the present invention.

FIG. 2 is a detailed diagram of the inrush current prevention circuit of FIG. 1;

FIG. 3 is a diagram showing a time chart of a power supply path opening / closing signal of an inrush current prevention circuit and a change in power supply potential of an electronic circuit unit.

[Explanation of symbols]

 Reference Signs List 1 motherboard 2 inrush current prevention circuit 3 electronic circuit unit 11 connector 12-1 to 12-n input line group of inrush current prevention circuit 13 output line of inrush current prevention circuit 21 control unit 21-1 to 21-m power supply path 21- 1-21-m Power supply path switching signal 31 Main circuit of unit

Claims (3)

[Claims] In a device in which a plurality of electronic circuit units are mounted on a motherboard via a connector and supplied with the same power, when a stopcock is inserted into the connector of the electronic circuit unit, an inrush current of the electronic circuit unit is first set. A hot-plug insertion method for preventing an excessive rush current of an electronic circuit unit by connecting a power supply pin and then connecting a main power supply pin with a time lag, comprising: A current stop circuit is provided, and when the electronic circuit unit is inserted as a cock, the opening and closing of the plurality of power supply paths is controlled to gradually increase the inrush current to the electronic circuit unit. Method. 2. The stopcock insertion method according to claim 1, wherein
A method for inserting a stopcock, wherein the inrush current prevention circuit detects the insertion of a stopcock for each electronic circuit unit and controls opening and closing of a power supply path corresponding to each electronic circuit unit. 3. An electronic device in which a plurality of electronic circuit units are mounted on a motherboard via a connector and supplied with the same power, and when a stopcock is inserted into the connector of the electronic circuit unit, the electronic device is first connected to the electronic circuit unit. An electronic device having a configuration in which an inrush current power supply pin is connected and then a main power supply pin is connected with a time delay to prevent an excessive inrush current of the electronic circuit unit. A plurality of power supply paths connected to the inrush current power supply pin, and a control for gradually increasing the inrush current to the electronic circuit unit by controlling opening and closing of the plurality of power supply paths when the electronic circuit unit is hot-plugged. And an inrush current prevention circuit comprising: