Constant voltage generating circuit

Abstract

The embodiment of the invention provides a constant voltage generation circuit, and relates to the technical field of circuit constant voltage. In the constant voltage generation circuit, the input end of a high-voltage domain module is used for being connected with an input power supply, and the voltage of the output end of the high-voltage domain module is the output voltage of the constant voltage generation circuit. The low-voltage domain module is used for adjusting operation of the high-voltage domain module. When the voltage is too high, the low-voltage domain module slowly turns off the MOS tube of the high-voltage domain in a current extraction mode, and compared with the mode that a voltage comparator is arranged to turn off the MOS tube in a switch switching mode, voltage noise generated by slow turn-off in the mode is low.

Description

Technical Field

[0001] This application relates to the technical field of circuit constant voltage, and particularly to a constant voltage generation circuit. Background Art

[0002] In some high-voltage application scenarios, the external input power supply is a high voltage with a large variation range, and a rated power supply rail needs to be provided for the chip before enabling inside the chip to make the chip work properly.

[0003] Therefore, a simple circuit for charging high-voltage signals is needed to generate a specific power supply rail for high-voltage signals with a wide input range. Summary of the Invention

[0004] The purpose of this application is to provide a constant voltage generation circuit to generate a specific power supply rail for high-voltage signals with a wide input range.

[0005] The constant voltage generation circuit includes a high-voltage domain module, a low-voltage domain module, and a first MOS transistor;

[0006] The input end of the high-voltage domain module is used to connect to an input power supply, and the voltage at the output end of the high-voltage domain module is the output voltage of the constant voltage generation circuit;

[0007] The low-voltage domain module includes a resistor voltage division unit (106), a first current unit (101), an intermediate current operation unit, and a fifth current unit (105);

[0008] The first current unit (101) is used to generate a reference current according to a reference voltage;

[0009] The intermediate current operation unit is used to generate a third current according to the voltage at the output end of the resistor voltage division unit (106), and generate a fourth current according to the part where the third current is higher than the reference current;

[0010] The intermediate current operation unit is respectively connected to the resistor voltage division unit (106), the first current unit (101), and the fifth current unit (105);

[0011] The fifth current unit (105) is used to copy the fourth current to the first MOS transistor; the fourth current is used for: when the first MOS transistor flows through the fourth current, it pulls down the voltage at the middle point or the input point of the high-voltage domain module;

[0012] The source electrode of the first MOS transistor is connected to the fifth current unit (105), the gate electrode of the first MOS transistor is connected to the power supply end of the low-voltage domain, and the drain electrode of the first MOS transistor is connected to the middle point or the input point of the high-voltage domain module.

[0013] Optionally, the high-voltage domain module includes a second MOS transistor, a clamping unit, and a current limiting unit;

[0014] The gate of the second MOS transistor is connected to the first end of the current limiting unit, and the second end of the current limiting unit and the drain of the second MOS transistor are used to access the input power supply;

[0015] The clamping unit is connected between the gate and the source of the second MOS transistor;

[0016] The gate of the second MOS transistor is connected to the drain of the first MOS transistor;

[0017] The voltage of the source of the second MOS transistor is the output voltage of the constant voltage generation circuit.

[0018] Optionally, the intermediate current operation unit includes a second current unit (102), a third current unit (103), and a fourth current unit (104);

[0019] The second current unit (102) is used to copy the reference current of the first current unit (101);

[0020] The resistor voltage dividing unit (106) is used to obtain a voltage from the high-voltage domain module and divide the voltage;

[0021] The third current unit (103) is used to generate a third current according to the voltage at the output end of the resistor voltage dividing unit (106);

[0022] The fourth current unit (104) is used to generate a fourth current when the voltage at the output end of the resistor voltage dividing unit (106) is greater than the reference voltage, and the sum of the fourth current and the reference current is the third current;

[0023] The input end of the resistor voltage dividing unit (106) is connected to the high-voltage domain module;

[0024] The output end of the resistor voltage dividing unit (106) is connected to the control end of the second current unit (102);

[0025] The voltage generating end of the second current unit (102) is connected to the third current unit (103);

[0026] The second current unit (102) and the fourth current unit (104) are connected in parallel and then connected in series with the third current unit (103);

[0027] One MOS transistor in the second current unit (102) is connected to one MOS transistor in the first current unit (101) in a current mirror manner;

[0028] One MOS transistor in the fourth current unit (104) is connected to one MOS transistor in the fifth current unit (105) in the form of a current mirror.

