BIPOLAR-TRANSISTOR RANDOM ACCESS MEMORY HAVING A REDUNDANCY CONFIGURATION

Abstract: A semiconductor memory device of a bipolar-transistor type includes a memory cell array (1), a redundancy array (2), a defective address memory circuit (6) for storing a defective address (A 0R , A 1R , ..., A 7R ), and a comparing circuit (7) for comparing an input address (A₀, A₁, ..., A₇) with the defective address (A 0R A 1R , ..., A 7R ). The defective address memory circuit (6) comprises a plurality of information memory circuits (6-0, 6-1, ..., 6-7) which includes a plurality of diode stages for determining their output amplitudes. When an input address coincides with the defective address stored in the address memory circuit (6), the redundancy array (2) is selected instead of the memory cell array (1).

Description: This invention relates to a bipolar-transistor type random access memory (RAM) having a redundancy configuration and, more particularly, to a defective address memory portion thereof. In a RAM device, a large number of memory cells are arranged along rows and columns. The density of defects generated in such a semiconductor memory device during the manufacture thereof is relatively independent of the integration density of the device. Rather, it derives from the semiconductor manufacturing technology. In general, the higher the integration density of the device, the greater the ratio of normal memory cells to defective memory cells. This is one of the advantages of increasing the integration density of a semiconductor memory device. Even if a device includes only one defective memory cell, however, the device cannot be operated normally and, therefore, must be scrapped. As a result, despite the lower ratio of defective memory cells, greater integration density means reduced manufacturing yield. In a metal-insulator-semiconductor (MIS) RAM, in order to overcome the problem of defective memory cells, use is made of redundancy memory cells. When a defective memory cell is detected, a redundancy memory cell row or column is selected instead of the memory cell row or column including the defective memory cell. In general, one or two redundancy memory cell rows or columns are usually provided. In such a redundancy configuration, in order to store address information of such a defective row or column and to disable regular decoders for selecting normal memory cells so as to select the redundancy row or column in response to an address of the defective row or column, a defective address memory circuit is required. In the prior art, however, since there has been no preferably defective address memory circuit for a bipolar-transistor type RAM, there has been no bipolar-transistor type RAM having a redundancy configuration. EP-A-0087610 describes a random access memory having a word group redundancy scheme using redundant and non redundant memory portions each with word group decoders a compare circuit and addressing means. It is an object of the invention to provide an information memory circuit suitable for a defective address memory circuit of the bipolar-transistor type RAM having a redundancy configuration. According to the present invention there is provided a semiconductor memory device of a bipolar-transistor type comprising; a memory cell array; a redundancy memory cell array; means for receiving an address signal; means for selecting a normal memory cell from said memory cell array in accordance with said address signal from said address receiving means; and means for comparing the address of said address signal from said address receiving means with said defective address of a defective memory cell of said memory cell array so as to disable said normal memory cell selecting means and select said redundancy memory cell array when the address of said address signal is different from said defective address characterised by means for storing said defective address and comprising a plurality of 1-bit memory circuits of a diode type, each circuit corresponding to each bit of said defective address. According to another aspect of the invention, there is provided an information memory circuit including at least three diode stages along a forward bias direction between a first power supply and a node; a diode stage linked along a backward bias direction between a write power supply and the first power supply; a shorted-junction type programmable read-only memory (PROM) cell linked between the write power supply and the node; and a switching element linked between the node and a second power supply for receiving a one bit address signal, thereby generating a high or low potential from the node in accordance with the short-circuited or non-short-circuited state of the PROM cell. In the above-mentioned information memory circuit, two diode stages can be provided instead of the three or more diode stages, and in this case, the diode along the backward bias direction is changed by one resistor, or one diode stage along a forward bias direction is provided on the side of the first power supply. According to a further aspect of the invention, there is provided an information memory circuit including at least three diode stages along a forward bias direction between a first power supply and a first node; a resistor linked between the first node and a second power supply; a diode stage linked between the first and second nodes and having the same conduction direction as the three or more diode stages; a resistor linked between the second node and the second power supply; a diode stage linked along a forward bias direction between the first power supply and a write power supply; a short-circuited-junction type PROM cell linked between the write power supply and the second node; and a switching element, linked between the second node