Bidirectional Level Shifter Circuit With Faster Transient Response
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Solution Overview
Problem
Conventional bidirectional level shifters suffer from insufficient pull-up capability, limited pull-down capability, and significant gate delay, resulting in slow signal transmission speed.
Innovation Solution
The proposed bidirectional signal conversion circuit includes a switch, pull-up resistors, and output-response enhancement circuits with AC coupling and output-stage configurations, which accelerate transient responses and improve signal transmission speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional bidirectional level shifter circuit configuration is used, then the circuit structure is simple, but the signal transmission speed is very slow
Solution Approach 1:
The patent applies dynamics by making the pull-up capability adjustable through a control signal. The first and second output-stage circuits can dynamically switch between different pull-up configurations (first pull-up resistor only, or first and second pull-up resistors in parallel) based on the state of the control signal, allowing the circuit to adapt its characteristics for optimal performance.
Solution Approach 2:
The patent changes the electrical parameters of the circuit by introducing a control signal that modifies the effective pull-up resistance. When the control signal is active, the circuit switches between different resistance configurations, thereby changing the pull-up strength and signal transmission characteristics to improve speed while maintaining simplicity.
2Speed
If additional circuits are added to improve pull-up capability, then the signal transmission speed improves, but the gate delay increases significantly
Solution Approach 1:
The control signal serves multiple functions: it controls the switching of the second output-stage circuit, activates the second pull-up resistor, and coordinates the operation of multiple circuit components. This multi-functionality allows the circuit to achieve improved signal transmission speed without adding significant gate delay, as the same control signal orchestrates multiple improvements simultaneously.
3Power
If pull-up resistors are used, then the voltage can be pulled up, but the pull-up capability is insufficient
Solution Approach 1:
The circuit dynamically adjusts its pull-up capability by switching between different resistor configurations. The first output-stage circuit provides a baseline pull-up capability using the first pull-up resistor, while the second output-stage circuit can activate the second pull-up resistor in parallel when additional pull-up strength is needed, creating a dynamic, adaptive pull-up system.
Solution Approach 2:
The circuit prepares multiple pull-up configurations in advance through the control signal mechanism. The first and second pull-up resistors are both present in the circuit, ready to be activated based on the control signal state. This preliminary preparation allows the circuit to quickly switch to the appropriate pull-up configuration without adding significant delay when enhanced pull-up capability is required.
Data Source
AI summary
A bidirectional signal conversion circuit is configured to perform a signal conversion between a first port and a second port, and includes a switch, a first pull-up resistor, a second pull-up resistor, a first output-response enhancement circuit, and a second output-response enhancement circuit. The switch is coupled between the first port and the second port, and operates according to a bias. The first (second) pull-up resistor is coupled between the first (second) port and a high (low) voltage terminal having a high (low) voltage. The first (second) output-response enhancement circuit includes a first (second) alternative-current (AC) coupling circuit and a first (second) output-stage circuit. When the first (second) port and the second (first) port functions as an input port and an output port respectively, the first (second) output-response enhancement circuit is operable to accelerate the transient response of the output port.