JPH10232729A - Device for circuit connecting to/disconnecting from hotline - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the generation of rapid current at the time of medium pin connection by limiting a 1st rush current through resistance and suppressing a 2nd rush current through inductance. SOLUTION: In the case of connecting time, a long pin 9 is first connected to VCC and a long pin 8 is connected to GND. A power supply current flows as a charging current through a rush resistor 6 to a load capacitor 1 and flows as a consumption current to a load resistor 2. When a medium pin 10 is connected to the VCC, the charging current to the load capacitor 1 and the consumption current to the load resistor 2 are allowed to flow gradually from the VCC through inductance 3 to the load almost from a remaining V0 (the voltage of load capacitor 1 and load resistor 2) to the VCC. At such a time, the current is branched to the parallel resistors of rush resistor 6 and parallel resistor 5 and the inductance 3. Since the exchange current from the power source VCC is prevented from getting rapid without enlarging the value of inductance 3, the load output voltage V0 is charged by 1st-order rush resistance 6 and branched to the rush resistance 6 and the parallel resistance 5 by 2nd-order rush and the current to the inductance is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a hot-swap circuit device.

[0002]

2. Description of the Related Art Various types of hot-swap circuit devices have been proposed. One example is disclosed in JP-A-6-22457.
FIG. 6 shows a circuit configuration shown in the conventional example of Japanese Unexamined Patent Application Publication No. 3 (1998) -316.

The configuration and operation will be described. In the figure,
The mating connector side is connected to one end of a load capacitance 1 and a load resistor 2 via a parallel connection of an inductance and a diode to a long pin 9 serving as a power supply VCC, and the mating connector side is connected to a power supply GND.
The other end of the load capacitor 1 and the other end of the load resistor 2 are connected to the long pin 8. Further, the middle pin 10 whose other connector side is the power supply VCC is connected to one end of the load capacitance 1 and one end of the load resistor 2. Further, the short pins 12 are connected for signals to constitute a hot-swap circuit device.

[0004] Even when a hot-swap circuit device inserts or removes a board into or from a mating system, a power supply voltage on the system side is generated by a charging current to the load capacitance 1 and a current consumption to the load resistor 2 which are sudden inrush currents. To prevent the system from malfunctioning and avoid malfunction of the system. At the time of insertion, an attempt is first made to gradually apply a current to 2 at the time of insertion. As a result, an operation of suppressing abrupt transfer of the power supply current on the system side is performed. Since the impedance of the inductance 3 is small at the time of static stabilization, the voltage becomes almost VCC.

Next, since the middle pin is directly connected to VCC, the voltage on the output side of load capacitance 1 and load resistor 2 reaches VCC. On the other hand, at the time of removal, there is no movement of electric charges as compared with the time of insertion, so that the power supply voltage drop is minimal. However, a reverse voltage of the inductance 3 is generated due to a current change caused by stopping the current to the long pin 9 due to the removal, and a voltage fluctuation occurs in the long pin 9. However, the clamp operation of the diode 4 suppresses the power supply VCC to a forward voltage VF of the diode. .

[0006]

Even in the above-described prior art hot-swap circuit, malfunction can be prevented by the operation of gradually flowing the rush current. However, the inductance 3 has a large physical size, and the mounted components on the board are not preferable. In particular, in the case where the load capacity 1, which is the load condition of the board, becomes large, the inductance 3 needs a large value in order to satisfy the operation of suppressing the oscillation of the transient phenomenon and the rise of the rush current, and therefore the size becomes large.
In addition, in the case where the current consumption is large, the voltage reached by the inductance 3 when the middle pin 10 is connected becomes small when the inductance 3 is settled. Since it is the product of the current consumption, the voltage is lower than VCC by the drop voltage, and this voltage difference has a drawback that a sudden current is generated when the middle pin is connected.