[0029] Optionally, the high-voltage domain module further includes a unidirectional conduction MOS transistor. The drain of the unidirectional conduction MOS transistor is connected to the drain of the second MOS transistor, and the source and gate of the unidirectional conduction MOS transistor are connected and used to access the input power supply.

[0030] Optionally, the high-voltage domain module further includes a capacitor unit;

[0031] The capacitor unit is connected between the gate and the source of the second MOS transistor.

[0032] Optionally, the first current unit (101) includes a second resistor unit, a third MOS transistor, and a fourth MOS transistor;

[0033] The second resistor unit, the third MOS transistor, and the fourth MOS transistor are connected in series in sequence;

[0034] The gate of the third MOS transistor is used to access the reference voltage;

[0035] The second current unit (102) includes a fifth MOS transistor;

[0036] The gate of the fourth MOS transistor is connected to the drain of the fourth MOS transistor, the source of the fourth MOS transistor is connected to the source of the fifth MOS transistor, the gate of the fourth MOS transistor is connected to the gate of the fifth MOS transistor, and the drain of the fifth MOS transistor is connected to the third current unit (103).

[0037] Optionally, the second current unit (102) further includes a sixth MOS transistor;

[0038] The gate of the sixth MOS transistor is connected to the output terminal of the resistor voltage division unit (106), the source of the sixth MOS transistor is connected to the third current unit (103), and the drain of the sixth MOS transistor is connected to the drain of the fifth MOS transistor.

[0039] Optionally, the third current unit (103) is a resistor, and the resistance of the third current unit (103) is the same as that of the second resistor unit.

[0040] Optionally, the fourth current unit (104) includes a seventh MOS transistor;

[0041] The drain of the seventh MOS transistor is connected to the source of the sixth MOS transistor;

[0042] The source electrode of the seventh MOS transistor is connected to the source electrode of the fifth MOS transistor;

[0043] The gate electrode of the seventh MOS transistor is connected to the fifth current unit (105) and to the drain electrode of the fifth MOS transistor.

[0044] Optionally, the fifth current unit (105) includes an eighth MOS transistor;

[0045] The gate electrode of the eighth MOS transistor is connected to the gate electrode of the seventh MOS transistor;

[0046] The source electrode of the eighth MOS transistor is connected to the source electrode of the seventh MOS transistor;

[0047] The drain electrode of the eighth MOS transistor is connected to the source electrode of the first MOS transistor;

[0048] The third MOS transistor and the sixth MOS transistor are PMOS transistors;

[0049] The fourth MOS transistor, the fifth MOS transistor, the seventh MOS transistor, and the eighth MOS transistor are NMOS transistors.

[0050] Optionally, the fifth current unit (105) includes a ninth MOS transistor, a tenth MOS transistor, and an eleventh MOS transistor;

[0051] The gate electrode of the ninth MOS transistor is connected to the gate electrode of the seventh MOS transistor;

[0052] The source electrode of the ninth MOS transistor is connected to the source electrode of the seventh MOS transistor;

[0053] The drain electrode of the ninth MOS transistor is connected to the drain electrode of the tenth MOS transistor;

[0054] The gate electrode of the tenth MOS transistor is connected to the gate electrode of the eleventh MOS transistor and to the drain electrode of the tenth MOS transistor;

[0055] The source electrode of the tenth MOS transistor is connected to the source electrode of the eleventh MOS transistor;

[0056] The drain electrode of the eleventh MOS transistor is connected to the source electrode of the first MOS transistor;

[0057] The third MOS transistor, the sixth MOS transistor, the tenth MOS transistor, and the eleventh MOS transistor are NMOS transistors;

[0058] The fourth MOS transistor, the fifth MOS transistor, the seventh MOS transistor, and the ninth MOS transistor are PMOS transistors.

