A Large Dynamic Range Switch Array Variable Gain Amplifier

Abstract

The invention relates to a large dynamic range switch array variable gain amplifier, which includes an external register, a gain stage module and a fine adjustment stage module. The gain stage module is composed of gain stage units connected in sequence, and the gain stage unit includes a transconductance operational amplifier. and the switch array, the fine-tuning module includes a transconductance operational amplifier and a variable resistor for adjusting the transconductance operational amplifier, and the control signal output terminal of the external register is divided into two ways to control the operation of the switch array and adjust the variable resistor resistance value. In the above technical solution, the switch array is used to control the opening and closing of each gain stage. The opening of the subsequent gain stages does not need to be conditional on the opening of the previous stages of gain stages. The gain settings of the gain stages can be distributed in an exponential manner. While improving the dynamic range, the gain accuracy of the overall system is improved; at the same time, the fine-tuning circuit structure of the variable resistor is used to further improve the gain accuracy.

Description

technical field [0001] The invention relates to the field of variable gain amplifiers, in particular to a large dynamic range switch array variable gain amplifier. Background technique [0002] The previous variable gain amplifier is formed by cascading multiple sub-stages with the same gain in sequence. The total gain is the sum of the gains of each sub-stage. When the gain needs to be lowered, each gain sub-stage is closed step by step from back to front; the gain of all sub-stage amplifiers is the same, so the accuracy of the whole variable gain amplifier is lower, which is equal to the gain of its sub-stage amplifier; and in order to improve The accuracy of the overall amplifier, the gain of each sub-stage amplifier cannot be designed too high, resulting in a low dynamic range of the variable gain amplifier, generally only 20-30dB, which has gradually failed to meet the requirements of today's high-sensitivity RF receivers, such as Bluetooth, ZigBee, wireless LAN networ...

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Problems solved by technology

[0002] The previous variable gain amplifier is formed by cascading multiple sub-stages with the same gain in sequence. The total gain is the sum of the gains of each sub-stage. When the gain needs to be lowered, each gain sub-stage is closed step by step from back to front; the gain of all sub-stage amplifiers is the same, so the accuracy of the whole variable gain amplifier is lower, which is equal to the gain of its sub-stage amplifier; and in order to improve The accuracy of the overall amplifier, the gain of each sub-stage amplifier cannot be designed too high, resulting in a low dynamic range of the variable gain amplifier, generally only 20-30dB, which has gradually failed to meet the requirements of today's high-sensitivity RF receivers, such as Bluetooth, ZigBee, wireless LAN network (WLAN), wireless body area network (WBAN) and global positioning system (GPS); at the same time, the exact same multiple gain sub-stage cascade structure leads to larger power consumption and chip area

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