A modulator whose output voltage follows changes in a reference voltage

Abstract

The application discloses a modulator which can output voltage following reference voltage variation, and is characterized in that the modulator comprises an RC unit, an isolation unit, a boosting unit and a driving control unit; the RC unit is connected with the isolation unit, and is used for receiving voltage V ref from a reference voltage source and filtering noise of the voltage V ref ; the isolation unit is connected with the RC unit and the boosting unit respectively, and is used for receiving the voltage V ref after noise filtering to generate an isolation voltage and inputting the isolation voltage into the boosting unit; the boosting unit is connected with the isolation unit, and is used for boosting the isolation voltage by a fixed voltage difference; and the driving control unit is connected with the boosting unit, and is used for stabilizing the boosting of the fixed voltage difference to provide driving for a subsequent circuit. The application has the advantages of simple circuit structure, convenient realization, reasonable and accurate generated boosting voltage and wide application range.

Description

Technical Field

[0001] This invention relates to the field of integrated circuits, and more specifically, to a modulator whose output voltage follows a reference voltage. Background Technology

[0002] In the field of integrated circuits, when a chip is designed for high voltage, a low-voltage modulator is typically required internally to generate a low voltage and power the internal low-voltage circuitry. Sometimes, the voltage of this modulator is not fixed and its value needs to change according to a reference level. For example, a modulator that changes with the LDO output voltage is required inside a high-voltage LDO (Low Dropout Regulator) circuit. However, the LDO output voltage is determined during application, and during operation, the downstream circuitry may experience momentary loads, which can interfere with the LDO's output performance, causing voltage fluctuations.

[0003] In the prior art, since the reference level of the modulator usually does not have driving capability, it cannot match the circuit requirements of following the reference voltage change to modulate the modulator voltage change.

[0004] Therefore, there is an urgent need for a modulator whose output voltage follows the reference voltage even when the reference voltage is not capable of driving. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a modulator whose output voltage follows the reference voltage. Through an RC unit, an isolation unit, a boost unit, and a drive control unit, the modulator achieves noise reduction, isolation, and boosting of the reference voltage source voltage, resulting in a higher output voltage value that can effectively drive the circuit as feedback.

[0006] The present invention adopts the following technical solution.

[0007] A modulator whose output voltage follows a reference voltage, wherein the modulator includes an RC unit, an isolation unit, a boost unit, and a drive control unit; the RC unit, connected to the isolation unit, is used to receive a voltage V from the reference voltage source. ref And filter out voltage V ref The noise is filtered out; an isolation unit, connected to the RC unit and the boost unit respectively, is used to receive the voltage V after the noise is filtered out. ref An isolation voltage is generated and input to the boost unit; the boost unit, connected to the isolation unit, is used to boost the isolation voltage by a fixed differential; the drive control unit, connected to the boost unit, is used to stabilize the boost voltage by the fixed differential to provide drive for the subsequent circuits.

[0008] Preferably, the RC unit includes a resistor R and a capacitor C; wherein one end of the resistor R is connected to a reference voltage source, and the other end is connected to one end of the capacitor C, serving as the output terminal of the RC unit; the other end of the capacitor C is grounded.

[0009] Preferably, the isolation unit includes an isolation MOS transistor Mn0, Mp0, and a second current source I0; wherein, the gate of Mn0 is connected to the output terminal of the RC unit, the source is connected to the gate of Mp0 and one end of the second current source I0 respectively, and the drain is connected to the source of Mp0 as the output terminal of the isolation unit; the drain of Mp0 and the other end of the second current source I0 are grounded.

[0010] Preferably, the boost unit includes a boost resistor R1, a transistor Mn1, and a transistor Mn2; wherein the gate of transistor Mn2 is connected to the gate and drain of transistor Mn1 and one end of boost resistor R1, respectively, the source of which is connected to the output of the isolation unit, and the drain of which serves as the output of the boost unit and is connected to the drive control unit; the source of transistor Mn1 is connected to the output of the isolation unit; the other end of boost resistor R1 serves as the output of the modulator, and the boosted voltage V is obtained. out .

[0011] Preferably, the first mirror current and the second mirror current in the boost unit are in a fixed ratio; wherein, the first mirror current is the source-drain current of Mn2; and the second mirror current is the source-drain current of Mn1.