[0059] Optionally, the breakdown voltage of the first MOS transistor is higher than that of the MOS transistors in the low-voltage domain module.

[0060] Compared with the prior art, the present application has the following beneficial effects:

[0061] The constant-voltage generating circuit provided by the embodiment of the present application discharges the gate voltage of the second MOS transistor through the first MOS transistor, thereby preventing the output voltage from being too high. Specifically, when the voltage of the input power supply is too high, the voltage output by the resistor voltage-dividing unit is relatively high, and the fourth current unit obtains a current and copies it to the first MOS transistor, and this current reduces the gate voltage of the second MOS transistor. Description of the Drawings

[0062] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings required for use in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0063] Figure 1 Schematic diagram of a constant-voltage generating circuit provided by an embodiment of the present application;

[0064] Figure 2 Schematic diagram of a low-voltage domain module provided by an embodiment of the present application, including a resistor voltage-dividing unit 106, a first current unit 101, an intermediate current operation unit 100, and a fifth current unit 105;

[0065] Figure 3 Schematic diagram of a low-voltage domain module provided by an embodiment of the present application, including a resistor voltage-dividing unit 106, a first current unit 101, a second current unit 102, a third current unit 103, a fourth current unit 104, and a fifth current unit 105;

[0066] Figure 4 Schematic diagram of a high-voltage domain module provided by an embodiment of the present application, including a second MOS transistor M2, a clamping unit, and a current-limiting unit;

[0067] Figure 5 Schematic diagram of a high-voltage domain module provided by an embodiment of the present application, further including a unidirectional conduction transistor M01 and a capacitor unit C1;

[0068] Figure 6 Schematic diagram of an implementation manner of a low-voltage domain module composed of a MOS transistor and a resistor provided by an embodiment of the present application;

[0069] Figure 7 For the PMOS transistor and NMOS transistor of the low-voltage domain module and Figure 6 Different implementation diagrams. Detailed implementation manners

[0070] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of this application. The described embodiments are some but not all of the embodiments of this application. Generally, the components of the embodiments of this application described in the accompanying drawings here can be arranged and designed in various different configurations.

[0071] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of this application that is claimed, but merely represents selected embodiments of this application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of this application without creative efforts fall within the scope of protection of this application. Without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0072] In the description of this application, it should be noted that:

[0073] Relative terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations;

[0074] "Connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium.

[0075] As Figure 1 , the constant-voltage generation circuit includes a high-voltage domain module, a low-voltage domain module, and a first MOS transistor M1.

[0076] The input end of the high-voltage domain module is used to connect to an input power supply, and the voltage at the output end of the high-voltage domain module is the output voltage of the constant-voltage generation circuit.

[0077] The voltage at the power supply end of the low-voltage domain module is lower than the input power supply voltage and lower than the output voltage of the constant-voltage generation circuit. The low-voltage domain module is used to regulate the operation of the high-voltage domain module.

[0078] As Figure 2 , the low-voltage domain module may include a resistor voltage division unit 106, a first current unit 101, an intermediate current operation unit 100, and a fifth current unit 105. The functions and connection relationships of each part are as follows:

[0079] The first current unit 101 is used to generate a reference current according to a reference voltage;

[0080] The intermediate current operation unit is used to generate a third current according to the voltage at the output end of the resistor voltage division unit 106, and generate a fourth current according to the part of the third current that is higher than the reference current; the intermediate current operation unit is respectively connected to the resistor voltage division unit 106, the first current unit 101, and the fifth current unit 105;

[0081] The fifth current unit 105 is used to copy the fourth current to the first MOS transistor; the fourth current is used for: when the first MOS transistor flows through the fourth current, it pulls down the voltage at the midpoint or input point of the high-voltage domain module;

[0082] The source of the first MOS transistor is connected to the fifth current unit 105, the gate of the first MOS transistor is connected to the power supply terminal of the low-voltage domain, and the drain of the first MOS transistor is connected to the midpoint or input point of the high-voltage domain module.

