阅读说明：本技术 电压产生电路以及使用该电压产生电路的半导体装置 (Voltage generating circuit and semiconductor device using the same ) 是由 村上洋树 于 2020-11-19 设计创作，主要内容包括：本发明提供了一种电压产生电路以及使用该电压产生电路的半导体装置,该电压产生电路能够追求省空间化、构成简易、并且产生高信赖性的电压。本发明的电压产生电路包含基准电压产生部、PTAT电压产生部、比较部以及选择部。基准电压产生部产生几乎没有温度依存性的基准电压。PTAT电压产生部产生具有正或负的温度依存性的温度依存电压,且温度依存电压在目标温度时具有与基准电压相等的电压。比较部比较基准电压以及温度依存电压。选择部基于比较部的比较结果,选择基准电压及温度依存电压的其中一个,并输出所选择的基准电压或温度依存电压。(The invention provides a voltage generating circuit and a semiconductor device using the same, wherein the voltage generating circuit is capable of pursuing space saving, simple structure and high reliability voltage generation. A voltage generation circuit includes a reference voltage generation unit, a PTAT voltage generation unit, a comparison unit, and a selection unit. The reference voltage generating unit generates a reference voltage having almost no temperature dependency. The PTAT voltage generating unit generates a temperature-dependent voltage having positive or negative temperature dependency, and the temperature-dependent voltage has a voltage equal to the reference voltage at the target temperature. The comparison unit compares the reference voltage and the temperature-dependent voltage. The selection unit selects one of the reference voltage and the temperature-dependent voltage based on the comparison result of the comparison unit, and outputs the selected reference voltage or temperature-dependent voltage.)

1. A voltage generation circuit, comprising:

a reference voltage generating section configured to generate a reference voltage having substantially no temperature dependency;

a temperature-dependent voltage generating unit configured to have a positive or negative temperature dependency and generate at least one temperature-dependent voltage having a voltage equal to the reference voltage at a target temperature;

a comparison section configured to compare the reference voltage and the temperature-dependent voltage; and

a selection section configured to select one of the reference voltage and the temperature-dependent voltage based on a comparison result of the comparison section, and output the selected reference voltage or the temperature-dependent voltage as a temperature compensation reference voltage.

2. The voltage generation circuit of claim 1,

the selection section is configured to select the reference voltage when below the target temperature and to select the temperature-dependent voltage when above the target temperature.

3. The voltage generation circuit of claim 1,

the selection section is configured to select the temperature-dependent voltage when below the target temperature and to select the reference voltage when above the target temperature.

4. The voltage generation circuit of claim 1,

the selection section is configured to select the larger of the reference voltage and the temperature-dependent voltage compared by the comparison section.

5. The voltage generation circuit of claim 1,

the selection section is configured to select the smaller of the reference voltage and the temperature-dependent voltage compared by the comparison section.

6. The voltage generation circuit of claim 1,

when the temperature-dependent voltage generating unit outputs a 1 st temperature-dependent voltage and a 2 nd temperature-dependent voltage having different temperature characteristics, the 1 st temperature-dependent voltage has a voltage equal to the reference voltage at a 1 st target temperature;

the 2 nd temperature dependent voltage has a voltage equal to the reference voltage at the 2 nd target temperature;

wherein, this comparison portion includes: a 1 st comparison circuit configured to compare the 1 st temperature-dependent voltage and the reference voltage; and a 2 nd comparison circuit configured to compare the 2 nd temperature-dependent voltage and the reference voltage;

wherein the selection section is configured to select one of the 1 st temperature-dependent voltage, the 2 nd temperature-dependent voltage, and the reference voltage based on a comparison result of the 1 st comparison circuit and the 2 nd comparison circuit.

7. The voltage generation circuit of claim 6,

the selection section is configured to select the 1 st temperature-dependent voltage when being lower than the 1 st target temperature; selecting the reference voltage between the 1 st target temperature and the 2 nd target temperature; the 2 nd temperature-dependent voltage is selected when the 2 nd target temperature is not lower than the 2 nd target temperature.

8. The voltage generation circuit of claim 6,

the selection section is configured to select the reference voltage when being lower than the 1 st target temperature; selecting one of the 1 st temperature-dependent voltage and the 2 nd temperature-dependent voltage between the 1 st target temperature and the 2 nd target temperature; the reference voltage is selected above the 2 nd target temperature.

9. The voltage generation circuit of claim 1,

when the reference voltage generating part generates a 1 st reference voltage and a 2 nd reference voltage, the temperature dependent voltage has a voltage equal to the 1 st reference voltage at a 1 st target temperature and has a voltage equal to the 2 nd reference voltage at a 2 nd target temperature;

wherein the selection part is configured to select the 1 st reference voltage when being lower than the 1 st target temperature; selecting the temperature-dependent voltage between the 1 st target temperature and the 2 nd target temperature; the 2 nd reference voltage is selected when the 2 nd target temperature is higher.

10. The voltage generation circuit of claim 1, further comprising:

and a conversion circuit for receiving the temperature compensation reference voltage outputted from the selection unit and converting the voltage level of the temperature compensation reference voltage.

11. The voltage generation circuit of claim 1,

the temperature-dependent generator includes a DC voltage adjuster for shifting the initial temperature-dependent voltage generated by the temperature-dependent generator in a positive or negative direction to generate the temperature-dependent voltage.

12. The voltage generation circuit of claim 1,

the reference voltage generating section includes a bandgap reference circuit.

13. A semiconductor device, comprising:

the voltage generation circuit of any one of claims 1 to 12; and

and a driving device for driving the circuit based on the reference voltage or the temperature-dependent voltage generated by the voltage generation circuit.

