A Circuit to Prevent Common-Mode Latch-up of a Fully Differential Operational Amplifier

Abstract

The invention provides a circuit for preventing common-mode latch-up of a full-differential operational amplifier, which relates to the field of integrated circuits. When the common-mode output of the full-differential operational amplifier is latched, an anti-latch protection circuit is triggered to work. When the low-level latch detection circuit detects that the common-mode output latch is at a low level, it controls the charging circuit to charge the output stage circuit, and releases the low-level latch state of the common-mode output; the high-level latch detection circuit detects that the common When the mode output latch is at a high level, the discharge circuit is controlled to discharge the output stage circuit, and the latch state of the common mode output high level is released. When the common-mode output of the fully differential operational amplifier releases the latch state and returns to the normal state, the anti-latch protection circuit does not work so as not to affect the operation of the differential operational amplifier. The invention can prevent the common-mode latch of the fully differential operational amplifier, and the anti-latch protection circuit is in a dormant state after the latch state is released, which does not affect the working performance of the fully differential operational amplifier and does not introduce additional power consumption.

Description

technical field [0001] The invention relates to the field of integrated circuits, in particular to a circuit for preventing common-mode latch-up of fully differential operational amplifiers. Background technique [0002] Fully differential operational amplifiers are widely used in wireless transceiver integrated circuits and are an important part of intermediate frequency analog signal processing modules. Fully differential operational amplifiers are generally used in negative feedback circuit networks, such as active filter circuits and variable gain amplifiers. As the operating speed and performance of these modules increase, the feedback network composed of fully differential op amps is also more complex and operates at higher frequencies, making the latch-up problem of the common mode output of the fully differential op amp more prominent. Usually, in order to solve the common-mode latch-up of the fully differential operational amplifier, it is necessary to increase the...

AI Technical Summary

Problems solved by technology

However, with the increase of the operating frequency and the complexity of the feedback network, increasing the gain of the common-mode feedback circuit will cause the deterioration of the phase margin, making the common-mode negative feedback into a positive feedback. At the same time, the increase of the gain of the common-mode feedback circuit will affect the main Differential Op Amp Performance and Power Consumption

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