CN218868203U - RC compensation loop - Google Patents
RC compensation loop Download PDFInfo
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- CN218868203U CN218868203U CN202221955449.XU CN202221955449U CN218868203U CN 218868203 U CN218868203 U CN 218868203U CN 202221955449 U CN202221955449 U CN 202221955449U CN 218868203 U CN218868203 U CN 218868203U
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- operational amplifier
- resistor
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- capacitor
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
- Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
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Abstract
The utility model aims at providing a simple structure, eliminate frequency oscillation's RC compensation loop. The utility model discloses an operational amplifier, RC circuit, MOS pipe and instrumentation amplifier, operational amplifier's syntropy input is inserted and is set for voltage, the RC circuit connection be in operational amplifier with between the MOS pipe, the drain electrode of MOS pipe inserts input voltage, the source electrode of MOS pipe with instrumentation amplifier's input is connected, instrumentation amplifier's output with operational amplifier's reverse input is connected. The utility model discloses be applied to integrated circuit's technical field.
Description
Technical Field
The utility model discloses be applied to integrated circuit's technical field, in particular to RC compensation loop.
Background
The operational amplifier is internally composed of a plurality of stages of direct current amplifiers, because the output of each stage of amplifier and the input of the next stage of amplifier have output impedance, input impedance and distributed capacitance, R-C phase shift networks exist among stages, an additional phase shift is generated after a signal passes through each stage of R-C network, in addition, an external bias resistor, an operational amplifier input capacitance, an operational amplifier output resistance, a capacitive load feedback capacitance and a plurality of stages of operational amplifiers are coupled through common internal resistance of a power supply and even poor grounding of distributed inductance on a power supply line, and the like, signals output by the operational amplifiers can form the additional phase shift result, the additional phase shift is added to 180 degrees through a negative feedback loop, and if the feedback quantity is large enough, negative feedback is converted into positive feedback to cause oscillation. Therefore, it is necessary to provide an RC compensation loop with a simple structure and capable of eliminating frequency oscillation.
SUMMERY OF THE UTILITY MODEL
The utility model aims to solve the technical problem that overcome prior art not enough, provide a simple structure, eliminate the oscillating RC compensation loop of frequency.
The utility model adopts the technical proposal that: the utility model discloses an operational amplifier, RC circuit, MOS pipe and instrumentation amplifier, operational amplifier's syntropy input inserts settlement voltage, the RC circuit connection be in operational amplifier with between the MOS pipe, the drain electrode of MOS pipe inserts input voltage, the source electrode of MOS pipe with instrumentation amplifier's input is connected, instrumentation amplifier's output with operational amplifier's reverse input is connected.
It can be seen from the above-mentioned scheme that the RC compensation loop includes input X, open-loop transmission path G and closed-loop feedback path H, realizes the amplification and the conversion of signal, input X is set voltage Vset, open-loop transmission path G includes operational amplifier MOS pipe and RC circuit, closed-loop feedback path H includes instrument amplifier has constituted PID loop regulation input output, and original loop adopts multistage op-amp structure and the low pass filter who increases, leads to the frequency response characteristic of loop and the open-loop phase-frequency characteristic that the data manual gave to be different, changes input current size simultaneously and changes open-loop gain promptly and can influence open-loop frequency response, the RC circuit is used for eliminating the frequency oscillation of loop control, improves the frequency response characteristic of system and promotes stability. By reducing the loop gain, reducing the feedback quantity and increasing the closed loop gain, the operational amplifier is easy to vibrate as voltage following, the amplification factor is increased, and the vibration disappears.
Preferably, the RC circuit includes a first resistor and a first capacitor, the first resistor is connected in parallel with the first capacitor, and the RC circuit is connected between the output end of the operational amplifier and the gate of the MOS transistor.
According to the scheme, the first resistor is connected to the operational amplifier to eliminate the phase lag of the feedback loop, the first resistor is connected with the first capacitor in parallel to form an RC parallel circuit, the RC parallel circuit can increase a zero point at a crossing frequency and a pole at a higher frequency, the frequency response characteristic of a system is improved, and the RC parallel circuit can break the frequency through direct current and alternating current signals: f0=1/2 π R1C1. When the frequency of the input signal is less than f0, the signal is direct current relative to the circuit, and the total impedance of the circuit is equal to R1; when the frequency of the input signal is larger than f0, the capacitive reactance of C1 is relatively small, and the total impedance is the resistance value of the resistor and is connected with the capacitive reactance. The total impedance is 0 when the frequency is high to some extent.
Preferably, the RC compensation loop further includes a second resistor, a second capacitor, and a third resistor, the output terminal of the operational amplifier is connected to the inverting input terminal of the operational amplifier through the second capacitor, the output terminal of the instrumentation amplifier is connected to the inverting input terminal of the operational amplifier through the second resistor, the non-inverting input terminal of the instrumentation amplifier is connected to the inverting input terminal of the instrumentation amplifier through the third resistor, and the third resistor is grounded.