14. The semiconductor device according to claim 13,

the driving device comprises a transistor connected with the memory unit;

wherein the driving device applies a driving voltage based on the reference voltage to the gate of the transistor in a temperature range lower than the target temperature; in a temperature range equal to or higher than the target temperature, a drive voltage based on a temperature-dependent voltage having a positive temperature slope is applied to the gate of the transistor.

15. The semiconductor device according to claim 14,

the memory cell includes a variable resistance element and an access transistor connected to the variable resistance element;

wherein the driving device applies the reference voltage or the temperature-dependent voltage to the gate of the access transistor via a word line.

Technical Field

The present invention relates to a voltage generating circuit, and more particularly, to a voltage generating circuit for generating a temperature compensated reference voltage.

Background

In a semiconductor device such as a memory or a logic, the reliability of a circuit is generally maintained by generating a temperature compensated voltage corresponding to an operating temperature and operating the circuit using the temperature compensated voltage. For example, in a memory circuit, when reading data, if the read current is reduced due to temperature variation, the read Margin (Margin) is reduced, and correct data cannot be read. Therefore, data is usually read by using a temperature compensated voltage to prevent the read current from decreasing, or to make the reference current for comparison with the read current have temperature dependency with the read current. For example, japanese patent application laid-open No. 2016-173869 discloses a method of generating a reference current by adding a Base (Base) current, which is independent of temperature and power supply voltage, to a voltage-compensated current and a temperature-compensated current.

As described above, the semiconductor device is equipped with a temperature compensation circuit, and generates a voltage having temperature dependency so as to correspond to a temperature change. Fig. 1(a) shows an example of a conventional temperature compensation circuit. The temperature compensation circuit includes: an On-chip temperature sensor 10; a logic unit 20 for receiving the detection result of the temperature sensor 10 and calculating a voltage level after temperature compensation; and an analog part 30 for outputting a temperature compensated voltage based on the operation result of the logic part 20.

The temperature sensor 10 includes: a reference circuit 12 for generating a temperature-independent reference voltage V_RETAnd a detection voltage V responsive to the operating temperature on the crystal_SEN(ii) a And an ADC (analog-to-digital converter) 14 receiving the reference voltage V_RETAnd detecting the voltage V_SENTo detect the voltage V_SENThe analog voltage of (2) is converted into a digital voltage. For example, as shown in FIG. 1(B), the ADC 14 is based on a reference voltage V_RETA minimum level is set. The logic portion 20 calculates how much temperature compensated voltage will be generated from the analog portion 30 based on a Trim Code (Trim Code) that compensates for manufacturing tolerances and the digital output from the temperature sensor 10. The analog part 30 includes a plurality of regulators for generating temperature-compensated voltages based on the calculation result of the logic part 20. For example, to read data from a memory cell, one of the regulators may generate a read voltage that is applied to the gate of a transistor.

FIG. 1(B) is a schematic view of a detected voltage V with a positive slope Tc in response to a change in temperature Ta_SENAnd the output of the ADC 14The relationship (2) of (c). As shown, the ADC 14 splits the sense voltage V by a step width between a minimum level and a maximum level_SENQuantization (digital processing). Therefore, the temperature compensated voltage finally outputted from the analog part 30 contains quantization noise (step width), and is not necessarily linear or a desired temperature compensated voltage. For example, a temperature compensated post-voltage V is required at a certain transition temperature_TpThe temperature compensated voltage V cannot be obtained due to the influence of quantization noise_TpTherefore, the operation performance of the circuit may not be realized. In addition, since the circuit scale of the on-chip temperature sensor 10 or the logic unit 20 is large, a large layout area is required, and the control of the logic unit 20 is complicated.

Disclosure of Invention

The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to provide a voltage generation circuit and a semiconductor device using the same, which are capable of generating a voltage with high reliability while reducing space and simplifying a configuration.

The voltage generation circuit of the present invention includes: a reference voltage generating unit that generates a reference voltage having substantially no temperature dependency; a temperature-dependent voltage generating unit that has a positive or negative temperature dependency and generates at least one temperature-dependent voltage having a voltage equal to the reference voltage at a target temperature; a comparison unit that compares the reference voltage and the temperature-dependent voltage; and a selection unit that selects one of the reference voltage and the temperature-dependent voltage based on a comparison result of the comparison unit, and outputs the selected reference voltage or the selected temperature-dependent voltage as a temperature-compensated reference voltage.

The semiconductor device of the present invention includes: the voltage generation circuit described above; and a driving device that drives the circuit based on the reference voltage or the temperature-dependent voltage generated by the voltage generation circuit. In one embodiment, the driving device includes a transistor connected to the memory cell; the driving device applies a driving voltage based on the reference voltage to the gate of the transistor in a temperature range lower than the target temperature; in a temperature range equal to or higher than the target temperature, a drive voltage based on a temperature-dependent voltage with a positive slope is applied to the gate of the transistor. In one embodiment, the memory cell includes a variable resistance element and an access transistor connected to the variable resistance element; the driving device applies the reference voltage or the temperature-dependent voltage to the gate of the access transistor via a word line.

According to the present invention, since the reference voltage and the temperature-dependent voltage are compared, the reference voltage or the temperature-dependent voltage is selected based on the comparison result, and the selected reference voltage or the temperature-dependent voltage is output, a voltage with high reliability can be obtained, and the voltage does not include quantization noise generated by the AD converter. In addition, since a temperature sensor mounted on a chip or logic for calculating a temperature compensation voltage from the result of the temperature sensor is not required as in the conventional technique, the circuit scale can be reduced and space saving is required.

Drawings

Fig. 1(a) to 1(B) illustrate a method of generating a reference voltage after temperature compensation using an existing temperature sensor mounted on a chip.

Fig. 2 is a block diagram showing the configuration of a voltage generation circuit according to embodiment 1 of the present invention.

