JPH03142778A - Reference voltage stabilization circuit for memory device - Google Patents

Abstract

PURPOSE: To output reference voltage kept at a fixed value even if temperature variation occurs by controlling a voltage value of an output side of a diode group so that voltage of an input side of a diode group is kept at a fixed value corresponding to variation of distributed voltage value fed back from a negative feedback section when reference voltage is varied. CONSTITUTION: This device has a negative feedback section 1 which distributes reference voltage applied to an output terminal and feeds back distributed voltage in accordance with a value of reference voltage to an output side of diode groups D1 , D2 . In this case, electric charges supplied from a power source voltage applying terminal VCC flow in the diode groups to some extent, while applied to an output terminal OUT. Then, as each of diodes D1 , D2 has the absolutely minimum voltage which must be applied for making a current flow to a forward direction, even if power source voltage is varied, a reference voltage value outputted to the output terminal OUT coincides with a total value of a statistic of threshold voltage of each of diodes D1 , D2 and voltage values of an output side of the diode groups. Thereby, even if ambient temperature is varied and threshold voltage of each diode is varied, reference voltage coinciding with the total value is controlled at a fixed value.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a reference voltage stabilization circuit, and in particular to a reference voltage for a memory device in which the reference voltage is kept constant even when temperature changes occur. Regarding stabilization circuits.

(Prior Art) Memory devices have conventionally required a reference voltage circuit that supplies a reference voltage that is always kept at a constant voltage regardless of changes in the voltage of a power supply.

Therefore, a reference voltage circuit shown in FIG. 2 is used.

That is, as shown in the figure, the conventional reference voltage circuit includes a resistor R1 that passes the charge from the power supply voltage application terminal CC, and a series-connected diode D1 and diode D2 that sequentially flow the charge that has passed through the resistor R1 in the forward direction. and a diode D2
The charge flowing through is sent to the ground potential terminal VSS. Also,
The voltage between the resistor R1 and the diode D1, ie, the reference voltage, is applied to the output terminal OUT.

Here, the diode D1 and the diode D2 have a minimum required voltage, that is, a threshold voltage Vs, which must be applied to cause current to flow in the forward direction.

In the above reference voltage circuit, when the potential of the power supply voltage application terminal VCC is stable, the diode D1 and the diode D
A small amount of charge passes through the output terminal OUT, and the value of the reference voltage applied to the output terminal OUT is maintained at twice Vs, that is, 2Vs.

Furthermore, when the voltage at the power supply voltage application terminal VCC fluctuates and, for example, the reference voltage exceeds 2Vs, the diode DI and the diode D2 each have a threshold voltage Vs, so the diode D1 and the diode D2 transfer the charge to the ground potential. The value of the reference voltage released to the terminal VSS is maintained at 2Vs.

(Problem M to be solved by the invention) However, in the above conventional reference voltage circuit,
Threshold voltage Vs of diode D1 and diode D2
decreases by about 2rnV when the temperature rises by 1°C, so there is a problem that the reference voltage value 2Vs output to the output terminal OUT fluctuates as the temperature changes.

SUMMARY OF THE INVENTION The present invention is intended to solve the above-mentioned problems of the prior art, and its purpose is to provide a reference voltage for memory devices that can output a reference voltage that is maintained at a constant value even when temperature changes occur. The purpose is to provide a stabilizing circuit.

Another object of the present invention is to provide a reference voltage stabilizing circuit for a memory device that can easily utilize a conventional reference voltage circuit and can be used in all types of memory devices.

[Meanings of the Invention (Means for Solving the Problems)] The present invention for solving the above problems consists of connecting in series a plurality of diodes that cause charges supplied from a power supply voltage application terminal to flow in the forward direction, and In a reference voltage stabilizing circuit for a memory device that applies a reference voltage at the entrance side of a group of diodes to an output terminal, the reference voltage applied to the output terminal is distributed and a distributed voltage corresponding to the value of the reference voltage is applied to the group of diodes. a negative feedback section that provides negative feedback to the output side of the diode group; and a negative feedback section that provides negative feedback to the output side of the group of diodes; and a control unit that controls the voltage value on the output side of the diode group so as to maintain the voltage value at the output side of the diode group.

(Function) In the reference voltage stabilizing circuit for a memory device of the present invention, the charge supplied from the power supply voltage application terminal slightly flows through the diode group and is applied to the output terminal.

Here, each diode has a minimum required voltage, that is, a threshold voltage, that must be applied in order for the current to flow in the forward direction, so even if the power supply voltage fluctuates, the reference voltage value output to the output terminal will vary. This value matches the sum of the total threshold voltage of the diodes and the voltage value on the exit side of the diode group.

Furthermore, even if the threshold voltage of each diode changes due to a change in ambient temperature, for example, the reference voltage that matches the above-mentioned sum value is controlled to a constant value.

That is, for example, when the threshold voltage of each diode decreases and the reference voltage decreases, the negative feedback section distributes the decreased reference voltage and outputs, for example, a lower distributed voltage to the control section than before the temperature change. Then, the control section increases the voltage value on the output side of the diode group in response to the distribution voltage that has changed to a lower value.

In other words, the decrease in the total value of the threshold voltages of each diode is compensated for by increasing the voltage value on the output side of the diode group, so the voltage value on the input side of the diode group, that is, the reference voltage value, is affected by fluctuations in ambient temperature. It is held at a constant value before.

In addition, when the threshold voltage of each diode increases and the reference voltage output to the output terminal increases, the negative feedback section outputs a higher distributed voltage to the control section than before the temperature change, and the output side of the diode group Lower the voltage value. In other words, the increase in the total value of the threshold voltage of each diode is absorbed by lowering the voltage value on the output side of the diode group, so the voltage value on the input side of the diode group, that is, the reference voltage value, remains at a constant value. is maintained.

Therefore, even if the threshold voltage of each diode fluctuates due to temperature changes, the negative feedback section and the control section work together to adjust the voltage on the output side of the diode group so as to cancel out the fluctuation in the threshold voltage of the diode. , the reference voltage value output to the output terminal is always kept at a constant value.

(Example) Practical examples of the present invention will be described below with reference to the drawings.

FIG. 1 shows a detailed circuit diagram of a reference voltage stabilizing circuit for a memory device according to an embodiment of the present invention.

As shown in the figure, the reference voltage stabilizing circuit of this embodiment is different from the conventional reference voltage circuit shown in FIG.
a negative feedback section 1 which distributes a reference voltage applied to T and negatively feeds back a distributed voltage according to the value of the reference voltage to the output side of the diode group; and a negative feedback section 1 when the value of the reference voltage fluctuates. A control section 2 is added to control the voltage value on the output side of the diode D2 so as to keep the voltage on the input side of the diode D1 at a constant value in accordance with the change in the divided voltage value that is negatively fed back from the diode D1.

Negative feedback section 1 includes a MOS transistor M1 whose drain side terminal and gate side terminal are connected to the output terminal 0tJT side, and a train side terminal and gate side connected to the junction N1 where the source side terminal of the MOS transistor M1 is connected. A MOS transistor M2 is connected to the terminals of the MOS transistor M2, and the source side terminal of the MOS transistor M2 is connected to the ground potential terminal vSS.
connected to.

The control unit 2 also includes a bias voltage adjusting transistor M3 whose drain side terminal is connected to the forward output side of the diode D2.
The voltage of the junction N1 is applied to the terminal on the gate side of No.3. Furthermore, the source side terminal of the bias voltage adjusting transistor M3 is connected to the ground potential terminal SS.

Here, MOS transistor M1 and MOS transistor M2 each have a predetermined internal resistance.

In addition, in the bias voltage adjustment transistor M3, the transconductance of the transistor M3 changes according to the voltage value applied to the gate side terminal.For example, when the value of the voltage applied to the gate side terminal becomes high, The value of conductance increases.

Furthermore, as explained in the conventional reference voltage circuit,
Diode D1 and diode D2 have a minimum required voltage, ie, a threshold voltage Vs, that must be applied to cause current to flow in the forward direction.

In the configuration of the reference voltage stabilizing circuit of this embodiment described above,
Voltage value V from power supply voltage application terminal VCC to output terminal OUT
A reference voltage of r is applied.

In other words, the MOS transistor M1 of the negative feedback section 1 becomes conductive due to the reference voltage applied to the output terminal OUT side, and further, the MOS transistor M1 lowers the reference voltage through its internal resistance and applies a predetermined divided voltage to the junction N1. Then, the MOS transistor M2 becomes conductive due to the divided voltage of the junction N1, and further, the MOS transistor M2 drops the divided voltage due to its internal resistance, and becomes the ground potential terminal VS.
Charge is released to S. That is, the value of the reference voltage applied to the output terminal OUT is distributed by the negative feedback section 1 to the MOS transistor M1 and the MOS transistor M2. Further, the bias voltage adjusting transistor M3 of the control section 2 is applied with the divided voltage of the junction N1 and becomes conductive, so that it has a transconductance of a predetermined value.

Therefore, the voltage applied to the input side of the diode D1, that is, the reference voltage value Vr applied to the output terminal ○tJT, is the threshold voltage Vs of each of the diode D1 and the diode D2.
It is controlled to a value that is the sum of the total value of and the potential difference between the drain side and the source side of the bias voltage adjusting transistor M3.

Next, the operation of the reference voltage stabilizing circuit according to the present embodiment when the ambient temperature in which the circuit is installed fluctuates will be explained.

For example, when the ambient temperature rises, the threshold voltage Vs of the diode D1 and the diode D2 decreases, and the reference voltage value Vr applied to the output terminal OUT slightly decreases. Then, the divided voltage at the junction N1 of the negative feedback section 1 also decreases together with the reference voltage, and the voltage applied to the bias voltage adjusting transistor M3 decreases. In other words, the transconductance of the bias voltage adjusting transistor M3 becomes smaller.

