CN110531817A - Low Noise Negative Regulator - Google Patents

Abstract

The invention discloses a low-noise negative regulator, which includes a fully integrated charge pump, a bias generator, an error amplifier, a transmission transistor, a voltage dividing resistor R1 and a voltage dividing resistor R2. The fully integrated charge pump provides negative voltage for the bias generator, error amplifier and pass transistor, the bias generator is connected to the error amplifier to provide bias current for its normal operation; the error amplifier is connected to the gate of the pass transistor , to provide a negative voltage for it. The transmission transistor is connected in series with the voltage dividing resistor R1 and the voltage dividing resistor R2 and grounded, and one end of the voltage dividing resistor R2 is connected to the input port of the error amplifier to form a negative feedback loop to realize dynamic adjustment of the output voltage of the transmission transistor. The present invention uses a fully integrated charge pump to provide power, which not only improves the integration of the entire voltage regulator, but also has low noise and low output impedance of the output voltage of the low-noise negative voltage regulator, and the low-noise negative voltage regulator is suitable for wide range.

Description

Low Noise Negative Regulator

technical field

The invention relates to the field of negative voltage, in particular to a low-noise negative voltage regulator.

Background technique

In recent years, the application of negative voltage has become more and more widespread, such as biphasic tissue stimulation, reduction of electrostatic leakage, high-performance voltage-controlled oscillators, etc. Therefore, in addition to promoting the integration of GaN HEMT, InGaP and other alternative technologies with CMOS processes in the foreseeable future, highly integrated regulated negative voltage generators may open up more new avenues for various new circuits and applications.

The generation of negative voltage involves three main blocks: oscillator and clock distributor, charge pump and regulation circuit. A charge pump utilizes a multiphase non-overlapping clock generated by an oscillator and a clock divider to induce a unidirectional transfer of negative charge through its internal stages, producing an unregulated negative voltage at its output. Since the charge pump output has the characteristics of large peak ripple, high noise content and high output impedance, the application range is narrow, so the voltage output by the charge pump needs to be regulated before applying it. However, due to the poor adjustment accuracy of the existing adjustment technology, the output voltage of the charge pump after adjustment by the existing adjustment circuit has high noise content and high output impedance. Therefore, a regulated charge pump output voltage cannot be used in all applications, especially those that require high precision voltage biasing.

Contents of the invention

The embodiment of the invention discloses a low-noise negative voltage regulator, which has wide applicability due to the low noise of the output voltage and low output impedance.

In a first aspect, an embodiment of the present invention provides a low-noise negative voltage regulator, including:

Fully integrated charge pump, bias generator, error amplifier, pass transistor, first divider resistor R1 and second divider resistor R2;

The positive pole of the fully integrated charge pump is grounded, the positive pole of the power supply of the bias generator is grounded or connected to a positive DC voltage, and the negative pole of the power supply is connected to the output port of the fully integrated charge pump; the output port of the bias generator connected to the second input port of the error amplifier;

The positive pole of the power supply of the error amplifier is grounded or connected to the positive DC voltage, and the negative pole of the power supply is connected to the output port of the fully integrated charge pump; the third input port of the error amplifier inputs a reference voltage; the output of the error amplifier a port connected to the gate of the transfer transistor;

The source of the transfer transistor is connected to the output port of the fully integrated charge pump; the drain of the transfer transistor is used as the output port of the low-noise negative voltage regulator, and is connected to the output port of the second sampling resistor R2 The second port is connected;

The first port of the second voltage dividing resistor R2 is connected to the second port of the first voltage dividing resistor R1, and the first port of the first voltage dividing resistor R1 is grounded or connected to the positive DC voltage;

Wherein, the fully integrated charge pump is used to provide a negative voltage for the bias generator, the error amplifier and the pass transistor;

The bias generator is used to provide a bias current for the error amplifier to make the error amplifier work normally; when the output voltage of the fully integrated charge pump changes continuously and obviously, the bias generator outputs The bias current remains constant for the error amplifier to work properly;