Fig. 3 is a block diagram showing the configuration of a voltage generation circuit according to embodiment 2 of the present invention.

Fig. 4 (a) to (C-2) show examples of waveforms of the temperature-compensated reference voltages generated in embodiments 1 and 2 of the present invention.

Fig. 5 is a block diagram showing the configuration of a voltage generation circuit according to embodiment 3 of the present invention.

Fig. 6 is a block diagram showing the configuration of a voltage generation circuit according to embodiment 4 of the present invention.

Fig. 7 (a) to (E-2) show examples of waveforms of the temperature-compensated reference voltages generated in embodiments 3 and 4 of the present invention.

Fig. 8(a) to 8(C) are detailed configuration examples of the voltage generation circuit according to embodiment 2 of the present invention.

Fig. 9 is a detailed configuration example of the voltage generation circuit according to embodiment 3 of the present invention.

Fig. 10 illustrates a configuration of a variable resistance random access memory to which a voltage generation circuit according to an embodiment of the present invention is applied.

Reference numerals:

10: temperature sensor

12: reference circuit

14: ADC (analog/digital converter)

20: logic unit

30: analogy part

100,100A,100B, 100C: voltage generating circuit

110, 110C: reference voltage generating unit

120,120A,120B, 120C: PTAT voltage generating part

122: DC voltage adjustment unit

130,130B, 130C: comparison part

140,140B, 140C: selection part

200: variable resistive memory

210: memory array

210-1,210-2, 210-m: sub-array

220: row decoder and driver circuit (X-DEC)

230: row decoder and driving circuit (Y-DEC)

240: column selection circuit (YMUX)

250: control circuit

260: sense Amplifier (SA)

270: write drive read bias circuit (WD)

AMP: differential amplifier circuit

BL: bit line

COMP 0-COMP 3: comparison results

Control: control signal

CP, CP0, CP 1: comparator with a comparator circuit

DI, DO: internal data bus

DQ: output end

GBL: global bit line

GSL: global source line

ibgr (vcc): supply voltage

INV: inverter with a capacitor having a capacitor element

P1, P2, P3: PMOS transistor

Q1, Q2: transistor with a metal gate electrode

R1-R8: resistance (RC)

SBL, SSL: selection signal

SL: source line

SW, SW1, SW2, SW 3: CMOS switch

Ta: temperature of

Tc: slope of temperature

Tg, Tg0, Tg 1: target temperature

Tg + P: target temperature

Tg-P: target temperature

V_GRET: reference voltage after temperature compensation

V_OFFSET: DC bias voltage

V_PTAT,V_PTAT0,V_PTAT1: voltage dependent on temperature

V_{PTAT_int}: initial temperature dependent voltage

V_RET,V_RET0,V_RET1: reference voltage

V_SEN: detecting voltage

VR: variable resistor

WL: word line

X-Add: column address

Y-Add: row address

Detailed Description

Next, embodiments of the present invention will be described with reference to the drawings. The performance of the design specification of the circuit of the semiconductor device can be accurately realized by the reference voltage after the temperature compensation generated by the voltage generating circuit of the invention. The temperature-compensated reference voltage of the present invention may include a voltage hardly dependent on temperature in a certain temperature range, and a combination of voltages dependent on temperature in a certain temperature range. The voltage generation circuit compares at least one voltage that is hardly dependent on temperature with at least one voltage that is dependent on temperature, selects either a higher voltage, a lower voltage, or a voltage that is generated by another method and hardly dependent on temperature or a voltage that is dependent on temperature, and outputs the selected voltage as a temperature-compensated voltage. For example, in a temperature range lower than the target temperature, a reference voltage with an almost constant slope is output; in a temperature range above the target temperature, a temperature-dependent voltage with a positive or negative slope is output.

The voltage generating device of the present invention can be mounted on various semiconductor devices, for example: a variable resistive or flash memory, a microprocessor, a microcontroller, logic, an application specific integrated circuit, a digital signal processor, a circuit device that processes video or audio, or a circuit that processes signals such as wireless signals, etc.

Fig. 2 is a block diagram illustrating the structure of a voltage generation circuit according to embodiment 1 of the present invention. The voltage generating circuit 100 of the present embodiment includes: the reference voltage generating part 110 generates a reference voltage V which hardly depends on temperature_RET(ii) a A PTAT (Proportional to absolute temperature) voltage generating part 120 for generating a temperature-dependent voltage V dependent on temperature_PTAT(ii) a A comparison unit 130 for comparing the reference voltage V_RETAnd a temperature dependent voltage V_PTAT(ii) a And a selection unit 140 for selecting the reference voltage V based on the comparison result of the comparison unit 130_RETAnd a temperature dependent voltage V_PTATAnd outputs the selected reference voltage V_RETOr a temperature-dependent voltage V_PTAT。

The Reference voltage generating section 110 includes a Band Gap Reference Circuit (hereinafter referred to as a BGR Circuit) and generates a voltage that hardly depends on a power supply voltage or an operating temperature, and the Reference voltage generating section 110 generates a Reference voltage V using the voltage generated by the BGR Circuit_RET. Although not shown, the reference voltage generating unit 110 may further include a trimming circuit to compensate for a manufacturing tolerance of the circuit. The trimming circuit includes, for example, a variable resistor, which changes a resistance value in response to a trimming code read from the nonvolatile memory, by which the trimming circuit changesReference voltage V for resistance adjustment_RETThe voltage level of (c).

