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A circuit and method for accelerating the stability of an operational amplifier

An amplifier circuit and stabilization technology, which is applied in the field of electronic circuits, can solve problems such as accelerating the stabilization process of operational amplifiers, fluctuations in output swings of operational amplifiers, and difficulties, and achieves the effects of saving power consumption and avoiding large pressure differences

Active Publication Date: 2018-07-20
AMICRO SEMICON CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, most op amp acceleration and stabilization technologies cannot solve the problem of image 3 Encountered applications
There are two reasons: 1. Since the op amp is configured in the amplification mode, even a small input signal change will cause a large swing change in the output of the op amp, and it is difficult to accelerate the stabilization process of the op amp by using the change in the input voltage difference between the two ends of the op amp; 2. When the input signal is a low-frequency signal, even if the swing output of the op amp fluctuates, since the output of the op amp can track the speed of the input signal change in time, there is no need to turn on the output of the op amp to accelerate the stabilization process, but due to the rapid switching of the input signal (such as Input signal source changes), at this time, it is required to turn on the output acceleration stabilization function of the op amp, and track the input signal changes of the op amp in time, which means that it is not possible to judge whether to enable the output acceleration stabilization process of the op amp directly based on the output DC level of the op amp

Method used

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  • A circuit and method for accelerating the stability of an operational amplifier
  • A circuit and method for accelerating the stability of an operational amplifier
  • A circuit and method for accelerating the stability of an operational amplifier

Examples

Experimental program
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Embodiment 1

[0027] Such as Figure 4 As shown, the circuit for accelerating the stability of the operational amplifier provided in this embodiment includes: an AC detection amplifier circuit, a first Schmitt comparator, a second Schmitt comparator, a PMOS transistor P0 and an NMOS transistor NM0. In order to facilitate the description of this embodiment, Figure 4A full-swing operational amplifier is given in , which has input vin and vip, output vout, power supply VCC and ground terminal, and the figure also shows the last stage drive tubes PM1 and NM1 of the operational amplifier.

[0028] Such as Figure 5 As shown, the AC detection amplifier circuit in this embodiment is composed of a capacitor c0, a PMOS transistor PM2, an NMOS transistor NM2, and a resistor r1. One end of the capacitor c0 is connected to the output vout of the full-swing operational amplifier, the other end is connected to one end of the resistor r1, and the other end of the resistor r1 is connected to the D pole ...

Embodiment 2

[0036] The difference between the second embodiment and the first embodiment is that the first embodiment uses the differential signals ac_p and ac_n to generate the corresponding control signals pd and pu; while the second embodiment only generates a single-ended signal ac_p according to the output AC signal vout of the detection op amp , and then subsequently connect a threshold comparator (typically a Schmitt comparator) to generate pu and pd pulse signals, such as Figure 9 As shown, at this time, two comparison reference voltages vref1 and vref2 need to be added, and this modification can also achieve the technical purpose of the present application.

[0037] The circuit and method for accelerating the stability of the operational amplifier proposed in the above embodiments use the detection of the AC signal amplitude of the output node of the operational amplifier to determine whether to enable the auxiliary acceleration and stabilization function, avoiding the requiremen...

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Abstract

The invention discloses a circuit and a method for accelerating stabilization of an operational amplifier. The circuit comprises an alternating-current detection amplifying circuit, a first comparator, a second comparator, a first switching device and a second switching device, wherein the alternating-current detection amplifying circuit is used for detecting an output vout of the operational amplifier and inputting an acquired detection signal into the first comparator and the second comparator respectively; an output of the first comparator is used for controlling the on / off of the first switching device; an output of the second comparator is used for controlling the on / off of the second switching device; the first switching device is used for connecting or disconnecting the output vout of the operational amplifier with or from a power supply VCC; and the second switching device is used for connecting or disconnecting the output of the operational amplifier with or from the ground. According to the circuit and the method for accelerating the stabilization of the operational amplifier, whether to enable an auxiliary stabilization accelerating function or not is determined by detection of an alternating-current signal amplitude of an output node of the operational amplifier; a requirement on a relatively high voltage difference at a differential input end of the operational amplifier is avoided; the situation that the auxiliary accelerating function does not need to be enabled due to direct detection of a direct-current level at the output node of the operational amplifier during tracking of a low-frequency input signal is avoided; and unnecessary power consumption is saved.

Description

technical field [0001] The invention relates to the technical field of electronic circuits, in particular to a circuit and method for accelerating the stability of an operational amplifier (op amp). Background technique [0002] Operational amplifiers (op amps for short) are widely used as the basic module of analog circuits, and require short stabilization time in many fields, for example, they are used in ADC front-end variable gain drivers. Existing technologies for accelerating the stabilization process of operational amplifiers either require a large voltage difference between the two input terminals of the operational amplifier, or directly detect the output DC level of the operational amplifier to accelerate the stabilization time in the case of a large swing output, such as figure 1 and figure 2 shown. For example patents US6359512 B1, US2012 / 0013378 A1, US8089314 B2. [0003] However, in some op amp applications, although the output swing of the op amp is large,...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H03F1/30H03F3/45
Inventor 杨秋平
Owner AMICRO SEMICON CORP