and the second power supply for receiving a one bit address signal and an output circuit, connected to the first and second nodes, for detecting the difference in potential in accordance with the short-circuited or non-short-circuited state of the PROM cell. In the above-mentioned information memory circuit, in order to separate the circuits for determining the potential at each of the first and second nodes, three diode stages are added to the second node. Also, the diode between the first power supply and the write power supply can be replaced by a resistor, and one stage of the three diode stages can be omitted. Also, the diode stage between the first power supply and the write power supply can be detected. However, instead of this, a diode stage is provided on the first power supply. In the above-mentioned configuration, if the short-circuited junction type PROM cell is not destroyed, the potential at the first node is low. On the other hand, if the short-circuited junction type PROM cell is destroyed, the potential at the first node is high. The data of the PROM cell can be read out by detecting the potential at the first node. Note that the difference in potential at the first node between the non-destroyed state and the destroyed state of the PROM cell corresponds to the forward direction potential of one diode stage. Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, wherein: Fig. 1 is a block diagram illustrating one example of a semiconductor device according to the invention; Fig. 2 is a block diagram of an address memory circuit of the device of Figure 1; Figs. 3 to 10 are circuit diagrams of alternative forms of the 1-bit memory circuit of Fig. 2; Figs. 11A and 11B are circuit diagrams of a comparing circuit of Figure 2; and Figs. 12A and 12B together form a block diagram illustrating another example of a semiconductor device according to the invention. In Fig. 1, which illustrates an embodiment of the present invention, a memory device comprises a 64K-bit static memory cell array 1, and a redundancy array 2. Note that the redundancy array can comprise more than two rows or columns, but, in this case, a one-row array is described in order to simplify the explanation. One row of the memory cell array 1 is selected by row address buffers 3, word decoders 4, and word drivers 5. That is, external row address signals A₀, A₁ ..., A₇ are received by emitter-followers Q₁₁ and are converted by the row address buffers 3 into internal row address signals A₀, A₁, ..., and A₇, and their inverted signals A ₀ A ₁, ..., A ₇, which are received by the word decoders 4 which drive one of the 256 word drivers 5, i.e. one of the word lines WL₀, WL₁, ..., WL₂₅₅. Similarly, one column of the memory cell array 1 is selected by column selection means (not shown). The device further comprises a defective address memory circuit 6, an address comparing circuit 7 for comparing an input address defined by the external address signals A₀, A₁, ..., and A₇ with the defective address defined by signals A 0R , A 1R , ..., and A 7R stored in the defective address memory circuit 6, and a driver circuit 8 for driving the redundancy array 2. If all of the memory cells are normal, no problem occurs and, accordingly, the circuit of Fig. 1 operates in the same way as the conventional devices. However, if a defective cell is detected in the memory cell array 1 of Fig. 1, the row address of a row including this defective cell (hereinafter referred to as a defective row address) is written into the defective address memory circuit 6. The row address signals A₀, A₁, ..., and A₇ are always compared with the defective address signals A 0R , A 1R , ..., and A 7R written into the address memory circuit 6. As a result, when any of the address signals A₀, A₁, ..., and A₇ coincide with the defective row address signals A 0R , A 1R , ..., and A 7R , respectively, the address comparing circuit 7 operates the driver 8 to select the word line WL R and drive the redundancy array 2, and simultaneously to disable the word drivers 5, thereby causing non-selection of the memory cell array 1. In Fig. 2, which is a detailed block circuit diagram of the defective address memory circuit 6 of Fig. 1, the circuit 6 comprises 1-bit memory circuits 6-0, 6-1, ..., and 6-7 corresponding to each of the row address signals A₀ , A₁ , ..., and A₇. That is, the row address signals A₀ , A₁ , ..., and A₇ are applied thereto, a high voltage such as +5 V is applied as a write voltage to the write terminal V P , and a low voltage such as -5 V is applied to the other terminal V n . Then, the row address signals A₀ , A₁ , ..., and A₇ are written into the 1-bit memory circuits 6-0, 6-1, ..., and 6-7, respectively. Thus, these signals can be read out as the defective address signals, ..., A 0R , A 1R , ..., and A 7R . Hereinafter, the 1-bit memory circuits will be explained in more detail. In Fig. 3, which illustrates a first example of the 1-bit memory circuit of Fig. 2, power supply V CC is, for example, the ground level GND, and power supply V EE is, for example, -5 V. If in a write mode for breaking down the PROM cell PC, the write power supply V P is +5 V, otherwise V P equals V CC (GND). Also, if in a write mode, the write power supply V n is lower than -5 V, otherwise V n equals V EE (-5 V). Further, PC designates a short-circuited junction type PROM cell which has diode characteristics after a write mode. That is, during a write mode, a larger voltage than the endurance voltage C E of the PROM cell, which is a kind of transistor, is applied to the emitter-collector thereof, thereby breaking it down. Provided between the power supply V CC and node N₁ is a series of three diode stages D₁ , D₂ , and D₃ , and a current source I S , thereby generating a voltage at node N₁ for a non-broken