The PTAT voltage generating section 120 generates a temperature-dependent voltage V with a positive slope_PTATOr a temperature-dependent voltage V with a negative slope_PTAT. In one embodiment, the PTAT voltage generating unit 120 may use the reference voltage V generated by the reference voltage generating unit 110_RETTo generate a temperature dependent voltage V_PTATBut not limited thereto; the PTAT voltage generating section 120 itself may generate the temperature-dependent voltage V_PTAT。

The PTAT voltage generating part 120 may be adjusted in advance to generate a voltage with a positive or negative slope required by the circuit when the operating temperature changes. For example, if a voltage with a positive slope α is required when the operating temperature of the circuit exceeds a certain temperature Tp, the PTAT voltage generating unit 120 may be adjusted in advance to generate the temperature-dependent voltage V with a positive slope α_PTAT. Alternatively, if a voltage with a negative slope β is required when the operating temperature of the circuit exceeds a certain temperature Tp, the PTAT voltage generating unit 120 may be adjusted in advance to generate the temperature-dependent voltage V with a negative slope β_PTAT. The PTAT voltage generating unit 120 is not particularly limited, and may include one or more resistors with positive temperature characteristics, one or more bipolar transistors with negative temperature characteristics, or resistors made of semiconductor materials, for example.

The comparison part 130 receives and compares the reference voltage V_RETVoltage V dependent on temperature_PTATAnd outputs the comparison result to the selection unit 140. The comparison part 130, for example, when the reference voltage V_RET≧ temperature-dependent voltage V_PTATWhen the signal is in the H level, outputting a signal in the H level; when the reference voltage V_RET< Voltage V dependent on temperature_PTATWhen the signal is at the L level, the signal is output.

Selection unit 140 selects reference voltage V based on the comparison result of comparison unit 130_RETAnd a temperature dependent voltage V_PTATThe higher or lower side, and outputs it. For example, when the reference voltage V is_RET≧ temperature-dependent voltage V_PTATWhile selecting the reference voltage V_RET(ii) a When the reference voltage V_RET< Voltage V dependent on temperature_PTATThen, a temperature-dependent voltage V is selected_PTAT. Alternatively, the relationship may be reversed, when the reference voltage V is set to_RET≧ temperature-dependent voltage V_PTATThen, a temperature-dependent voltage V is selected_PTAT(ii) a When the reference voltage V_RET< Voltage V dependent on temperature_PTATWhile selecting the reference voltage V_RET。

FIGS. 4 (A) and (B) are schematic diagrams of the reference voltage V_RETVoltage V dependent on temperature_PTATAn example of the relationship (2). In the graph (a) in fig. 4, the reference voltage generating section 110 generates the reference voltage V having almost no slope in response to the change in the temperature Ta_RETThe PTAT voltage generating section 120 generates a temperature-dependent voltage V having a positive slope_PTAT. The unit of the temperature Ta is, for example, [. degree.C. ]]Reference voltage V_RETVoltage V dependent on temperature_PTATHas a unit of, for example, volt [ V ]]. The target temperature Tg is when the reference voltage V is_RETEqual to the temperature-dependent voltage V_PTATThe temperature corresponding to the temperature, and the temperature compensation is performed with the target temperature Tg as a boundary. The PTAT voltage generating part 120 may be adjusted in advance to generate the reference voltage V at the target temperature Tg_RETCrossing, positive slope temperature dependent voltage V_PTAT。

In an embodiment corresponding to the diagram (a) in fig. 4, the output of the selection unit 140 is as shown in (a-1) in fig. 4, and the selection unit 140 selects the reference voltage V_RETAnd a temperature dependent voltage V_PTATThe higher of the two is taken as an output. Therefore, the temperature compensated reference voltage V output by the voltage generation circuit 100_GRETEqual to the reference voltage V in a temperature range lower than the target temperature Tg_RET(ii) a Equal to a temperature-dependent voltage V in a temperature range above a target temperature Tg_PTAT。

In another embodiment corresponding to the diagram (a) in fig. 4, the output of the selection unit 140 is as shown in (a-2) in fig. 4, and the selection unit 140 selects the reference voltage V_RETAnd a temperature dependent voltage V_PTATThe lower one is taken as the output. In this case, the temperature output by the voltage generation circuit 100 is compensatedCompensated reference voltage V_GRETEqual to a temperature-dependent voltage V in a temperature range lower than the target temperature Tg_PTAT(ii) a Equal to the reference voltage V in a temperature range above the target temperature Tg_RET。

On the other hand, in fig. 4 (B), the reference voltage generating section 110 generates the reference voltage V having almost no slope in response to the change in the temperature Ta_RETThe PTAT voltage generating section 120 generates a temperature-dependent voltage V having a negative slope_PTAT. The PTAT voltage generating part 120 may be adjusted in advance to generate the reference voltage V at the target temperature Tg_RETCrossing, and satisfactory negative slope temperature dependent voltage V_PTAT。

In an embodiment corresponding to the diagram (B) in FIG. 4, the output of the selection unit 140 is shown as (B-1) in FIG. 4, and the selection unit 140 selects the reference voltage V_RETAnd a temperature dependent voltage V_PTATThe higher of the two is taken as an output. Therefore, the temperature compensated reference voltage V output by the voltage generation circuit 100_GRETEqual to a temperature-dependent voltage V in a temperature range lower than the target temperature Tg_PTAT(ii) a Equal to the reference voltage V in a temperature range above the target temperature Tg_RET。

In another embodiment corresponding to the diagram (B) in fig. 4, the output of the selection unit 140 is as shown in (B-2) in fig. 4, and the selection unit 140 selects the reference voltage V_RETAnd a temperature dependent voltage V_PTATThe lower of the two is used as output. In this case, the temperature compensated reference voltage V output by the voltage generation circuit 100_GRETEqual to the reference voltage V in a temperature range lower than the target temperature Tg_RET(ii) a Equal to a temperature-dependent voltage V in a temperature range above a target temperature Tg_PTAT。

Temperature compensated reference voltage V output by voltage generation circuit 100_GRETCan be directly provided for corresponding circuits; alternatively, the voltage may be converted to a desired voltage level by a conversion circuit such as an operational amplifier or a regulator, and then supplied to a corresponding circuit.