[0007]

A hot-swap circuit device according to the present invention has a configuration in which a resistor and then a parallel connection of an inductance, a diode, and a resistor are inserted in time series, and the primary rush current is limited by the resistor. In addition, the secondary rush current is suppressed by inductance so that the remaining charging voltage is almost equal to the power supply voltage.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS This hot-swap circuit device is used in the information control system shown in FIG. 3, reference numeral 250 denotes a power supply unit board, reference numerals 200 to 202 denote control boards, and reference numeral 300 denotes a power supply unit board.
Denotes a connector, 400 denotes a power supply VCC, GND, a back board on which signals are wired, and control boards 200 to 202.
The hot-swap circuit device 100 according to the present invention mounted on the device is configured. In this configuration, in a live state, for example, the control board 200
And operate via the back board 400 so as not to affect the other control boards such as the influence of the drop of the power supply voltage VCC.

An embodiment of a hot-swap circuit device according to the present invention will be described below with reference to FIG. A connector pin 301 connected to the power supplies VCC and GND is a backboard connector. The load pin 1 (C) and the load resistor 2 (R) are connected to the long pin 9 via the resistor 6 (R1), and the load capacitor is connected to the middle pin 10 through the parallel connection of the inductance 3 and the resistor 5 (R2) of the diode 4. 1 is connected to one end of the load resistor 2, the long pin 8 serving as the power supply GND is connected to the load capacitor 1 and the other end of the load resistor 2, and the short pin 11 is connected directly to the power supply VCC by one end of the load capacitor 1 and one end of the load resistor 2. It is a configuration to be connected to. The short pin 11
Although a short pin is connected for a signal, a power supply system will be described here. Next, the operation will be described below.

In the case of insertion, first, the long pin 9
To CC, the long pin 8 connects to GND. Rush resistance 6 (R
1), the power supply current = (VCC−Vo) / R1 (the output voltage Vo is the voltage of the load capacitance 1 (C) and the voltage of the load resistance 2) is supplied to the load capacitance 1 as a charging current, and the consumption current = V to the load resistance 2
Flows in as o / R. This attained voltage is determined by the voltage divided by the inrush resistor 6 and the load resistor 2. As the value of the inrush resistor 6 decreases, the charging speed increases and the current change increases, but the attained voltage increases. An appropriate value is selected in consideration of the influence of the power supply VCC drop.

Next, when the middle pin 10 is connected to the power supply VCC, the charging current gradually flows from the VCC to the load via the inductance 3 to the load capacity 1 from the remaining Vo to almost the VCC, and the consumption current to the load resistor 2. At this time, the current transmitted and received from the power supply flows through the rush resistor 6, the parallel resistor 5, and the inductance 3. That is, the current is divided into the parallel resistance of the rush resistance 6 and the parallel resistance 5 and the inductance 3. The inrush current due to the inductance 3 can be increased slowly as the value of the inductance 3 increases, but the size of the inductance 3 increases. Further, the ultimate voltage time is also increased.

Here, the operation for keeping the value of the inductance 3 from increasing and the current from the power supply VCC not to be abrupt is as follows: (1) The load output voltage Vo is charged in advance by the inrush resistor 6 having an appropriate value of the primary inrush. (2) The current is further divided by the inrush resistor 6 (R1) and the parallel resistor 5 (R2) in the secondary inrush to reduce the current to the inductance 3 (L) and the current change. That is, in the transient operation, the value (L) of the inductance 3 is selected in consideration of a critical region where no vibration occurs (K = 1). This value is

[0013]

(Equation 1)

Compared with the conventional circuit configuration having only the inductance 3 and no inrush resistor 6 and parallel resistor 5, the present invention makes it difficult to vibrate by {1 + R / (R1 // R2)} times.
(K is large). Accordingly, the value of the inductance 3 (L) used is also 1 / {1 + R / (R1 // R2)}, and the apparent L value of the inductance 3 may be a small value.

