TW565848B - Low power supply voltage detector circuit - Google Patents

Abstract

A supply-voltage detection circuit is commonly used for preventing the erasing and programming of a nonvolatile memory device during the supply voltage lower than detect point. A low voltage detector is coupled to the low voltage input and has circuitry to provide a first not-ready signal when the supply voltage on the supply voltage input falls below a predetermined low voltage threshold. The not-ready signal prevents erasing or programming operations to occur in the nonvolatile memory device. A low voltage detector according to the present invention can have the detection potential variation be controlled in 0.3V range despite of the manufacturing variation or temperature dependency of the devices.

Description

Summary of the Invention: The present invention relates to a voltage detection device, and in particular, it does not affect X to the device itself, which is affected by changes in the threshold voltage value due to different operating temperatures or different manufacturing processes. Voltage detection device with stable voltage detection. Flash EPROM plays a pivotal role in non-volatile storage ICs. These flash memories have the ability to be electrically erased, programmed gramming, or read memory cells in the chip. Because these flash memories can be programmed or erased by applying voltage to these devices, systems that add flash memory must provide these flash memory supplies. Voltage (Vcc) and stylized, voltage (jpp). For the current system that gradually adopts low voltage as the operating voltage, "fortunately" most flash memory can be designed from low voltage (about 1.8 volts) to high voltage (about 12 volts). Programmable operation can be completed smoothly under voltage source. However, it is still important to note that when a computer system such as a personal digital assistant (PDA) system uses flash memory as its storage medium, the voltage of the battery may affect the operation of the entire device. And what will happen? At this time, the control signal and the programming or erasing operation in the system will not be guaranteed to be useful: ί, the programming or erasing: generated, these will further reduce the chip Of life. Ping Cha has this reason

9578twf.pul Page 5 565848 V. Description of the Invention (2) — The supply voltage detection circuit is also designed to monitor the change of the voltage. Once the battery voltage is lower than a predetermined range, these circuits will produce an undefined Not-Ready Signals to inform the system as a basis for response. For example, the circuit diagram shown in Figure 丨 supplies the non-volatile memory cell 12 with an operating voltage Vcc coupled to the non-volatile memory cell 12 and a low-voltage detector.装置 14。 Device 14. When the supplied operating voltage is lower than the low voltage value, this low voltage detection ^ 14 will output a low voltage detection initial signal (L〇w v〇Hage

Signal j LVcc) represents that the value of the supplied operating voltage is less than the safe value. But ^ :, most detection circuits have a supply voltage of about 3.3V. However, for low-voltage detection circuits (such as 丨 · 8 volts), the reduction in voltage will make these detection circuits quite difficult to design. In addition, reducing the power consumption and increasing the area occupied by the chip Factors in the overall complexity of this detection path. · Figure 2 is a block diagram of a conventional power detection device 200. The series resistors R1 and R2 are connected in series between the power supply voltage Vdd and the ground potential, and the resistor M and an NMOS transistor M1 are also connected between the power supply voltage VDD and the ground potential. The gate of the NMOS transistor M1 is connected to the node N1 between the resistors R1 and R2, and at the same time one end of a capacitor C1 is connected between the node N1 and the ground potential. One of the series connection pM0s transistor M3 and NM0S transistor M2 is connected between this power supply voltage VDD and the ground potential, and the other source / drain of PM0S transistor M3 is connected to this power supply voltage VDD, and the other source / drain of NMOS transistor M2 is connected to the ground potential. The gates of PM0S transistor M3 and NM0S transistor M2 are connected to

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Node N2, which is located between the resistor R3 and the transistor M1. In addition, a capacitor C2 is also connected to the node ... and the power supply voltage CMOS transistors M4 and M5 have the same as the transistors M2 and ... structure. The gates of the transistors M4 and M5 are connected to the node N3 between the transistors M2 and ... and the gates between the body and the M5 are connected to the ground potential via a capacitor (; 3 and the node N4 is The nodes connected to transistors M4 and M5. The input and output terminals of this CMOS transistor M2 and M3 are nodes N2 and N3 respectively. The input and output terminals of CMOS transistors M4 and M5 are the node equivalent power When the supply voltage VDD rises from a ground potential (Ground, GNDj for short below) to a predetermined voltage level, a high voltage pulse will be output to represent a low voltage detection signal (L0wv〇ltage

