CN214315209U - High-performance dual-channel operational amplifier - Google Patents

Abstract

High performance dual-channel operational amplifier, the utility model relates to an electronic technology, in particular to integrated circuit technique. The utility model discloses a first order amplifier circuit, second level amplifier circuit and third level amplifier circuit, first order amplifier circuit includes first order initial signal input geminate transistor, and second level amplifier circuit includes preceding stage input geminate transistor and second level initial signal input geminate transistor, and first order amplifier circuit includes two current sources, its characterized in that, first order amplifier circuit's current source passes through resistance ground connection. The utility model discloses weaken the proportional relation between a plurality of gain level transconductance in the multistage amplifier circuit to under the unchangeable prerequisite of holding circuit performance, reduce the circuit consumption, can use in multiple circuits such as instrumentation amplifier, wave filter, power management. The operational amplifier realizes high bandwidth, high gain, low noise and low offset, and has lower power consumption.

Description

High-performance dual-channel operational amplifier

Technical Field

The utility model relates to an electronic technology, in particular to integrated circuit technique.

Background

In analog electronic devices, an instrumentation amplifier is a precision differential signal amplifier and is widely applied to systems such as data acquisition, sensors, high-speed signal conditioning, medical instruments and the like. The core circuit of the instrumentation amplifier is an operational amplifier. In the design of the low-power-consumption and high-precision instrument amplifier, an operational amplifier with low power consumption, high bandwidth, high gain and low noise is indispensable. However, as semiconductor integrated circuits are developed, the feature size of CMOS processes has reached the nanometer level, so that the intrinsic gain of CMOS devices is reduced. It is difficult to obtain a high gain in the conventional two-stage operational amplifier. The three-stage operational amplifier can obtain higher gain, but needs to use two-stage Miller compensation to meet a certain phase margin, and has higher power consumption. Therefore, the traditional two-stage or three-stage operational amplifier is difficult to meet the design requirements of the low-power consumption and high-precision instrumentation amplifier.

SUMMERY OF THE UTILITY MODEL

The utility model aims to solve the technical problem that a high performance dual-channel operational amplifier of low-power consumption is provided.

The utility model provides a technical scheme that technical problem adopted is, high performance dual-channel operational amplifier, including first order amplifier circuit, second level amplifier circuit and third level amplifier circuit, first order amplifier circuit includes first order initial signal input geminate transistor, and second level amplifier circuit includes preceding stage input geminate transistor and second level initial signal input geminate transistor, and first order amplifier circuit includes two current sources, its characterized in that, first order amplifier circuit's current source passes through resistance ground connection.

Furthermore, the transconductance of the front-stage input geminate transistors is less than one tenth of that of the second-stage initial signal input geminate transistors.

The utility model discloses only use one-level miller compensation in dual-channel operational amplifier, through setting up the dominant pole with the low frequency signal route at the second gain level, and highly keep apart low frequency signal route and high frequency signal route in order to guarantee that the loop is stable. Compare with traditional circuit, the utility model discloses weaken the direct ratio relation between a plurality of gain level transconductance in the multistage amplifier circuit to under the unchangeable prerequisite of holding circuit performance, reduce the circuit consumption, can use in multiple circuits such as instrumentation amplifier, wave filter, power management. The operational amplifier realizes high bandwidth, high gain, low noise and low offset, and has lower power consumption.

Drawings

Fig. 1 is a circuit diagram of the prior art.

Fig. 2 is a circuit diagram of the present invention.

Detailed Description

With reference to figure 2 of the drawings,

the transistors M1-M11 form a folded cascode amplifier, denoted as A₁₁；

The transistors M15-M25 form a folded cascode amplifier (Q2 and Q3 in FIG. 1), denoted as A₁₂Wherein M16 and M17 are used for receiving the initial signal V_1PAnd V_1NTherefore, the input is called as a second-stage initial signal input geminate transistor;

the transistors M12-M14 and M18-M25 form a folded cascode amplifier (Q1 and Q3 in FIG. 1), denoted as A₂(ii) a In A₂In the method, the input signals of M13 and M14 come from a preamplifier A₁₁Therefore, M13 and M14 are referred to as front-stage input pair tubes;

transistors M26, M27 form a common source amplifier, denoted A₃；

All input geminate transistors work in a subthreshold region, so that the bias current is the minimum on the premise that the transconductance of the input geminate transistors is certain.

Wherein A is₁₁、A₂、A₃A three-stage amplifying circuit is formed and is a low-frequency signal path;

A₁₂、A₃the two-stage amplifying circuit is a high-frequency signal path.

When the signal frequency is low, the low frequency signal path dominates to provide high open loop gain. When the signal frequency is high, the high frequency signal path dominates to provide high bandwidth. When the signal is at a medium frequency, the high and low frequency signal paths are active simultaneously.

In the prior art, the low frequency signal path requires two stages of miller compensation (capacitor C in fig. 1)_M、C_M1) And A is₁₁、A₂、A₃The input pair transistor transconductance relation is as follows: g_m2,3< g_m13,14< g_m26,27. Because transconductance is directly correlated with bias current, offset voltage and noise of the operational amplifier are g_m2,3In inverse proportion. To reduce offset voltage and noise, g must be increased_m2,3Further, the power consumption of the whole operational amplifier is increased in equal proportion.

The utility model discloses can make preceding stage input geminate transistor's transconductance g through reducing transistor M12, M13, M14's width to length ratio_m13,14Input geminate transistor g smaller than second-stage initial signal_m16,171/10, the low frequency path and the high frequency path are isolated, and the circuit only uses one-stage Miller compensation, so that the transconductance g is increased_m2,3When g is_m13,14、g_m26,27Remain unchanged. Thereby increasing only a small amount of power consumption while reducing the offset voltage and noise of the operational amplifier. In addition, the source ends of the transistors M4 and M5 are added with resistors, so that the equivalent transconductance g of the transistors can be reduced_m4,5Further reducing offset voltage and noise.

Claims (2)

1. High performance dual-channel operational amplifier, including first order amplifier circuit, second level amplifier circuit and third level amplifier circuit, first order amplifier circuit includes first order initial signal input geminate transistor, and second level amplifier circuit includes preceding stage input geminate transistor and second level initial signal input geminate transistor, and first order amplifier circuit includes two current sources, its characterized in that, first order amplifier circuit's current source passes through resistance ground.

2. The high performance dual-channel operational amplifier of claim 1, wherein the transconductance of the preceding input pair of transistors is less than one tenth the transconductance of the second initial input pair of transistors.

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