Switchable Op-Amp Input Pairs for Bandwidth and 1/F Noise Tradeoffs
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Solution Overview
Problem
Conventional communication devices require multiple amplifiers for different modes of operation, leading to increased device size and cost due to the need for separate amplifier circuits optimized for specific cellular technologies like GSM and LTE, each with unique performance characteristics.
Innovation Solution
A single switchable amplifier with a core amplifier circuit and switchable input transistor pairs that can be configured to either small or large transistor pairs, allowing for selection between high bandwidth and low 1/f noise performance based on the operational mode, thereby eliminating the need for multiple amplifier circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple amplifiers are used for different cellular technologies, then performance characteristics for each mode are optimized, but device size and cost increase
Solution Approach 1:
The patent merges multiple amplifier circuits into a single amplifier by providing a first input transistor pair and a second input transistor pair that can be selectively activated. The first input transistor pair is optimized for GSM mode with larger transistor size for low 1/f noise, while the second input transistor pair is optimized for LTE mode with smaller transistor size for high frequency performance. Switches selectively connect either the first or second input transistor pair to the amplifier core based on the operating mode, eliminating the need for separate amplifier circuits for each cellular technology.
Solution Approach 2:
The single amplifier is designed to perform multiple functions by supporting both GSM and LTE modes through selectable input transistor pairs. The amplifier core remains universal and can process signals from either input transistor pair, making the amplifier multi-functional across different cellular technologies without requiring separate dedicated amplifiers for each mode.
2Reliability
If multiple amplifiers are used for different cellular technologies, then performance characteristics for each mode are optimized, but device cost increases
Solution Approach 1:
The patent merges multiple amplifier circuits into a single amplifier by providing a first input transistor pair and a second input transistor pair that can be selectively activated. The first input transistor pair is optimized for GSM mode with larger transistor size for low 1/f noise, while the second input transistor pair is optimized for LTE mode with smaller transistor size for high frequency performance. Switches selectively connect either the first or second input transistor pair to the amplifier core based on the operating mode, eliminating the need for separate amplifier circuits for each cellular technology.
3Reliability
If large input transistor pair is used, then 1/f noise performance improves, but bandwidth decreases
Solution Approach 1:
The patent implements dynamic switching between the first and second input transistor pairs based on the operating mode. The switches selectively connect either the first input transistor pair (optimized for low 1/f noise in GSM mode) or the second input transistor pair (optimized for high bandwidth in LTE mode) to the amplifier core. This dynamic reconfiguration allows the amplifier to adapt its transistor pair selection to the specific performance requirements of each cellular technology.
4Speed
If small input transistor pair is used, then bandwidth improves, but 1/f noise performance worsens
Solution Approach 1:
The patent implements dynamic switching between the first and second input transistor pairs based on the operating mode. The switches selectively connect either the first input transistor pair (optimized for low 1/f noise in GSM mode) or the second input transistor pair (optimized for high bandwidth in LTE mode) to the amplifier core. This dynamic reconfiguration allows the amplifier to adapt its transistor pair selection to the specific performance requirements of each cellular technology.
Data Source
AI summary
Techniques for designing a switchable amplifier are described. In one aspect, a switchable amplifier including a core amplifier circuit configured to selectively enable one or more parallel input transistor pairs is described. The core amplifier circuit comprises a permanently enabled input transistor pair. In another aspect, a device operable between a first mode of operation and a second mode of operation comprising a receiver logic circuit for selectably enabling and disabling a plurality of input transistor pairs within a switchable amplifier is described where the switchable amplifier also includes a core amplifier circuit coupled to the receiver logic circuit for selectably enabling and disabling a transistor pair therein. The described switchable amplifiers result in the ability to provide varying amplifier performance characteristics based upon the current mode of operation of the device.