JPH10240395A - On-board type printed board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the fault extension of bus connection reception signals to a non-detached reception substrate at the time of detaching the live line of the reception substrate by disconnecting the signal line of a transmission buffer and a bus at the time of detaching the reception substrate by a live line detachment protective circuit. SOLUTION: This printed board is provided with the reception substrates 211 and 212 for performing inter-package communication with a transmission substrate 10 through the bus, a power source part 3 provided with the power supply system of ON/OFF corresponding to the detachment of the reception substrates 211 and 212 , a reception buffer 6 provided between a pull-up resistor 4 and a CPU 7 and the live line detachment protective circuit 22 provided in the preceding stage of the pull-up resistor 4 for disconnecting the signal line of the transmission buffer 6 and the bus 2 at the time of detaching the reception substrates 211 and 212 . In such a manner, by providing the live line detachment protective circuit 22, at the time of detaching the live line of the reception substrate 211 , the fault extension of the bus connection reception signals to the non-detached reception substrate 212 is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed circuit board having an on-board type power supply system, which is used when a receiving board is inserted or removed from a device while power is on (hereinafter referred to as hot-swapping). The present invention relates to an on-board type printed circuit board capable of preventing disturbance of a connection reception signal.

[0002]

2. Description of the Related Art When a faulty board is replaced for maintenance replacement or the like, the fault is usually recovered after the power of the corresponding device is turned off. However, in a data transmission apparatus that needs to be operated for 24 hours, it is necessary to replace a faulty board without turning off the power. Therefore, the faulty board is functionally separated by a redundant circuit, and then the faulty board is replaced. Was.

FIG. 5 is a block diagram showing a conventional on-board type printed circuit board disclosed in, for example, Japanese Patent Application Laid-Open No. 7-28564. In the figure, reference numeral 1 denotes a receiving board for performing inter-board communication by connecting a bus 2. Reference numeral 3 denotes a power supply unit provided on each receiving board 1, and reference numeral 4 denotes a pull-up resistor provided at a connection between the power supply unit 3 and the bus 2. The input unit is set to a normal level corresponding to no signal when there is no signal. To keep. Reference numeral 5 denotes a diode inserted in series with the pull-up resistor 4 to prevent a backflow from the connection portion when the power is off.

Next, the operation will be described. FIG. 6 is a configuration diagram showing a conventional hot-swap protection circuit for an on-board type printed circuit board. In the figure, the same reference numerals as those in FIG. 5 denote the same or corresponding parts, and a description thereof will be omitted. 6 each receive a substrate 1 _1, 1 ₂ of the reception buffer, 10 a transmission board connected to each receiving substrate 1 _1, 1 ₂ via the bus 2, 11
Is a transmission buffer provided on each transmission board 10.

[0005] First, a particular when withdrawing the receiving substrate 1 ₁ maintenance, etc., the received substrate 1 ₁ is powered OFF (0
V), and the power of the other receiving substrate 1 ₂ is in a state of ON (5V). In this state, the output of the transmission buffer 11 of the transmission board 10 is at a high level. Each receiving substrate 1 _1, 1 ₂ of the pull-up resistor 4 _1, 4 diode 5 ₁ to _2, 5 ₂ power from the input side of the reception buffer ₆₁ of the receiving substrate 1 ₁ because it is inserted in series Current is prevented from flowing to the side.

Therefore, when the output of the transmission buffer 11 in the transmission board 10 is at a high level, the power of the reception board is turned off.
Even when the voltage becomes F (0 V), as described above, the output of the transmission buffer 11 of the transmission board 10 maintains the high level state. The bus 2 in the normal state (no signal state) is not limited in its application to the printed circuit board to become a high level, even for a printed circuit board comprising a low level, the diode 5 _1,
5 _second orientation is applicability by reversed.

[0007]

Since THE INVENTION Problems to be Solved] Conventional on-board PCB is constructed as described above, for example, power OFF which occurs during insertion and removal of the receiving substrate 1 _1, 1 ₂
It was impossible to prevent the current from flowing into the receiving buffers 6 ₁ and 6 ₂ depending on the state. Therefore, (when power OFF) during insertion of the receiving substrate 1 ₁ has a problem in respect to the receiving substrate 1 ₂ not swap the like it is not possible to prevent failure spreading bus connection receiving signal.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem, and it is possible to prevent the spread of a bus connection received signal from a non-inserted receiving board when the receiving board is hot-swapped. It is intended to obtain a board type printed circuit board.

