Temperature self-compensation operational amplifier

Abstract

The utility model discloses a temperature self-compensation operational amplifier with low power supply and low power consumption. The temperature sensing module is used for measuring environment temperature, the temperature reading module is connected with the temperature sensing module, the gm-boost module is connected with the temperature reading module, the temperature reading module can convert data output by the temperature sensing module and input the data to the gm-boost module, and the gm-boost module is connected with the gm-boost module. And the gm-boost module is connected with the operational amplifier main body module, and the output geminate transistor of the operational amplifier main body module is controlled by the gm-boost module, so that the operational amplifier gain at different working environment temperatures can be self-adjusted. The temperature self-compensation circuit has the advantages that the gain of the operational amplifier can be self-adjusted at different temperatures, so that the temperature self-compensation of the operational amplifier at different temperatures is realized, and the temperature drift of the gain of the operational amplifier is greatly reduced.

Description

Technical Field

[0001] The utility model relates to an operational amplifier, in particular to a temperature self-compensating operational amplifier with low power supply and low power consumption. Background Art

[0002] The operational amplifier is one of the basic units in the circuit, and its characteristic is that it has a large amplification factor. The output signal of the operational amplifier is generally an operation on the input signal. Because it was often used in analog computers to perform mathematical operations in the early days, it is habitually called an operational amplifier. In circuit application examples, operational amplifiers are generally combined with some functional modules, such as feedback networks or frequency compensation, to achieve better performance.

[0003] With the development of semiconductor technology, higher requirements are placed on operational amplifiers. However, the temperature drift of operational amplifiers will always interfere with the system, and it is difficult to eliminate this interference in other ways. How to ensure that the gain of the operational amplifier does not drift with temperature has become a technical problem that needs to be solved urgently. Summary of the invention

[0004] The technical problem to be solved by the utility model is to provide a temperature self-compensating operational amplifier which can self-adjust the operational amplifier gain at different temperatures to realize temperature self-compensation of the operational amplifier and thus greatly reduce the temperature drift of the gain.

[0005] In order to solve the above technical problems, the temperature self-compensating operational amplifier of the utility model includes a temperature sensing module for measuring the ambient temperature, a temperature reading module connected to the temperature sensing module, and a gm-boost module connected to the temperature reading module. The temperature reading module can convert the data output by the temperature sensing module and input it to the gm-boost module. The gm-boost module is connected to the operational amplifier main module and makes the output of the operational amplifier main module controlled by the gm-boost module, so that the operational amplifier gain under different working ambient temperatures can be self-adjusted.

[0006] The gm-boost module is composed of a PGA, and a control end of the PGA is connected to the temperature readout module to receive a signal from the temperature readout module to adjust the PGA gain.

[0007] The operational amplifier main body module includes an input pair of tubes PM1 and PM2 and output tubes PM3, PM4, NM1, and NM2. The output tubes PM3, PM4, NM1, and NM2 are connected to the gm-boost module.

[0008] The input end of the PGA is respectively connected to the drain end of the output tubes PM3 and PM4 and the gate end of NM1 and NM2 in the operational amplifier main module, and the output end of the PGA is respectively connected to the gate end of the output tube of the operational amplifier module.

[0009] The temperature sensing module includes a current source I D1 , current source I D2 And BJT tube Q1 and BJT tube Q2, the BJT tube Q1 is controlled by the current source I D1 The BJT tube Q2 is biased by the current source I D2 The collector and emitter of the BJT tube Q1 and BJT tube Q2 obtain two temperature-dependent voltages V be1 With voltage V be2 .

[0010] The advantages of the utility model are:

[0011] Compared with the traditional operational amplifier, the utility model uses a temperature sensor to collect the ambient temperature and uses temperature reading and g m -boost module cooperates with the structural design, while achieving the normal amplification performance of the input signal, that is: while keeping the operational amplifier gain unchanged, especially through the set temperature sensor and gm-boost module, the gain of the operational amplifier can be self-adjusted at different temperatures, thereby realizing self-compensation of the operational amplifier at different temperatures, thereby greatly reducing the temperature drift of the operational amplifier gain. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a principle block diagram of the temperature self-compensating operational amplifier of the utility model;

[0013] Figure 2 This is a circuit diagram of the temperature sensing module in the utility model;

[0014] Figure 3 g in the utility model m -Boost and OTA circuit diagram. DETAILED DESCRIPTION

[0015] The temperature self-compensating operational amplifier of the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation modes.

[0016] As shown in the figure, the temperature self-compensating operational amplifier of the present invention comprises a temperature sensing module 101, a temperature reading module 102, a gm-boost module 103 and an operational amplifier main body module 104 (OTA module), wherein the temperature sensor is used to monitor the working environment temperature of the operational amplifier, and the temperature reading module is used to convert the output signal detected by the temperature sensor into voltage data. Specifically, the input end of the temperature reading module 102 is connected to the output of the temperature sensor module 101, and the temperature sensor can measure the ambient temperature in real time to distinguish different working environment temperatures. The temperature sensor module completes the monitoring of the external temperature and inputs the signal to the next-level temperature reading module. The temperature reading module 102 is connected to the gm-boost module 103, and the temperature reading module is used to amplify the signal output by the temperature sensor. The gm-boost can adjust its own gain under the control of the output signal of the temperature reading module, that is, the temperature reading module controls the gm-boost module 103. m -boost has different working states at different ambient temperatures; the gm-boost module 103 is connected to the operational amplifier main module 104, the operational amplifier main module 104 is used to amplify the input signal, and the architecture can adopt the traditional operational amplifier architecture, and its gain can be g m -boost is used for adjustment. As can be seen from the figure, the output pair of the operational amplifier of the operational amplifier main module is controlled by the gm-boost module, so that the operational amplifier gain at different temperatures can be self-adjusted. The temperature self-compensated operational amplifier can realize self-adjustment of gain at different temperatures, thereby greatly reducing the gain change with the working environment temperature.