mode. In this case, the diode stages D₁ , D₂ , and D₃ are forwardly biased. That is, the potential at node N₁ is -0.8 x 3 = -2.4 V determined by the diode stages D₁ , D₂ , and D₃. Here, note that 0.8 V is the forward voltage of one diode stage. Also, in order to determine the potential at node N₁ after a writing mode for the PROM cell PC, diode stage D₀ is provided between the power supply V CC and the write power supply V P . The diode stage D₀ is reversely biased during a write mode. After a write mode, since the PROM cell PC serves as a one diode stage, the potential at node N₁ is the voltage corresponding to two diode stages, i.e., -0.8 x 2 = -1.6 V. Thus, in the circuit of Fig. 3, during a non-write (non broken-down) mode of the PROM cell PC, the potential at node N₁ is -2.4 V, and after a write mode, the potential at node N₁ is -1.6 V. Thus, the difference of 0.8 V in potential is generated at node N₁. Note that a transistor Q₁ is used for a write operation of the PROM cell PC. Next, the write operation of the circuit of Fig. 3 will be explained. In order to carry out a write operation, the write power supply V P is raised to +5 V from the exterior, while the write power supply V n is retained at -5 V. At this time, when the address signal A i is at a high level the write transistor Q₁ is turned ON. As a result, a voltage higher than the duration voltage C E such as 7 V (which voltage is, in this case, about 10 V) is applied to the PROM cell PC, and accordingly, a current I W flows through the emitter-collector of the PROM cell PC, thereby breaking down the emitter-base thereof. In Fig. 4, which illustrates a second example of the 1-bit memory circuit of Fig. 2, the diode stages D₀ and D₃ of Fig. 3 are deleted, and a resistor R₀ is provided between the power supplies V CC and V P . Note that the value of the resistor R₀ is relatively small. Therefore, the potential at node N₁ for a non-broken-mode is -0.8 x 2 = -1.6 V determined by the diodes D₁ and D₂ , and the potential at node N₁ after a write operation is -0.8 V. Thus, also in the circuit of Fig. 4, the difference 0.8 V in potential is generated at node N₁. In Fig. 5, which illustrates a third example of the 1-bit memory circuit of Fig. 2, the resistor R₀ of Fig. 4 is deleted, and a diode D₀ is provided on the side of the power supply V CC . However, the operation of the circuit of Fig. 5 is about the same as that of Fig. 4. In Figs. 3, 4, and 5, a resistor can be provided instead of the current source I S . In Fig. 6, which ilustrates a fourth example of the 1-bit memory circuit of Fig. 2, provided between the power supplies V CC and V n is a series circuit formed by three diode stages D₁ , D₂ , and D₃ , and resistors R₁ and R₂ for generating a reference voltage. That is, the potential at node N₁ is the reference voltage which equals -0.8 x 3 = -2.4 V determined by the diode stages D₁ , D₂ , and D₃. Also, in order to determine the potential at node N₂ during a non-broken-mode of the PROM cell PC; a diode D₄ and a resistor R₂ are added to the diodes D₁ , D₂ , and D₃ between the power supplies V CC and V n . That is, in this case, the potential at node N₂ is -0.8 x 4 = -3.2 V determined by the diodes D₁ , D₂ , D₃ , and D₄. Also, in this case, the potential at node N₂ after a write operation is -0.8 x 2 = -1.6 V determined by the diode stage D₀ and the PROM cell PC. Thus, in the circuit of Fig. 6, during a non-broken-mode of the PROM cell PC, the potential at node N₁: -2.4 V, and the potential at node N₂: -3.2 V. As a result, among transistors Q₂ and Q₃ forming a current switch, the transistor Q₂ is turned ON, while the transistor Q₃ is turned OFF, and therefore, the potential at node N₃ becomes at a high level (V CC ). Thus, as the base potential of an output transistor Q₄ increases, the potential of the defective address signal A iR becomes high. On the other hand, after a write mode of the PROM cell PC, the potential at node N₁: -2.4 V, and the potential at node N₂: -1.6 V. As a result, among the transistors Q₂ and Q₃ forming a current switch, the transistor Q₂ is turned OFF, while the transistor Q₃ is turned ON, and therefore, the potential at node N₃ becomes at a low level. Thus, as the base potential of the output transistor Q₄ decreases, the potential of the defective address signal A iR becomes low. In Fig. 7, which illustrates a fifth example of the 1-bit memory circuit of Fig. 2, in order to separate the circuit for determining the potential at node N₁ from the circuit for determining the potential at node N₂ during a non-broken-mode, three diode stages D₁', D₂', and D₃' are provided. However, the operation of the circuit of Fig. 7 is the same as that of Fig. 6. Thus, in the circuits of Figs. 6 and 7, the potential at node N₂ is increased or decreased by the potential corresponding to one diode stage as compared with the reference voltage at node N₁ , in accordance with the presence or absence of a write operation (breakdown) of the PROM cell PC. Also, the logic amplitude corresponding to one diode stage is read out by the following transistors Q₂ , Q₃ , and Q₄. In Fig. 8, which illustrates a sixth example of the 1-bit memory circuit of Fig. 2, the diode D₃ of Fig. 6 is deleted, and a resistor R₀ is provided between the power supplies V CC and V P . Note that the value of the resistor R₀ is relatively small. Therefore, the potential at node N₁ as the reference voltage is -0.8 x 2 = -1.6 V determined by the diodes D₁ and D₂. The potential at node N₂ during a non-broken-mode of the PROM cell PC is -0.8 x 3 = -2.4 V determined by the diodes D₁ , D₂ , and D₄. The potential at node N₂ after a write mode of the PROM cell PC is -0.8 V determined by the PROM cell PC corresponding to one diode stage. Thus, after a write mode of the PROM cell PC, the potential