CN214799419U - Single-power-supply operational amplifier circuit - Google Patents
Single-power-supply operational amplifier circuit Download PDFInfo
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- CN214799419U CN214799419U CN202022987875.9U CN202022987875U CN214799419U CN 214799419 U CN214799419 U CN 214799419U CN 202022987875 U CN202022987875 U CN 202022987875U CN 214799419 U CN214799419 U CN 214799419U
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Abstract
The application relates to a single power supply operational amplifier circuit, including: the amplifying circuit supplies power to the single power supply and is used for amplifying an input signal; the bias circuit is connected with the first input end of the amplifying circuit and is used for superposing bias voltage on the first input end of the amplifying circuit; and the clamping circuit is connected with the first input end of the amplifying circuit and used for limiting the voltage of the first input end of the amplifying circuit so as to protect the operational amplifier from being damaged due to overlarge voltage of an input signal. According to the embodiment of the application, the input end of the single power supply operational amplifier circuit is superposed with the bias voltage, the bias voltage precision is high, and the operational amplifier input impedance is not affected, so that the single power supply operational amplifier circuit effectively amplifies the input alternating current signal.
Description
Technical Field
The application relates to the field of circuits, in particular to a single-power-supply operational amplifier circuit.
Background
At present, the operational amplifier circuit has single power supply and double power supply. The input and output voltages of the dual-power operational amplifier circuit can span positive and negative voltages, but basically have no rail-to-rail capability, namely, the input voltage range is positive and negative symmetrical and has a certain distance with the positive and negative power supply voltages; the output voltage range is positive and negative symmetrical, and has a certain distance with the positive and negative power supply voltages. The single power supply operational amplifier circuit has better rail-to-rail capability, namely, the input and output voltage range is larger than the power supply voltage. The input can realize linear amplification from a negative power supply, and the circuit is simple.
When the single power supply operational amplifier works, only the direct current voltage with positive ground (same-direction input) or negative ground (reverse input) can be amplified, if the alternating current signal with the ground is input, only the positive half wave or the negative half wave can be amplified, and the other half wave can generate serious distortion because of cut-off.
SUMMERY OF THE UTILITY MODEL
In order to solve the technical problem or at least partially solve the technical problem, the application provides a single-power-supply operational amplifier circuit, which enables a single-power-supply operational amplifier to effectively amplify an input alternating current signal by superposing a bias voltage on an input end of the single-power-supply operational amplifier, wherein the bias voltage has high precision and does not affect the input impedance of the operational amplifier.
In a first aspect, the utility model discloses a single power supply operational amplifier circuit, include:
the amplifying circuit is powered by a single power supply and is used for amplifying an input signal;
the bias circuit is connected with the first input end of the amplifying circuit and is used for superposing bias voltage on the first input end of the amplifying circuit;
and the clamping circuit is connected with the first input end of the amplifying circuit and is used for limiting the voltage of the first input end of the amplifying circuit.
Optionally, the bias circuit includes:
the voltage division circuit is connected with the direct current power supply of the amplifying circuit and is used for dividing the direct current power supply of the amplifying circuit;
and the voltage-controlled switch circuit is connected with the voltage division circuit and the first input end of the amplifying circuit and is used for superposing the output voltage of the voltage division circuit to the first input end of the amplifying circuit.
Optionally, the voltage divider circuit includes:
the first end of the first resistor is connected with a first direct current power supply;
and the first end of the second resistor is connected with the second end of the first resistor, and the second end of the second resistor is grounded.
Optionally, the voltage-controlled switching circuit includes:
and the G pole of the N-type field effect transistor is connected with the second end of the first resistor, the D pole of the N-type field effect transistor is connected with the first end of the second resistor, and the S pole of the N-type field effect transistor is connected with the first input end of the amplifying circuit.
Optionally, the clamping circuit includes:
the cathode of the first diode is connected with a second direct-current power supply, and the anode of the first diode is connected with the first input end of the amplifying circuit;
and the cathode of the second diode is connected with the anode of the first diode, and the anode of the second diode is grounded.
Optionally, the amplifying circuit is an in-phase single power supply amplifying circuit.
Optionally, the resistance values of the first resistor and the second resistor are set according to the magnitude of the target bias voltage.
Optionally, the amplifying circuit includes:
the non-inverting input end of the first operational amplifier is connected with the S pole of the N-type field effect transistor;
a first end of the third resistor is grounded, and a second end of the third resistor is connected with the inverting input end of the first operational amplifier;
a fourth resistor connected across the inverting input and the output of the first operational amplifier.