Detector Signal) LVCC. This function can be completed by one end connected to the valley level C1 and c3, and one end connected to the power supply voltage VDD capacitor C2. When the supplied power is the potential of the power supply voltage VDD, these capacitors Cl, C2, and C3 will not be charged. Therefore, nodes N1, N2, and N3 will have the same voltage level, such as power Supply voltage VDD or ground potential GND. The node "will first become a high potential, and the capacitors Cl, C2, and C3 will be sequentially charged, and the voltage levels at the nodes N1 j and N3 will be VX = VDD * R2 / (R1 + R2), the ground voltage And the power supply voltage VDD, therefore, the output of node 4 will be at a low voltage level. X As described above, when VX voltage is higher than the threshold voltage of transistor M1 565848 V. Description of the invention (4) (Threshold vo 11age, In the rainy season ^ vy ^ ^ ^, when the electric day and sun point N4 will become a low voltage level. Below the threshold voltage (Thresh〇id voltage) of transistor M1, transistor node N4 will become a high voltage level Therefore, the circuit will be able to detect that the power supply voltage VDD is higher or lower than VTH1 * (R1 + R2) / R2. The threshold value of the VTH1 series transistors is just the value of R2 and the shutdown of the transistor. Width / Length adjustment, you can adjust the detected voltage range. Generally speaking, this circuit can inform the low battery voltage level, and further, this low battery voltage level stops before destroying the entire system Any operation. But = if this circuit is in a two-speed system, it will make the whole The operating voltage range is therefore quite narrow. Because the voltage that can be detected by the traditional detection circuit shown in Figure 2 is determined by the threshold voltage of transistor M1. In this way, this circuit will have Considerable Manufacturing Variation, as well as the influence factors of temperature. In addition, the slope of (R1 + R 2) / R 2 will make the whole situation worse. Due to the above considerations, we can know The maximum and minimum voltages that can be detected will be greater than 0.5 volts, which will seriously affect the performance, applicability and performance of the circuit. The reasons for the above situation will be described in detail below. The circuit in Figure 2 uses The circuit simulation software PSPICE simulates its operation. First, it is assumed that during the simulation, the temperature is fixed, so only the effect caused by the differences in the manufacturing process needs to be considered. Because the threshold voltage of the transistor M1 has a manufacturing difference of about ± 0 · 1 to ± 0 · 2 volts '(assuming that the value of resistor R1 is equal to the value of resistor r 2)' The voltage level detected will be twice the difference in the manufacturing process.

565848 V. Description of the invention (5) ^ The power supply voltage VDD shown in Figure 3 is a direct current rising voltage, and the left level of the power will change linearly with the power supply voltage VDD. ^ V = N4 voltage level That is, the output of the detection circuit in FIG. 2. In these two scenarios: 减少 Reduction of the resistance value of the 'resistance R2 under the same resistance value condition will make the proposed line more flat (Flatter), and therefore, there will be a large difference in voltage level. Here, the value of the parameter is used to represent (R1 + R2) / R2, and the threshold difference between 1 is equal to one, that is, when the minimum k value is, the difference in debt voltage level will be k times. _1Explain the effect of temperature dependence, please refer to Figure 4. For the traditional mode of the body and the smart transistor, the temperature difference is similar to the explained content. The difference of the threshold value will be affected by the parameter k value, and the value of k is greater than one. Therefore, this difference will result in an amplifier-like result. Considering the manufacturing difference and temperature dependence, the difference between the two voltage levels will not be set, and the difference in the detected voltage level will be different even though the traditional voltage detection device can operate at high voltage (about (Greater than 3V), however, it is inevitable to reduce the degree of change between detection ranges due to manufacturing differences and temperature dependence. However, the value of dare to be small From the conventional voltage debt measuring device in the above figure 2, it can be seen that it is impossible to reduce it to a small voltage change amount, such as 0.4 volts. Therefore, higher detection accuracy cannot be achieved. The purpose of the present invention is to provide a voltage detection device.

