An integrated operational amplifier voltage protection circuit

Abstract

The utility model provides a kind of integrated operational amplifier voltage protection circuit, comprising: input stage module, intermediate stage module, output stage module and power module;The input stage module includes triode Q4, triode Q5, triode Q7, triode Q8;The intermediate stage module includes triode Q9 and triode Q11;Emitting electrode of triode Q9 is connected with base of triode Q11, the collector of triode Q9 and triode Q11 is connected to form first compound tube;The output stage module is quasi-complementary output stage, including triode Q1 and triode Q2, triode Q6 and triode Q10, resistance R1, resistance R2, triode Q3;The voltage stabilizing protection module includes current-limiting resistance R3 and stabilizing diode D2 constitute limiting circuit.The circuit of the utility model in the control system of electronic product, can effectively protect electronic components, improve product reliability, meet needs.

Description

Technical Field

[0001] This utility model relates to the field of voltage protection circuits, and in particular to an integrated operational amplifier voltage protection circuit. Background Technology

[0002] Integrated operational amplifiers (op-amps) can be damaged if their input and output voltages exceed their safe operating range. To ensure the reliability and long-term stability of integrated op-amp circuits, voltage protection circuits are required to effectively protect them.

[0003] Currently, there is no dedicated integrated operational amplifier voltage protection circuit; only separate input voltage protection, output voltage protection, and power supply protection are provided.

[0004] The main purpose of input voltage protection is to prevent excessive differential-mode or common-mode voltage from damaging the operational amplifier. Common implementation methods include current-limiting resistors and Zener diode clamping: a current-limiting resistor is connected in series at the input terminal, and a Zener diode is connected in parallel across it to limit the voltage within a safe range. Input-to-ground protection: to prevent electrostatic interference or overvoltage, a reverse Zener diode or diode can be connected in parallel between the input terminal and ground to discharge abnormal current.

[0005] Output protection primarily addresses oscillation issues caused by overcurrent, short circuits, or capacitive loads, including: Current-limiting resistor and Zener diode: A current-limiting resistor is connected in series at the output terminal to limit the maximum output current and prevent overload damage; at the same time, a Zener diode is connected in parallel to clamp the output voltage and ensure that it does not exceed the power supply voltage range.

[0006] Capacitive load oscillation suppression: To prevent self-excited oscillation caused by capacitive load, a small-capacity compensation capacitor (such as a few pF to tens of pF) can be connected in parallel at the output terminal to stabilize the frequency response.

[0007] Such separate protection mechanisms for integrated operational amplifiers cannot meet people's requirements for voltage protection circuits for integrated operational amplifiers. Utility Model Content

[0008] This invention provides an integrated operational amplifier voltage protection circuit, addressing the current lack of circuits that protect the voltage of integrated operational amplifiers.

[0009] The technical solution for achieving the technical objective of this utility model is: an integrated operational amplifier voltage protection circuit, comprising: an input stage module, an intermediate stage module, an output stage module, and a power supply module; The input stage module includes transistors Q4, Q5, Q7, and Q8; Transistors Q4 and Q5 form a differential amplifier circuit with dual-ended input and single-ended output, where the signal is input from the base of transistors Q4 and Q5 and output from the collector of transistor Q5; the emitters of transistors Q4 and Q5 are connected to the positive terminal of the power supply. The current mirror source composed of transistors Q7 and Q8 serves as the active load of the differential amplifier circuit; the base and collector of transistor Q7 are connected to the base of transistor Q8 and the collector of transistor Q4; the emitters of transistors Q7 and Q8 are connected to the negative terminal of the power supply; the collector of transistor Q8 is connected to the collector of transistor Q5. The intermediate stage module includes transistors Q9 and Q11; the emitter of transistor Q9 is connected to the base of transistor Q11, and the collectors of transistors Q9 and Q11 are connected to form a first composite transistor; the base of the first composite transistor is connected to the output terminal of the differential amplifier circuit, and the emitter of the first composite transistor is connected to the negative terminal of the power supply, forming a first common-emitter amplifier circuit with base input and collector output of the first composite transistor; The output stage module is a quasi-complementary output stage, including transistors Q1 and Q2, transistors Q6 and Q10, resistors R1 and R2, and transistor Q3. The emitter of transistor Q1 is connected to the base of transistor Q2, and the collectors of transistors Q1 and Q2 are connected to form a second composite transistor. The emitter of transistor Q6 is connected to the base of transistor Q10, and the collectors of transistors Q6 and Q10 are connected to form a third composite transistor. Resistors R1 and R2 are connected in series between the amplified output of the first common-emitter amplifier circuit and the positive terminal of the power supply. The base of transistor Q3 is connected to the common terminal of resistors R1 and R2, and the collector and emitter are connected to the other ends of resistors R1 and R2, respectively, to form a multiplier circuit. The bases of the second and third composite transistors are connected to the other ends of resistors R1 and R2, respectively, to form a second amplifier and a third amplifier. The voltage regulation and protection module includes a current-limiting resistor R3 and a Zener diode D2 forming a limiting circuit; The power module has a positive power terminal and a negative power terminal.