Next, embodiment 2 of the present invention will be explained. FIG. 3 schematically shows a gateThe same reference numerals are given to the same components as those in fig. 2 in the structure of the voltage generation circuit 100A according to embodiment 2. In embodiment 2, the PTAT voltage generating section 120A includes a DC (direct current) voltage adjusting section 122 configured to adjust the temperature-dependent voltage V_PTATIs biased in the positive or negative direction. As described above, the temperature-dependent voltage V_PTATCan be set to the reference voltage V at the target temperature Tg_RETHowever, the target temperature Tg may need to be adjusted in a positive or negative direction due to factors such as manufacturing tolerances of the circuit.

For example, as shown in (C) of fig. 4, the initial temperature-dependent voltage V generated by the PTAT voltage generating section 120A_{PTAT_int}At a target temperature Tg and a reference voltage V_RETHowever, since the target temperature Tg is affected by the manufacturing tolerance of the circuit, the target temperature Tg is shifted to Tg-P or Tg + P by the DC voltage adjustment unit 122 in the present embodiment. As shown in (C-1) of FIG. 4, DC voltage adjustment section 122 can adjust initial temperature-dependent voltage V_{PTAT_int}Plus a DC bias voltage V_OFFSETThereby generating a temperature dependent voltage V_PTATTo shift the target temperature Tg down to Tg-P. Alternatively, as shown in (C-2) of fig. 4, DC voltage adjustment unit 122 can adjust initial temperature-dependent voltage V_{PTAT_int}Minus DC bias voltage V_OFFSETThereby generating a temperature dependent voltage V_PTATTo shift the target temperature Tg upwards to Tg + P.

Next, embodiment 3 of the present invention will be explained. Fig. 5 is a block diagram of a voltage generation circuit 100B according to embodiment 3 of the present invention, and the same reference numerals are given to the same components as those in fig. 2. In embodiment 3, the PTAT voltage generating part 120B generates the reference voltage V and the target temperatures Tg0 and Tg1 which are different from each other_RETTwo crossing temperature-dependent voltages V_PTAT0、V_PTAT1. Two temperature dependent voltages V_PTAT0、V_PTAT1May have the same or different slopes. The comparison unit 130B individually compares the reference voltages V_RETVoltage V dependent on temperature_PTAT0And a reference voltage V_RETVoltage V dependent on temperature_PTAT1And comparing the individualThe results COMP0 and COMP1 are output to the selection unit 140B.

Selection unit 140B selects reference voltage V based on the logical combination of comparison results COMP0 and COMP1_RETTemperature dependent voltage V_PTAT0、V_PTAT1As a temperature compensated reference voltage V_GRET. In FIG. 7, (A), (B), (C), and (D) show several examples. In the example of (A) in FIG. 7, the temperature-dependent voltage V_PTAT0Has a negative slope and is compared with a reference voltage V at a target temperature Tg0_RETCrossing; temperature dependent voltage V_PTAT1Has a positive slope and is compared with a reference voltage V at a target temperature Tg1_RETAnd (4) crossing. According to the example of (A) in FIG. 7, in one embodiment, the output of the selection portion 140B can be as shown in the example of (A-1) in FIG. 7, and the selection portion 140B selects the temperature-dependent voltage V with higher voltage in the temperature range lower than the target temperature Tg0_PTAT0As a reference voltage V after temperature compensation_GRETAnd output; selecting a reference voltage V with a higher voltage in a temperature range from a target temperature Tg0 to a target temperature Tg1_RETAs a reference voltage V after temperature compensation_GRETAnd output; selecting a temperature-dependent voltage V having a high voltage in a temperature range of not less than a target temperature Tg1_PTAT1As a reference voltage V after temperature compensation_GRETAnd output. In addition, according to the example of (a) in fig. 7, in another embodiment, the output of the selection portion 140B can be as shown in the example of (a-2) in fig. 7, and the selection portion 140B selects the reference voltage V with a lower voltage in a temperature range lower than the target temperature Tg0_RETAs a reference voltage V after temperature compensation_GRETAnd output; selecting a temperature-dependent voltage V with a low voltage in a temperature range from a target temperature Tg0 to a target temperature Tg1_PTAT0、V_PTAT1As a reference voltage V after temperature compensation_GRETAnd output; selecting a reference voltage V with a lower voltage in a temperature range of the target temperature Tg1 or higher_RETAs a reference voltage V after temperature compensation_GRETAnd output.

In the example of (B) in FIG. 7, the temperature-dependent voltage V_PTAT0Has a positive slope and is compared with a reference voltage V at a target temperature Tg0_RETCrossing; temperature ofDependent on voltage V_PTAT1Has a negative slope and is compared with a reference voltage V at a target temperature Tg1_RETAnd (4) crossing. According to the example of (B) in FIG. 7, in one embodiment, the output of the selection portion 140B can be as shown in the example of (B-1) in FIG. 7, and the selection portion 140B selects the lower temperature-dependent voltage V in the temperature range lower than the target temperature Tg0_PTAT0As a reference voltage V after temperature compensation_GRETAnd output; selecting a reference voltage V with a lower voltage in a temperature range from the target temperature Tg0 to the target temperature Tg1_RETAs a reference voltage V after temperature compensation_GRETAnd output; selecting a temperature-dependent voltage V having a low voltage in a temperature range of the target temperature Tg1 or higher_PTAT1As a reference voltage V after temperature compensation_GRETAnd output. In addition, according to the example shown in fig. 7 (B), in another embodiment, the output of the selection part 140B can be shown as the example shown in fig. 7 (B-2), and the selection part 140B selects the reference voltage V with a higher voltage in a temperature range lower than the target temperature Tg0_RETAs a reference voltage V after temperature compensation_GRETAnd output; selecting a temperature-dependent voltage V with a high voltage in a temperature range from a target temperature Tg0 to a target temperature Tg1_PTAT0、V_PTAT1As a reference voltage V after temperature compensation_GRETAnd output; selecting a reference voltage V with a high voltage in a temperature range of the target temperature Tg1 or higher_RETAs a reference voltage V after temperature compensation_GRETAnd output.

