Novel CMOS (complementary metal oxide semiconductor) body-driven transconductance amplifier circuit with ultralow voltage, ultralow power consumption and high common-mode stability

Abstract

The invention discloses a novel CMOS (Complementary Metal Oxide Semiconductor) body-driven transconductance amplifier circuit with ultralow voltage, ultralow power consumption and high common-mode stability, which is characterized in that a transconductance stabilizing and enhancing technology is introduced on the basis of an existing rail-to-rail body-driven transconductance amplifier, so that stable high transconductance in a rail-to-rail input range is realized; compared with a rail-to-rail body driving transconductance amplifier in the prior art, the rail-to-rail body driving transconductance amplifier has the minimum transconductance change within the rail-to-rail range and has the high transconductance energy consumption ratio. The transconductance amplifier provided by the invention can be used in a low-voltage and low-power-consumption system such as a biomedical system, and has a wide application range.

Description

Technical Field

[0001] The present invention belongs to the field of low-voltage and low-power analog integrated circuits, and in particular relates to a novel CMOS body-driven transconductance amplifier circuit with ultra-low voltage, ultra-low power consumption and high common-mode stability. Background Art

[0002] At present, the research on wearable technology and biomedicine is deepening and showing great potential. In the integrated circuits in these fields, batteries are widely used, which leads to the contradiction between lightweight design and working time. Therefore, the requirements for power supply and energy consumption are very strict. Therefore, low voltage and low power consumption design has become one of the hottest topics in analog integrated circuit design.

[0003] The operational transconductance amplifier (OTA) is the most widely used and important block in analog circuits because it determines the performance of the entire circuit, such as filters, analog-to-digital converters (ADCs), digital-to-analog converters (DACs), and other circuits. For applications with power supply voltages below 1V, especially below the MOS threshold voltage, the circuit requires high-performance amplifiers with the lowest possible power supply voltage and power consumption. In low-voltage environments, amplifiers need to have excellent input and output voltage ranges because the signals may be close to the power rails. To meet these needs, rail-to-rail amplifiers are often used in low-voltage circuits, such as bandpass filters (BPFs) or lowpass filters (LPFs) used in electrocardiograph (ECG) systems and electromyography (EMG) systems, comparators for ultra-low power successive approximation register analog-to-digital converters (SAR ADCs), detection circuits in biomedical implants, comparators for energy harvesting systems, and wireless sensors for Internet of Things (IoT) applications.

[0004] Several techniques have been explored to achieve amplifiers with rail-to-rail capability for use in ultra-low voltage environments. Bulk-driven technology has become a subject of great interest due to its inherent large common-mode input range and the independent bulk voltage control capability of the transistors. Bulk-driven MOS amplifiers have two major problems: low transconductance values, and transconductance instability at common-mode voltages. Summary of the invention

[0005] In order to solve the above problems existing in the existing body-driven amplifier, the present invention provides a new type of CMOS body-driven transconductance amplifier circuit with ultra-low voltage, ultra-low power consumption and high common-mode stability. The technical problem to be solved by the present invention is achieved by the following technical solutions:

[0006] The present invention provides a novel ultra-low voltage, ultra-low power consumption, and high common-mode stability CMOS body-driven transconductance amplifier circuit, comprising input transistors Mp1, Mp2, Mp3, Mp4, Mp5, Mp6, Mn1, Mn2, Mn5, Mn6, current source transistors Mp7, Mp8, Mn7, Mn8, and current mirror transistors Mn3 and Mn4.

[0007] The body electrodes of Mp1 and Mp2, Mp3 and Mp4, Mn1 and Mn5, Mn2 and Mn6 are connected to a differential input voltage. The differential input voltage includes a differential voltage positive input terminal VIN+ and a differential voltage negative input terminal VIN–, and the phase of the input voltage terminal VIN+ is 180° different from the phase of the input voltage terminal VIN–.

[0008] Mp1 and Mp2, Mp3 and Mp4, Mn1 and Mn5, Mn2 and Mn6, Mn3 and Mn4 are connected in the form of gate current mirrors, among which Mp2, Mp3, Mn5, Mn6 and Mn3 are connected in the form of diodes. The gates of Mp5 and Mp6 are connected in the form of cross coupling, and the body electrodes of Mp7, Mp8, Mn7, Mn8, Mn3 and Mn4 are connected to the gates.

