Pin Driver Circuit Switching for High-Fidelity Voltage Swings
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Solution Overview
Problem
Existing pin drivers in electronic device testing systems face challenges in maintaining high waveform fidelity and timing precision due to spurious signals caused by parasitic capacitance, especially when switching between different voltage swing ranges, which affects the ability to test a variety of devices effectively.
Innovation Solution
A circuit design with a controller and multiple switches connected in parallel, where the controller generates control signals to selectively turn on switches to manage current levels and reduce parasitic capacitance, using a wired-OR logic and diodes to clamp the output voltage, allowing for precise control of voltage transitions and minimizing spurious signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If large switch size is used to drive large voltage swing ranges fast, then voltage transition speed is improved, but parasitic capacitance increases causing spurious signals that negatively impact timing precision
Solution Approach 1:
The patent applies dynamics by making the switch size adjustable rather than fixed. The pin driver circuit can dynamically change its effective switch size based on the required voltage swing range. For large voltage swings, larger switches provide fast transition. For small voltage swings, smaller switches reduce parasitic capacitance and spurious signals, maintaining timing precision.
Solution Approach 2:
The patent changes the parameter of switch size to resolve the contradiction. By having multiple switches with different sizes or the ability to adjust switch size, the system can optimize the balance between transition speed and spurious signal generation depending on the specific testing requirements.
2Productivity
If large switch size is used to meet maximum transition speed requirement, then productivity is improved, but spurious signals become relatively larger in proportion when driving smaller voltage swing ranges, significantly negatively impacting timing precision
Solution Approach 1:
The system dynamically adjusts switch size based on the voltage swing range required. When testing requires small voltage swings, the circuit uses smaller switches to minimize spurious signals, even though this reduces maximum transition speed capability. When large voltage swings are needed, larger switches are used to provide sufficient drive capability.
3Adaptability or versatility
If the test system is designed to drive large voltage swing ranges fast, then adaptability to different device types is improved, but waveform fidelity deteriorates when driving small voltage swing ranges due to spurious signals
Solution Approach 1:
The pin driver circuit dynamically adapts its switch size to match the required voltage swing range. For Class A memory device testing with small voltage swings (25-500 mV), smaller switches are used to maintain high waveform fidelity. For Class AB device testing with large voltage swings (>500 mV or >5V), larger switches are used to provide fast transition capability.
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
The solution enables high-fidelity voltage transitions across various voltage swing ranges, reducing spurious signals and improving timing precision, thereby enhancing the test system's capability to handle both small and large voltage swings with minimal disturbances.
Implementation Method 1
using a wired-OR logic and diodes to clamp the output voltage
Implementation Method 2
Spurious signals may be caused by parasitic capacitance in the voltage driver circuits of the test system
Data Source
AI summary
A circuit may include a controller, at least one bridge circuit, and a plurality of switches. The plurality of switches may be connected parallel to each other, each may have a switch output connected to the bridge circuit. The bridge circuit, upon receiving a current from the plurality of switches, may generate an output based on a reference voltage. The controller may generate a plurality of control signals, based on a voltage transition range, to selectively turn on the plurality of the switches in more than one combination, to supply a current to the output.