It can be seen from the above solution that the third resistor is a current-limiting resistor, and the current-limiting resistor prevents overvoltage from driving excessive current through the internal electrostatic discharge clamping diode, the open-loop transfer path G further includes the first resistor, the first capacitor, and the second capacitor, and the closed-loop feedback path H includes the second resistor and the third resistor.
When the frequency is the high band, the gain is:
when the frequency is a direct current frequency band, the gain is approximately a steady state value:
phase argument added by RC compensator:
the increased phase margin will reduce the oscillation across the frequency point.
Drawings
FIG. 1 is a schematic circuit diagram of the present invention;
fig. 2 is a schematic block diagram of the present invention.
Detailed Description
As shown in fig. 1 to fig. 2, in this embodiment, the utility model discloses an operational amplifier Amp, RC circuit, MOS pipe and instrumentation amplifier INA, operational amplifier Amp's syntropy input end access settlement voltage Vset, the RC circuit is connected operational amplifier Amp with between the MOS pipe, the drain electrode of MOS pipe inserts input voltage Vin, the source electrode of MOS pipe with instrumentation amplifier INA's input is connected, instrumentation amplifier INA's output with operational amplifier Amp's reverse input end is connected.
In this embodiment, the RC circuit includes a first resistor R2 and a first capacitor C2, the first resistor R2 is connected in parallel with the first capacitor C2, and the RC circuit is connected between the output end of the operational amplifier Amp and the gate of the MOS transistor.
In this embodiment, the RC compensation loop further includes a second resistor R1, a second capacitor C1, and a third resistor Rsense, an output end of the operational amplifier Amp is connected to an inverting input end of the operational amplifier Amp through the second capacitor C1, an output end of the instrumentation amplifier INA is connected to the inverting input end of the operational amplifier Amp through the second resistor R1, a same-direction input end of the instrumentation amplifier INA is connected to the inverting input end of the instrumentation amplifier INA through the third resistor Rsense, and the third resistor Rsense is grounded.
The utility model discloses a theory of operation:
the operational amplifier is characterized in that a homodromous input end is connected with a set voltage, a first resistor is connected with a first capacitor in parallel and is connected between an output end of the operational amplifier and a grid electrode of an MOS (metal oxide semiconductor) tube, a drain electrode of the MOS tube is connected with the input voltage, a source electrode of the MOS tube is connected with an input end of an instrumentation amplifier, an output end of the instrumentation amplifier is connected with a reverse input end of the operational amplifier, the first resistor is connected with the first capacitor in parallel to form an RC (resistor-capacitor) parallel circuit, the RC parallel circuit can increase a zero point crossing frequency and a pole crossing higher frequency, improve the frequency response characteristic of a system, eliminate the frequency oscillation of loop control, improve the frequency response characteristic of the system and improve the stability.
Claims (3)
1. An RC compensation loop, characterized by: the operational amplifier Amp comprises an operational amplifier Amp, an RC circuit, an MOS tube and an instrument amplifier INA, wherein a set voltage Vset is connected to the same-direction input end of the operational amplifier Amp, the RC circuit is connected between the operational amplifier Amp and the MOS tube, an input voltage Vin is connected to the drain electrode of the MOS tube, the source electrode of the MOS tube is connected with the input end of the instrument amplifier INA, and the output end of the instrument amplifier INA is connected with the reverse input end of the operational amplifier Amp.
2. An RC compensation loop as claimed in claim 1, wherein: the RC circuit comprises a first resistor R2 and a first capacitor C2, the first resistor R2 is connected with the first capacitor C2 in parallel, and the RC circuit is connected between the output end of the operational amplifier Amp and the grid electrode of the MOS tube.
3. An RC compensation loop as claimed in claim 1, wherein: the RC compensation loop further comprises a second resistor R1, a second capacitor C1 and a third resistor Rsense, the output end of the operational amplifier Amp is connected with the reverse input end of the operational amplifier Amp through the second capacitor C1, the output end of the instrument amplifier INA is connected with the reverse input end of the operational amplifier Amp through the second resistor R1, the same-direction input end of the instrument amplifier INA is connected with the reverse input end of the instrument amplifier INA through the third resistor Rsense, and the third resistor Rsense is grounded.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202221955449.XU CN218868203U (en) | 2022-07-27 | 2022-07-27 | RC compensation loop |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202221955449.XU CN218868203U (en) | 2022-07-27 | 2022-07-27 | RC compensation loop |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN218868203U true CN218868203U (en) | 2023-04-14 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202221955449.XU Active CN218868203U (en) | 2022-07-27 | 2022-07-27 | RC compensation loop |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN218868203U (en) |
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2022
- 2022-07-27 CN CN202221955449.XU patent/CN218868203U/en active Active
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