Multi-Voltage Semiconductor Startup Node Clamping Against Shoot-Through
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Solution Overview
Problem
Existing semiconductor devices with multiple power supply voltages face issues of shoot-through currents and increased power consumption due to differing supply timings, particularly when some power supply voltages are initially supplied, leading to high-impedance states and unnecessary leakage currents.
Innovation Solution
A semiconductor device design that includes a first switch connected between a second power supply line and a node, which turns on when the second power supply voltage is at a reference voltage and off as it approaches its final voltage, preventing shoot-through currents and reducing power consumption by clamping the node to ground during the transition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a P-type transistor is used as a switch to clamp the input node potential during power supply transition, then shoot-through current is prevented, but unnecessary leakage current occurs constantly after activation due to voltage difference between gate and source
Solution Approach 1:
The patent makes the switch dynamic by controlling its on/off state based on the power supply voltage transition status. During power supply transition, the switch is turned on to clamp the input node and prevent shoot-through current. After the transition completes, the switch is turned off to eliminate unnecessary leakage current. This dynamic control resolves the contradiction by making the protective function active only when needed.
Solution Approach 2:
The patent employs feedback control to detect the power supply voltage transition status and automatically control the switch state. A detection circuit monitors whether the power supply voltage has completed its transition, and based on this feedback, the control circuit adjusts the switch from on-state to off-state. This feedback mechanism ensures the switch operates correctly without manual intervention, preventing both shoot-through current and unnecessary power consumption.
2Adaptability or versatility
If power supply voltages are supplied at different timings upon activation, then the semiconductor device can operate with multiple power supply voltages, but nodes go to high-impedance state causing shoot-through current
Solution Approach 1:
The patent applies preliminary action by turning on the switch before the power supply voltage transition completes. This preliminary action clamps the input node potential to a safe level, preventing the node from entering the high-impedance state that would cause shoot-through current. The switch remains on throughout the transition period, ensuring protection is in place before any harmful condition can develop.
Data Source
AI summary
A first block operates with a first power supply voltage and a reference voltage. A second block operates with a second power supply voltage and a reference voltage. Upon activation of a semiconductor device, a voltage of a first power supply line changes from the reference voltage to the first power supply voltage earlier than when a voltage of the second power supply line changes from the reference voltage to the second power supply voltage. A first switch is connected between the second power supply line and a node which transfers a signal to be processed by the first block or the second block. The first switch is on when the voltage of the second power supply line is the reference voltage and turns off as the voltage of the second power supply line approaches the second power supply voltage.