Therefore, the potential difference between the drain side and the source side of the bias voltage adjusting transistor M3 increases, and the voltage value on the exit side of the diode D2 increases.

In other words, since the decrease in the total value of the threshold voltage Vs of each diode D1 and D2 is compensated for by increasing the voltage value on the output side of the diode D2, the voltage value on the input side of the diode D1, that is, the reference voltage value Vr is held at a constant value before the ambient temperature increases.

Further, when the ambient temperature decreases, the threshold voltage Vs of the diode D1 and the diode D2 increases slightly, and the reference voltage value Vr applied to the output terminal 0[JT increases. Then, the divided voltage of the junction N1 applied to the bias voltage adjusting transistor M3 increases, so that the transconductance of the bias voltage adjusting transistor M3 increases.

Therefore, the potential difference between the drain side and the source side of the bias voltage adjusting transistor M3 becomes smaller, and the voltage value on the exit side of the diode D2 decreases.

In other words, by lowering the voltage value on the output side of diode D2 by the increase in the total value of the threshold voltage Vs of each diode Di and D2, the voltage value on the input side of diode D1, that is, the reference voltage value Vr, is lowered by the ambient temperature. is held at a constant value before falling.

Therefore, even if the ambient temperature rises (falls) and the reference voltage value Vr applied to the output terminal OUT falls (increases), the negative feedback section 1 and the control section 2 cooperate to prevent fluctuations in the reference voltage. The voltage on the input side of the diode D1 is controlled so as to cancel the voltage, and the reference voltage applied to the output terminal OUT is always kept at a constant value.

Furthermore, since the reference voltage stabilizing circuit of this embodiment is a conventional reference voltage circuit with a negative feedback section 1 and a control section 2 added, the conventional reference voltage circuit can be easily used and can be applied to all memory devices. can be used.

In the above embodiment of the reference voltage stabilizing circuit for a memory device, the diode group is connected in two stages in series, but the number of diodes can be set to a desired value.

Further, although the MOS transistors of the negative feedback section 1 are connected in two stages in series, the number of MOS transistors can be set to a desired value.

The present invention is not limited to the above-described embodiments, but can be implemented in any appropriate manner by making appropriate design changes.

[Effects of the Invention] As explained above, according to the present invention, a plurality of diodes that allow charges supplied from a power supply voltage application terminal to flow in the forward direction are connected in series, and a reference voltage on the entrance side of the group of diodes is output. In a memory device reference voltage stabilizing circuit applied to a terminal, a negative feedback section divides the reference voltage applied to the output terminal and negatively feeds back a distributed voltage according to the value of the reference voltage to the output side of the diode group. and a voltage on the output side of the diode group so as to keep the voltage on the input side of the diode group at a constant value in accordance with the change in the distribution voltage value that is negatively fed back from the negative feedback section when the value of the reference voltage fluctuates. Since the present invention includes a control section that controls the voltage value, even if the threshold voltage of the diode changes due to a temperature change, it is possible to output a reference voltage that is kept at a constant value. In addition, a conventional reference voltage circuit can be easily used, and all memory devices can be used.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a detailed circuit diagram of a reference voltage stabilizing circuit for a memory device according to an embodiment of the present invention, and FIG. 2 is a circuit diagram of a conventional reference voltage circuit. 1... Negative feedback section 2... Control section D1, D2
...Diode Ml, M2...MOS transistor M3...Bias voltage adjustment transistor CC ■SS E1 Figure CC ■SS Figure 2

Claims (3)

[Claims] (1) In a reference voltage stabilizing circuit for a memory device, which connects in series a plurality of diodes that cause charges supplied from a power supply voltage application terminal to flow in the forward direction, and applies a reference voltage on the inlet side of the group of diodes to an output terminal. , a negative feedback section that distributes the reference voltage applied to the output terminal and negatively feeds back the distributed voltage according to the value of the reference voltage to the output side of the diode group; and a control unit that controls the voltage value on the output side of the diode group so as to maintain the voltage on the input side of the diode group at a constant value in accordance with the change in the distribution voltage value that is negatively fed back from the feedback unit. Characteristic reference voltage stabilization circuit for memory devices. (2) The negative feedback section includes a plurality of MOs whose drain side and source side are connected in series between the output terminal side and the ground potential terminal side.
2. The reference voltage stabilizing circuit for a memory device according to claim 1, further comprising an S transistor, wherein the reference voltage is divided by each internal resistor of the MOS transistor group, and the distributed voltage determined by the reference voltage is negatively fed back. (3) The control section includes a bias voltage adjustment transistor whose drain side is connected to the output side of the diode group and whose source side is connected to a ground potential terminal, and a negative feedback section is connected to the gate side terminal of the bias voltage adjustment transistor. A reference voltage for a memory device, characterized in that a feedback distributed voltage is applied and a transconductance value between the drain side and the source side of the bias voltage adjustment transistor is changed in accordance with a change in the distributed voltage. Stabilization circuit.