JP2792478B2 - Hot-swap circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot-swap circuit for preventing malfunction or damage of an electronic circuit when an electronic circuit package is replaced while power is on.

[0002]

2. Description of the Related Art For example, an electronic exchange includes a plurality of electronic circuit packages having arbitrary functions, a power supply package for supplying power to each electronic circuit package, and
Wiring for electrically connecting the packages is formed, and a back wiring board (hereinafter, referred to as BWB) in which connectors are arranged corresponding to slots into which the packages are inserted.

[0003] When replacing an electronic circuit package that has malfunctioned or the like for maintenance of such an electronic device, performing the replacement while the power of the electronic device is turned on is called hot swapping or hot swapping. At this time, it is important that electronic circuits other than the package to be replaced do not malfunction and that the electronic circuit and the connector of the package to be replaced are not damaged. To address these issues, each electronic circuit package is provided with a hot-swap circuit.

In a conventional hot-swap circuit, the length of a connector pin is generally changed according to the type of a power supply, a ground line, a signal, and the like, and the electrical connection time is shifted to reduce an inrush current, thereby reducing power supply fluctuation. A method to prevent this is adopted.

Further, in addition to the above structure,
In JP-A-57420 and JP-A-63-154018, the power supply to the electronic circuit in the package is stopped at the moment when the package is inserted by a hot-swap circuit using a transistor, and an arbitrary time elapses. After doing
A method is disclosed in which electric power is supplied to an electronic circuit to prevent discharge generated in a connector when a package is inserted, thereby protecting pins of the connector.

In Japanese Patent Application Laid-Open Nos. Hei 3-283278 and Hei 3-283276, a main power supply for supplying power to an electronic circuit and a capacity of the electronic circuit are charged before connecting the main power supply. A method is disclosed in which a sub power supply is provided in a power supply package, and a resistor or an inductance for reducing an inrush current is inserted in series with the power supply line in the vicinity of the connector.

[0007]

However, among the conventional hot-swap circuits described above, in the hot-swap circuit in which the power supply time to the electronic circuit is controlled by using a transistor, the electronic circuit operates. Even in a steady state, all the current consumed by the electronic circuit is supplied through the transistor, so that the power supply voltage supplied to the electronic circuit is reduced due to the voltage drop of the transistor, and the circuit may malfunction. . In addition, since it is necessary to use a transistor having a large current capacity, the shape of the transistor becomes large, and a large heat sink is required.
The area for mounting other elements has been limited.

On the other hand, in a hot-swap circuit provided with a resistor or an inductance for reducing an inrush current, when the power consumption of an electronic circuit is large, a resistor or an inductance having a large current capacity is required. To become
When a resistor is used, the resistance value decreases,
When the package is inserted, the inrush current becomes large and the contact portion of the pin cannot be protected.When using an inductance, it is necessary to select a component that does not saturate even with a large current. Therefore, the area for mounting other elements has been limited. The present invention has been made in order to solve the problems of the conventional technology as described above, and when hot-inserting an electronic circuit package having a large power consumption, protects the pins of the connector, and provides An object of the present invention is to provide a hot-swap circuit that prevents a malfunction.

[0009]

In order to achieve the above object, a hot-swap circuit according to the present invention is capable of malfunctioning an electronic circuit when an arbitrary electronic circuit package constituting an electronic device is replaced while power is on. And a hot-swap circuit for preventing damage to the electronic device, the electronic device, a main power supply for supplying power to the electronic circuit, a sub-power supply for pre-charging the electronic circuit, and the electronic circuit package And a connector for providing an electrical interface with the main power supply and the sub-power supply, an input terminal, an output terminal, and the input terminal. A control terminal for controlling an electrical connection time between the electronic terminal and the output terminal; and a transistor circuit having the output terminal connected to the electronic circuit. The connector of the package includes three types of pins having different lengths, and among the three types of pins, the longest pin is connected to the input terminal of the transistor circuit, and the connector of the electronic device is connected to the auxiliary power supply. And an intermediate pin is connected to the electronic circuit, and is disposed corresponding to a pin of the connector of the electronic device connected to the main power supply, and a shortest pin is connected to the transistor circuit. It is characterized in that it is connected to a control terminal and arranged corresponding to a pin of a connector of the electronic device connected to the sub-power supply.