[0009]

According to a first aspect of the present invention, there is provided an on-board type printed circuit board having a transmission buffer and a bus at the time of insertion / removal of a reception board by a hot-swap protection circuit provided before the reception buffer. Are separated from each other.

In the on-board type printed circuit board according to the present invention, the receiving board is determined by whether or not the voltage value of the power supply section exceeds the Zener voltage value by the Zener diode constituting the hot-swap protection circuit. This is to determine whether it has been removed or inserted.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below. Embodiment 1 FIG. Figure 1 is a block diagram showing an on-board printed circuit board with a live insertion protection circuit according to a first embodiment of the present invention. In the figure, 21 _1, 21 ₂ Bath 2
A receiving board 22 for performing inter-board communication by connection of the receiving board 21 is provided between the bus 2 and the receiving buffer 6;
_A hot-swap protection circuit for disconnecting signal lines between the transmission buffer 11 and the reception buffer 6 when hot-swapping ₁ and 212 ₂ ;
Power supply unit provided in each reception substrate 21 _1, 21 ₂ is 4 is the pull-up resistor provided at the connection between the power source portion 3 and the bus 2, the receiving substrate 21 _1, 21 ₂ of the hot plug Occasionally, the voltage of the power supply unit 3 becomes 0 V, thereby forming a pull-down resistor. 6 is a reception buffer for holding signal data received via the bus 2, 7 each received substrate 1 _1, 1 ₂ is provided CPU, 10 each receiving wiring board 21 ₁ via the bus 2, 21
Transmission boards 11 connected to ₂ are transmission buffers provided on each transmission board 10.

FIG. 2 is a block diagram showing a hot-swap protection circuit for an on-board type printed circuit board according to Embodiment 1 of the present invention. In FIG.
When the state becomes the FF state, the state becomes the OFF state, and the signal line between the transmission buffer 11 and the reception buffer 6 is disconnected.
-FET, 32 is a P-FET that is turned off when the voltage between G and S becomes equal to or lower than the Zener voltage of the Zener diode 33, and 33 is a Zener diode that monitors the voltage value of the power supply unit 34.

Next, the operation will be described. First, when it is received the substrate 21 ₁ Nomigakatsu swapping, that the voltage value of the power supply unit 34 is to 0V, and the voltage between G-S of P-FET 32 becomes equal to or less than the Zener voltage of the Zener diode 33 , P-FET 32 are turned off. as a result,
The N-FET 31 is also turned off, and the signal lines of the transmission buffer 11 and the reception buffer 6 are disconnected. On the other hand, at the time of insertion receives the substrate 21 _1, the voltage value of the power supply unit 34 is OFF
When the state changes from the ON state to the ON state, the voltage value of the power supply unit 34 becomes equal to or higher than the Zener voltage of the Zener diode 33, and P
-The FET 32 is turned on. As a result, the N-FET
31 is also in the ON state, and the signal lines of the transmission buffer 11 and the reception buffer 6 are connected.

[0014] As described above, according to the first embodiment, the hot plug protection circuit 22 to disconnect the signal lines of the transmission buffer 11 when it is received the substrate 21 ₁ Nomigakatsu swapping a reception buffer 6 With the provision, the receiving substrate 2
At the time of hot-swap of 1 _1, the receiving board 21 ₂
This can prevent the interference of the bus connection received signal from being transmitted.

The hot-swap protection circuit 22 may use a CR integration circuit, a voltage monitoring IC, or a hot-swap lever having a mechanical configuration.

Embodiment 2 Third Embodiment FIG. 3 is a configuration diagram showing a hot-swap protection circuit for an on-board type printed circuit board according to a second embodiment of the present invention. In the figure, the same reference numerals as those in the first embodiment denote the same or corresponding parts, and will be described. Is omitted. Live insertion protection circuit according to the second embodiment 41, 42 zener diode for detecting a hot plug operation of the receiving substrate 21 _1, 43 is a photo-coupler to separate the signal lines of the transmission buffer 11 and the receive buffer 6 .
In the first embodiment, the N-FET 3
1, the P-FET 32 and the Zener diode 33 are used, but a Zener diode 42 and a photocoupler 43 may be used as shown in the second embodiment.