The error amplifier is used to dynamically adjust the output voltage of the error amplifier according to the feedback voltage input from its first input port and the reference voltage input from its third input port;

The transfer transistor is used to adjust its drain output voltage according to the voltage input to its gate; the output voltage of the error amplifier is the input voltage of the transfer transistor gate;

The first voltage dividing resistor R1 and the second voltage dividing resistor R2 form a voltage dividing network, and the first port of the second voltage dividing resistor R2 is connected to the first input port of the error amplifier to form a negative feedback loop.

In a feasible embodiment, the error amplifier dynamically adjusts the output voltage of the error amplifier according to the feedback voltage input from its first input port and the reference voltage input from its third input port, including:

When the feedback voltage is greater than the reference voltage, the output voltage of the error amplifier increases.

In a feasible embodiment, the transfer transistor adjusts its drain output voltage according to the voltage input to its gate, including:

When the input voltage at the gate of the pass transistor increases, the output voltage at the drain of the pass transistor decreases.

In a feasible embodiment, the low-noise negative regulator further includes a resistor R _LOAD and a capacitor C _EXT ;

Both the first port of the resistor R _LOAD and the first port of the capacitor C _EXT are grounded or connected to the positive DC voltage, and the second port of the resistor R _LOAD and the second port of the capacitor C _EXT are both connected to the the drain of the pass transistor is connected;

Wherein, the capacitance of the capacitor C _EXT is greater than 220nF.

It can be seen that, in the solution of the embodiment of the present invention, the low-noise negative voltage regulator includes a fully integrated charge pump, a bias generator, an error amplifier, a transfer transistor, a first voltage dividing resistor R1 and a second voltage dividing resistor R2. The positive terminal of the fully integrated charge pump is grounded, and the negative terminal of the fully integrated charge pump is connected in series with a resistor to provide a negative voltage for the bias generator, error amplifier and pass transistor mentioned above. The above-mentioned bias generator provides a bias current for the above-mentioned error amplifier, so that the error amplifier can work normally. The output port of the error amplifier is connected to the gate of the transfer transistor, that is, the output voltage of the error amplifier is the input voltage of the transfer transistor. The drain of the transfer transistor is grounded by connecting the first voltage dividing resistor R1 and the second voltage dividing resistor R2 in series, and the connection point of the first voltage dividing resistor and the second voltage dividing resistor is connected to the first input port of the error amplifier , forming a negative feedback loop. The voltage input to the first input port of the error amplifier is the feedback voltage, and the third input port is connected to the reference voltage. When the feedback voltage is greater than the reference voltage, the output voltage of the error amplifier increases, that is, the input voltage of the gate of the transfer transistor increases, and the output voltage of the drain of the transfer transistor decreases. When the output voltage at the drain of the pass transistor decreases, the feedback voltage of the above-mentioned error amplifier also decreases. Such repeated adjustments make the feedback voltage and the reference voltage tend to be equal, and the negative feedback loop has a very high DC gain at this time. The present invention uses a fully integrated fully integrated charge pump to provide power, which not only improves the integration of the entire voltage regulator, but also has low noise and low output impedance of the output voltage of the low-noise negative voltage regulator, and the low-noise negative voltage regulator The press has wide applicability.

Description of drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. Those skilled in the art can also obtain other drawings based on these drawings without creative work.

FIG. 1 is a schematic structural diagram of a low-noise negative voltage regulator provided by an embodiment of the present invention;

FIG. 2 is a schematic structural diagram of another low-noise negative voltage regulator provided by an embodiment of the present invention;

FIG. 3 is a schematic structural diagram of another low-noise negative voltage regulator provided by an embodiment of the present invention;

FIG. 4 is a schematic structural diagram of another low-noise negative regulator provided by an embodiment of the present invention.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention.