[0083] When the voltage of the input power supply is too high, the voltage output by the resistor voltage division unit is relatively high, the fourth current unit obtains the current and copies it to the first MOS transistor M1, and the current of the first MOS transistor M1 pulls down the voltage at the midpoint or input of the high-voltage domain module to prevent the output voltage from being too high, achieving the effect of stabilizing the output voltage.

[0084] The intermediate current operation unit includes a second current unit 102, a third current unit 103, and a fourth current unit 104; as Figure 3 , the low-voltage domain module may include a resistor voltage division unit 106, a first current unit 101, a second current unit 102, a third current unit 103, a fourth current unit 104, and a fifth current unit 105. The source of the first MOS transistor M1 is connected to the fifth current unit 105, the gate of the first MOS transistor M1 is connected to the power supply terminal of the low-voltage domain, and the drain of the first MOS transistor M1 is connected to the high-voltage domain module. In one embodiment, the first MOS transistor M1 serves as a medium connecting the high-voltage domain and the low-voltage domain, the first MOS transistor M1 is a high-voltage transistor, the low-voltage domain module can be implemented using low-voltage transistors, and the breakdown voltage of the first MOS transistor M1 can be higher than that of the MOS transistors in the low-voltage domain module.

[0085] The functions and connection relationships of each part of the low-voltage domain module are as follows:

[0086] The first current unit 101 is used to generate a reference current according to the reference voltage VREF;

[0087] The second current unit 102 is used to copy the reference current of the first current unit 101; one MOS transistor in the second current unit 102 is connected to one MOS transistor in the first current unit 101 in the form of a current mirror;

[0088] The resistor voltage division unit 106 is used to obtain a voltage from the high-voltage domain module and divide the voltage; the input end of the resistor voltage division unit 106 is connected to the high-voltage domain module; the output end of the resistor voltage division unit 106 is connected to the control end of the second current unit 102; the voltage generation end of the second current unit 102 is connected to the third current unit 103; the control end of the second current unit 102 can be the gate of a MOS transistor, and the voltage generation end of the second current unit 102 can be the source of the MOS transistor;

[0089] The third current unit 103 is used to generate a third current according to the voltage at the output end of the resistor voltage division unit 106;

[0090] The fourth current unit 104 is used to generate a fourth current when the voltage at the output end of the resistor voltage division unit 106 is greater than the reference voltage VREF. The fourth current unit 104 is connected in parallel with the second current unit 102 and then connected in series with the third current unit 103. Therefore, there is the following relationship: the fourth current + the reference current = the third current;

[0091] The fifth current unit 105 is used to copy the fourth current to the first MOS transistor M1. One MOS transistor in the fourth current unit 104 is connected to one MOS transistor in the fifth current unit 105 in a current mirror manner.

[0092] Such as Figure 4 , the high-voltage domain module may include a second MOS transistor M2, a clamping unit, and a current limiting unit; the clamping unit may include a Zener diode Z1, and the current limiting unit may include a first resistor unit R1. There are the following connection relationships:

[0093] The gate of the second MOS transistor M2 is connected to the first end of the current limiting unit, and the second end of the current limiting unit and the drain of the second MOS transistor M2 are used to connect to the input power supply VIN;

[0094] The clamping unit is connected between the gate and the source of the second MOS transistor M2;

[0095] The gate of the second MOS transistor M2 is connected to the drain of the first MOS transistor M1;

[0096] The voltage at the source of the second MOS transistor M2 is the output voltage of the constant voltage generation circuit.