In the example of (C) in FIG. 7, the temperature-dependent voltage V_PTAT0Has a positive slope and is compared with a reference voltage V at a target temperature Tg0_RETCrossing; temperature dependent voltage V_PTAT1Has a positive slope and is compared with a reference voltage V at a target temperature Tg1_RETAnd (4) crossing. Temperature dependent voltage V_PTAT0Voltage V with temperature dependence of slope of_PTAT1May or may not be equal. Accordingly, the output of the selection unit 140B can select the temperature-dependent voltage V having a lower voltage in a temperature range lower than the target temperature Tg0, as shown in (C-1) of fig. 7_PTAT0As a reference voltage V after temperature compensation_GRETAnd output; at a target temperature Tg 0-Tg 1Within the enclosure, a temperature-dependent voltage V is selected_PTAT0Voltage V dependent on temperature_PTAT1Reference voltage V between_RETAs a reference voltage V after temperature compensation_GRETAnd output; selecting a temperature-dependent voltage V having a high voltage in a temperature range of not less than a target temperature Tg1_PTAT1As a reference voltage V after temperature compensation_GRETAnd output.

In the example of (D) in FIG. 7, the temperature-dependent voltage V_PTAT0Has a negative slope and is compared with a reference voltage V at a target temperature Tg0_RETCrossing; temperature dependent voltage V_PTAT1Has a negative slope and is compared with a reference voltage V at a target temperature Tg1_RETAnd (4) crossing. Temperature dependent voltage V_PTAT0Voltage V with temperature dependence of slope of_PTAT1May or may not be equal. Accordingly, the output of the selection unit 140B can select the temperature-dependent voltage V having a higher voltage in a temperature range lower than the target temperature Tg0 as shown in (D-1) of FIG. 7_PTAT0As a reference voltage V after temperature compensation_GRETAnd output; a temperature-dependent voltage V between the target temperature Tg0 and Tg1_PTAT0Voltage V dependent on temperature_PTAT1Between the selection reference voltage V_RETAs a reference voltage V after temperature compensation_GRETAnd output; selecting a temperature-dependent voltage V having a low voltage in a temperature range of the target temperature Tg1 or higher_PTAT1As a reference voltage V after temperature compensation_GRETAnd output.

Thus, according to the present embodiment, the temperature-compensated reference voltage V having different temperature characteristics can be generated by using the two boundaries (target temperatures Tg0, Tg1)_GRETThe variability of the temperature compensation voltage can be increased. In addition, the DC voltage adjustment section 122 described in embodiment 2 can be applied to embodiment 3.

Next, embodiment 4 of the present invention will be explained. Fig. 6 is a block diagram of a voltage generation circuit 100C according to embodiment 4 of the present invention, and the same reference numerals are given to the same components as those in fig. 5. In embodiment 4, the reference voltage generating part 110C generates two reference voltages V with different voltage values_RET0、V_RET1. In this case, two temperature-dependent voltages V_PTAT0、V_PTAT1Will respectively correspond to two reference voltages V_RET0、V_RET1Crossing at two target temperatures. The comparison unit 130B compares the two reference voltages V_RET0、V_RET1And two temperature-dependent voltages V_PTAT0、V_PTAT1And outputs a plurality of comparison results COMP0, COMP1, COMP2, COMP3 to the selection section 140C. The selection unit 140C selects the reference voltage V based on the logical combination of the comparison results COMP0, COMP1, COMP2, and COMP3_RET0、V_RET1Temperature dependent voltage V_PTAT0、V_PTAT1As a temperature compensated reference voltage V_GRETAnd output.

In the example of (E) in FIG. 7, the temperature-dependent voltage V_PTAT0Has positive slope and is respectively connected with the reference voltage V at the target temperatures Tg0 and Tg1_RET0、V_RET1Crossing; temperature dependent voltage V_PTAT1Having a negative slope (the present embodiment is set such that its absolute value is dependent on the temperature V_PTAT0Equal to each other) and is respectively equal to the reference voltage V at the target temperatures Tg1 and Tg0_RET0、V_RET1And (4) crossing. According to the example of (E) in FIG. 7, in one embodiment, the output of the selection part 140C can be shown as the example of (E-1) in FIG. 7, and the selection part 140C selects the reference voltage V in the temperature range lower than the target temperature Tg0_RET0(i.e., the lower of these reference voltages) as the post-temperature-compensated reference voltage V_GRETAnd output; selecting a temperature-dependent voltage V in a temperature range from a target temperature Tg0 to a target temperature Tg1_PTAT0As a reference voltage V after temperature compensation_GRETAnd output; selecting a reference voltage V in a temperature range of a target temperature Tg1 or higher_RET1(i.e., the higher of these reference voltages) as the post-temperature-compensated reference voltage V_GRETAnd output. According to the example of (E) in FIG. 7, in another embodiment, the output of the selection part 140C can be selected by the selection part 140C in the temperature range lower than the target temperature Tg0 as in the example of (E-2) in FIG. 7_RET1(i.e., the higher of these reference voltages) As a reference voltage V after temperature compensation_GRETAnd output; selecting a temperature-dependent voltage V in a temperature range from a target temperature Tg0 to a target temperature Tg1_PTAT1As a reference voltage V after temperature compensation_GRETAnd output; selecting a reference voltage V in a temperature range of a target temperature Tg1 or higher_RET0(i.e., the lower of these reference voltages) as the post-temperature-compensated reference voltage V_GRETAnd output.