Referring to FIG. 1 , an embodiment of the present invention provides a schematic structural diagram of a low-noise negative voltage regulator. As shown in FIG. 1 , the low-noise negative voltage regulator includes a fully integrated charge pump, a bias generator, an error amplifier, a pass transistor, a first voltage-dividing resistor R1 and a second voltage-dividing resistor R2.

The positive pole of the fully integrated charge pump is grounded, the negative pole of the power supply of the bias generator is connected to the output port of the fully integrated charge pump, the voltage of the output port of the fully integrated charge pump is, and the voltage V _UNREG is a negative voltage.

The positive electrode of the bias generator is grounded, and the output port of the bias generator is connected to the second input port of the error amplifier. The positive pole of the power supply of the error amplifier is grounded, the negative pole of the power supply is connected to the output port of the above-mentioned fully integrated charge pump, and the third input port of the error amplifier inputs a reference voltage; pole) connected.

The source of the above-mentioned transfer transistor is connected to the output port of the above-mentioned fully integrated charge pump; the output port (that is, the drain) of the transfer transistor is connected to the second port of the second voltage-dividing resistor R2, and the second voltage-dividing resistor The first port of R2 is connected to the second port of the first voltage dividing resistor R1, and the first port of the first voltage dividing resistor R1 is grounded. The second port of the first voltage-dividing resistor R1 or the first port of the second voltage-dividing resistor R2 is connected to the first input port of the above-mentioned error amplifier to form a negative feedback loop, and the input of the first input port of the above-mentioned error amplifier voltage is the feedback voltage.

Wherein, the above-mentioned fully integrated charge pump is used to provide negative voltage for the above-mentioned bias generator, error amplifier and transfer transistor.

Further, the operating frequency range of the above-mentioned fully integrated charge pump is 20MHz to 100MHz, compared with the voltage regulator using the traditional external capacitor charge pump with an operating frequency of 100kHz to 900kHz, the noise suppression of the low-noise negative voltage regulator The effect has been improved by 70dB to 90dB, which ensures that the low-noise negative regulator has superior noise performance.

The above-mentioned bias generator is used to provide a bias current for the above-mentioned error amplifier so that it can work normally; when the output voltage of the fully integrated charge pump changes, the bias current output by the bias generator remains unchanged, In order to make the error amplifier work normally;

The above-mentioned error amplifier is used for dynamically adjusting the output voltage of the above-mentioned error amplifier according to the feedback voltage input from its first input port and the reference voltage input from its third port.

In a feasible embodiment, the above-mentioned error amplifier dynamically adjusts the output voltage of the above-mentioned error amplifier according to the feedback voltage input by its first input port and the reference voltage input by its third port, including:

When the feedback voltage is greater than the reference voltage, the error amplifier increases its output voltage.

The above-mentioned transfer transistor is used for adjusting the voltage V _REG of the drain of the transfer transistor according to the input voltage of the gate.

Wherein, the above-mentioned transfer transistor is a relatively large deep N-well device, and its size enables it to work in a saturation region under the maximum load condition. The above-mentioned pass transistor provides the load current in the above-mentioned negative feedback loop, which is exactly the same as the pass transistor used in a typical voltage regulator. The voltage of the input terminal (ie, the gate) of the above-mentioned transfer transistor is controlled by the output voltage of the above-mentioned error amplifier.

In a feasible embodiment, the above-mentioned transfer transistor adjusts the voltage V _REG of the drain of the transfer transistor according to the input voltage of its gate, including:

When the input voltage to the gate of the pass transistor increases, the voltage V _REG at the drain of the pass transistor decreases.

Specifically, when the feedback voltage of the above-mentioned error amplifier is greater than its reference voltage, the voltage at the output port of the error amplifier (that is, the output voltage) increases, and the voltage at the gate of the above-mentioned transfer transistor increases; if the gate voltage of the transfer transistor increases , then the drain voltage of the pass transistor decreases, that is, the voltage V _REG at the output port of the pass transistor decreases.