[0010] When the power module is connected, a power terminal protection module is also included; the power terminal protection module includes a diode D1 and a power terminal negative diode D3 disposed at the positive terminal of the power terminal; the P terminal of diode D1 and the N terminal of diode D3 are respectively connected to the positive terminal of the power terminal and the negative terminal of the power terminal.

[0011] Furthermore, the aforementioned integrated operational amplifier voltage protection circuit also includes a power supply protection module, which includes a diode D1 disposed at the positive terminal of the power supply and a diode D3 disposed at the negative terminal of the power supply; the P terminal of diode D1 and the N terminal of diode D3 are respectively connected to the positive terminal of the power supply and the negative terminal of the power supply.

[0012] The circuit of this invention can effectively protect electronic components, improve product reliability, and meet the requirements in the control system of electronic products.

[0013] The present invention will be described in more detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0014] Appendix Figure 1 This is a block diagram of the integrated operational amplifier voltage protection circuit of Embodiment 1 of this utility model; Appendix Figure 2 This is a circuit schematic diagram of Embodiment 1 of the present invention; Appendix Figure 3 The background noise level is 174MHz when the circuit of Embodiment 1 of this utility model is applied. Appendix Figure 4 The background noise index at 512MHz is shown in Embodiment 1 of this utility model. Detailed Implementation

[0015] like Figure 1 and Figure 2 As shown, this embodiment is an integrated operational amplifier voltage protection circuit, including: an input stage module, an intermediate stage module, an output stage module, a voltage regulation protection module, a power supply module, and a power supply terminal protection module; The power module has a positive power supply terminal +VCC and a negative power supply terminal VEE. The power supply is a circuit that supplies power to the integrated circuit operational amplifier power protection circuit. It is generally a DC output with a positive terminal output +VCC and a negative terminal output VEE. In most cases, +VCC is a power supply of +3VDC to +12VDC, which can be selected as needed. The negative terminal output VEE is exactly the opposite of the positive terminal output. The voltage value is the same, but the direction is opposite.

[0016] like Figure 1 As shown, the power supply module and protection: the negative voltage power supply module and the positive voltage power supply module supply power to the operational amplifier circuit. The power supply protection provides overvoltage and overcurrent protection for the positive and negative power supplies respectively, so as to avoid abnormal voltage damage to the circuit.

[0017] Cascaded operational amplifier circuits: the input stage receives and initially processes the signal, the intermediate stage performs signal amplification and other operations, and the output stage outputs the processed signal. The three stages work together to achieve signal amplification and operation functions.

[0018] Voltage regulation protection: It regulates the output signal of the output stage to ensure the stability of the output voltage, and also provides overvoltage protection when the circuit is abnormal, maintaining the safety of the circuit and the downstream load. The whole system constitutes a complete voltage protection and signal processing system from power supply to signal processing to output protection.

[0019] Specific circuit as follows Figure 2 As shown: 1. Power supply protection section Positive power supply protection uses diode D1: Diode D1 is connected between the positive power supply (+Vcc) and the circuit. When the power supply is reversed, diode D1 provides protection by utilizing its reflective cutoff function.