A hot-swap circuit for preventing a malfunction or damage of an electronic circuit when an arbitrary electronic circuit package constituting an electronic device is replaced while the power is turned on,
The electronic device has a main power supply for supplying power to the electronic circuit, a sub-power supply for pre-charging the electric circuit, and a connector for providing an electrical interface with the electronic circuit package. A connector for providing an electrical interface with the main power supply and the sub power supply, an input terminal, an output terminal, and an electrical connection time between the input terminal and the output terminal. Having a control terminal for controlling, having a transistor circuit in which the electronic circuit is connected to the output terminal,
The electronic circuit includes three types of pins having different lengths in a connector of the electronic device, and a longest one of the three types of pins is connected to the sub-power supply and connected to an input terminal of the transistor circuit. It is arranged corresponding to the pin of the connector of the package, the middle pin is connected to the main power supply, and arranged corresponding to the pin of the connector of the electronic circuit package connected to the electronic circuit, and the shortest pin is It is characterized in that it is connected to the sub-power supply and arranged corresponding to a pin of a connector of the electronic circuit package connected to a control terminal of the transistor circuit.

[0011] The hot-swap circuit of the present invention configured as described above, when an electronic circuit package is inserted into an electronic device,
The main power supply and the sub power supply are electrically connected in order from the longest pin by the pins having different lengths provided in the connector.

At this time, first, the sub-power supply and the transistor circuit are connected via the longest pin, and the electric circuit is charged. Here, the transistor circuit controls the electrical connection time between the electronic circuit and the sub-power supply, so that after an elapse of an arbitrary time from the contact of the longest pin, the current starts flowing through the electronic circuit. This eliminates the discharge and the like and prevents the pins from being damaged.

Next, when the main power supply and the electronic circuit are connected by an intermediate pin, the inrush current of the main power supply is reduced because a voltage is applied to the electronic circuit in advance by the sub power supply, and the fluctuation of the main power supply is reduced. Is prevented.

Finally, by connecting the input terminal of the transistor circuit and the control terminal via the electronic device by the shortest pin, the transistor connecting the sub-power supply and the electronic circuit becomes non-conductive. Power is supplied to the electronic circuit only from the main power supply, and the power consumption of the transistor becomes zero.

[0015]

Next, the present invention will be described with reference to the drawings.

FIG. 1 is a circuit diagram showing the configuration of the hot-swap circuit of the present invention, and FIG. 2 is a signal waveform diagram showing the operation of the hot-swap circuit shown in FIG.

In FIG. 1, a power supply package 1
A connector CN1 for providing an electrical interface with a WB (back wiring board); a main power supply E1 for supplying power to the electronic circuit package 1; and a sub-power supply E2 for supplying power to the hot-swap circuit. Are provided, and the power supply voltages of the main power supply E1 and the sub power supply E2 are maintained at substantially the same potential. The pins 1a and 1c of the connector CN1 are connected to the sub power supply E2, the pin 1b is connected to the main power supply E1, and the pin 1d is connected to ground (ground potential) GND.

On the other hand, the electronic circuit package 2 includes BWB
Connector CN2 for electrical interface with the
Is provided on the connector CN2 for power supply.
It has three types of pins with medium and short lengths. Here, the longest pins 2a and 2d are respectively arranged corresponding to the pins 1a and 1d of the connector CN1 of the power supply package 1, the middle pin 2b is located at the pin 1b of the connector CN1, and the shortest pin 2c is located at the connector CN1. It is arranged corresponding to each of the pins 1c.