Since the output port of the pass transistor is connected in series with the first divider resistor R1 and the second divider resistor R2 and then grounded, if the voltage V _REG at the drain of the pass transistor decreases, the voltage at the second port of the first divider resistor R1 decreases. Small, that is, the feedback voltage of the error amplifier is reduced, so that the voltage difference between the feedback voltage of the error amplifier and the reference voltage is reduced. This is repeated until the feedback voltage of the error amplifier is equal to its reference voltage. At this point, the low-noise negative regulator described above has very high DC gain.

In a feasible embodiment, the low-noise negative regulator further includes a resistor R _LOAD and a capacitor C _EXT , the second port of the resistor R _LOAD and the second port of the capacitor C _EXT are both connected to the drain of the transfer transistor connected; the first port of the resistor R _LOAD and the first port of the capacitor C _EXT are grounded.

Wherein, the capacitance of the capacitor C _EXT is larger than 220nF.

By placing a large external capacitor (i.e., the capacitor C _EXT ) at the output node of the above-mentioned low-noise negative regulator to ensure the stability of the above-mentioned negative feedback loop together with the instantaneous output impedance, thereby further ensuring the loop transfer function The position of the dominant pole in . For the supported load current range, all parasitic poles (including those at the pass transistor gate) are outside the unity-gain bandwidth, so the negative feedback loop described above is unconditionally stable. The input noise and ripple of the fully integrated charge pump is effectively filtered due to the high feedback loop gain and the frequency below -3dB that can be set by the above-mentioned external capacitor _CEXT , resulting in a low output impedance and low noise regulated output.

It can be seen that, in the solution of the embodiment of the present invention, the low-noise negative voltage regulator includes a fully integrated charge pump, a bias generator, an error amplifier, a transfer transistor, a first voltage dividing resistor R1 and a second voltage dividing resistor R2. The positive terminal of the fully integrated charge pump is grounded, and the negative terminal of the fully integrated charge pump is connected in series with a resistor to provide a negative voltage for the bias generator, error amplifier and pass transistor mentioned above. The above-mentioned bias generator provides a bias current for the above-mentioned error amplifier, so that the error amplifier can work normally. The output port of the error amplifier is connected to the gate of the transfer transistor, that is, the output voltage of the error amplifier is the input voltage of the gate of the transfer transistor. The drain of the transfer transistor is grounded by connecting the first voltage dividing resistor R1 and the second voltage dividing resistor R2 in series, and the connection point of the first voltage dividing resistor and the second voltage dividing resistor is connected to the first input port of the error amplifier , forming a negative feedback loop. The voltage input to the first input port of the error amplifier is the feedback voltage, and the third input port is connected to the reference voltage. When the feedback voltage is greater than the reference voltage, the output voltage of the error amplifier increases, that is, the input voltage of the gate of the transfer transistor increases, and the output voltage of the drain of the transfer transistor decreases. When the output voltage at the drain of the pass transistor decreases, the feedback voltage of the above-mentioned error amplifier also decreases. Such repeated adjustments make the feedback voltage and the reference voltage tend to be equal, and the negative feedback loop has a very high DC gain at this time. The present invention uses a fully integrated fully integrated charge pump to provide power, which not only improves the integration of the entire voltage regulator, but also has low noise of the output voltage of the low noise negative voltage regulator, because it is different from the traditional external capacitor Charge pump, the fully integrated charge pump in the present invention uses a higher operating frequency, so that the output noise of this low-noise negative voltage regulator has been improved by 70dB to 90dB, which greatly optimizes the low-noise negative voltage regulator. Noise, and the output impedance is small, the low noise negative regulator has wide applicability.

Referring to FIG. 2 , FIG. 2 is a schematic structural diagram of another low-noise negative regulator provided by the present invention. As shown in FIG. 2 , the low-noise negative voltage regulator includes: a fully integrated charge pump, a bias generator, an error amplifier, a transfer transistor, a first voltage dividing resistor R1 and a second voltage dividing resistor R2.