[0009] Mp1 and Mn3, Mp4 and Mn4, Mp7 and Mn5, Mp8 and Mn6 are connected in series to form a path from VDD to GND. In addition, the parallel structure of Mp2 and Mp5 is connected in series with the parallel structure of Mn7 and Mn1 to form a path from VDD to GND, and the parallel structure of Mp6 and Mp3 is connected in series with the parallel structure of Mn2 and Mn8 to form a path from VDD to GND. The source of Mp1 to Mp6 is connected to VDD, and the source of Mn1 to Mn8 is connected to GND. The gates of Mp7, Mp8 and Mn7, Mn8 are connected to the external bias voltage V bias1 and V bias2 .

[0010] The drain connection point of Mp4 and Mn4 is the output point of the transconductance amplifier.

[0011] Compared with the prior art, the present invention has the following beneficial effects:

[0012] The present invention provides a novel CMOS body-driven transconductance amplifier circuit with ultra-low voltage, ultra-low power consumption and high common-mode stability, which has the smallest transconductance variation within the rail-to-rail range and a higher transconductance energy consumption ratio, thereby solving the problems of low transconductance of body-driven MOS amplifiers and unstable transconductance under common-mode voltage.

[0013] In addition, the transconductance amplifier proposed by the present invention can be used in low-voltage and low-power systems such as biomedical systems, and has a wide range of applications.

[0014] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural schematic diagram of an ultra-low voltage body driven transconductance amplifier circuit in the prior art;

[0016] Figure 2 It is a structural schematic diagram of a novel ultra-low voltage, ultra-low power consumption, and high common-mode stability CMOS body-driven transconductance amplifier circuit provided by an embodiment of the present invention;

[0017] Figure 3 It is a schematic diagram of transconductance simulation results of a novel ultra-low voltage, ultra-low power consumption, and high common-mode stability CMOS body-driven transconductance amplifier circuit provided by an embodiment of the present invention compared with an existing transconductance amplifier. DETAILED DESCRIPTION

[0017] The present invention is further described in detail below with reference to specific embodiments, but the embodiments of the present invention are not limited thereto.

[0018] Figure 1 Schematic diagram of the structure of the ultra-low voltage body drive transconductance amplifier circuit in the prior art. Figure 1 As shown, in the body-driven transconductance amplifier, the current source MOS tubes Mn1 and Mn2 provide two identical bias currents, the input MOS tubes Mp1 to Mp4 convert the input voltage signal into a differential current signal, and then the current mirror circuits Mn3 and Mn4 are used to realize the current output function.

[0019] The sizes of Mp1 to Mp4 are the same, and the static current is equal, which is set to I DS According to the MOS transconductance formula in the subthreshold region, the body transconductances of Mp1 to Mp4 are equal, which is

[0020]

[0021] where T is the absolute temperature, n is the dip of the weak inversion curve, k is the Boltzmann constant, q is the charge of the electron or hole, and γ p is the body effect coefficient Φ F,p is the potential difference between the Fermi level of the substrate and the intrinsic silicon, V BS,p is the source-to-body voltage. In addition, V BS =VCM–VDD.

[0022] The transconductance of the entire amplifier is

[0023] G m =2g mb,p (2)

[0024] The ratio of the transconductance current is

[0025]

[0026] However, the absolute value of transconductance and transconductance energy consumption of the body-driven transconductance amplifier in the prior art are relatively low. In addition, there is also the problem that the transconductance value changes when the input signal common mode voltage VCM changes, thereby affecting various performances of the amplifier. Taking VDD = 0.4V as an example, when the input signal common mode voltage VCM changes from 0 to 0.4V, the transconductance of the amplifier changes by more than 20%.

[0027] In view of this, the present invention provides a novel CMOS body-driven transconductance amplifier circuit with ultra-low voltage, ultra-low power consumption and high common-mode stability.

[0028] Figure 2 1 is a schematic diagram of a novel ultra-low voltage, ultra-low power consumption, high common-mode stability CMOS body-driven transconductance amplifier circuit provided by an embodiment of the present invention. Figure 2 As shown, Figure 1 As shown, in the novel body-driven transconductance amplifier, current source MOS tubes Mp7, Mp8 and Mn7, Mn8 provide bias current, input MOS tubes Mp1~Mp6 and Mn1, Mn2, Mn5, Mn6 convert input voltage signals into differential current signals, and then current mirror circuits Mn3 and Mn4 are used to realize the current output function.