[0012] Preferably, the drive control unit includes a first current source I1, mirror transistors Mp3 and Mp2, and a drive transistor Mp1; wherein, the source of mirror transistor Mp3 is connected to the power supply voltage, the gate is connected to the gate and drain of mirror transistor Mp2 and the output terminal of the boost unit, the drain is connected to the gate of drive transistor Mp1 and one end of the first current source I1; the other end of the first current source I1 is grounded; the source of mirror transistor Mp2 is connected to the power supply voltage; the source of drive transistor Mp1 is connected to the power supply voltage, and the drain is connected to the other end of the boost resistor R1 in the boost unit, serving as the output terminal of the modulator.

[0013] Preferably, the third mirror current in the drive control unit is in a fixed ratio to the first mirror current; wherein, the third mirror current is the source-drain current of Mp3, which is equal to the current of the first current source I1 of the drive control unit; the first mirror current is the source-drain current of Mp2, which is equal to the source-drain current of Mn2 in the boost unit.

[0014] Preferably, the ratio of the first and second mirror currents is determined by the size ratio of mirror transistors Mn2 and Mn1 in the boost unit; the ratio of the third and first mirror currents is determined by the size ratio of mirror transistors Mp3 and Mp2 in the drive control unit.

[0015] Preferably, the sum of the first mirror current and the second mirror current in the boost unit is greater than the current of the second current source I0 in the isolation unit, so as to ensure that there is a source-drain current on the MOS transistor Mp0 in the isolation unit.

[0016] Preferably, the boost voltage is V. out =V′ ref +V gs_Mn1 +V R1 ; where V′ ref The isolation voltage is provided by the voltage V from the reference voltage source. out Together with the isolation unit, V was determined. gs_Mn1 V is the gate-source voltage of the Mn1 transistor in the boost unit. R1 This is the voltage across resistor R1 in the boost unit.

[0017] The beneficial effects of this invention are that, compared with the prior art, the modulator in this invention, whose output voltage follows the reference voltage, can achieve noise reduction, isolation, and voltage boosting of the output voltage through an RC unit, an isolation unit, a boost unit, and a drive control unit. This results in a higher output voltage value, which can be used as feedback to fully drive the circuit. The circuit structure of this invention is simple, easy to implement, and generates a reasonable and accurate boost voltage, making it widely applicable.

[0018] The beneficial effects of the present invention also include:

[0019] 1. Because the output voltage in a circuit varies over a wide range and its specific value is difficult to predict, a consistently high power supply voltage is required to drive the output voltage circuit. This ensures the output voltage provides sufficient driving capability for subsequent circuits. However, this high power supply voltage results in significant and persistent power losses, leading to increased circuit temperature and impacting device performance. The method described in this invention eliminates the need for a high power supply voltage, enabling the regulated voltage to fully perform its driving function. This provides effective power dissipation for the circuit and prevents unnecessary energy loss and temperature-related effects on output accuracy.

[0020] 2. In existing technologies, when the output voltage is very small, it lacks driving capability. In this case, some circuits can be driven based on the reference voltage. The technical solution in this invention can not only be applied to the output voltage, but also, in order to continue powering subsequent circuits, it can be additionally applied to the output terminal of the reference voltage, thereby generating driving capability by boosting the reference voltage. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the circuit structure of a modulator whose output voltage follows the change of a reference voltage according to the present invention. Detailed Implementation

[0022] The present application will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention, and should not be construed as limiting the scope of protection of the present application.

[0023] Figure 1 This is a schematic diagram of the circuit structure of a modulator whose output voltage follows a reference voltage change, according to the present invention. Figure 1 As shown, a modulator whose output voltage follows a reference voltage varies includes an RC unit, an isolation unit, a boost unit, and a drive control unit; the RC unit, connected to the isolation unit, receives a voltage V from the reference voltage source. ref And filter out voltage V ref The noise is filtered out; an isolation unit, connected to the RC unit and the boost unit respectively, is used to receive the voltage V after the noise is filtered out. ref To generate an isolation voltage; a boost unit, connected to the isolation unit, is used to boost the isolation voltage by a fixed voltage difference; a drive control unit, connected to the boost unit, is used to stabilize the boost voltage by a fixed voltage difference to provide drive for subsequent circuits.

[0024] It is understood that in the modulator of this invention, an RC circuit can be used to realize the operation of passing DC and blocking AC input signals. The output signal of the isolation unit is basically the same as that of the input signal, but it can isolate the circuit so that the load change of the back end will not affect the magnitude change of the output voltage of the front end circuit.

[0025] In addition, the boost unit can boost voltage based on the characteristics of the boost resistor and MOSFET.

[0026] In addition, the use of a drive control unit ensures that multiple branches in the circuit have proportionally fixed currents, thereby guaranteeing that the output voltage is obtained by adding a fixed voltage to the original output voltage. This method effectively simplifies the acquisition of the output voltage while ensuring its stability and accuracy.