Wherein, the positive pole of the above-mentioned fully integrated charge pump is grounded, the negative pole of the power supply of the above-mentioned bias generator is connected to the output port of the above-mentioned fully integrated charge pump, the voltage of the output port of the fully integrated charge pump is V _UNREG , and the voltage V _UNREG is negative Voltage.

The positive pole of the power supply of the bias generator is connected to the positive DC power supply VCC, and the negative pole of the power supply is connected to the output port of the fully integrated charge pump, that is, the negative pole of the power supply of the bias generator is connected to the voltage V _UNREG . The output port of the bias generator is connected with the second input port of the error amplifier to provide bias current for the error amplifier to make it work normally.

When the negative voltage of the bias generator (that is, the voltage at the output port of the fully integrated charge pump) changes, the bias generator keeps the voltage at its output port constant, so that the error amplifier can work normally.

The positive pole of the power supply of the error amplifier is connected to the positive DC power supply VCC, and the negative pole of the power supply is connected to the output port of the fully integrated charge pump, that is, the negative pole of the power supply of the error amplifier is connected to the voltage V _UNREG . The third input port of the error amplifier is connected to the reference voltage. The output port of the error amplifier is connected to the input port of the pass transistor (ie, the gate of the pass transistor) for controlling the voltage V _REG of the output port of the pass transistor (ie, the drain of the pass transistor).

The source of the transfer transistor is connected to the output port of the fully integrated charge pump, that is, the source of the transfer transistor is connected to the voltage V _UNREG . The output port of the above-mentioned transfer transistor (that is, the drain of the transfer transistor) is connected to the second port of the second voltage-dividing resistor R2, and the first port of the second voltage-dividing resistor R2 is connected to the first port of the first voltage-dividing point resistor R1. The second port is connected, and the first port of the first voltage dividing resistor R1 is connected to the above-mentioned positive DC power supply VCC.

The first port of the second voltage divider R2 or the second port of the first voltage divider resistor R1 is connected to the first input of the error amplifier to form a negative feedback loop.

It should be pointed out that when both the positive poles of the bias amplifier and the positive poles of the error amplifier are connected to the positive DC voltage, the output voltage of the low-noise negative regulator (that is, the drain voltage V _REG of the pass transistor) ranges from is +V _REF to -|V _UNREG -V _DROPOUT |, where V _DROPOUT is the drop voltage across the above pass transistor.

Further, the above-mentioned low-noise negative regulator further includes a resistor R _LOAD and a capacitor C _EXT . The second port of the resistor R _LOAD and the second port of the capacitor C _EXT are connected to the output port of the transmission transistor; the first port of the resistor R _LOAD and the first port of the capacitor C _EXT are connected to the positive DC power supply VCC.

Wherein, the capacitance of the capacitor C _EXT is larger than 220nF.

In a feasible embodiment, the above-mentioned fully integrated charge pump is a fully integrated fully integrated charge pump.

It should be noted that, for the specific description of the embodiment shown in FIG. 2 , reference may be made to the relevant description of the embodiment shown in FIG. 1 , and no further description is given here.

In the solution of the embodiment of the present invention, the positive ground of the bias generator, the error amplifier and the transmission transistor in the low-noise negative voltage regulator is changed to be connected to the positive DC power supply, which makes the low-noise negative voltage regulator can be used Standard positive DC input, and the output voltage of the low-noise negative voltage regulator can be extended from negative DC voltage to positive DC voltage, which increases the application range of the low-noise negative voltage regulator.

Referring to FIG. 3 , FIG. 3 is a schematic structural diagram of another low-noise negative voltage regulator provided by the present invention. As shown in FIG. 3 , the low-noise negative voltage regulator includes: a fully integrated charge pump, a bias generator, an error amplifier, a transfer transistor, a first voltage dividing resistor R1 and a second voltage dividing resistor R2.