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5. Description of the invention (6) The accuracy of monitoring the change of the supply voltage. In addition, it can also reduce the impact on the voltage detection due to the difference in granulation or the change in operating temperature. ^

To achieve the above item 4, the present invention provides a low-power supply voltage detection circuit for receiving a supply voltage, including a comparison voltage generator, a reference voltage generator, and a difference amplifier. The above comparison voltage generator generates and outputs a comparison voltage according to the supply voltage. The reference voltage generator generates a reference voltage in a line-dependent relationship according to the supply voltage. The difference amplifier is coupled to the comparison voltage generator and the reference voltage generator to receive the comparison voltage and the reference voltage and output a low voltage detection signal. When the test voltage is greater than the comparison voltage, the low voltage detection signal will be one. The first voltage, standard, is used to indicate that the supply voltage is lower than a predetermined debt test voltage value. When the test voltage is less than the comparison voltage, the low voltage detection signal will be a second voltage level, which is used to indicate that the supply voltage is higher than a predetermined voltage. Detection voltage value. The above-mentioned low-power supply voltage detection circuit, wherein the comparison voltage generator is also increased when the supply voltage is increased, but when the supply voltage exceeds a predetermined voltage value, the comparison voltage will approach a solid. Fixed voltage value. . / The above-mentioned low power supply voltage detection circuit, wherein the comparison voltage is generated: ft includes a voltage divider circuit. The voltage divider circuit is divided into two groups based on the voltage divider for ff. The first group in # includes a first resistor. The second group is composed of a resistor and a transistor. When the supply voltage increases, the comparison voltage is the second component voltage in the partial voltage divided by the two groups. Threshold voltage of one of the transistors in the two groups

Page 10 565848 V. Description of the invention (7) After the value, the comparison voltage will approach the threshold voltage value. In the above low-power supply voltage detection circuit, the reference voltage generator linearly outputs the reference voltage according to the value of the supply voltage. When the supply voltage decreases, the reference voltage also decreases linearly. When the supply voltage increases, the 'reference voltage' It also increases linearly. The reference voltage generator linearly outputs the reference voltage value after the supply voltage is divided by a voltage dividing circuit. The voltage dividing circuit is divided into two groups to divide the supply voltage according to the voltage. The first group consists of a transistor, the second group consists of a resistor, and the reference voltage is the partial voltage of the second group. In order to make the above and other objects, features, and advantages of the present invention more comprehensible, the following describes a preferred embodiment in conjunction with the accompanying drawings, which are described in detail as follows: Figure numbers illustrate non-volatile memory cells. 1 2 Low voltage detection device 1 4 Power detection split 2 〇Resistor R1, R2, R3 NMOS transistor M1, m2, MVT, M12 PMOS transistor M3, MPL, Ml 1 Node Nl, N2, N3, N4 Capacitors Cl, C2 CMOS transistors M4 and M5 Resistors R3

9578twf.ptd Page 11 565848 V. Description of Invention (8)

NMOS transistor MVT node N2 output voltage detection circuit 5 00 Comparison voltage generator 510, 610, 910 Difference amplifier 520, 620, 920 Reference voltage generator 530, 630, 930 Inverter 940 For an explanation of the embodiment, please refer to FIG. 5 , Is a voltage detection circuit. The circuit block diagram is as shown in Figure 6. First, referring to the voltage detection circuit 60 0 in FIG. 6, a differential amplifier 620 is connected in the middle part, a comparison voltage generator 610 is located on the left part, and a reference voltage generator 630 is located on the right side. The comparison voltage generator 610 and the reference voltage generator 630 respectively output a comparison voltage (Comparative Voltage) and a reference voltage (Reference Voltage) to the difference amplifier 6 2 0. The difference amplifier 6 2 0 has a very good function. When the comparison voltage level (Comparative Voltage Potential) is higher than the test voltage, it will output a high voltage value close to one of the power supply voltage VDD voltage levels. Conversely, if the level of the comparison voltage is lower than the reference voltage " ", a low voltage value will be output. " For the detailed circuit diagram, please refer to Figure 5 and describe it as follows. In the figure, a circuit in which a resistor R3 and a NMOS transistor MVT are connected in series is between the power supply voltage VDD and the ground potential, where the voltage between R3 and R3, =