Thus, according to the present embodiment, two reference voltages V having almost no temperature dependency are used_RET0、V_RET1And two temperature-dependent voltages V having temperature dependence_PTAT0、V_PTAT1Can generate a more complex post-temperature-compensated reference voltage V_GRET. In addition, if such a temperature compensated reference voltage V is used_GRETIf the voltage level is converted to a desired voltage level by a conversion circuit such as a regulator or an operational amplifier, temperature compensation of the converted voltage can be performed.

Fig. 8(a) to 8(C) are schematic circuit diagrams of a voltage generation circuit 100A according to embodiment 2 of the present invention. Reference voltage generating unit 110 includes a BGR circuit that hardly depends on variations in power supply voltage Vcc or temperature changes. For example, as shown in the figure, the BGR circuit includes the 1 st and 2 nd current paths between the power voltage Vcc and the ground voltage GND; the 1 st current path includes a PMOS transistor P1, a resistor R1, and a bipolar transistor Q1 connected in series; the 2 nd current path includes a PMOS transistor P2, a resistor R2, a resistor R3, and a bipolar transistor Q2 (the emitter area m of the bipolar transistor Q2 is n times the emitter area of the bipolar transistor Q1) connected in series. The inverting input (-) of the differential amplifier circuit AMP is connected to the connection node between the resistor R1 and the bipolar transistor Q1; the non-inverting input terminal (+) is connected to the connection node of the resistor R2 and the resistor R3; the output terminals are commonly connected to the gates of the PMOS transistors P1, P2. By selecting the resistors R1, R2, R3 and the bipolar transistors Q1, Q2 appropriately, the reference voltage V having almost no temperature dependency can be outputted from the connection node between the PMOS transistor P2 and the resistor R2_RET。

The PTAT voltage generating part 120A is connected in series toA PMOS transistor P3 between the power supply voltage Vcc and the ground voltage GND, resistors R4, R5, R6, a variable resistor VR, and a DC voltage adjustment unit 122. The gate of the PMOS transistor P3 communicates with the PMOS transistors P1 and P2 of the BGR circuit, and the current iBGR communicating with the BGR circuit is supplied to the current path through the PMOS transistor P3. The variable resistor VR adjusts tolerance of the circuit, for example, by switching a Tap (Tap) of the resistor division according to a trimming code prepared in advance. By selecting the resistors R4, R5 and R6 appropriately, the temperature-dependent voltage V can be outputted from the connection node between the resistor R5 and the resistor R6_PTAT。

Fig. 8(B) shows an example of the configuration of DC voltage adjustment unit 122. DC voltage adjustment unit 122 includes a differential amplification circuit having an inverting input (-) for receiving a reference voltage V_RETThe divided voltage divided by the resistor R has its non-inverting input terminal (+) receiving the voltage of the voltage dividing node between the resistors R7 and R8, and its output coupled to the resistor R7. By adjusting the resistor R, the DC voltage adjustment part 122 outputs the DC bias voltage V_OFFSETFor biasing the initial temperature-dependent voltage V_{PTAT_int}。

Fig. 8(C) schematically shows the configuration of the comparison unit 130 and the selection unit 140. The comparing part 130 includes a comparator COMP which receives and compares the reference voltage V_RETVoltage V dependent on temperature_PTATAnd outputs a signal of H or L level to represent the reference voltage V_RETVoltage V dependent on temperature_PTATThe comparison result of (1). The selection part 140 includes an inverter INV that receives an output of the comparison part 130; and a CMOS switch SW including a plurality of CMOS transistors. In this embodiment, one of the CMOS transistors of the CMOS switch SW receives the reference voltage V_RETAnd the other CMOS transistor receives a temperature dependent voltage V_PTATAnd the CMOS switch SW selects the reference voltage V based on the inverted value of the comparison result of the comparator COMP (i.e., the output of the inverter INV)_RETVoltage V dependent on temperature_PTATAnd the selected one is used as the reference voltage V after temperature compensation_GRETAnd (6) outputting. Selection unit 140 selects temperature-dependent voltage V based on the comparison result of comparator COMP_PTATAnd a reference voltage V_RETThe higher of which is taken as output. For example, when the temperature is highDependent on voltage V_PTATReference voltage V_RETThe output of the comparator COMP is at H level, and the input temperature-dependent voltage V is coupled to the CMOS switch SW_PTATIs turned on and coupled to a reference voltage V_RETIs turned off and outputs a temperature dependent voltage V_PTATAs a reference voltage V after temperature compensation_GRET。

Fig. 9 shows an example of the structure of a voltage generating circuit 100B according to embodiment 3 of the present invention. In embodiment 3, the reference voltage generating part 110 generates the reference voltage V_RETThe PTAT voltage generating section 120B generates two temperature-dependent voltages V_PTAT0、V_PTAT1And the comparing part 130B receives the reference voltage V_RETAnd these temperature-dependent voltages V_PTAT0、V_PTAT1. The comparison unit 130B includes: a comparator CP0 for comparing the reference voltage V_RETVoltage V dependent on temperature_PTAT0And outputs a comparison result COMP 0; and a comparator CP1 for comparing the reference voltage V_RETVoltage V dependent on temperature_PTAT1And outputs a comparison result COMP 1.