The structure diagram shown in Figure 3 also shows the equivalent voltage source V _{CP_0} and equivalent resistance R _CP deduced from the characteristic curve of the above-mentioned fully integrated charge pump, and the equivalent resistance R _O1 and R _O2 of the error amplifier and the transmission The equivalent resistance R _{O_PT} and the equivalent capacitance R _{gs_PT} of the transistor.

As shown in Figure 3, the anode of the equivalent voltage source V _{CP_0 of the above-mentioned fully integrated charge pump is grounded, and the cathode of the equivalent voltage source V CP_0 is} connected to the first port of the above-mentioned equivalent resistance R _CP , the equivalent resistance R _CP The second port of the fully integrated charge pump is the output port (ie, negative pole), the voltage of the output port of the fully integrated charge pump is V _UNREG , and the voltage V _UNREG is a negative voltage. The negative pole of the power supply of the above-mentioned bias generator is connected with the output port of the above-mentioned fully integrated charge pump.

It should be pointed out that the anode of the above-mentioned equivalent voltage source V _{CP_0} is the anode of the above-mentioned fully integrated charge pump.

The positive pole of the power supply of the above-mentioned bias generator is grounded, and the negative pole of the power supply is connected to the output port of the above-mentioned fully integrated charge pump, that is, the negative pole of the power supply of the above-mentioned bias generator is connected to the above-mentioned voltage V _UNREG . The output port of the bias generator is connected with the second input port of the error amplifier to provide bias current for the error amplifier to make it work normally.

As shown in Figure 3, the first port of the equivalent resistance R _O1 and the first port of the equivalent resistance R _O2 of the error amplifier are connected to the output port of the error amplifier, the second port of the equivalent resistance R _O1 is grounded, The second port of the equivalent resistor R _O2 is connected to the output port of the fully integrated charge pump.

The positive pole of the power supply of the error amplifier is grounded, and the negative pole of the power supply is connected to the output port of the fully integrated charge pump, that is, the negative pole of the power supply of the error amplifier is connected to the voltage V _UNREG . The third input port of the error amplifier is connected to the reference voltage. The output port of the error amplifier is connected to the input port of the transfer transistor (ie, the gate of the transfer transistor) for controlling the voltage of the output port of the transfer transistor (ie, the drain of the transfer transistor).

As shown in Figure 3, the second port of the equivalent capacitance C _{gs_PT} of the above-mentioned transmission pass transistor and the second port of the equivalent resistance R _{O_PT} are all connected to the source of the above-mentioned transmission transistor, and the first port of the above-mentioned equivalent capacitance C _{gs_PT} The port is connected to the gate of the pass transistor, and the first port of the equivalent capacitor R _{O_PT} is connected to the drain of the pass transistor.

The source of the transfer transistor is connected to the output port of the fully integrated charge pump, that is, the source of the transfer transistor is connected to the voltage V _UNREG . The drain of the above-mentioned transfer transistor is connected to the second port of the second voltage-dividing resistor R2, and the first port of the second voltage-dividing resistor R2 is connected to the second port of the first voltage-dividing point resistor R1. A first port of the voltage dividing resistor R1 is grounded.

The first port of the second voltage divider R2 or the second port of the first voltage divider resistor R1 is connected to the first input of the error amplifier to form a negative feedback loop.

Further, the above-mentioned low-noise negative regulator further includes a resistor R _LOAD and a capacitor C _EXT . The second port of the resistor R _LOAD and the second port of the capacitor C _EXT are connected to the drain of the transfer transistor; the first port of the resistor R _LOAD and the first port of the capacitor C _EXT are grounded.

The capacitance of the capacitor C _EXT is greater than 220nF.

It should be noted here that, for the specific description of the embodiment shown in FIG. 3 , reference may be made to the relevant description of the embodiment shown in FIG. 1 , and no further description is given here.

