Driver amplifier with programmable single-ended and differential outputs
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Solution Overview
Problem
Current output drivers in wireless communication devices can only provide either differential or single-ended outputs, limiting their functionality and efficiency, especially when paired with differential or single-ended power amplifiers.
Innovation Solution
A programmable output driver with a shunt configuration and programmable attenuators allows for selective operation in both single-ended and differential modes by controlling switches and attenuators to achieve desirable impedance, enabling the driver amplifier to drive power amplifiers with either single-ended or differential signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an output driver is designed to provide only differential or single-ended outputs, then the circuit design is simple, but the adaptability to different power amplifier types is limited
Solution Approach 1:
The output driver is designed to provide both differential and single-ended outputs through a unified circuit architecture. The differential output path includes a first switch coupled in shunt configuration to the first path, while the single-ended output path uses the same switch to ground the first path when activated. This multi-functional design allows the same output driver to interface with both differential and single-ended power amplifiers without requiring separate dedicated circuits for each mode.
Solution Approach 2:
The output driver incorporates programmable attenuators and switches that can be dynamically configured based on the required output mode. The first switch can be selectively activated to ground the first path for single-ended operation, while programmable attenuators adjust signal levels. This dynamic reconfiguration capability enables the circuit to adapt its behavior and impedance characteristics according to whether differential or single-ended output is needed, resolving the contradiction between versatility and complexity.
2Loss of energy
If a single-ended output driver is used with a differential power amplifier, then a balun is required which increases transformer area, but using a differential output driver with a single-ended power amplifier causes signal losses
Solution Approach 1:
The output driver enables dynamic changing of output signal characteristics (differential or single-ended) based on the power amplifier type. When a single-ended power amplifier is detected or selected, the driver outputs single-ended signals directly, eliminating the need for balun transformation and associated losses. When a differential power amplifier is used, the driver switches to differential output mode, avoiding the need for input baluns at the PA side. This parameter change capability directly addresses the energy loss issue by matching signal types to amplifier requirements.
Solution Approach 2:
The invention converts the potential harm of mismatched signal types (single-ended to differential or vice versa) into benefit by providing programmable output modes. Instead of forcing a mismatch that requires lossy baluns, the system can be configured to output the appropriate signal type directly, turning what would have been a harmful mismatch into a beneficial direct connection that eliminates transformation losses and reduces transformer area requirements.
3Productivity
If fixed output mode driver amplifiers are used, then the design is straightforward, but the efficiency across various wireless standards is reduced
Solution Approach 1:
The output driver incorporates programmable attenuators and switches that can be dynamically configured based on the required output mode. The first switch can be selectively activated to ground the first path for single-ended operation, while programmable attenuators adjust signal levels. This dynamic reconfiguration capability enables the circuit to adapt its behavior and impedance characteristics according to whether differential or single-ended output is needed, resolving the contradiction between versatility and complexity.
Solution Approach 2:
The output driver enables dynamic changing of output signal characteristics (differential or single-ended) based on the power amplifier type. When a single-ended power amplifier is detected or selected, the driver outputs single-ended signals directly, eliminating the need for balun transformation and associated losses. When a differential power amplifier is used, the driver switches to differential output mode, avoiding the need for input baluns at the PA side. This parameter change capability directly addresses the energy loss issue by matching signal types to amplifier requirements.
Data Source
AI summary
An output driver with programmable single-ended and differential outputs includes a first switch, a first output attenuator, and a programmable attenuator. The first switch is coupled in a shunt configuration to a first path of a differential output of a first amplifier. The first output attenuator is included in the first path and is coupled to the first switch in accordance with the shunt configuration. The programmable attenuator is included in a second path of the differential output of the first amplifier.