[0097] The function of the current limiting unit includes preventing excessive current, and the function of the clamping unit includes enabling the second MOS transistor M2 to obtain a stable gate-source voltage. The high-voltage domain circuit plays a role in charging the output end VDD from the input power supply VIN.

[0098] When the voltage of the input power supply is too high, the voltage output by the resistor voltage division unit is relatively high. The fourth current unit obtains a current and copies it to the first MOS transistor M1. The current of the first MOS transistor M1 pulls down the gate voltage of the second MOS transistor M2, thereby preventing the output voltage from being too high and achieving the effect of stabilizing the output voltage.

[0099] As Figure 5 , the high-voltage domain module may further include a unidirectional conduction transistor M01. The drain of the unidirectional conduction transistor M01 is connected to the drain of the second MOS transistor M2, and the source and gate of the unidirectional conduction transistor M01 are connected and used to access the input power supply. The unidirectional conduction transistor may be a MOS transistor, and its parasitic diode conducts. The functions of the unidirectional conduction transistor M01 include preventing the current of the second MOS transistor M2 from flowing backward when the voltage of the input power supply VIN accidentally decreases. The unidirectional conduction transistor M01 may be replaced by a diode. The anode of the diode is connected to the input power supply VIN, and the cathode of the diode is connected to the drain of the second MOS transistor M2.

[0100] As Figure 5 , the high-voltage domain module may further include a capacitor unit C1; the capacitor unit C1 is connected between the gate and source of the second MOS transistor M2. The functions of the capacitor unit C1 include providing the gate-source voltage for the second MOS transistor M2 when the voltage of the input power supply VIN is accidentally insufficient.

[0101] Figure 6 And Figure 7 show two implementation manners of the low-voltage domain module, and the difference lies in the selection of NMOS transistors and PMOS transistors. Except for the cross-line parts in the figure, all circuit cross parts are connected to each other.

[0102] As Figure 6 And Figure 7 , the first current unit 101 may include a second resistor unit R2, a third MOS transistor M3, and a fourth MOS transistor M4, and has the following connection relationship:

[0103] The second resistor unit R2, the third MOS transistor M3, and the fourth MOS transistor M4 are connected in series in sequence. Therefore, their currents are the same and are all reference currents;

[0104] The gate of the third MOS transistor M3 is used to access the reference voltage VREF. The reference voltage VREF is a low voltage and a stable voltage. The ultimate goal is to obtain a stable high-voltage output based on the relatively low and stable reference voltage VREF.

[0105] The second current unit 102 may include a fifth MOS transistor M5, and has the following connection relationship:

[0106] The gate of the fourth MOS transistor M4 is connected to the drain of the fourth MOS transistor M4, the source of the fourth MOS transistor M4 is connected to the source of the fifth MOS transistor M5, and the gate of the fourth MOS transistor M4 is connected to the gate of the fifth MOS transistor M5. The fifth MOS transistor M5 can copy the current of the fourth MOS transistor M4. The drain of the fifth MOS transistor M5 is connected to the third current unit 103.

[0107] The second current unit 102 may further include a sixth MOS transistor M6, and there are the following connection relationships:

[0108] The gate of the sixth MOS transistor M6 is connected to the output terminal of the resistor voltage dividing unit 106, the source of the sixth MOS transistor M6 is connected to the third current unit 103, the drain of the sixth MOS transistor M6 is connected to the drain of the fifth MOS transistor M5, and the currents of the sixth MOS transistor M6 and the fifth MOS transistor M5 are the same.

[0109] The third current unit 103 may be a resistor, and the resistance of the third current unit 103 may be the same as that of the second resistor unit R2. At this time:

[0110] (1) When the voltage VDIV output from the resistor voltage dividing unit to the gate of the sixth MOS transistor M6 is the same as the reference voltage VREF, the currents of the third current unit 103 and the second resistor unit R2 are the same; at this time, the third current unit 103 and the second resistor unit R2 form the same structure as the first current unit 101 and have the same current; the fourth current unit 104 has no current and is equivalent to not existing. Therefore, the first MOS transistor M1 does not get current, and the gate voltage of the second MOS transistor M2 will not be discharged through the first MOS transistor M1.