9578twf.ptd Page 12 565848 V. Description of the invention (9) It is connected to the power supply voltage VDD, and one source / non-pole of the NMOS transistor MVT is grounded. The gate of the NMOS transistor MVT and the source / non-terminal connected to the resistor R3 are simultaneously connected to the node N2. These components constitute a comparison voltage generator 510, like the comparison voltage generator 61 shown in Fig. 6, in order to generate the comparison voltage level. The difference amplifier 620 in FIG. 6 is the same as the difference amplifier 520 in FIG. 5 and is composed of the transistor M1 to the core. Transistors are similar to NMOS transistors, that is, they have the same gate width / counter sound, b (Gate Width / Gate Length ^ together. The gate of transistor M1 is connected to the comparison voltage generator $ 10 is the node N2, and the gate of the transistor M2 is connected to the node N1 of the reference voltage generator 530, which is like the reference voltage generator ° 630 shown in Fig. 6. The drain of the transistor M1 is The gate and drain connected to the PM0s transistor M3, which is the node 中 in the figure. Transistor M3 and ... are similar to iPM0s transistors, that is, they have the same gate width / length ratio (Gate

Width / Gate Length ratio), and their sources are connected together (node N3), and their sources are also connected to the power supply voltage VDD. The transistors and M4 are connected to the node N4. This node "is the output of the output voltage detection circuit 50 0. The reference voltage generator 530 is composed of two resistors R1 and", this is connected in series The resistors R1 and R2 are connected to the fΪ and 1 ^ connection points of the power supply voltage VDD and the ground potential. The node N1 is used as the input terminal of the reference voltage two-voltage generator 530 pair difference amplifier 52. The methods of making these circuits are detailed below. The whole picture described in Figure 5 is 9578twf.ptd Page 13 565848 5. Description of the Invention (ίο) This circuit is used as a low power detection circuit. The reference voltage generator 5 3 0 uses a very simple circuit design, and the voltage level at the node N 丨 can be easily paid ', that is, VN1 = R2 / (R1 + R2) * VDD. Similarly, in the comparison voltage generator 5 10, the voltage level of the node N 2 can be obtained according to the following formula: &

VN2 = RMVT / (RMVT + R3), when VN2 <VTH; VN2 = VTH, when VN2 > = VTH where VTH represents the threshold voltage of NMOS transistor MVT, and rMVT represents the resistance value of NMV transistor MVT. When considering the voltage levels of the nodes ... and! ^ 2, that is, VN1 and VN2, because these two voltage values have different voltage changes, there will be an intersection at a certain point as shown in Figure 7. Therefore, the detection voltage level of the power supply voltage VDD is when the voltage levels of the nodes N1 and ... are equal, that is, when VN1 = VN2. Because the threshold voltage of NMTOS transistor MVT will be due to manufacturing differences, there are ±, 0, and 0. 1 to ± 0 · 2 volts, or a temperature dependence of about -2mV / ° C, so when the operating temperature is from _45t: to 95t :, the maximum threshold voltage value and the minimum threshold The difference in voltage values will be very large. Also, for the same reason as above, although the voltage of node N1 will linearly follow the value of the power supply voltage VDD, but because the threshold value is different, the detected voltage will be affected by the value of a parameter k. At the level, this parameter k is a value greater than one. Therefore, the result of the low-power detection circuit will be that this difference changes is worth amplifying. The device can work very well at high voltage (, 々 is greater than 3V), but it inevitably needs to be reduced due to manufacturing differences.