[0027] Preferably, the RC unit includes a resistor R and a capacitor C; wherein one end of the resistor R is connected to a reference voltage source, and the other end is connected to one end of the capacitor C, serving as the output terminal of the RC unit; the other end of the capacitor C is grounded.

[0028] It is understood that in this invention, one end of the resistor R is connected to the voltage V output by the reference voltage source. ref Connection. As can be seen, the resistor and capacitor can receive the output of the reference voltage source and filter out glitches, interference, noise, etc., resulting in a smoother and more stable output signal. The values ​​of R and C can be determined according to the actual circuit conditions, but are usually related to the voltage V.ref The value is related to the circuit's behavior. Since the RC circuit filters out high-frequency signals, the RC circuit in this invention can be used to generate a stable output.

[0029] The stable output of the RC unit is then input into the isolation unit.

[0030] Preferably, the isolation unit includes isolation MOS transistors Mn0 and Mp0 and a current source I0; wherein, the gate of Mn0 is connected to the output terminal of the RC unit, the source is connected to the gate of Mp0 and one end of the second current source I0 respectively, and the drain is connected to the source of Mp0 as the output terminal of the isolation unit; the drain of Mp0 and the other end of the second current source I0 are grounded.

[0031] Understandably, in this invention, the gates of the two MOS transistors in the isolation unit are connected to the preceding circuit. For Mn0, as the magnitude of the stable voltage output by the RC power supply changes, the source voltage of Mn0 is determined due to the presence of the second current source I0, and it changes with the voltage output by the RC unit. The source of Mn0 and the gate of Mp0 are connected together, and the boost unit current is required to be greater than the second current source I0 to ensure that Mp0 has source-drain current. Thus, the source voltage of Mp0 is determined and changes with the voltage output by the RC unit.

[0032] Therefore, by reasonably setting the transistor parameters of Mn0 and Mp0, the second current source I0 and the boost unit current, the isolation voltage at the output of the isolation unit can be made equal to the voltage at the input. Furthermore, due to the isolation by the two transistors, the output voltage of the isolation unit will not be affected by the input voltage.

[0033] Preferably, the boost unit includes a boost resistor R1, a transistor Mn1, and a transistor Mn2; wherein the gate of transistor Mn2 is connected to the gate and drain of transistor Mn1 and one end of boost resistor R1, respectively, the source of which is connected to the output of the isolation unit, and the drain of which serves as the output of the boost unit and is connected to the drive control unit; the source of transistor Mn1 is connected to the output of the isolation unit; the other end of boost resistor R1 serves as the output of the modulator, and the boosted voltage V is obtained. out .

[0034] It is understood that the boost unit in this invention includes not only the resistor R1 and transistor Mn1 for boosting the voltage, but also transistor Mn2, which is a mirror image of transistor Mn1. In this invention, due to the mirror connection of the two MOS transistors, mirror currents are generated at the source and drain of each transistor. The mirror current generated on the branch of transistor Mn1 can be used in conjunction with the parameters of transistor Mn1 and the resistance value of resistor R1 to boost the isolation voltage. Furthermore, the boost voltage here is the output voltage of the modulator in this invention.

[0035] Preferably, the first mirror current and the second mirror current in the boost unit are in a fixed ratio; wherein, the first mirror current is the source-drain current of Mn2; and the second mirror current is the source-drain current of Mn1.

[0036] In this invention, the first and second mirror currents in the boost unit are the source and drain currents of transistors Mn2 and Mn1, respectively. By reasonably setting the ratio between the first and second mirror currents, the current flowing through transistor Mp0 can be further determined; in other words, the relationship between the output voltage and the input voltage of the isolation unit can be determined.

[0037] Preferably, the drive control unit includes a first current source I1, mirror transistors Mp3 and Mp2, and a drive transistor Mp1; wherein, the source of mirror transistor Mp3 is connected to the power supply voltage, the gate is connected to the gate and drain of mirror transistor Mp2 and the output terminal of the boost unit, the drain is connected to the gate of drive transistor Mp1 and one end of the first current source I1; the other end of the first current source I1 is grounded; the source of mirror transistor Mp2 is connected to the power supply voltage; the source of drive transistor Mp1 is connected to the power supply voltage, and the drain is connected to the other end of the boost resistor R1 in the boost unit, serving as the output terminal of the modulator.