Referring to FIG. 4 , FIG. 4 is a schematic structural diagram of another low-noise negative voltage regulator provided by the present invention. As shown in FIG. 4 , the low-noise negative voltage regulator includes: a fully integrated charge pump, a bias generator, an error amplifier, a transfer transistor, a first voltage dividing resistor R1 and a second voltage dividing resistor R2.

The structure diagram shown in Figure 4 also shows the equivalent voltage source V _{CP_0} and equivalent resistance R _CP deduced from the characteristic curve of the above-mentioned fully integrated charge pump, the equivalent resistance R _O1 of the error amplifier, R _O2 and the transmission The equivalent resistance R _{O_PT} and the equivalent capacitance R _{gs_PT} of the transistor.

As shown in Figure 4, the anode of the equivalent voltage source V _{CP_0 of the above-mentioned fully integrated charge pump is grounded, and the cathode of the equivalent voltage source V CP_0 is} connected to the first port of the above-mentioned equivalent resistance R _CP , and the equivalent resistance R _CP The second port of the fully integrated charge pump is the output port (ie, negative pole), the voltage of the output port of the fully integrated charge pump is V _UNREG , and the voltage V _UNREG is a negative voltage. The negative pole of the power supply of the above-mentioned bias generator is connected with the output port of the above-mentioned fully integrated charge pump.

The positive pole of the power supply of the bias generator is connected to the positive DC voltage VCC, and the negative pole of the power supply is connected to the output port of the fully integrated charge pump, that is, the negative pole of the power supply of the bias generator is connected to the voltage V _UNREG . The output port of the bias generator is connected with the second input port of the error amplifier to provide bias current for the error amplifier to make it work normally.

As shown in Figure 4, the first port of the equivalent resistance R _O1 and the first port of the equivalent resistance R _O2 of the error amplifier are connected to the output port of the error amplifier, the second port of the equivalent resistance R _O1 is grounded, The second port of the equivalent resistor R _O2 is connected to the output port of the fully integrated charge pump.

The positive pole of the power supply of the error amplifier is connected to the positive DC voltage VCC, and the negative pole of the power supply is connected to the output port of the fully integrated charge pump, that is, the negative pole of the power supply of the error amplifier is connected to the voltage V _UNREG . The third input port of the error amplifier is connected to the reference voltage. The output port of the error amplifier is connected to the input port of the transfer transistor (ie, the gate of the transfer transistor) for controlling the voltage of the output port of the transfer transistor (ie, the drain of the transfer transistor).

As shown in Fig. 4, the second port of the equivalent capacitance C _{gs_PT} of the above-mentioned transmission pass transistor and the second port of the equivalent resistance R _{O_PT} are connected to the source of the above-mentioned transmission transistor, and the first port of the above-mentioned equivalent capacitance C _{gs_PT} The port is connected to the gate of the pass transistor, and the first port of the equivalent capacitor R _{O_PT} is connected to the drain of the pass transistor.

The source of the transfer transistor is connected to the output port of the fully integrated charge pump, that is, the source of the transfer transistor is connected to the voltage V _UNREG . The drain of the above-mentioned transfer transistor is connected to the second port of the second voltage-dividing resistor R2, and the first port of the second voltage-dividing resistor R2 is connected to the second port of the first voltage-dividing point resistor R1. A first port of a voltage dividing resistor R1 is connected to the aforementioned positive DC power supply VCC.

The first port of the second voltage divider R2 or the second port of the first voltage divider resistor R1 is connected to the first input of the error amplifier to form a negative feedback loop.

It should be pointed out that when both the positive poles of the bias amplifier and the positive poles of the error amplifier are connected to the positive DC voltage VCC, the output voltage of the low-noise negative regulator (that is, the drain voltage V _REG of the pass transistor) The range is +V _REF to -|V _UNREG -V _DROPOUT |, where V _DROPOUT is the drop voltage across the aforementioned pass transistor.