[0111] (2) When the voltage VDIV output from the resistor voltage dividing unit to the gate of the sixth MOS transistor M6 > the reference voltage VREF, the current of the third current unit 103 = the third current > the current of the second resistor unit R2 = the reference current; the fourth current = the third current - the reference current > 0, that is, the part of the third current that is more than the current of the second current unit 102 flows to the fourth current unit 104. Finally, the first MOS transistor M1 gets current, and the gate voltage of the second MOS transistor M2 will be discharged through the first MOS transistor M1.

[0112] (3) When the voltage VDIV output from the resistor voltage dividing unit to the gate of the sixth MOS transistor M6 < the reference voltage VREF, the current of the third current unit 103 = the third current < the current of the second resistor unit R2 = the reference current, and the part of the third current that is more than the current of the second current unit 102 does not flow to the fourth current unit 104. The fourth current unit 104 does not get current. Similar to the above (1), the gate voltage of the second MOS transistor M2 will not be discharged through the first MOS transistor M1.

[0113] AsFigure 6 , Figure 7 , the fourth current unit 104 may include a seventh MOS transistor M7; there is the following connection relationship:

[0114] The drain of the seventh MOS transistor M7 is connected to the source of the sixth MOS transistor M6;

[0115] The source of the seventh MOS transistor M7 is connected to the source of the fifth MOS transistor M5;

[0116] The gate of the seventh MOS transistor M7 is connected to the fifth current unit 105 and is connected to the drain of the fifth MOS transistor M5.

[0117] The fifth current unit 105 has two implementation manners:

[0118] Figure 6 In the shown implementation manner, the third MOS transistor M3, the sixth MOS transistor M6, the tenth MOS transistor M10, and the eleventh MOS transistor M11 are NMOS transistors; the fourth MOS transistor M4, the fifth MOS transistor M5, the seventh MOS transistor M7, and the ninth MOS transistor M9 are PMOS transistors; the fifth current unit 105 includes the ninth MOS transistor M9, the tenth MOS transistor M10, and the eleventh MOS transistor M11; there is the following connection relationship:

[0119] The gate of the ninth MOS transistor M9 is connected to the gate of the seventh MOS transistor M7;

[0120] The source of the ninth MOS transistor M9 is connected to the source of the seventh MOS transistor M7;

[0121] The drain of the ninth MOS transistor M9 is connected to the drain of the tenth MOS transistor M10;

[0122] The gate of the tenth MOS transistor M10 is connected to the gate of the eleventh MOS transistor M11 and is connected to the drain of the tenth MOS transistor M10;

[0123] The source of the tenth MOS transistor M10 is connected to the source of the eleventh MOS transistor M11;

[0124] The drain of the eleventh MOS transistor M11 is connected to the source of the first MOS transistor M1.

[0125] Figure 7 In the shown implementation manner, the third MOS transistor M3 and the sixth MOS transistor M6 are PMOS transistors; the fourth MOS transistor M4, the fifth MOS transistor M5, the seventh MOS transistor M7, and the eighth MOS transistor M8 are NMOS transistors; the fifth current unit 105 includes the eighth MOS transistor M8; there is the following connection relationship:

[0126] The gate of the eighth MOS transistor M8 is connected to the gate of the seventh MOS transistor M7;

[0127] The source of the eighth MOS transistor M8 is connected to the source of the seventh MOS transistor M7;

[0128] The drain of the eighth MOS transistor M8 is connected to the source of the first MOS transistor M1.

[0129] Figure 7 The advantage of the shown embodiment is that the number of MOS transistors is less and the structure is simple.