[0038] In this invention, the connection method of the drive control unit forms a pair of current branches with a fixed ratio. Since Mp3 and Mp2 are connected in a mirror manner, and the branch containing Mp3 has a fixed current, namely the current generated by current source I1, Mp2 will form a mirror current according to a preset ratio based on the current in the branch containing Mp3. As mentioned above, based on the mirror effect of tube Mn2, tube Mn1 will further generate another mirror current with a preset ratio, thereby making the output voltage fixed.

[0039] Preferably, the third mirror current in the drive control unit is in a fixed ratio to the first mirror current; wherein, the third mirror current is the source-drain current of Mp3, which is equal to the current of the first current source I1 of the drive control unit; the first mirror current is the source-drain current of Mp2, which is equal to the source-drain current of Mn2 in the boost unit.

[0040] As mentioned above, the proportional relationship of the current in the drive control unit of this invention is as shown above.

[0041] Preferably, the ratio of the first and second mirror currents is determined by the size ratio of mirror transistors Mn2 and Mn1 in the boost unit; the ratio of the third and first mirror currents is determined by the size ratio of mirror transistors Mp3 and Mp2 in the drive control unit.

[0042] In this invention, the proportional relationship between the various mirror currents can be determined by the size of the tube, such as setting the width-to-length ratio of the tube.

[0043] In one embodiment of the present invention, the current in all three branches of the circuit can be the same under the action of two pairs of mirrored MOSFETs. Furthermore, due to the identical current, each component is in a stable conducting state under the set voltage, and the voltage value across each device is also sufficiently stable. Therefore, by reasonably setting the relevant parameters of each MOSFET, the voltage at the output of the isolation unit can also be made stable.

[0044] Given a fixed output voltage for the isolation unit, the effect of the mirror current allows for a stable final feedback output voltage value by properly setting the parameters of each MOSFET and voltage divider resistor.

[0045] Preferably, the sum of the first mirror current and the second mirror current in the boost unit is greater than the current of the current source I0 in the isolation unit, so as to ensure that there is a source-drain current on the MOS transistor Mp0 in the isolation unit.

[0046] In this invention, to ensure the circuit can conduct normally, it is necessary to ensure that current flows through the transistor Mp0. That is, the sum of the first and second mirror currents must be greater than the current of the second current source I0, so that the portion of the current exceeding the second current source I0 can flow out through Mp0. Therefore, in this invention, loop control between Mn0 and Mp0 can be used to make the isolation voltage output by the isolation unit approximately equal to the voltage at its input terminal.

[0047] It is understood that in this invention, due to the function of the boost unit, the isolation voltage is further increased, and the driving function of the output voltage in this invention is realized.

[0048] Preferably, the boost voltage is V. out =V′ ref +V gs_Mn1 +V R1 ;in,

[0049] V′ ref The isolation voltage is provided by the voltage V from the reference voltage source. ref Together with the isolation unit, it is determined that

[0050] V gs_Mn1 This represents the gate-source voltage of transistor Mn1 in the boost unit.

[0051] V R1 This is the voltage across resistor R1 in the boost unit.

[0052] It is understandable that, since the output of the isolation circuit is connected to the source of the MOSFET Mn1, and one end of the resistor R1 is connected to the gate of the MOSFET Mn1, the output voltage connected to the other end of the resistor R1 should be the sum of the isolation voltage, the gate-source voltage difference of Mn1, and the voltage across R1, which is what is described in the formula.

[0053] It should be noted that in this invention, the voltage division of R1 is related to the resistance value of R1 and the current flowing through R1. However, once the circuit is determined, since the resistance value of R1 remains constant, the current flowing through R1 is a mirror current, equivalent to the current flowing through the first branch, namely the branch current of MOSFET Mp3 and current source I1. Therefore, the current in this branch will not change under the condition that the power supply voltage Vcc remains constant; that is, the voltage across R1 is fixed.

[0054] In addition, when the mirror current is stable, the gate-source on-state voltage of the Mn1 transistor is also constant.

[0055] The beneficial effects of this invention are that, compared with the prior art, the modulator in this invention, whose output voltage follows the reference voltage, can achieve noise reduction, isolation, and voltage boosting of the reference voltage source voltage through an RC unit, an isolation unit, a boost unit, and a drive control unit. This results in a higher output voltage value, which can be used as feedback to fully drive the circuit. The circuit structure of this invention is simple, easy to implement, and generates a reasonable and accurate boost voltage, making it widely applicable.

[0056] The applicant of this invention has provided a detailed description of the embodiments of the invention in conjunction with the accompanying drawings. However, those skilled in the art should understand that the above embodiments are merely preferred embodiments of the invention. The detailed description is only intended to help readers better understand the spirit of the invention and is not intended to limit the scope of protection of the invention. On the contrary, any improvements or modifications made based on the inventive spirit of the invention should fall within the scope of protection of the invention.