Further, the above-mentioned low-noise negative regulator further includes a resistor R _LOAD and a capacitor C _EXT . The second port of the resistor R _LOAD and the second port of the capacitor C _EXT are connected to the drain of the transmission transistor; the first port of the resistor R _LOAD and the first port of the capacitor C _EXT are connected to the positive DC power supply VCC.

The capacitance of the capacitor C _EXT is greater than 220nF.

It should be noted here that, for the specific description of the embodiment shown in FIG. 4 , reference may be made to the related description of the embodiment shown in FIG. 1 , which will not be repeated here.

The embodiments of the present invention have been described in detail above, and specific examples have been used in this paper to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only used to help understand the method and core idea of the present invention; at the same time, for Those skilled in the art will have changes in the specific implementation and scope of application based on the idea of the present invention. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims (4)

1. a kind of negative voltage-stablizer of low noise characterized by comprising fully integrated charge pump, bias generator, error amplifier, Transmission transistor, the first divider resistance R1 and the second divider resistance R2；

The plus earth of the fully integrated charge pump；The positive pole of the bias generator is grounded or connects positive direct-current voltages, Power cathode is connected with the output port of the fully integrated charge pump；The output port of the bias generator and the error Second input port of amplifier is connected；

The positive pole of the error amplifier is grounded or connects the positive direct-current voltages, power cathode and the fully integrated charge The output port of pump is connected；The third input port input reference voltage of the error amplifier；The error amplifier Output port is connected with the grid of the transmission transistor；

The source electrode of the transmission transistor is connected with the output port of the fully integrated charge pump；The leakage of the transmission transistor Output port of the pole as the negative voltage-stablizer of the low noise, and be connected with the second port of the second sampling resistor R2；

The first port of the second divider resistance R2 is connected with the second port of the first divider resistance R1, and described first The first port of divider resistance R1 is grounded or connects the positive direct-current voltages；

Wherein, the fully integrated charge pump, for being provided for the bias generator, the error amplifier and transmission transistor Negative voltage；

The bias generator is used for, and provides bias current for the error amplifier, works normally the error amplifier； When the output voltage of the fully integrated charge pump changes, the bias current of the bias generator output is remained unchanged, So that the error amplifier works normally；

The error amplifier, what feedback voltage and its third input port for being inputted according to its first input port inputted Reference voltage dynamic adjusts the output voltage of the error amplifier；

The transmission transistor, the voltage swing for being inputted according to its grid adjust its output voltage that drains；The error is put The output voltage of big device is the input voltage of the transfer transistor gate；

The first divider resistance R1 and the second divider resistance R2 constitutes potential-divider network, the first end of the second divider resistance R2 Mouth is connect with the first input port of the error amplifier, constitutes negative feedback loop.

2. the negative voltage-stablizer of low noise according to claim 1, which is characterized in that the error amplifier is first defeated according to it The feedback voltage of inbound port input and the reference voltage dynamic of its third input port input adjust the defeated of the error amplifier Voltage out, comprising:

When the feedback voltage is greater than the reference voltage, the output voltage of the error amplifier increases.

3. the negative voltage-stablizer of low noise according to claim 1 or 2, which is characterized in that the transmission transistor is according to its grid The voltage swing of pole input adjusts its output voltage that drains, comprising:

When the input voltage of the transfer transistor gate increases, the output voltage of the transmission transistor drain electrode reduces.

4. the negative voltage-stablizer of low noise according to claim 1-3, which is characterized in that the negative voltage-stablizer of low noise It further include resistance R_LOADWith capacitor C_EXT；

The resistance R_LOADFirst port and the capacitor C_EXTFirst port be grounded or connect the positive direct-current voltages, institute State resistance R_LOADSecond port and capacitor C_EXTSecond port be connected with the output port of the transmission transistor；

Wherein, the capacitor C_EXTCapacitance be greater than 220nF.