[0130] Regarding Figure 6 the advantage of the shown embodiment, assume that for Figure 7 the same VREF of 1V, for the NMOS transistor, the sixth MOS transistor M6 in the low-voltage domain of 5V, the highest VGS is 1V, but for Figure 7 the PMOS transistor, the sixth MOS transistor M6 is up to 4V, and the current of the sixth MOS transistor M6 is larger and the power is larger. Therefore Figure 6 the advantage of the shown embodiment is that with a smaller VREF, there is less power.

[0131] In summary, the constant-voltage generation circuit realizes a simple high-voltage charging circuit for generating a rated power supply rail through the combination of charging in the high-voltage domain and control in the low-voltage domain, generates a rated power supply rail within a wide input voltage range, and the generated power supply rail is regulated by the internal reference voltage VREF, and the circuit implementation is simple.

[0132] By slowly turning off the charging transistor (the second MOS transistor M2) in the high-voltage domain by extracting current, compared with setting a voltage comparator to turn off in the form of switching, this method plays a role in slowly turning off and the generated VDD voltage has no ripple, reducing the noise generated by the ripple.

[0133] The device and system embodiments described above are merely illustrative, and some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. Those of ordinary skill in the art can understand and implement without creative work.

[0134] The above is only a preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present application should be covered by the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A constant voltage generation circuit, characterized in that, It includes a high-voltage domain module, a low-voltage domain module, and a first MOS transistor; The input end of the high-voltage domain module is used to connect to an input power supply, and the voltage at the output end of the high-voltage domain module is the output voltage of the constant-voltage generation circuit; The low-voltage domain module includes a resistor voltage division unit (106), a first current unit (101), an intermediate current operation unit, and a fifth current unit (105); The first current unit (101) is used to generate a reference current according to a reference voltage; The intermediate current operation unit is used to generate a third current according to the voltage at the output end of the resistor voltage division unit (106), and generate a fourth current according to the part of the third current that is higher than the reference current; The intermediate current operation unit is respectively connected to the resistor voltage division unit (106), the first current unit (101), and the fifth current unit (105); The fifth current unit (105) is used to copy the fourth current to the first MOS transistor; the fourth current is used for: when the first MOS transistor flows through the fourth current, it pulls down the voltage at the midpoint or input point of the high-voltage domain module; The source electrode of the first MOS transistor is connected to the fifth current unit (105), the gate electrode of the first MOS transistor is connected to the power supply end of the low-voltage domain, and the drain electrode of the first MOS transistor is connected to the midpoint or input point of the high-voltage domain module.

2. The constant voltage generation circuit according to claim 1, wherein The high-voltage domain module includes a second MOS transistor, a clamping unit, and a current limiting unit; The gate electrode of the second MOS transistor is connected to the first end of the current limiting unit, and the second end of the current limiting unit and the drain electrode of the second MOS transistor are used to connect to the input power supply; The clamping unit is connected between the gate electrode and the source electrode of the second MOS transistor; The gate electrode of the second MOS transistor is connected to the drain electrode of the first MOS transistor; The voltage at the source electrode of the second MOS transistor is the output voltage of the constant-voltage generation circuit.

3. The constant voltage generation circuit according to claim 1, wherein, The intermediate current operation unit includes a second current unit (102), a third current unit (103), and a fourth current unit (104); The second current unit (102) is used to copy the reference current of the first current unit (101); The resistor voltage division unit (106) is used to obtain a voltage from the high-voltage domain module and divide the voltage; The third current unit (103) is used to generate a third current according to the voltage at the output end of the resistor voltage division unit (106); The fourth current unit (104) is used to generate a fourth current when the voltage at the output end of the resistor voltage division unit (106) is greater than the reference voltage, and the sum of the fourth current and the reference current is the third current; The input end of the resistor voltage division unit (106) is connected to the high-voltage domain module; The output end of the resistor voltage division unit (106) is connected to the control end of the second current unit (102); The voltage generation end of the second current unit (102) is connected to the third current unit (103); The second current unit (102) and the fourth current unit (104) are connected in parallel and then connected in series with the third current unit (103); One MOS transistor in the second current unit (102) is connected to one MOS transistor in the first current unit (101) in the form of a current mirror; One MOS transistor in the fourth current unit (104) is connected to one MOS transistor in the fifth current unit (105) in the form of a current mirror.