at node N₁: -1.6 V; and the potential at node N₂: -2.4 V. Thus, in the same way as in the circuit of Fig. 6, the potential of the defective address signal A iR is high. On the other hand, after a write mode of the PROM cell PC, the potential at Node N₁: -1.6 V; and the potential at Node N₂: -0.8 V. Thus, in the same way as in the circuit of Fig. 6, the potential of the defective address signal A iR is low. In Fig. 9, which illustrates a seventh example of the 1-bit memory circuit of Fig. 2, the resistor R₀ of Fig. 8 is deleted, and a diode D₀ is provided on the side of the power supply V CC . However, the operation of the circuit of Fig. 9 is about the same as that of Fig. 8. In Fig. 10, which illustrates an eighth example of the 1-bit memory circuit of Fig. 2, in order to separate the circuit for determining the potential at node N₁ from the circuit for determining the potential at node N₂ , two diode stages D₁' and D₂' are added. However, the operation of circuit of Fig. 10 is the same as that of Fig. 8. Thus, in the circuits of Figs. 8, 9, and 10, the potential at node N₂ is increased or decreased by the potential corresponding to one diode stage as compared with the reference voltage at node N₁ , in accordance with the presence or absence of a write operation (breakdown) of the PROM cell PC. Also, the logic amplitude corresponding to one diode stage is read out by the following transistors Q₂ , Q₃ , and Q₄. The output A iR of the circuit of Fig. 3, 4, 5, 6, 7, 8, 9, or 10 is supplied to the address comparing circuit 7 of Fig. 1. As illustrated in Figs. 11A and 11B, the address comparing circuit 7 comprises eight exclusive-OR circuits EOR₀ , EOR₁ , ..., EOR₇ , and a NOR circuit NR. That is, when the address signals A₀ , A₁ , ..., and A₇ are completely coincided with the defective address signals A 0R , A 1R , ..., and A 7R , the outputs S₀ , S₁ , ..., and S₇ of the exclusive-OR circuits ERO₀ , EOR₁ , ..., and EOR₇ are all low, so that the output S out of the NOR circuit NR becomes high, thereby operating the driver 8 and, simultaneously, disabling the word drivers 5. On the other hand, when at least one bit of the address signals A₀ , A₁ , ..., and A₇ is not coincided with the corresponding one of the defective address signals A 0R , A 1R , ..., and A 7R , at least one of the outputs S₀ , S₁ , ..., and S₇ of the exclusive-OR circuits EOR₀ , EOR₁ , .., and EOR₇ is high, so that the output S out of the NOR circuit NR becomes low, thereby disabling the driver 8 and, simultaneously, enabling the word drivers 5. In Fig. 11, note that V R is a reference voltage, which is predetermined as suitable for the logic amplitude of the defective address memory circuit 6-i. For example, in the case of the circuit as illustrated in Fig. 3 or 5, V R is about -2.0 V, while in the case of the circuit as illustrated in Fig. 4, V R is about -1.2 V. Also, V RD of Fig. 11 is a predetermined reference voltage. Note that the number of diode stages (D₁ , D₂ , and D₃) of Figs. 3 through 10 can be increased. However, in Fig. 7 (or 10), when the number of diode stages D₁ to D₃ (or D₁ and D₂) is increased, the number of diode stages D₁' to D₃' (or D₁' and D₂') must be also increased. In the 1-bit memory circuits as illustrated in Figs. 3 through 10, the logic amplitude is defined by the number of diode stages, and accordingly, such circuits are helpful in the configuration of the defective address memory circuit for storing a defective address in a bipolar-transistor type RAM having a redundancy configuration. However, in the case of a write operation in the circuits of Figs. 3 through 10, a very large write current I W is necessary, and as a result, the write transistor Q₁ becomes large and also its load becomes large. Therefore, as illustrated in Fig. 1, when the address signals A₀ , A₁ , ..., and A₇ having a large logic amplitude are supplied directly to the row address buffers 3 and to the defective address memory circuit 6, the large load of the write transistor Q₁ is also applied to the address signals A₀ , A₁ , ..., and A₇ even during a non-write mode, thus causing a problem wherein an address access time is delayed during a normal state. In Figs. 12A and 12B, which illustrates another embodiment of the present invention, each of the row address signals A₀ , A₁ , ..., and A₇ are supplied via emitter-followers Q₁₁ and Q₁₂ , diodes D₁₁ , D₁₂ , and D₁₃ , and resistors R₁₁ and R₁₂ to the defective address memory circuit 6. For example, if the high and low levels of an address signal are -0.8 V and -1.8 V, respectively, the address amplitude is 1.0 V (= 1.8 - 0.8), and therefore, the high and low levels at the inputs of the row address buffers 3 are -1.6 V (= -0.8 - 0.8) and -2.6 (= -1.8 - 0.8), respectively, and the address amplitude is also 1.0 V. On the other hand, at each node N₄ on the input side of the defective address memory circuit 6, the high level -0.8 V of the address signals A₀ , A₁ , ..., and A₇ becomes -0.8 - 0.8 x 5 = -4.8 V by two stages of the emitter-followers and three stages of the diodes D₁₁ , D₁₂ , and D₁₃ , and also the low level -1.8 V becomes -1.8 - 0.85 x 5= -5.8 V by two stages of the emitter-followers Q₁₁ and Q₁₂ and three stages of the diodes. In this case, since the lowest power supply voltage is -5.0 V, the low level at each node N₃ is -5.0 V. Therefore, the address amplitude at each node N₃ is small and is 0.2 V (= 5.0 - 4.8). The address amplitude of the gates of the write transistors Q₁ is further decreased by resistors R₁₁ and R₁₂. For example, when the address amplitude is at the gates of the write transistors Q₁ , the address amplitude is reduced 0.1/1 = 1/10 by the two stages of the emitter followers, the three stages of the diodes, and the resistors. Thus, during a non-write mode, since the address