[0020] Similarly, diode D3 is used for negative power supply protection: Diode D3 is connected between the negative power supply - Vee and the circuit. Its principle is similar to D1; when an abnormal positive voltage occurs at the negative power supply, diode D3 cuts off, preventing positive current from flowing into the circuit. Under normal operating conditions, diode D3 allows the negative power supply to provide bias to the circuit, ensuring the circuit can operate normally in dual-power supply mode.

[0021] 2. Input level The input stage module includes transistors Q4, Q5, Q7, and Q8; Transistors Q4 and Q5 form a differential amplifier circuit with dual-ended input and single-ended output, where the signal is input from the base of transistors Q4 and Q5 and output from the collector of transistor Q5; the emitters of transistors Q4 and Q5 are connected to the positive terminal of the power supply. The current mirror source composed of transistors Q7 and Q8 serves as the active load of the differential amplifier circuit; the base and collector of transistor Q7 are connected to the base of transistor Q8 and the collector of transistor Q4; the emitters of transistors Q7 and Q8 are connected to the negative terminal of the power supply; the collector of transistor Q8 is connected to the collector of transistor Q5. Differential Input Pair (Transistors Q4 and Q5): Transistors Q4 and Q5 form a differential amplifier circuit, a common structure for the input stage of integrated operational amplifiers. The differential amplifier circuit effectively suppresses common-mode signals (such as power supply noise and environmental interference) while amplifying the differential-mode signal (the difference between the input signals UI). This improves the circuit's anti-interference capability and signal processing accuracy. Constant Current Source Bias (Transistors Q7 and Q8): Transistors Q7 and Q8 form a constant current source circuit, providing a stable bias current to transistors Q4 and Q5. The constant current source ensures stable operation of the input stage under different input signal conditions, improving the linearity and stability of the input stage.

[0022] 3. Intermediate level The intermediate stage module includes transistors Q9 and Q11; the emitter of transistor Q9 is connected to the base of transistor Q11, and the collectors of transistors Q9 and Q11 are connected to form a first composite transistor; the base of the first composite transistor is connected to the output terminal of the differential amplifier circuit, and the emitter of the first composite transistor is connected to the negative terminal of the power supply, forming a first common-emitter amplifier circuit with base input and collector output of the first composite transistor; The first common-emitter amplifier circuit is completed by signal amplification transistors Q9 and Q11. Transistors Q9 and Q11, along with other transistors, constitute the intermediate stage amplifier circuit, whose main function is to further amplify the signal output from the input stage to obtain sufficient gain. Resistors R1 and R2 provide bias resistors for transistor Q3, which acts as a current amplifier or auxiliary signal amplifier, improving the overall amplification capability of the intermediate stage. The intermediate stage significantly amplifies the weak signal from the input stage to meet the driving requirements of the output stage.

[0023] 4. Output stage The output stage module is a quasi-complementary output stage, including transistors Q1 and Q2, transistors Q6 and Q10, resistors R1 and R2, and transistor Q3. The emitter of transistor Q1 is connected to the base of transistor Q2, and the collectors of transistors Q1 and Q2 are connected to form a second composite transistor. The emitter of transistor Q6 is connected to the base of transistor Q10, and the collectors of transistors Q6 and Q10 are connected to form a third composite transistor. Resistors R1 and R2 are connected in series between the amplified output of the first common-emitter amplifier circuit and the positive terminal of the power supply. The base of transistor Q3 is connected to the common terminal of resistors R1 and R2, and the collector and emitter are connected to the other ends of resistors R1 and R2, respectively, to form a multiplier circuit. The bases of the second and third composite transistors are connected to the other ends of resistors R1 and R2, respectively, to form a second amplifier and a third amplifier. The complementary symmetry output third composite transistor consists of transistors Q6 and Q10, which together form a complementary symmetry power amplifier circuit (typically a Class B or Class AB amplifier). This structure can provide a large output current to drive the load. During the positive half-cycle of the signal, transistor Q6 is turned on and transistor Q10 is turned off, with current flowing from transistor Q6 to the load; during the negative half-cycle, transistor Q10 is turned on and transistor Q6 is turned off, with current flowing from the load back to transistor Q10. This enables bidirectional amplification of AC signals, improving output power and efficiency.