4. The constant voltage generation circuit according to claim 2, characterized in that, The high-voltage domain module further includes a unidirectional conduction MOS transistor or a capacitor unit; The drain of the unidirectional conduction MOS transistor is connected to the drain of the second MOS transistor, and the source and gate of the unidirectional conduction MOS transistor are connected and used to access the input power supply; The capacitor unit is connected between the gate and the source of the second MOS transistor.

5. The constant voltage generating circuit according to claim 3, wherein The first current unit (101) includes a second resistor unit, a third MOS transistor, and a fourth MOS transistor; The second resistor unit, the third MOS transistor, and the fourth MOS transistor are connected in series in sequence; The gate of the third MOS transistor is used to access the reference voltage; The second current unit (102) includes a fifth MOS transistor; The gate of the fourth MOS transistor is connected to the drain of the fourth MOS transistor, the source of the fourth MOS transistor is connected to the source of the fifth MOS transistor, the gate of the fourth MOS transistor is connected to the gate of the fifth MOS transistor, and the drain of the fifth MOS transistor is connected to the third current unit (103).

6. The constant voltage generation circuit according to claim 5, characterized in that The second current unit (102) further includes a sixth MOS transistor; The gate of the sixth MOS transistor is connected to the output terminal of the resistor voltage division unit (106), the source of the sixth MOS transistor is connected to the third current unit (103), and the drain of the sixth MOS transistor is connected to the drain of the fifth MOS transistor.

7. The constant voltage generating circuit according to claim 5 or 6, characterized in that, The third current unit (103) is a resistor, and the resistance of the third current unit (103) is the same as that of the second resistor unit.

8. The constant voltage generating circuit according to claim 6, wherein, The fourth current unit (104) includes a seventh MOS transistor; The drain of the seventh MOS transistor is connected to the source of the sixth MOS transistor; The source of the seventh MOS transistor is connected to the source of the fifth MOS transistor; The gate of the seventh MOS transistor is connected to the fifth current unit (105) and is connected to the drain of the fifth MOS transistor.

9. The constant voltage generation circuit according to claim 8, wherein The fifth current unit (105) includes an eighth MOS transistor; The gate of the eighth MOS transistor is connected to the gate of the seventh MOS transistor; The source of the eighth MOS transistor is connected to the source of the seventh MOS transistor; The drain of the eighth MOS transistor is connected to the source of the first MOS transistor; The third MOS transistor and the sixth MOS transistor are PMOS transistors; The fourth MOS transistor, the fifth MOS transistor, the seventh MOS transistor, and the eighth MOS transistor are NMOS transistors; Or: The fifth current unit (105) includes a ninth MOS transistor, a tenth MOS transistor, and an eleventh MOS transistor; The gate of the ninth MOS transistor is connected to the gate of the seventh MOS transistor; The source of the ninth MOS transistor is connected to the source of the seventh MOS transistor; The drain of the ninth MOS transistor is connected to the drain of the tenth MOS transistor; The gate of the tenth MOS transistor is connected to the gate of the eleventh MOS transistor and to the drain of the tenth MOS transistor; The source of the tenth MOS transistor is connected to the source of the eleventh MOS transistor; The drain of the eleventh MOS transistor is connected to the source of the first MOS transistor; The third MOS transistor, the sixth MOS transistor, the tenth MOS transistor, and the eleventh MOS transistor are NMOS transistors; The fourth MOS transistor, the fifth MOS transistor, the seventh MOS transistor, and the ninth MOS transistor are PMOS transistors.

10. The constant voltage generation circuit according to claim 1, characterized in that, The breakdown voltage of the first MOS transistor is higher than that of the MOS transistors in the low-voltage domain module.

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