Next, the operation will be described. Receiving board 21
_{When only 1 is} hot-plugged, the voltage value of the power supply unit 34 becomes 0
When the voltage becomes V, the voltage value of the power supply unit 34 becomes equal to or lower than the Zener voltage of the Zener diode 42. As a result, the photocoupler 43 is turned off, and the signal lines of the transmission buffer 11 and the reception buffer 6 are disconnected. On the other hand, at the time of insertion receives the substrate 21 _1, the voltage value of the power supply unit 34 by the ON state from the OFF state, the voltage value of the power supply unit 34 is equal to or higher than zener voltage of the Zener diode 42. As a result, the photocoupler 43 is turned on, and the signal lines of the transmission buffer 11 and the reception buffer 6 are connected.

[0018] As described above, according to the second embodiment, when the hot plug of Embodiment 1 similarly to the receiving substrate 21 to the _first embodiment, fault spillover bus connection receiving signal to the received substrate 21 ₂ which is not insertion Can be prevented.

Embodiment 3 FIG. 4 is a configuration diagram showing a hot-swap protection circuit for an on-board type printed circuit board according to a third embodiment of the present invention. In the figure, the same reference numerals as those in the first embodiment denote the same or corresponding parts. Is omitted. In the first embodiment, the hot-swap protection circuit 2
2 shows an example using an N-FET 31, a P-FET 32, and a zener diode 33, but as shown in FIG. 4, a hot-swap protection circuit 51 may use a zener diode 52 and a relay 53. , Embodiment 1
And during live insertion of the receiving substrate 21 ₁ in the same manner, the effect is obtained that a fault spreading bus connection receiving signal to the received substrate 21 ₂ not insertion can be prevented.

[0020]

As described above, according to the first aspect of the present invention, the signal line between the transmission buffer and the bus is connected by the hot-swap protection circuit provided before the reception buffer when the reception board is inserted or removed. Since the receiving board is configured so as to be separated, there is an effect that it is possible to prevent the spread of a bus connection received signal to a receiving board that has not been inserted or removed when the receiving board is hot-swapped.

According to the second aspect of the present invention, in the Zener diode constituting the hot-swap protection circuit, the receiving board is removed or inserted depending on whether the voltage value of the power supply section exceeds the Zener voltage value. Since it is configured to judge whether the receiving board has been hot-plugged, there is an effect that it is possible to prevent the spread of the bus connection received signal to the receiving board that is not inserted or removed when the receiving board is hot-swapped.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an on-board type printed circuit board provided with a hot-swap protection circuit according to Embodiment 1 of the present invention;

FIG. 2 is a configuration diagram showing a hot-swap protection circuit for an on-board type printed circuit board according to Embodiment 1 of the present invention;

FIG. 3 is a configuration diagram showing a hot-swap protection circuit of an on-board type printed circuit board according to Embodiment 2 of the present invention;

FIG. 4 is a configuration diagram showing a hot-swap protection circuit for an on-board type printed circuit board according to Embodiment 3 of the present invention;

FIG. 5 is a configuration diagram showing a conventional on-board type printed circuit board disclosed in, for example, Japanese Patent Application Laid-Open No. 7-28564.

FIG. 6 is a configuration diagram showing a conventional hot-swap protection circuit for an on-board type printed circuit board.

[Explanation of symbols]

2 bus, 3 power supply section, 4 pull-up resistor, 6 reception buffer, 7 CPU, 10 transmission board, 21 ₁ , 21
₂ receiving board, 22 hot-swap protection circuit, 33, 42,
52 Zener diode.

Claims (2)

[Claims] 1. A receiving board for performing inter-package communication with a transmitting board via a bus, a power supply having an on / off power supply system in accordance with insertion / removal of the receiving board, and a power supply for connecting the power supply to the bus. A pull-up resistor provided between the pull-up resistors for holding the signal line at a normal level when there is no signal; a reception buffer provided between the pull-up resistor and the CPU; An on-board printed circuit board having a hot-swap protection circuit for separating a signal line between the transmission buffer and the bus when a receiving board is inserted or removed. 2. The hot-swap protection circuit includes a zener diode that determines whether the receiving board has been removed or inserted, based on whether the voltage value of the power supply unit exceeds the zener voltage value. On-board type printed circuit board.