Optionally, the single power supply operational amplifier circuit further includes: the first end of the first capacitor is grounded, and the first end of the first capacitor is connected with the first end of the third resistor and used for filtering;
and the first end of the second capacitor is connected with an input signal source, and the second end of the second capacitor is connected with the non-inverting input end of the first operational amplifier and used for blocking direct current.
The application discloses single power supply operational amplifier circuit includes: the amplifying circuit supplies power to the single power supply and is used for amplifying an input signal; the bias circuit is connected with the first input end of the amplifying circuit and is used for superposing bias voltage on the first input end of the amplifying circuit; and the clamping circuit is connected with the first input end of the amplifying circuit and is used for limiting the voltage of the first input end of the amplifying circuit. According to the embodiment of the application, the bias voltage is superposed on the input end of the single-power-supply operational amplifier, the bias voltage precision is high, and the input impedance of the operational amplifier is not influenced, so that the single-power-supply operational amplifier can effectively amplify the input alternating current signal.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and together with the description, serve to explain the principles of the application.
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, and it is obvious for those skilled in the art to obtain other drawings without inventive exercise.
FIG. 1 is a block diagram of a single power supply op-amp circuit, shown in accordance with an exemplary embodiment;
FIG. 2 is a block diagram of a biasing circuit shown in accordance with an exemplary embodiment;
FIG. 3 is a block diagram of a bias circuit according to an exemplary embodiment;
FIG. 4 is a diagram illustrating a clamp circuit architecture in accordance with an exemplary embodiment;
FIG. 5 is a block diagram illustrating a single power supply op-amp circuit in accordance with an exemplary embodiment;
fig. 6 is a block diagram illustrating a single power supply op-amp circuit in accordance with an exemplary embodiment.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
Fig. 1 is a block diagram illustrating a single power supply operational amplifier circuit according to an exemplary embodiment, as shown in fig. 1, the single power supply operational amplifier circuit comprising:
an amplification circuit 110, powered using a single power supply, for amplifying an input signal;
a bias circuit 120 connected to the first input terminal of the amplifier circuit, for superimposing a bias voltage on the first input terminal of the amplifier circuit;
and the clamping circuit 130 is connected with the first input end of the amplifying circuit and is used for limiting the voltage of the first input end of the amplifying circuit.
In the embodiment of the present application, the bias circuit 120 is superimposed on the input end of the amplifying circuit 110, so that the bias voltage generated by the bias circuit 120 is added to the input signal, so that the amplifying circuit 110 is not distorted when amplifying the ac signal, and the clamp circuit 130 is used at the input end of the amplifying circuit 120 to protect the clamp circuit 130 and the amplifying circuit 110.
Fig. 2 is a block diagram illustrating a bias circuit according to an exemplary embodiment, where the bias circuit 220 includes, as shown in fig. 2:
a voltage dividing circuit 221 connected to the dc power supply of the amplifying circuit 210, for dividing the dc power supply of the amplifying circuit 210;
the voltage-controlled switch circuit 222 is connected to the voltage divider circuit 221, and further connected to the first input terminal of the amplifier circuit 210, and is configured to superimpose the output voltage of the voltage divider circuit 221 onto the first input terminal of the amplifier circuit 210.
In the embodiment of the application, due to the switching characteristic of the voltage-controlled switching circuit, the voltage-controlled switching circuit has very high input impedance and very low output impedance, the change of the output current hardly affects the bias voltage, the bias voltage precision is high, the operational amplifier input impedance is not affected, and the voltage-dividing circuit does not need to adopt a resistor with a very large resistance value, so that the thermal noise caused by the resistor in the voltage-dividing circuit can be effectively reduced.
Fig. 3 is a diagram illustrating a structure of a bias circuit according to an exemplary embodiment, and as shown in fig. 3, the voltage dividing circuit 321 includes:
a first resistor R1, wherein a first end of the first resistor R1 is connected with a first direct current power supply;
a second resistor R2, a first end of the second resistor R2 is connected with a second end of the first resistor R1, and a second end of the second resistor R2 is grounded.
In the embodiment of the present application, due to the switching characteristic of the voltage-controlled switch circuit 322, the bias circuit 320 has the characteristics of high input impedance and low output impedance, the high input impedance characteristic of the amplifying circuit 310 is not affected, and the first resistor R1 and the second resistor R2 do not need to adopt resistors with large resistance values.