Claims

1. A modulator whose output voltage follows a reference voltage, characterized in that: The modulator includes an RC unit, an isolation unit, a boost unit, and a drive control unit; wherein, The RC unit, connected to the isolation unit, is used to receive voltage from the reference voltage source. and filter out the voltage noise; The isolation unit is connected to the RC unit and the boost unit respectively, and is used to receive the voltage after noise filtering. To generate an isolation voltage, and input the isolation voltage to the boost unit; The isolation unit includes isolation MOSFETs Mn0 and Mp0, and a second current source I0; wherein... The gate of Mn0 is connected to the output terminal of the RC unit, the source is connected to the gate of Mp0 and one end of the second current source I0, and the drain is connected to the source of Mp0 as the output terminal of the isolation unit. The drain of Mp0 and the other end of the second current source I0 are grounded; The boost unit is connected to the isolation unit and is used to boost the isolation voltage by a fixed voltage difference. The drive control unit is connected to the boost unit and is used to stabilize the boost voltage with a fixed pressure difference to provide drive for the subsequent circuit.

2. The modulator whose output voltage follows a reference voltage as described in claim 1, characterized in that: The RC unit includes a resistor R and a capacitor C; wherein... One end of the resistor R is connected to the reference voltage source, and the other end is connected to one end of the capacitor C, serving as the output terminal of the RC unit; The other end of the capacitor C is grounded.

3. A modulator whose output voltage follows a reference voltage as described in claim 2, characterized in that: The boost unit includes a boost resistor R1, a transistor Mn1, and a transistor Mn2; wherein... The gate of the mirror transistor Mn2 is connected to the gate and drain of the mirror transistor Mn1 and one end of the boost resistor R1, respectively. The source is connected to the output terminal of the isolation unit, and the drain is connected to the drive control unit as the output terminal of the boost unit. The source of the mirror transistor Mn1 is connected to the output terminal of the isolation unit; The other end of the boost resistor R1 serves as the output terminal of the modulator, where the voltage is boosted to obtain the output voltage. .

4. A modulator whose output voltage follows a reference voltage as described in claim 3, characterized in that: The first mirror current and the second mirror current in the boost unit are in a fixed ratio; wherein... The first mirror current is the source-drain current of Mn2; The second mirror current is the source-drain current of Mn1.

5. A modulator whose output voltage follows a reference voltage as described in claim 4, characterized in that: The drive control unit includes a first current source I1, mirror transistors Mp3 and Mp2, and a drive transistor Mp1; wherein... The source of the mirror transistor Mp3 is connected to the power supply voltage, the gate is connected to the gate and drain of the mirror transistor Mp2 and the output terminal of the boost unit, and the drain is connected to the gate of the driving transistor Mp1 and one end of the first current source I1. The other end of the first current source I1 is grounded; The source of the mirror transistor Mp2 is connected to the power supply voltage; The source of the driving transistor Mp1 is connected to the power supply voltage, and the drain is connected to the other end of the boost resistor R1 in the boost unit, serving as the output terminal of the modulator.

6. A modulator whose output voltage follows a reference voltage as described in claim 5, characterized in that: In the drive control unit, the third mirror current is in a fixed ratio to the first mirror current; wherein... The third mirror current is the source-drain current of Mp3, which is equal to the current of the first current source I1 of the drive control unit; The first mirror current is the source-drain current of Mp2, which is equal to the source-drain current of Mn2 in the boost unit.

7. A modulator whose output voltage follows a reference voltage as described in claim 6, characterized in that: The ratio of the first and second mirror currents is determined by the size ratio of the mirror transistors Mn2 and Mn1 in the boost unit; The ratio of the third and first mirror currents is determined by the size ratio of mirror transistors Mp3 and Mp2 in the drive control unit.

8. A modulator whose output voltage follows a reference voltage as described in claim 7, characterized in that: The sum of the first mirror current and the second mirror current in the boost unit is greater than the current of the second current source I0 in the isolation unit, so as to ensure that there is a source-drain current on the MOS transistor Mp0 in the isolation unit.

9. A modulator whose output voltage follows a reference voltage as described in claim 8, characterized in that: The boost voltage is taken as follows: ;in, The boost voltage is the output voltage of the modulator; The isolation voltage is provided by the voltage from the reference voltage source. Together with the isolation unit, it is determined that This refers to the gate-source voltage of the Mn1 transistor in the boost unit. The voltage across resistor R1 in the boost unit is denoted as .

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