amplitude input to the defective address memory circuit 6 is reduced as compared with the address amplitude input to the row address buffers 3, application of a large load of the write transistors Q₁ can be substantially avoided to the address buffers 3. That is, even when the gate capacity C G of the transistor Q₁ is large, the fluctuation of charges C G ΔV is reduced if the voltage amplitude ΔV is reduced. Thus, the load of the write transistors can be neglected. During a write mode, since the voltage V P is increased from 0 V to 5 V, the address amplitude at the write transistors Q₁, becomes large, and in this case, the address amplitude at the address buffers 3 also increases, which, however, has no effect on the address buffers 3 during a write mode. Note that, in Fig. 12, two stages of emitter-followers, three stages of diodes, and the like are used as the level shift down means. However, the number of such stages can be modified as occasion demands or in accordance with the power supply voltage. For example, all the five stages may consist of diodes. Also, if the write voltage is high, the number of such stages can be more than 6. Further, if the lowest power supply voltage is higher than -5 V, the number of such stages can be less than 4. Thus, in Figs. 12A and 12B, during a no-write mode, since the address amplitude applied to the write transistors Q₁ can be reduced, the large load of these write transistors is not applied to the address signals, and as a result, the address access time can be reduced.

Claims: A semiconductor memory device of a bipolar-transistor type comprising; a memory cell array (1); a redundancy memory cell array (2); means for receiving an address signal (A₀ ∼ A₇); means (3, 4, 5) for selecting a normal memory cell from said memory cell array in accordance with said address signal (A₀ ∼ A₇) from said address receiving means; and means (7) for comparing the address of said address signal (A₀ ∼ A₇) from said address receiving means with said defective address (A 0R ∼ A 7R ) of a defective memory cell of said memory cell array (1) so as to disable said normal memory cell selecting means (3, 4, 5) and select said redundancy memory cell array (2) when the address of said address signal (A₀ ∼ A₇) is different from said defective address (A 0R ∼ A 7R ); characterised by: means (6) for storing said defective address and comprising a plurality of 1-bit memory circuits (6-0, 6-1, ..., 6-7) of a diode type, each circuit corresponding to each bit of said defective address (A 0R ∼ A 7R ). A device as set forth in claim 1, wherein each of 1-bit memory circuits (6-0 ∼ 6-7) comprises; a first power supply means (V CC ); a second power supply means (V EE ); a write power supply means (V P ); a node (N₁); at least three diode stages (D₁ ∼ D₃) linked along a forward bias direction between said first power supply means (V CC ) and said node (N₁); a current source (I S ) or resistor linked between said node (N₁) and said second power supply means (V EE ); a diode stage (D₀) linked along a backward bias direction between said write power supply means (V P ) and said first power supply means (V CC ); a short-circuited junction type PROM cell (PC) linked between said write power supply means (V P ) and said node (N₁); and a switching element (Q₁), linked between said node (N₁) and said second power supply means (V EE ), for receiving one bit of said address signal (A₀ ∼ A₇), whereby generating a high or low potential from said node (N₁) in accordance with the short-circuited or non-short-circuited state of said PROM cell (PC). A device as set forth in claim 1, wherein each of 1-bit memory circuits (6-0 ∼ 6-7) comprises; a first power supply means (V CC ); a second power supply means (V EE ); a write power supply means (V P ); a node (N₁); at least two diode stage (D₁ , D₂) linked along a forward bias direction between said first power supply means (V CC ) and said node (N₁); a current source (I S ) or resistor linked between said node (N₁) and said second power supply means (V EE ); a resistor (R₀) linked between said write power supply means (V P ) and said first power supply means (V CC ); a short-circuited junction type PROM cell (PC) linked between said write power supply means (V P ) and said node (N₁); and a switching element (Q₁), linked between said node (N₁) and said second power supply means (V EE ), for receiving one bit of said address signal (A₀ ∼ A₇), whereby generating a high or low potential from said node (N₁) in accordance with the short-circuited or non-short-circuited state of said PROM cell (PC). A device as set forth in claim 1, wherein each of 1-bit memory circuits (6-0 ∼ 6-7) comprises; a first power supply means (V CC ); a second power supply means (V EE ); a write power supply means (V P ); first and second nodes (N₀ , N₁); a diode stage (D₀) linked along a forward bias direction between said first power supply means (V CC ) and said first node (N₀); at least two diode stages (D₁ , D₂) linked along a forward bias direction between said first node (N₀) and said second node (N₁); a current source (I S ) or resistor linked between said second node (N₁) and said second power supply means (V EE ); a direct link between said write power supply means (V P ) and said first node (N₀); a short-circuited junction type PROM cell (PC) linked between said write power supply means (V P ) and said second node (N₁); and a switching element (Q₁), linked between said second node (N₁) and said second power supply means (V EE ), for receiving one bit of said address signal (A₀ ∼ A₇), whereby generating a high or low potential from said node (N₁) in accordance with the short-circuited or non-short-circuited state of said PROM cell (PC). A device as set forth in claim 1, wherein each of said 1-bit memory circuits (6-0 ∼ 6-7) comprises; a first power supply means (V CC ); a second power supply means (V EE ); a write power supply means (V P ); first and second nodes (N₁ , N₂); at least three diode stages (D₁ ∼ D₃) along a forward bias direction between said first power supply means (V CC ) and said first node (N₁); a first resistor (R₁) linked between said first node (N₁) and said second power supply means (V EE ); a diode stage (D₄) linked between said first and second nodes (N₁ , N₂), and having the same conduction direction as said at least three diode stages (D₁ ∼ D₃); a second resistor (R₂) linked between said second node (N₂) and said second power supply means (V EE ); a diode stage (D₀) linked along a forward bias direction linked between said first power supply means (V CC ) and said write power supply means (V P ); a short-circuited junction type PROM cell (PC) linked between said write power supply means (V P ) and said second node (N₂); a switching element (Q₁), linked between said second node (N₂) and said second power supply means (V EE ), for receiving one bit of said address signal (A₀ ∼ A₇); and output means (Q₂ ∼ Q₄ , R₃), connected to said first and second nodes (N₁ , N₂), for detecting the difference in potential in accordance with the short-circuited or non-short-circuited state of said PROM cell (PC). A device as set forth in claim 1, wherein each of said 1-bit memory circuits (6-0 ∼ 6-7) comprises; a first power supply means (V CC ); a second power supply means (V EE ); a write power supply means (V P ); first and second nodes (N₁ , N₂); at least three diode stages (D₁ ∼ D₃) along a forward bias direction between said first power supply means (V CC ) and said first node (N₁); a first resistor (R₁) linked between said first node (N₁) and said second power supply means (V EE ); at least four diode stages (D₁' ∼ D₃', D₄) linked along a forward bias direction between said first power supply means (V CC ) and said second node (N₂); a second resistor (R₂) linked between said second node (N₂) and said second power supply means (V EE ); a diode stage (D₀) linked along a forward bias direction linked between said first power supply means (V CC ) and said write power supply means (V P ); and a short-circuited-junction type PROM cell (PC) linked between said write power supply means (V P ) and said second node (N₂); a switching element (Q₁), linked between said second node (N₂) and said second power supply means (V EE ), for receiving one bit of said address signal (A₀ ∼ A₇); and output means (Q₂ ∼ Q₄ , R₃), connected to said first and second nodes (N₁ , N₂), for detecting the difference in potential in accordance with the short-circuited or non-short-circuited state of said PROM cell (PC). A device as set forth in claim 1, wherein each of said 1-bit memory circuits (6-0 ∼ 6-7) comprises; a first power supply means (V CC ); a second power supply means (V EE ); a write power supply means (V P ); first and second nodes (N₁ , N₂); at least two diode stages (D₁ , D₂) along a forward bias direction between said first power supply means (V CC ) and said first node (N₁); a first resistor (R₁) linked between said first node (N₁) and said second power supply means (V EE ); a diode stage (D₄) linked between said first and second nodes (N₁ , N₂), and having the same conduction direction as said at least two diode stages (D₁ , D₂); a second resistor (R₂) linked between said second node (N₂) and said second power supply means (V EE ); a resistor (R₀) linked between said first power supply means (V CC ) and said write power supply means (V P ); a short-circuited-junction type PROM cell (PC) linked between said write power supply means (V P ) and said second node (N₂); a switching element (Q₁), linked between said second node (N₂) and said second power supply means (V EE ), for receiving one bit of said address signal (A₀ ∼ A₇); and output means (Q₂ ∼ Q₄ , R₃), connected to said first and second nodes (N₁ , N₂), for detecting the difference in potential in accordance with the short-circuited or non-short-circuited state of said PROM cell (PC). A device as set forth in claim 1, wherein each of said 1-bit memory circuits (6-0 ∼ 6-7) comprises; a first power supply means (V CC ); a second power supply means (V EE ); a write power supply means (V P ); first, second, and third nodes (N₀ , N₁ , N₂); a diode stage (D₀) linked along a forward bias direction between said first power supply means (V CC ) and said first node (N₀); at least two diode stages (D₁ , D₂) along a forward bias direction between said first and second nodes (N₀ , N₁); a first resistor (R₁) linked between said second node (N₁) and said second power supply means (V EE ); a diode stage (D₄) linked between said first and second nodes (N₁ , N₂), and having the same conduction direction as said at least two diode stages (D₁ , D₂); a direct link between said first node (N₀) and said write power supply means (V P ); a second resistor (R₂) linked between said second node (N₂) and said second power supply means (V EE ); a short-circuited junction type PROM cell (PC) linked between said write power supply means (V P ) and said third node (N₂); a switching element (Q₁), linked between said third node (N₂) and said second power supply means (V EE ), for receiving one bit of said address signal (A₀ ∼ A₇); and output means (Q₂ ∼ Q₄ , R₃), connected to said second and third nodes (N₁ , N₂), for detecting the difference in potential in accordance with the short-circuited or non-short-circuited state of said PROM cell (PC). A device as set forth in claim 1, wherein each of said 1-bit memory circuits (6-0 ∼ 6-7) comprises; a first power supply means (V CC ); a second power supply means (V EE ); a write power supply means (V P ); first and second nodes (N₁ , N₂); at least two diode stages (D₁ , D₂) along a forward bias direction between said first power supply means (V CC ) and said first node (N₁); a first resistor (R₁) linked between said first node (N₁) and said second power supply means (V EE ); at least three diode stages (D₁', D₂', D₄) linked along a forward bias direction between said first power supply means (V CC ) and said second node (N₂); a second resistor (R₂) linked between said second node (N₂) and said second power supply means (V EE ); a resistor (R₃) linked between said first power supply means (V CC ) and said write power supply means (V P ); a short-circuited junction type PROM cell (PC) linked between said write power supply means (V P ) and said second node (N₂); a switching element (Q₁), linked between said second node (N₂) and said second power supply means (V EE ), for receiving one bit of said address signal (A₀ ∼ A₇); and output means (Q₂ ∼ Q₄ , R₃), connected to said first and second nodes (N₁ , N₂), for detecting the difference in potential in accordance with the short-circuited or non-short-circuited state of said PROM cell (PC). A device as set forth in claim 1, further comprising means, linked between said address receiving means and said defective address storing means, for transmitting said address signal (A₀ ∼ A₇) to said defective address storing means during a defective address writing mode and allowing no transmission of said address signal (A₀ ∼ A7) to said defective address storing means. A device as set forth in claim 10, wherein said switching means comprises level shift means for reducing the output amplitude of said address receiving means so that the input amplitude of said defective address storing means is smaller than the output amplitude of said defective address storing means. A device as set forth in claim 11, wherein said level shift means comprises one or more stages of emitter followers, diodes, or resistors. An information memory device comprising: a first power supply means (V CC ); a second power supply means (V EE ); a write power supply means (V P ); a node (N₁); at least three diode stages (D₁ ∼ D₃) linked along a forward bias direction between said first power supply means (V CC ) and said node (N₁); a current source (I S ) or resistor linked between said node (N₁) and said second power supply means (V EE ); a diode stage (D₀) linked along a backward bias direction between said write power supply means (V P ) and said first power supply means (V CC ); a short-circuited-junction type PROM cell (PC) linked between said write power supply means (V P ) and said node (N₁); and a switching element (Q₁), linked between said node (N₁) and said second power supply means (V EE ), for receiving a one bit address signal, whereby generating a high or low potential from said node (N₁) in accordance with the short-circuited or non-short-circuited state of said PROM cell (PC). An information memory device comprising: a first power supply means (V CC ); a second power supply means (V EE ); a write power supply means (V P ); a node (N₁); at least two diode stages (D₁ , D₂) linked along a forward bias direction between said first power supply means (V CC ) and said node (N₁); a current source (I S ) or resistor linked between said node (N₁) and said second power supply means (V EE ); a resistor (R₀) linked between said write power supply means (V P ) and said first power supply means (V CC ); a short-circuited-junction type PROM cell (PC) linked between said write power supply means (V P ) and said node (N₁); and a switching element (Q₁), linked between said node (N₁) and said second power supply means (V EE ), for receiving a one bit address signal, whereby generating a high or low potential from said node (N₁) in accordance with the short-circuited or non-short-circuited state of said PROM cell (PC). An information memory device comprising: a first power supply means (V CC ); a second power supply means (V EE ); a write power supply means (V P ); first and second nodes (N₀ , N₁); a diode stage (D₀) linked along a forward bias direction between said first power supply means (V CC ) and said first node (N₀); at least two diode stages (D₁ , D₂) linked along a forward bias direction between said first node (N₀) and said second node (N₁); a current source (I S ) or resistor linked between said second node (N₁) and said second power supply means (V EE ); a direct link between said write power supply means (V P ) and said first node (N₀); a short-circuited junction type PROM cell (PC) linked between said write power supply means (V P ) and said second node (N₁); and a switching element (Q₁), linked between said second node (N₁) and said second power supply means (V EE ), for receiving a one bit address signal, whereby generating a high or low potential from said node (N₁) in accordance with the short-circuited or non-short-circuited state of said PROM cell (PC). An information memory device comprising: a first power supply means (V CC ); a second power supply means (V EE ); a write power supply means (V P ); first and second nodes (N₁ , N₂); at least three diode stages (D₁ ∼ D₃) along a forward bias direction between said first power supply means (V CC ) and said first node (N₁); a first resistor (R₁) linked between said first node (N₁) and said second power supply means (V EE ); a diode stage (D₄) linked between said first and second nodes (N₁ , N₂), and having the same conduction direction as said at least three diode stages (D₁ ∼ D₃); a second resistor (R₂) linked between said second node (N₂) and said second power supply means (V EE ); a diode stage (D₀) linked along a forward bias direction linked between said first power supply means (V CC ) and said write power supply means (V P ); a short-circuited junction type PROM cell (PC) linked between said write power