The selection unit 140B includes: three NAND gates (NAND gates) configured to perform logical operations of various combinations of the comparison results COMP0, COMP1 of the comparators CP0, CP 1; a plurality of inverters, the input terminals of which are coupled to the outputs of the NAND gates, respectively; and CMOS switches SW1, SW2, SW3 coupled to the inverters, respectively. The input terminal of the CMOS switch SW1 receives a temperature dependent voltage V_PTAT0(ii) a The input terminal of the CMOS switch SW2 receives a reference voltage V_RET(ii) a And the input of the CMOS switch SW3 receives a temperature dependent voltage V_PTAT1. One of the CMOS switches SW1, SW2 and SW3 is turned on according to the logic operation result of COMP0 and COMP1, thereby the temperature dependent voltage V is turned on_PTAT0、V_PTAT1And a reference voltage V_RETMay be selected as the temperature compensated reference voltage V_GRETAnd output.

Next, fig. 10 illustrates a structure of a variable resistance random access memory as an example of a semiconductor device to which the voltage generation circuit according to the embodiment of the present invention is applied. Variable resistive memory of the present embodiment200 includes a memory array 210, a row decoder and driver circuit (X-DEC)220, a column decoder and driver circuit (Y-DEC)230, a column select circuit (YMUX)240, a control circuit 250, a sense amplifier 260, and a write drive read bias circuit 270, and the embodiments described above for generating a temperature compensated reference voltage V_GRETThe voltage generating circuit 100. The memory array 210 has a plurality of memory cells arranged in rows and columns, each memory cell including a variable resistance element and an access transistor. A column decoder and driver circuit (X-DEC)220 selects and drives a word line WL based on a column address X-Add. The column decoder and driving circuit (Y-DEC)230 generates selection signals SBL and SSL for selecting the global bit lines GBL and the global source lines GSL, respectively, based on the column addresses Y-Add. The column selection circuit (YMUX)240 selects a connection between the global bit line GBL and the bit line BL based on the selection signal SBL, and selects a connection between the global source line GSL and the source line SL based on the selection signal SSL. The control circuit 250 controls each unit based on commands, addresses, data, and the like received from the outside. The sense amplifier 260 senses data read from the memory cell through the selected global bit line GBL and the bit line BL. Write drive/read bias circuit 270 applies a bias voltage for read operation to selected global bit line GBL and bit line BL, and applies a voltage for set/reset in write operation.

Memory array 210 includes m sub-arrays 210-1,210-2, …, 110-m, with m column select circuits (YMUX)240 connected to the m sub-arrays, respectively. m column selection circuits (YMUX)240 are connected to the sense amplifier 260 and the write drive/read bias circuit 270, respectively. In a read operation, the read data sensed by the sense amplifier 260 is output to the control circuit 250 through the internal data bus DO; in the write operation, write data inputted from the outside is received from the control circuit 250 to the write drive/read bias circuit 270 through the internal data bus DI.

When accessing a memory cell, a word line WL is selected by a column decoder and a driver circuit (X-DEC)220 to turn on an access transistor, and the selected memory cell is electrically connected to a selected bit line BL and a source line SL via a column selection circuit (YMUX) 240. In the write operation, a voltage corresponding to the setting or resetting generated by the write driver/read bias circuit 270 is applied to the selected memory cell through the selected bit line BL and the selected source line SL. In a read operation, a read voltage generated by the write driver/read bias circuit 270 is applied to a selected memory cell through a selected bit line BL and a selected source line SL; the voltage or current corresponding to the set or reset variable resistive element can be sensed by the sense amplifier 260 through the selected bit line BL and the selected source line SL. In general, the variable resistance element is written to a low resistance state, which we call SET; the variable resistance element is written to a high resistance state, which we call "RESET".

Temperature compensated reference voltage V generated by voltage generation circuit 100_GRETThe write drive/read bias circuit 270 or the column decoder and driver circuit (X-DEC)220 can be used to generate a word line voltage for driving the access transistor, a set or reset voltage for writing a selected memory cell, and a bias voltage for reading the selected memory cell.

For example, when the operating temperature is higher than room temperature (25 ℃), the word line voltage driving the access transistor may become insufficient, and the drain current flowing through the access transistor may decrease. Therefore, it is desirable that the word line voltages generated by the column decoder and driving circuit 220 have the following forms: the temperature range from low temperature to room temperature is constant; rising with a positive slope over a temperature range exceeding room temperature. Therefore, the voltage generation circuit 100 generates the temperature-compensated reference voltage V whose target temperature Tg matches the room temperature as shown in (a-1) diagram in fig. 4_GRETA reference voltage V compensated by the temperature_GRETThe generated voltage is supplied to the row decoder and driver circuit 220. The row decoder and driving circuit 220 may compensate the temperature-compensated reference voltage V_GRETDriving the access transistor as a word line voltage; alternatively, the word line may be converted to a desired voltage level by a conversion circuit such as an operational amplifier or a regulator, and then used as the word lineThe voltage drives the access transistor.

Thus according to the present embodiment, the reference voltage V is compared_RETAnd an analogically generated temperature-dependent voltage V_PTATBased on the comparison result, a reference voltage V is selected_RETAnd a temperature dependent voltage V_PTATTherefore, it is possible to achieve space saving of the layout without requiring a temperature sensor or logic mounted on a chip having a large circuit scale as in the conventional technique. In addition, in the present embodiment, since a DA converter (digital/analog converter) is not used as in the prior art, it is possible to suppress the deterioration of the accuracy of the reference voltage due to quantization noise. The voltage generation circuit of the present embodiment can be applied to the variable resistive memory described above, and can also be applied to a temperature compensation circuit of a semiconductor device such as various memories or logics.

The preferred embodiments of the present invention have been described in detail, but the present invention is not limited to the specific embodiments, and various modifications and changes can be made within the scope of the gist of the present invention described in the claims.