565848 V. Description of the invention (11) The degree of change between the maximum and minimum i of the detection range caused by the dependence on the difference between temperature and temperature. In Figure 5, the level of the comparison voltage (VN2) is generated by the comparison voltage generator 5 10, and its value is mainly determined by the threshold value of the transistor MVT. The reference voltage (VN1) is generated by the reference voltage generator 530. If the comparison voltage VN2 generated by the comparison voltage generator 510 can generate an ideal comparison voltage VN2 value as shown in FIG. 8, the voltage detection circuit 500 is caused by a difference in manufacturing and a difference in operating temperature. Detecting error conditions will be significantly reduced. Therefore, this problem depends on how to generate the ideal comparison voltage VN2 value as shown in FIG. 8. The voltage detection circuit of a preferred embodiment provided by the present invention, such as the detailed circuit diagram of the voltage detection circuit of one embodiment shown in FIG. 9, will have a function that is relatively close to this ideal comparison voltage output. In FIG. 9, the middle part is a differential amplifier (Different Amplifier) 920, the left part is a comparison voltage generator 910, and the right is a reference voltage generator 930. The comparison voltage generator 91 and the reference voltage generator 930 respectively output a comparison voltage (Comparative Voltage) and a reference voltage (Reference Voltage) to the difference amplifier 920. The output of the difference amplifier outputs an Low Voltage Detector Signal (LVCC) via an Inverter 940. This lvcc signal outputs a value close to the power supply voltage VDD if the potential of the node N4 is a logic low potential, and outputs a zero potential if the potential of the node N4 is a logic high potential. The above LVCC voltage level is used to represent whether the power supply voltage VDD is lower than a predetermined detection voltage.

9578twf.ptd Page 15 565848 V. Description of the invention (12) '-If the level is lower than the detection voltage level, the LVCC voltage level will be high. If it is higher than the detection voltage level, then The LVCC voltage level will be low. The above-mentioned comparison voltage generator 910 may be composed of two voltage division parts connected in series, and the comparison voltage is outputted by using this voltage division part. The voltage division of the first part may be composed of, for example, a resistor R2, and the voltage division of the second part may be composed of, for example, a circuit in which an NMOS transistor MVT is connected in series with the resistor R1. Therefore, as shown in the figure, the resistor R2, the NMOS transistor MVT, and the resistor R1 are connected in series between the power supply voltage VDD and the ground potential. One end of the resistor R3 is connected to the power supply voltage VDD 'and the NM 0 S transistor. One source / non-pole of VT is connected to resistor R1 'and grounded at the other end of resistor R1. The gate of the NMOS transistor MVT and the source / drain terminal connected to the resistor R3 are connected to the node at the same time! ^ 2. These components constitute a comparison voltage generator 910 to generate a comparison voltage level. The difference amplifier 920 shown in Fig. 9 is composed of transistors M1 to M5. Transistors M1 and M2 are similar NMOS transistors, that is, they have the same Gate Width / Gate Length ratio, and their sources are connected together. The gate of the transistor ... is connected to the node N2 in the comparison voltage generator 910, and the gate of the transistor M2 is connected to the node N1 of the reference voltage generator 930. The drain of the transistor M1 is connected to the gate and the drain of the PMOS transistor M3, that is, the node N3 in the figure. Transistors M3 and M4 are similar PM0S transistors, that is, they have the same Gate Width / Gate Length ratio, and their sources are connected together (node N3), while their sources are with

9578twf.ptd Page 16 565848 V. Description of the invention (13) ---- Power supply voltage VDD. The drain electrode of the transistor M2 is connected to the reference voltage generator 930, which is composed of two voltage-dividing parts, and uses the voltage divided by the power supply voltage VDD to generate the reference voltage. The reference voltage is linearly dependent on the power supply voltage VDD. That is, when the power supply voltage VDD decreases, the reference voltage decreases linearly. When the power supply voltage VDD increases, the reference voltage linearly increases. . As for the linearly increasing ratio, it must depend on the function of the two-part voltage division. A feature of the present invention is that the reference voltage is stably controlled and output by utilizing the adjustment of the divided voltage. The first part of the two voltage divisions is, for example, composed of a pM0s transistor Mp] L. The gate of the PMOS transistor MPL is grounded to keep the transistor in the ON state. The second voltage dividing part may be composed of, for example, a resistor R2. However, the present invention is not limited to a resistor or a transistor having a fixed resistance value, and may be composed of an adjustable resistor and a variable resistor. This is based on design needs. The pM0s transistor MPL and the resistor RL connected in series are connected between the power supply voltage VDD and the ground potential. The connection point between the PM0S transistor MPL and the resistor RL is node N1, and this node ... serves as the input terminal of the reference voltage generator 930 to the difference amplifier 92. By adjusting the gate width / gate length ratio of the PM0S transistor MPL, the reference voltage output by the reference voltage generator mo can be controlled. The circuit diagram of the embodiment in FIG. 9 is very close to the voltage detection circuit described in FIG. 5 except for some differences. These differences include, first