A bypass capacitor C1 is connected in parallel to the electronic circuit 10 having an arbitrary function, and a power supply terminal Vc of the electronic circuit 10 is connected to an intermediate pin 2b and ground GND.
Are connected to the longest pins 2d, respectively. The emitter E of the transistor Tr is connected to the longest pin 2a,
The collector C of the transistor Tr is connected to the power supply terminal Vc. The base B of the transistor Tr is connected to one end of the resistor R2 and the shortest pin 2c, respectively, and the other end of the resistor R2 not connected to the base B of the transistor Tr is connected to the ground GND. A resistor R1 and a capacitor C2 are connected in parallel between the emitter E and the base B of the transistor Tr.

The BWB 3 has connectors CN3 and CN4 for electrically interfacing with the power supply package 1 and the electronic circuit package 2, and the power supply package 1 and the electronic circuit package 2 are electrically connected via the BWB 3. You.

In such a configuration, the operation of the hot-swap circuit of the present invention will now be described.

When the electronic circuit package 2 is inserted into the connector CN4 of the BWB, first, the longest pins 2a and 2d of the connector CN2 are respectively connected to the pins 4a and 4b of the connector CN4.
a, 4d. Assuming that the time at this time is time T0, at time T0, the voltage of the sub power supply E2 is applied to the emitter E and the base B of the transistor Tr.

Here, a potential difference is transiently generated in the base B of the transistor Tr with respect to the emitter E by a circuit including the resistors R1 and R2 and the capacitor C2.
At time T1, the voltage V _BE reaches a voltage sufficient to make the transistor Tr conductive. From time T0 to time T1, the longest pin 2a of connector CN2 and connector CN4
Current does not flow because the transistor Tr is in a non-conducting state, and no discharge occurs at the time of contact, so that the pin of the connector is not damaged.

Next, after the lapse of time T1, the transistor T
r becomes conductive, the emitter E of the transistor Tr
-The voltage of the sub power supply E2 is applied to the bypass capacitor C1 and the electronic circuit 10 via the collector C, and the charge of the electric charge of the bypass capacitor C1 and the electronic circuit 10 is started.

The bypass capacitor C1 and the electronic circuit 1
For the charging time of 0, the resistors R1, R2 and the capacitor C2 are selected and the time constant is set so that the intermediate pin 2b is completed by the time T2 when it contacts the pin 4b of the connector CN4 (Vc in FIG. 2). Range from to). Therefore, at time T2, the voltages of the bypass capacitor C1 and the electronic circuit 10 reach the voltage of the sub power supply E2, and in this state, the main power supply E1 is connected to the electronic circuit 10.

Here, since the potential difference between the sub power supply E2 and the main power supply E1 is suppressed to a maximum of about 6%, the time T
2 is 5V × 6% = 0.
The voltage is within 3 V, and the voltage fluctuation of the main power supply E1 due to the insertion of the electronic circuit package 2 is prevented.

Finally, at time T3, the shortest pin 2c
Is in contact with the pin 4c of the connector CN4, the emitter E and the base B of the transistor Tr are short-circuited via the wiring in the power supply package 1 as shown in FIG.

Therefore, the electronic circuit 10 after time T3
In the steady operation state, power is supplied to the electronic circuit 10 only from the main power supply E1, and the power consumption becomes zero because the transistor Tr is in a non-conductive state. Therefore, since a small-capacity current capacity can be selected as the transistor Tr of the hot-swap circuit, the cost increases,
The mounting area does not increase.

In the above description, an example in which pins having different lengths are provided in the connector CN2 of the electronic circuit package 2 is shown. The circuit package may be provided on the BWB connector CN4.

[0030]

Since the present invention is configured as described above, the following effects can be obtained.