In the embodiment of the present application, the first resistor R1 and the second resistor R2 can adopt resistors with the same resistance, so that the output voltage of the voltage dividing circuit 321 is half of the output voltage of the first dc power supply.
In this embodiment, the actual resistance values of the first resistor R1 and the second resistor R2 and the voltage of the first dc power supply may be set according to the bias voltage required by the single power amplifier circuit and the power consumption requirement.
As shown in fig. 3, the voltage-controlled switching circuit 322 includes:
and the G pole of the N-type field effect transistor M1 is connected with the second end of the first resistor R1, the D pole of the N-type field effect transistor M1 is connected with the first end of the second resistor R2, and the S pole of the N-type field effect transistor M1 is connected with the first input end of the amplifying circuit.
The N-type fet M1 is a voltage-type device, the depth of conduction is determined by the magnitude of the voltage Vgs between the gate and the source, and the larger Vgs, the smaller the on-resistance rds (on) between the gate and the source. When Vgs is greater than or equal to the conducting threshold, the N-type fet M1 enters a conducting state from a cut-off state, and as the voltage of Vgs increases, the on-resistance rds (on) decreases, the N-type fet M1 conducts more sufficiently, the conducting voltage drop of the N-type fet M1 is much smaller than the output voltage of the voltage dividing circuit 321, the dc bias voltage is approximately equal to the output voltage of the voltage dividing circuit 321, the dc bias voltage is superimposed on the first input end of the amplifying circuit 310, the N-type fet M1 is in a stable working state after being conducted, the bias voltage is equivalent to a voltage stabilizing source, the bias voltage precision is high, and the input impedance characteristic of the operational amplifier is not affected.
In this embodiment, the first dc power supply may adopt a dc power supply that is the same as the dc power supply of the amplifying circuit, and when the first resistor R1 is the same as the second resistor R2, the N-type fet M1 is turned on, and the dc bias is approximately half of the voltage VCC of the dc power supply of the amplifying circuit, so that the single power supply operational amplifier circuit obtains the maximum output dynamic response range.
Fig. 4 is a diagram illustrating a structure of a clamping circuit according to an exemplary embodiment, and as shown in fig. 4, the clamping circuit 430 includes:
a first diode D1, a cathode of the first diode D1 being connected to the second dc power source, an anode of the first diode D1 being connected to the first input terminal of the amplifying circuit 410;
a second diode D2, the cathode of the second diode D2 is connected with the anode of the first diode D1, and the anode of the second diode D2 is grounded.
In this embodiment, the second dc power supply may adopt a dc power supply that is the same as the dc power supply of the amplifying circuit 410, and the clamping circuit 430 limits the voltage at the first input terminal of the amplifying circuit 410 to (0-the conduction voltage drop) - (VCC + the conduction voltage drop), so as to protect the operational amplifier circuit.
Fig. 5 is a block diagram illustrating a single power supply operational amplifier circuit according to an exemplary embodiment, wherein the amplifier circuit 510 is an in-phase single power supply amplifier circuit. As shown in fig. 5, the amplifying circuit 510 includes:
a first operational amplifier A1, wherein the non-inverting input terminal of the first operational amplifier A1 is connected with the S pole of the N-type field effect transistor M1;
a third resistor R3, a first end of the third resistor R3 being connected to ground, a second end of the third resistor R3 being connected to the inverting input of the first operational amplifier A1;
a fourth resistor R4, the fourth resistor R4 being connected across the inverting input and the output of the first operational amplifier A1.
Fig. 6 is a block diagram illustrating a single power supply operational amplifier circuit according to an exemplary embodiment, wherein the amplifier circuit 610 is an in-phase single power supply amplifier circuit. As shown in fig. 6, the amplifying circuit 610 includes:
a first operational amplifier A1, wherein the non-inverting input terminal of the first operational amplifier A1 is connected with the S pole of the N-type field effect transistor M1;
a first capacitor C1, wherein the first end of the first capacitor C1 is grounded for filtering;
a second capacitor C2, a first end of the second capacitor C2 is connected to an input signal source, and a second end of the second capacitor C2 is connected to a non-inverting input terminal of the first operational amplifier a1 for blocking dc;
a third resistor R3, a first end of the third resistor R3 being connected to the second end of the first capacitor C1, a second end of the third resistor R3 being connected to the inverting input of the first operational amplifier A1;
a fourth resistor R4, the fourth resistor R4 being connected across the inverting input and the output of the first operational amplifier A1.