supply means (V P ) and said second node (N₂); a switching element (Q₁), linked between said second node (N₂) and said second power supply means (V EE ), for receiving a one bit address signal; and output means (Q₂ ∼ Q₄, R₃), connected to said first and second nodes (N₁ , N₂), for detecting the difference in potential in accordance with the short-circuited or non-short-circuited state of said PROM cell (PC). An information memory device comprising: a first power supply means (V CC ); a second power supply means (V EE ); a write power supply means (V P ); first and second nodes (N₁ , N₂); at least three diode stages (D₁ ∼ D₃) along a forward bias direction between said first power supply means (V CC ) and said first node (N₁); a first resistor (R₁) linked between said first node (N₁) and said second power supply means (V EE ); at least four diode stages (D₁' ∼ D₃', D₄) linked along a forward bias direction between said first power supply means (V CC ) and said second node (N₂); a second resistor (R₂) linked between said second node (N₂) and said second power supply means (V EE ); a diode stage (D₀) linked along a forward bias direction linked between said first power supply means (V CC ) and said write power supply means (V P ); a short-circuited junction type PROM cell (PC) linked between said write power supply means (V P ) and said second node (N₂); a switching element (Q₁), linked between said second node (N₂) and said second power supply means (V EE ), for receiving a one bit address signal; and output means (Q₂ ∼ Q₄ , R₃), connected to said first and second nodes (N₁ , N₂), for detecting the difference in potential in accordance with the short-circuited or non-short-circuited state of said PROM cell (PC). An information memory device comprising: a first power supply means (V CC ); a second power supply means (V EE ); a write power supply means (V P ); first and second nodes (N₁ , N₂); at least two diode stages (D₁ , D₂) along a forward bias direction between said first power supply means (V CC ) and said first node (N₁); a first resistor (R₁) linked between said first node (N₁) and said second power supply means (V EE ); a diode stage (D₄) linked between said first and second nodes (N₁ , N₂), and having the same conduction direction as said at least two diode stages (D₁ , D₂); a second resistor (R₂) linked between said second node (N₂) and said second power supply means (V EE ); a resistor (R₀) linked between said first power supply means (V CC ) and said write power supply means (V P ); a short-circuited junction type PROM cell (PC) linked between said write power supply means (V P ) and said second node (N₂); a switching element (Q₁), linked between said second node (N₂) and said second power supply means (V EE ), for receiving a one bit address signal; and output means (Q₂ ∼ Q₄ , R₃), connected to said first and second nodes (N₁ , N₂), for detecting the difference in potential in accordance with the short-circuited or non-short-circuited state of said PROM cell (PC). An information memory device comprising: a first power supply means (V CC ); a second power supply means (V EE ); a write power supply means (V P ); first, second, and third nodes (N₀ , N₁ , N₂); a diode stage (D₀) linked along a forward bias direction between said first power supply means (V CC ) and said first node (N₀); at least two diode stages (D₁ , D₂) along a forward bias direction between said first and second nodes (N₀ , N₁); a first resistor (R₁) linked between said second node (N₁) and said second power supply means (V EE ); a diode stage (D₄) linked between said first and second nodes (N₁ , N₂), and having the same conduction direction as said at least two diode stages (D₁ , D₂); a second resistor (R₂) linked between said second node (N₂) and said second power supply means (V EE ); a direct link between said first node (N₀) and said write power supply means (V P ); a short-circuited junction type PROM cell (PC) linked between said write power supply means (V P ) and said third node (N₂); a switching element (Q₁), linked between said third node (N₂) and said second power supply means (V EE ), for receiving a one bit address signal; and output means (Q₂ ∼ Q₄ , R₃), connected to said second and third nodes (N₁ , N₂), for detecting the difference in potential in accordance with the short-circuited or non-short-circuited state of said PROM cell (PC). An information memory device comprising: a first power supply means (V CC ); a second power supply means (V EE ); a write power supply means (V P ); first and second nodes (N₁ , N₂); at least two diode stages (D₁ , D₂) along a forward bias direction between said first power supply means (V CC ) and said first node (N₁); a first resistor (R₁) linked between said first node (N₁) and said second power supply means (V EE ); at least three diode stages (D₁', D₂', D₄) linked along a forward bias direction between said first power supply means (V CC ) and said second node (N₂); a second resistor (R₂) linked between said second node (N₂) and said second power supply means (V EE ); a resistor (R₃) linked between said first power supply means (V CC ) and said write power supply means (V P ); and a short-circuited junction type PROM cell (PC) linked between said write power supply means (V P ) and said second node (N₂); a switching element (Q₁), linked between said second node (N₂) and said second power supply means (V EE ), for receiving a one bit address signal; and output means (Q₂ ∼ Q₄ , R₃), connected to said first and second nodes (N₁ , N₂), for detecting the difference in potential in accordance with the short-circuited or non-short-circuited state of said PROM cell (PC).

Inventors: OKAJIMA, YOSHINORI
Applicants: FUJITSU LIMITED
Application year: 1985
Main classification: G06F11
IPC codes: G11C29