9578twf.ptd Page 17 565848 V. Description of the invention (14) First, a PMOS transistor MPL replaces the resistor ri in the reference voltage generator 530 shown in Figure 5. Second, the capacitance and ^^ "? Into this circuit. The capacitor CCPA1 includes one end connected to the ground and the other end connected to the node N1 to stabilize the reference voltage output by the reference voltage generator 930. The capacitor CCPA2 includes one end connected to the ground and the other end connected to the source terminal (node N2) of the transistor MVT in order to stabilize the comparison voltage output by the comparison voltage generator 910. In Fig. 9, the pMOS transistor MpL is connected in series with a resistor RL, one end is remotely connected to the power supply voltage VDD, and the other end is grounded. When the voltage level of the power supply voltage VDD is higher than the threshold voltage of the transistor MPL, the transistor MpL will be turned off, and the voltage level of the node ^ will soon drop to the ground level. The reference to Figure 10 is the ideal reference voltage value and the actual reference voltage generated by the voltage detection device according to the preferred embodiment of the present invention. It shows that using a pM0s transistor MpL to replace the original resistor will be very practical and has its special effect. The point is as above / jin explained 'at the intersection of the voltage values VN1 and · 2 of the nodes N1 and ~ 2 is very important.' From this point onwards ', when the power supply voltage ㈣Γ / position i! N 屮 2 will be greater than VN1' Therefore In the preferred embodiment of FIG. 9, the voltage near zero voltage detection signal will be output-connected to V- ^ A VN;: ^ ^ ^ ^ ^ Μ The high voltage value of the power supply voltage VDD is: LVCC will The output-close power is very important. ^ V is due to Λ, and the detection point supplied at this junction is, for example, 丨 2 volts. The specifications of the road design require that the marginal value of Hurengu is from 1.1 volts to i 3 volts

Page 18 565848 V. Description of the invention (15) U ί times: The purpose can be achieved. First, how to control the detection rate and how to control the difference to meet the requirements of this regulation. Take this specification as an example, this requirement will be easily met. The selection of ▲ k in the figure ^ keeps all parameters unchanged in this circuit, the only resistance value of J resistor R1. After adding the resistance to the resistor from zero, the voltage level VN2 at point N2 will rise, which will affect the intersection point = position and finally the detection point. The second option is to keep the parameters in this circuit unchanged, except for the PMOS transistor MPL's pole width / gate ratio (Rat10 of Gate Width / Gate Length). Adjusting the transistor, the gate width / gate length ratio of mpl can change the current of the transistor MPL,, and 'and thus affect the voltage level at node N1. Because the intersection of VN1 and VN2 is the most critical point, adjusting the gate width / gate length t of the transistor MPL will achieve the purpose of adjusting the control detection point. With regard to the second option mentioned above, in order to achieve detection point control within a predetermined range, such as the above-mentioned 0.3 volt specification as an example, the ideal reference voltage shown in Figure 8 will be very low. The level waveform shows that the dependence of the vehicle and voltage generator on the difference in temperature and temperature will not affect the difference in detection. In the voltage detection device of the preferred embodiment in FIG. 9, it can be known that if the value of the resistor R1 is fixed, the voltage VN1 of the node N1 will be fixed. In this circuit, the only factor that affects the difference in debt measurement points is Transistor II. It seems that the transistor MPL itself has process differences and temperature dependence, but if the resistance value of the resistor RL is carefully selected, its characteristics will make the effect of k-degree dependence relatively small. And this design! 1 9578twf.ptd Page 19 565848 V. Description of the Invention (16) The range of the detection point can be controlled within the above-mentioned predetermined range, regardless of process differences and temperature changes. ^ = The present invention has been disclosed as above with a preferred embodiment, but it is not intended to be limited to the present invention. Anyone skilled in the art can make various changes and modifications without departing from the scope of the present invention. Retouching, therefore, the scope of companion compliance of the present invention shall be determined by the scope of the appended patent application. Guarantee