Further, when the power supply VCC of the short pin 11 is directly connected to the load capacitance 1 and the load resistance 2, the ultimate voltage of the load is

[0016]

## EQU2 ## VCC- {parallel connection value of winding resistance of inductance 3 and inrush resistance 6 and parallel resistance 5 * steady current (= Vo / R)} (Expression 2) Comparing only the winding resistance and the like, the drop voltage decreases and approaches the VCC, and a sharp current when the short pin 11 is connected can be reduced. FIG. 2 shows the above-described temporal operation of the inrush current, the load current, and the load output voltage. As compared with the conventional example, the operation configuration is such that the current in the load capacity 1 and the load resistance 2 does not suddenly change and the peak current is suppressed.

FIG. 4 shows another embodiment of the present invention. FIG. 1 shows 41 Schottky diodes. 4 has a lower forward voltage (VF ') than the diode of FIG. 4, and the clamping voltage at the diode with respect to the fluctuation voltage of the long pin 10 at the time of removal becomes smaller than VCC-VF' (VF '<VF). Of the connector pins 301 is less likely to be affected.

FIG. 5 shows another embodiment of the present invention. The difference from FIG. 1 is that there is no resistor 5. Inductance 3
This is an application example in which the number of parts is reduced although the effect of reducing the value of is reduced.

[0019]

According to the present invention, the inductance value,
The size can be reduced, and when the power supply VCC is directly connected to the load, the ultimate voltage of the load is close to VCC, and a hot-swap circuit device with reduced spike current can be realized.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a hot-swap circuit according to an embodiment of the present invention.

FIG. 2 is an operation waveform diagram of the hot-swap circuit device according to one embodiment of the present invention.

FIG. 3 is a block diagram of a system using the hot-swap circuit device according to one embodiment of the present invention.

FIG. 4 is a hot-swap circuit diagram of one embodiment of the present invention.

FIG. 5 is a hot-swap circuit diagram of one embodiment of the present invention.

FIG. 6 is a hot-swap circuit diagram of a conventional example.

[Explanation of symbols]

1: load capacity, 2: load resistance, 3: inductance, 4
... Diode, 5 resistance, 6 inrush resistance, 8, 9 long pin, 10 middle pin, 11 short pin, 301 connector pin.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kenichi Kurosawa 7-1-1, Omikacho, Hitachi City, Ibaraki Prefecture Within Hitachi Research Laboratory, Hitachi, Ltd. (72) Inventor Tsutomu Yamada 7-1 Omikacho, Hitachi City, Ibaraki Prefecture No. 1 Inside Hitachi, Ltd.Hitachi Research Laboratories (72) Inventor Koji Masui 5-2-1 Omikacho, Hitachi City, Ibaraki Prefecture Inside Omika Plant, Hitachi Ltd. (72) Inventor Akihiro Ohashi Omika, Hitachi City, Ibaraki Prefecture 5-2-1, Machi-cho, Ltd. Omika Plant, Hitachi, Ltd. (72) Inventor Masahiro Matsuda 5-2-1, Omika-cho, Hitachi City, Ibaraki Pref.

Claims (4)

[Claims] A hot-swap circuit device for connecting and disconnecting an electronic circuit mounted on a board in a hot-line state from a backboard of a system including at least one printed board and a board. , A second connector, a third connector, a resistor in the first connector, an inductance and a diode and a resistor connected in parallel to the second connector, and the third connector directly loads the power supply of the backboard in time series. A hot-swap circuit device, wherein a power supply current is supplied to the electronic circuit on the side. 2. A hot-swap system according to claim 1, wherein a power supply of said backboard is supplied in time series to said electronic circuit on a load side through said inductance and said diode connected in parallel to said second connector. Circuit device. 3. A hot-swap circuit device according to claim 1, wherein said diode is a Schottky diode. 4. The power supply according to claim 1, wherein the power supply on the backboard side is supplied in time series to the electronic circuit on the load side via the resistor, the inductance connected in parallel, the diode, and the resistor. Wire insertion / extraction circuit device.