The bias circuit adopted by the embodiment of the application comprises a voltage division circuit, wherein the input end of the voltage division circuit is connected with a first direct current power supply and is used for dividing the direct current power supply of the first direct current power supply; and the voltage-controlled switch circuit is connected with the output end of the voltage division circuit and the first input end of the single-power-supply operational amplifier circuit and is used for superposing the output voltage of the voltage division circuit to the first input end of the single-power-supply operational amplifier circuit. Due to the switching characteristic of the voltage-controlled switching circuit, the voltage-dividing circuit does not need to adopt a resistor with a large resistance value, the thermal noise caused by the resistor in the voltage-dividing circuit can be effectively reduced, the bias voltage is equivalent to a voltage-stabilizing source, the bias voltage has high precision, and the input impedance characteristic of the operational amplifier is not influenced.
It is noted that, in this document, relational terms such as "first" and "second," and the like, may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
The above description is merely exemplary of the present application and is presented to enable those skilled in the art to understand and practice the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (10)
1. A single power supply operational amplifier circuit, comprising:
the amplifying circuit is powered by a single power supply and is used for amplifying an input signal;
the bias circuit is connected with the first input end of the amplifying circuit and is used for superposing bias voltage on the first input end of the amplifying circuit;
and the clamping circuit is connected with the first input end of the amplifying circuit and is used for limiting the voltage of the first input end of the amplifying circuit.
2. The single power supply operational amplifier circuit of claim 1 wherein the bias circuit comprises:
the voltage division circuit is connected with the first direct current power supply and is used for dividing the voltage of the first direct current power supply;
and the voltage-controlled switch circuit is connected with the voltage division circuit and the first input end of the amplifying circuit and is used for superposing the output voltage of the voltage division circuit to the first input end of the amplifying circuit.
3. The single power supply operational amplifier circuit as defined in claim 2 wherein said voltage divider circuit comprises:
a first resistor, a first end of the first resistor being connected to the first direct current power supply;
and the first end of the second resistor is connected with the second end of the first resistor, and the second end of the second resistor is grounded.
4. The single power supply operational amplifier circuit of claim 3, wherein the voltage controlled switching circuit comprises:
and the G pole of the N-type field effect transistor is connected with the second end of the first resistor, the D pole of the N-type field effect transistor is connected with the first end of the second resistor, and the S pole of the N-type field effect transistor is connected with the first input end of the amplifying circuit.
5. The single-power-supply operational amplifier circuit as claimed in claim 3, wherein the resistances of the first resistor and the second resistor are set according to a magnitude of a target bias voltage.
6. The single power supply operational amplifier circuit as defined in claim 1 wherein said clamping circuit comprises:
the cathode of the first diode is connected with a second direct-current power supply, and the anode of the first diode is connected with the first input end of the amplifying circuit;
and the cathode of the second diode is connected with the anode of the first diode, and the anode of the second diode is grounded.
7. The single power supply operational amplifier circuit as defined in claim 1 wherein said amplifier circuit is an in-phase single power supply amplifier circuit.
8. The single power supply operational amplifier circuit as defined in claim 4 wherein said amplifier circuit comprises:
the non-inverting input end of the first operational amplifier is connected with the S pole of the N-type field effect transistor;
a first end of the third resistor is grounded, and a second end of the third resistor is connected with the inverting input end of the first operational amplifier;
a fourth resistor connected across the inverting input and the output of the first operational amplifier.
9. The single power supply operational amplifier circuit of claim 8, wherein the single power supply operational amplifier circuit further comprises:
and the first end of the first capacitor is grounded, and the first end of the first capacitor is connected with the first end of the third resistor for filtering.
10. The single power supply operational amplifier circuit of claim 8, wherein the single power supply operational amplifier circuit further comprises:
and the first end of the second capacitor is connected with an input signal source, and the second end of the second capacitor is connected with the non-inverting input end of the first operational amplifier and used for blocking direct current.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202022987875.9U CN214799419U (en) | 2020-12-10 | 2020-12-10 | Single-power-supply operational amplifier circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202022987875.9U CN214799419U (en) | 2020-12-10 | 2020-12-10 | Single-power-supply operational amplifier circuit |
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| Publication Number | Publication Date |
|---|---|
| CN214799419U true CN214799419U (en) | 2021-11-19 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202022987875.9U Active CN214799419U (en) | 2020-12-10 | 2020-12-10 | Single-power-supply operational amplifier circuit |
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|---|---|
| CN (1) | CN214799419U (en) |
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