[0024] 5. The voltage regulation protection section consists of a current-limiting resistor R3 and a Zener diode D2. The Zener diode D2 and the current-limiting resistor R3 together form the output voltage regulation and protection circuit. When the output voltage Uo exceeds the Zener diode D2's regulation voltage, the Zener diode D2 will break down in reverse, clamping the output voltage near its regulation value to prevent excessive output voltage from damaging subsequent circuits. The current-limiting resistor R3 limits the current flowing through D2, preventing excessive current from damaging D2 and ensuring the normal operation of the voltage regulation and protection function.

[0025] In summary, this integrated operational amplifier voltage protection circuit prevents damage to the circuit from abnormal power supply through power supply protection at the power supply end, preprocesses the signal at the input stage, amplifies the signal at the intermediate stage, drives the load at the output stage, and ensures that the output voltage is stable and safe through the voltage regulation protection circuit, so that the entire circuit can work stably and reliably under various conditions.

[0026] The circuit in this embodiment is used to control the frequency of the filter. Through the combined application of an integrated operational amplifier and an active LC filter for frequency gating, the test results show good background noise, stable frequency selection control, and high reliability. Figure 3 and Figure 4 As shown.

Claims

1. An integrated operational amplifier voltage protection circuit, characterized in that: include: Input stage module, intermediate stage module, output stage module, voltage regulation and protection module, power supply module, power supply terminal protection module; The power module has a positive power terminal (+VCC) and a negative power terminal (VEE). The input stage module includes transistors Q4, Q5, Q7, and Q8. Transistors Q4 and Q5 form a differential amplifier circuit with dual-ended input and single-ended output, where signals are input from the bases of transistors Q4 and Q5 and output from the collector of transistor Q5. The emitters of transistors Q4 and Q5 are connected to the positive terminal (+VCC) of the power supply. Transistors Q7 and Q8 form a current mirror source, serving as the active load of the differential amplifier circuit. The base and collector of transistor Q7 and the base of transistor Q8 are connected to the collector of transistor Q4. The emitters of transistors Q7 and Q8 are connected to the negative terminal (VEE) of the power supply. The collector of transistor Q8 is connected to the collector of transistor Q5. The intermediate stage module includes transistors Q9 and Q11; the emitter of transistor Q9 is connected to the base of transistor Q11, and the collectors of transistors Q9 and Q11 are connected to form a first composite transistor; the base of the first composite transistor is connected to the output terminal of the differential amplifier circuit, and the emitter of the first composite transistor is connected to the negative terminal (VEE) of the power supply, forming a first common-emitter amplifier circuit with base input and collector output of the first composite transistor; The output stage module is a quasi-complementary output stage, including transistors Q1 and Q2, transistors Q6 and Q10, resistors R1 and R2, and transistor Q3. The emitter of transistor Q1 is connected to the base of transistor Q2, and the collectors of transistors Q1 and Q2 are connected to form a second composite transistor. The emitter of transistor Q6 is connected to the base of transistor Q10, and the collectors of transistors Q6 and Q10 are connected to form a third composite transistor. Resistors R1 and R2 are connected in series between the amplified output of the first common-emitter amplifier circuit and the positive terminal (+VCC) of the power supply. The base of transistor Q3 is connected to the common terminal of resistors R1 and R2, and the collector and emitter are connected to the other ends of resistors R1 and R2, respectively, to form a multiplier circuit. The bases of the second and third composite transistors are connected to the other ends of resistors R1 and R2, respectively, to form a second amplifier and a third amplifier. The voltage regulation protection module includes a current-limiting resistor R3 and a Zener diode D2 forming a limiting circuit.

2. The integrated operational amplifier voltage protection circuit according to claim 1, characterized in that: When the power module is connected, a power supply protection module is also included; The power supply protection module includes a diode D1 located at the positive terminal (+VCC) and a diode D3 located at the negative terminal (VEE); the P terminal of diode D1 and the N terminal of diode D3 are connected to the positive terminal (+VCC) and the negative terminal (VEE) of the power supply, respectively.

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