An electronic device has two power sources, a main power source and a sub power source, and an electronic circuit package has a connector for providing an electrical interface with the main power source and the sub power source; an input / output terminal; A control terminal for controlling a typical connection time, a transistor circuit having an output terminal connected to an electronic circuit, a connector of an electronic circuit package having three types of pins having different lengths, and the longest pin is a transistor Connected to the input terminal of the circuit and arranged corresponding to the pin of the connector of the electronic device to which the sub power supply is connected, the middle pin is connected to the electronic circuit and connected to the pin of the connector of the electronic device to which the main power supply is connected The shortest pin is connected to the control terminal of the transistor circuit, and the shortest pin is connected to the pin of the connector of the electronic device to which the sub power supply is connected, so that the longest pin is connected. Since current flows to the connector pin after the elapse of a given time Te, it is not damaging the pins.

Also, since the main power is applied to the electronic circuit by the sub-power while the same voltage as the main power is applied to the electronic circuit, the potential of the main power may fluctuate due to the insertion of the electronic circuit package. There is no.

Further, in the steady state, power is directly supplied from the main power supply to the electronic circuit, and the transistor is in a non-conductive state, so that the power consumption of the transistor becomes zero. Therefore, a transistor having a small capacity can be selected as the transistor of the hot-swap circuit, and there is no increase in cost and no increase in mounting area.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a configuration of a hot-swap circuit of the present invention.

FIG. 2 is a signal waveform diagram showing an operation state of the hot-swap circuit shown in FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Power supply package 2 Electronic circuit package 3 BWB 10 Electronic circuit 1a-1d, 2a-2d, 3a-3d, 4a-4d
Pin C1 Bypass capacitor C2 Capacitor CN1 to CN4 Connector E1 Main power supply E2 Sub power supply R1, R2 Resistor Tr Transistor

Claims (2)

(57) [Claims] 1. A hot-swap circuit for preventing a malfunction or damage of an electronic circuit when an arbitrary electronic circuit package constituting the electronic apparatus is replaced while a power is turned on. A main power supply for supplying power to the electronic circuit, a sub-power supply for pre-charging the electronic circuit, and a connector for providing an electrical interface with the electronic circuit package; A connector for providing an electrical interface with the main power supply and the sub power supply, an input terminal, an output terminal, and a control terminal for controlling an electrical connection time between the input terminal and the output terminal. ,
A transistor circuit in which the electronic circuit is connected to the output terminal; and a connector of the electronic circuit package including three types of pins having different lengths. The longest one of the three types of pins is the transistor. Connected to an input terminal of a circuit and arranged corresponding to a pin of a connector of the electronic device connected to the sub power supply, and an intermediate pin connected to the electronic circuit and connected to the main power supply. It is arranged corresponding to the pin of the connector of the electronic device, the shortest pin is connected to the control terminal of the transistor circuit, and is arranged corresponding to the pin of the connector of the electronic device connected to the auxiliary power supply. Features a hot-swap circuit. 2. A hot-swap circuit for preventing a malfunction or damage of an electronic circuit when an arbitrary electronic circuit package constituting the electronic apparatus is replaced with the power turned on. A main power supply for supplying power to the electronic circuit, a sub-power supply for pre-charging the electronic circuit, and a connector for providing an electrical interface with the electronic circuit package; A connector for providing an electrical interface with the main power supply and the sub power supply, an input terminal, an output terminal, and a control terminal for controlling an electrical connection time between the input terminal and the output terminal. ,
A transistor circuit in which the electronic circuit is connected to the output terminal; and a connector of the electronic device including three types of pins having different lengths. Among the three types of pins, the longest pin is the sub power supply. Connected to a pin of the connector of the electronic circuit package connected to the input terminal of the transistor circuit, and an intermediate pin is connected to the main power supply and connected to the electronic circuit. It is arranged corresponding to the pin of the connector of the electronic circuit package, and the shortest pin is connected to the sub-power supply and arranged corresponding to the pin of the connector of the electronic circuit package connected to the control terminal of the transistor circuit. A hot-swap circuit characterized in that: