Charge Pump Level-Shifter Circuit for High Data Rate Settling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High data rate input signals cause a speed bottleneck in the level-shifter of the Stratix II GX charge pump circuit, leading to reduced output current and incomplete settling of charge pump current, resulting in errors in the control voltage on the loop filter capacitor and reduced tolerance to jitter in the input data signal.
Innovation Solution
A charge pump circuit with thin-oxide transistors and a level-shifter that includes a cross-coupled pair of transistors to shift the voltage of input signals, enabling the charge pump to operate at higher speeds and improve settling performance by regulating the output voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If thick-oxide transistors are used in the charge pump to function with 3-volt supply voltage, then the charge pump can obtain large control voltage range, but the level-shifter experiences speed bottleneck at high data rates
Solution Approach 1:
The patent changes the oxide thickness parameter of the transistors from thick-oxide to thin-oxide. This parameter change enables the transistors to operate at higher speeds while still functioning with the 3-volt supply voltage, thereby resolving the speed bottleneck in the level-shifter at high data rates while maintaining the large control voltage range
2Speed
If the level-shifter operates at high speed, then the charge pump can handle high data rates, but the output current settles incompletely resulting in control voltage errors
Solution Approach 1:
The patent changes the transistor oxide thickness parameter to thin-oxide, which improves the switching speed and settling time of the charge pump. This allows the charge pump to complete its current settling process even at high data rates, thereby maintaining control voltage accuracy while handling high data rates
Solution Approach 2:
The patent implements a feedback mechanism where the charge pump output is monitored and adjusted to ensure complete settling. The feedback loop detects incomplete settling conditions and adjusts the charge pump operation to ensure accurate control voltage generation, resolving the issue of control voltage errors at high speeds
Data Source
AI summary
A charge pump circuit includes at least one switching transistor and a level-shifter. The level-shifter has a cross-coupled pair of transistors. The level-shifter shifts a voltage of a first input signal to generate a level-shifted signal. The level-shifted signal controls a conductive state of the switching transistor to regulate an output voltage of the charge pump. A feedback loop circuit includes a detector and a charge pump. The detector compares an input signal to a feedback signal to generate first and second output signals. The charge pump includes at least two thin-oxide switching transistors and a level-shifter in another embodiment. The level-shifter shifts a voltage of the first output signal of the detector to generate a level-shifted signal. The two switching transistors are driven by the level-shifted signal and the second output signal of the detector to regulate an output voltage of the charge pump.