Page 565848 Simple illustration of the diagram Simple illustration of the diagram: Figure 1 illustrates a block diagram of a conventional voltage detection device; Figure 2 illustrates a detailed circuit diagram of the conventional voltage detection device in Figure 1; Figure 3 FIG. 4 illustrates a circuit simulation result of the conventional voltage detection device in FIG. 2; FIG. 4 illustrates a circuit simulation result of the conventional voltage detection device in FIG. 2 considering a change in operating temperature; and FIG. 5 illustrates a kind of Detailed circuit diagram of the voltage detection device; FIG. 6 is a block diagram illustrating the voltage detection device in FIG. 5; FIG. 7 is a diagram illustrating the voltage changes of the nodes N1 and N2 of the voltage detection device in FIG. 5; FIG. 8 is another voltage change diagram illustrating nodes N1 and N2 of the voltage detection device in FIG. 5; FIG. 9 is a detailed circuit diagram illustrating the voltage detection device of a preferred embodiment of the present invention; and FIG. The figure is a comparison diagram of the ideal reference voltage value and the actual reference voltage value generated by the voltage detection device according to the preferred embodiment of FIG. 9 of the present invention.

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Claims (1)

565848 6. Scope of patent application 1 · A low-power supply voltage detection circuit for receiving a supply voltage, including a comparison voltage generator 'to generate and output a comparison voltage according to the supply voltage; a reference voltage generator according to the supply The voltage is used to generate a reference voltage according to a linear dependency relationship; and the reference voltage generator and the reference voltage are coupled to generate the comparison voltage and the reference voltage and output a low voltage-difference amplifier to receive, wherein when the reference The voltage is greater than the first voltage level voltage value, and the second voltage value when the test is performed. 2 · Rushen Road, where the electrical value is compared, the 3. Rushen Road, where the generator, uses the detection signal voltage circuit to include a first set of voltages less than the level, please patent the comparison pressure and compare Please call for patent. The comparison is made by two sets of resistors. When the comparison voltage is used, the low voltage detection signal will be used to indicate that the supply voltage is lower than a predetermined detection voltage. The test signal will be a low-power supply voltage detection electric voltage generator used to indicate that the supply voltage is higher than the predetermined detection voltage range described in item 1 according to when the supply voltage increases, but when the A supply voltage exceeding a predetermined voltage will approach a fixed voltage value. The low-power supply voltage detection electric voltage generator described in the second item of the scope includes a voltage dividing circuit, wherein the data is divided by the supply voltage, wherein the first group is composed of a package and the second group is Including one emperor and three i-Qi 9578twf.ptd Page 22 565848 6. Scope of patent application When the supply voltage increases, the comparison voltage is the second component voltage value of the partial voltage of the two groups of supply voltage, but when the supply voltage exceeds the After one threshold voltage value of the transistor in the two groups, the comparison voltage will approach the threshold voltage value. 4 · The low-power supply voltage detection circuit as described in item 1 of the patent application range, wherein the reference voltage generator linearly outputs the reference voltage according to the value of the supply voltage, and when the supply voltage decreases, the The reference voltage also decreases linearly. When the supply voltage increases, the reference voltage also increases linearly. 5. The low-power supply voltage detection circuit according to item 4 of the scope of the patent application, wherein the reference voltage generator linearly outputs the reference voltage value after dividing the supply voltage through a voltage dividing circuit, where The voltage dividing circuit is divided into two groups to divide the supply voltage, wherein the first group includes a transistor, the second group includes a resistor, and the reference voltage is the second voltage. Partial pressure of the group. 6 · The low-power supply voltage debt test circuit described in item 5 of the scope of the patent application, wherein the reference voltage can be adjusted according to a gate width / gate length ratio of one of the transistors in the first group. Adjust a threshold voltage value of the transistor to control the voltage level of the low voltage detection signal. 7. The low power supply voltage detection circuit according to item 1 of the scope of the patent application, wherein a capacitor is further included at the output end of the comparison voltage generator to maintain the potential of the comparison voltage. 8 · The low-power supply voltage detection circuit described in item 1 of the scope of the patent application, wherein a capacitor is further included at the wheel output end of the reference voltage generator, ^ 578twf .ptci Page 23 565848 6. Scope of patent application Used to maintain the potential of the reference voltage. 9. The low-power supply voltage detection circuit according to item 1 of the patent application scope, further comprising an inverting device for receiving the output of the difference amplifier and inverting the output to output the low voltage according to the inversion Detection signal. 9578twf.ptd Page 24