Parallel Driver Circuit With Body Bias for MIPI Output Compliance
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Solution Overview
Problem
The decrease in voltage of high-speed communication drivers in electronic apparatuses, such as those following MIPI standards, affects the output level of low-speed communication drivers, leading to non-compliance with specifications due to increased output impedance and leakage currents.
Innovation Solution
An electronic circuit with multiple high-speed drivers operating in parallel and a low-speed driver, where the body bias voltage is trimmed to optimize the output impedance and output level, ensuring both meet predetermined standards by adjusting the number of parallel high-speed drivers and applying a body bias voltage to control the threshold voltage of MOSFETs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the voltage of high-speed communication drivers is decreased, then power consumption is reduced, but the output level of low-speed communication drivers deteriorates due to increased output impedance and leakage currents
Solution Approach 1:
The driver circuit is segmented into multiple parallel high-speed drivers (first drivers) and a separate low-speed driver (second driver). Each segment can be independently controlled and optimized. The high-speed drivers are configured with transistors having bodies connected to specific potential lines, allowing independent voltage control for high-speed operation while maintaining proper output levels for low-speed communication through the separate second driver.
Solution Approach 2:
Different parts of the circuit are given different electrical characteristics suitable for their specific function. The first drivers use transistors with bodies connected to a first potential line optimized for high-speed communication, while the second driver uses transistors with bodies connected to a second potential line optimized for low-speed communication output levels. This local differentiation allows each part to operate optimally without compromising the other.
2Reliability
If multiple first drivers are coupled in parallel to meet output impedance standards, then the output impedance is improved, but the circuit complexity increases
Solution Approach 1:
The first drivers are designed to serve multiple functions: they provide high-speed communication capability and simultaneously contribute to meeting output impedance standards when coupled in parallel. The same parallel configuration that achieves the required output impedance also provides the necessary high-speed data transmission capability, making the circuit structure multi-functional and reducing overall complexity.
3Reliability
If the number of first drivers operating in parallel is increased to meet output impedance standards, then the output impedance compliance is improved, but the power consumption increases
Solution Approach 1:
The body potential of the transistors in the first drivers is changed by connecting bodies to a specific first potential line rather than using conventional ground connections. This parameter change allows the drivers to achieve proper output impedance compliance with fewer parallel units, thereby reducing the total power consumption while still meeting the required output impedance standards for high-speed communication.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration allows the electronic apparatus to maintain compliant output levels and impedance for both high-speed and low-speed communication drivers, even under reduced voltage conditions, by optimizing the body bias voltage and number of parallel high-speed drivers.
Implementation Method 1
application of an electrical potential to bodies of the transistors of the first drivers, the electrical potential causing an output level of the second driver to meet a predetermined standard
Data Source
AI summary
An electronic circuit that includes a plurality of first drivers coupled in parallel, the first drivers each including transistors coupled in series and transmitting data at a predetermined communication speed, and a second driver that includes transistors coupled in series and transmitting data at a communication speed lower than the communication speed of the first driver. The number of first drivers operating in parallel is sufficient for output impedance of the first drivers to meet a predetermined standard through application of an electrical potential to bodies of the transistors of the first drivers. The electrical potential causes an output level of the second driver to meet a predetermined standard.