[0017] Furthermore, the gm-boost module 103 is composed of a PGA, the control end of the PGA is connected to the temperature readout module to receive the signal of the temperature readout module, so as to adjust the PGA gain in real time according to the working environment temperature, the input end of the PGA is respectively connected to the drain end of the output tubes PM3 and PM4 of the operational amplifier module and the gate end of the output tubes NM1 and NM2, the output end of the PGA is respectively connected to the gate end of the output tube of the operational amplifier module, and the gain of the OTA will be adjusted to different sizes according to the different gain sizes of the PGA; the operational amplifier main body module 104 includes an input pair of tubes PM1 and PM2 and output tubes PM3, PM4, NM1, and NM2, the output tubes PM3, PM4, NM1, and NM2 are connected to the gm-boost module, and the gate and drain voltages thereof are determined by the gm-boost module. m -boost module control, so as to achieve OTA gain control. As can be seen from the figure, the OTA module has a folded common source and common gate structure, which is consistent with g m -boost module is connected to adjust the gain according to the working environment temperature, realizing the normal amplification function of the operational amplifier while achieving extremely small temperature drift.

[0018] See also Figure 3 , Figure 3 Yes m -boost module and OTA module implementation, where OTA is implemented using the traditional folded common source and common gate, where PM1 and PM2 are the input pair of OTA, PM3 and PM4 are the output pair of OTA, and NM1 and NM2 are the output pair of OTA. Two PGAs are used as g m The main components of the -boost module are connected to the gate and drain terminals of the two pairs of output transistors. m -Boost module control port V ctrl With V ctr2 They are connected to the output of the temperature readout module respectively. As the output of the temperature readout module changes, the gains of PGA1 and PGA2 will also change, which will eventually lead to a change in the gain of the folded cascode. When the gain of the folded cascode drifts with temperature, the gain of the folded cascode will be changed by g m The -boost module can control the OTA gain, thereby achieving a very small temperature drift of the operational amplifier under different operating ambient temperatures.

[0019] Furthermore, the temperature sensor is based on the principle of the bandgap circuit and is implemented by a pair of differential BJTs. As can be seen from the figure, the temperature sensing module 101 includes a current source I D1 , current source I D2 As well as BJT tubes Q1 and Q2, BJT tube Q1 is affected by the current source I D1 The BJT tube Q2 is biased by the current source I D2 The bias of D1 The current magnitude is I D2 n times, the collector and emitter of BJT tube Q1 and BJT tube Q2 obtain two temperature-related voltages V be1 With voltage V be2 , the difference between these two voltages is ΔV be for

[0020]

[0021] Here k is the Boltzmann constant, T is the absolute temperature, q is the electron charge, and ΔV be Proportional to absolute temperature (PTAT), independent of process and bias conditions, hence ΔV be The change of working environment temperature can be measured.

[0022] In addition, the temperature readout module is implemented using a closed-loop operational amplifier with resistor feedback. After the temperature sensor signal is input into the temperature readout module, it can be amplified by A V After multiplication, it is output in the form of voltage.

[0023] Of course, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by technicians in this technical field within the essential scope of the present invention should also fall within the protection scope of the present invention.

Claims

1. A temperature self-compensating operational amplifier, characterized in that: The invention comprises a temperature sensing module (101) for measuring the ambient temperature, a temperature reading module (102) connected to the temperature sensing module (101), and a gm-boost module (103) connected to the temperature reading module (102); the temperature reading module (102) is capable of converting data output by the temperature sensing module and inputting the data to the gm-boost module (103); the gm-boost module (103) is connected to an operational amplifier main body module (104) and enables the operational amplifier output pair of the operational amplifier main body module to be controlled by the gm-boost module, thereby enabling the operational amplifier gain under different working ambient temperatures to be self-adjusted.

2. The temperature self-compensating operational amplifier according to claim 1, characterized in that: The gm-boost module (103) is composed of a PGA, and a control end of the PGA is connected to the temperature reading module to receive a signal from the temperature reading module.

3. The temperature self-compensating operational amplifier according to claim 1 or 2, characterized in that: The operational amplifier main body module (104) comprises an input pair of tubes PM1 and PM2 and output tubes PM3, PM4, NM1 and NM2, wherein the output tubes PM3, PM4, NM1 and NM2 are connected to a gm-boost module.

4. The temperature self-compensating operational amplifier according to claim 2, characterized in that: The input end of the PGA is respectively connected to the drain end of the output tubes PM3 and PM4 and the gate end of NM1 and NM2 in the operational amplifier main module, and the output end of the PGA is respectively connected to the gate end of the output tube of the operational amplifier module.

5. The temperature self-compensating operational amplifier according to claim 4, characterized in that: The temperature sensing module (101) comprises a current source (I D1 ), current source (I D2 ) and BJT tube (Q1) and BJT tube (Q2), the BJT tube (Q1) can be driven by a current source (I D1 ) is biased, the BJT tube (Q2) can be biased by the current source (I D2 ) bias, the collector and emitter of the BJT tube (Q1) and BJT tube (Q2) obtain two temperature-dependent voltages (V be1 ) and voltage (V be2 ).

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