[0029] Figure 2 The size of the left and right half circuits is symmetrical, and the size ratios between the pMOS and nMOS halves are marked. Therefore, the size ratios of all pMOS and nMOS are known, and the ratio of their currents is equal to the size ratio.

[0030] Quiescent current I DS The corresponding body transconductance of pMOS and nMOS is

[0031]

[0032] and

[0033]

[0034] The body transconductance of pMOS and nMOS shows opposite change trends to VCM, and the sum of the two has better stability with respect to VCM. Assuming that when VCM changes between GND and VDD, the absolute value of the change in body transconductance of pMOS and nMOS is Δg mb,p and Δg mb,n , the ratio of the quiescent current of nMOS and pMOS is set to Δg mb,p / Δg mb,n , the body transconductance changes of pMOS and nMOS are offset to the maximum.

[0035] The gate cross-coupling structure of Mp5 and Mp6 forms a negative impedance. As a result, the small-signal currents of Mp2, Mp3, Mp5, Mp6 and Mn1, Mn2, Mn5, Mn6 are replicated to Mp1 and Mp4 at a greater magnification, and the transconductance of the amplifier is enhanced.

[0036] Let the current in Mp1 be I DS , considering the size ratios of pMOS and nMOS, the transconductance of the entire amplifier is

[0037]

[0038] The static current is 2[2 + M + (1 + M)y / (1 + x)]I DS , and the ratio of the transconductance current is

[0039]

[0040] In the example of the present invention, M satisfies 0.5 < M < 1, x < 1, y < 1, and there is

[0041]

[0042] Obviously, the ratio of the transconductance current of the novel ultra-low voltage, ultra-low power consumption, and high common-mode stability CMOS body-driven transconductance amplifier is greater than that of the ultra-low voltage body-driven transconductance amplifier in the prior art.

[0043] Figure 3 Shows the comparison of the transconductance of the novel transconductance amplifier and the existing transconductance amplifier when VCM varies between GND and VDD.

[0044] From the above embodiments, it can be seen that the beneficial effects of the present invention are as follows:

[0045] The present invention provides a novel ultra-low voltage, ultra-low power consumption, and high common-mode stability CMOS body-driven transconductance amplifier circuit, including: input transistors Mp1, Mp2, Mp3, Mp4, Mp5, Mp6, Mn1, Mn2, Mn5, Mn6, current source transistors Mp7, Mp8, Mn7, Mn8, and current mirror transistors Mn3, Mn4.

[0046] By introducing a complementary CMOS structure and a negative impedance structure as transconductance optimization techniques on the basis of the existing body-driven transconductance amplifier, the stability and enhancement of the body transconductance are achieved.

[0047] The novel ultra-low voltage, ultra-low power consumption, and high common-mode stability CMOS body-driven transconductance amplifier circuit proposed by the present invention can be used in low-voltage and low-power consumption systems, and has a wide range of applications.

[0048] In the description of the present invention, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0049] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification.

[0050] Although the present application is described herein in conjunction with various embodiments, in the process of implementing the claimed application, those skilled in the art may understand and implement other changes to the disclosed embodiments by viewing the drawings, the disclosed content, and the appended claims. In the claims, the word "comprising" does not exclude other components or steps, and "one" or "an" does not exclude multiple situations. A single processor or other unit can implement several functions listed in the claims. Certain measures are recorded in different dependent claims, but this does not mean that these measures cannot be combined to produce good results. The above content is a further detailed description of the present invention in conjunction with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, without departing from the concept of the present invention, several simple deductions or substitutions can be made, which should be deemed to belong to the scope of protection of the present invention.

Claims

1. A novel ultra-low voltage, ultra-low power consumption, high common-mode stability CMOS body-driven transconductance amplifier circuit, characterized in that: include: PMOS input differential pair, NMOS differential pair, PMOS current source, NMOS current source and NMOS current mirror. The PMOS input differential pair includes transistors Mp1, Mp2, Mp3, Mp4, Mp5, Mp6, the NMOS input differential pair includes transistors Mn1, Mn2, Mn5, Mn6, the PMOS current source includes transistors Mp7, Mp8, the NMOS current source includes transistors Mn7, Mn8, and the NMOS current mirror includes transistors Mn3, Mn4. Wherein: The sources of Mp1, Mp2, Mp3, Mp4, Mp5, Mp6, Mp7, and Mp8 are connected to the analog ground. The sources of Mn1, Mn2, Mn3, Mn4, Mn5, Mn6, Mn7, and Mn8 are connected to the analog positive power supply. The gate of Mp1 is connected to the gate of Mp2, the gate of Mp3 is connected to the gate of Mp4, the gate of Mn1 is connected to the gate of Mn5, the gate of Mn2 is connected to the gate of Mn6, and the gate of Mn3 is connected to the gate of Mn4. The gate of Mp2 is connected to the drain of Mp2, the gate of Mp3 is connected to the drain of Mp3, the gate of Mp5 is connected to the drain of Mp6, the gate of Mp6 is connected to the drain of Mp5, the gate of Mn5 is connected to the drain of Mn5, the gate of Mn6 is connected to the drain of Mn6, and the gate of Mn3 is connected to the drain of Mn3. The gate of Mp7 and Mp8 is connected to the external bias voltage V bias1 Connect the gates of Mn7 and Mn8 to the external bias voltage V bias2 The drain of Mp1 is connected to the drain of Mn3, the drain of Mp4 is connected to the drain of Mn4, the drain of Mp7 is connected to the drain of Mn5, and the drain of Mp8 is connected to the drain of Mn6. The drains of Mp2 and Mp5 are connected to the drains of Mn1 and Mn7, and the drains of Mp3 and Mp45 are connected to the drains of Mn2 and Mn8. The output point of the circuit is the connection point of the drain of Mp4 and the drain of Mn4.

2. According to claim 1, a novel ultra-low voltage, ultra-low power consumption, high common-mode stability CMOS body-driven transconductance amplifier circuit is characterized in that: All NMOS tubes in the circuit are deep N-well process NMOS.

3. The novel ultra-low voltage, ultra-low power consumption, high common-mode stability CMOS body-driven transconductance amplifier circuit according to claim 1, characterized in that: The body electrodes of Mp1, Mp3, Mp6, Mn2, and Mn5 are connected to the differential input voltage positive input terminal VIN+, and the body electrodes of Mp2, Mp4, Mp5, Mn1, and Mn6 are connected to the differential input voltage positive input terminal VIN–. The phase of the input voltage terminal VIN+ is 180° different from the phase of the input voltage terminal VIN–. The body electrode of Mp7 is connected to the gate of Mp7, the body electrode of Mp8 is connected to the gate of Mp8, the body electrode of Mn7 is connected to the gate of Mn7, the body electrode of Mn8 is connected to the gate of Mn8, the body electrode of Mn3 is connected to the gate of Mn3, and the body electrode of Mn4 is connected to the gate of Mn4.

4. The novel ultra-low voltage, ultra-low power consumption, high common-mode stability CMOS body-driven transconductance amplifier circuit according to claim 2, characterized in that: The potential of the analog ground is 0V, and the potential of the analog positive power supply is 0.4V.

5. The novel ultra-low voltage, ultra-low power consumption, high common-mode stability CMOS body-driven transconductance amplifier circuit according to claim 1, characterized in that: The sizes of Mp1, Mp2, Mp3, and Mp4 are the same. The size ratio of Mp1, Mp5, and Mp7 is 1:M:(1+M)y / (1+x). The size ratio of Mp4, Mp6, and Mp8 is 1:M:(1+M)y / (1+x). The size ratio of Mn1, Mn7, and Mn5 is 1:x:y. The size ratio of Mn2, Mn8, and Mn6 is 1:x:y. The size ratio of Mn3 to Mn1 is 1:(1+M) / (1+x). The size ratio of Mn4 to Mn2 is 1:(1+M) / (1+x).

6. The novel ultra-low voltage, ultra-low power consumption, high common-mode stability CMOS body-driven transconductance amplifier circuit according to claim 1, characterized in that: The transconductance of the transconductance amplifier circuit is composed of a PMOS body transconductance and an NMOS body transconductance, and is amplified by a negative resistance structure.

7. The novel ultra-low voltage, ultra-low power consumption, high common-mode stability CMOS body-driven transconductance amplifier circuit according to claim 1, characterized in that: The common-mode stability of the transconductance of the transconductance amplifier circuit is formed by the cancellation of the opposite changes of the PMOS body transconductance and the NMOS body transconductance with the common mode.

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