High-Voltage Output Control Circuit for Low-Voltage PMOS Cutoff
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Solution Overview
Problem
Conventional high voltage control circuits for semiconductor devices fail to operate effectively in low voltage devices with power supply voltages of 2.3 V or 1.8 V, as they cannot fully turn off high voltage PMOS transistors, leading to continued current flow and potential voltage transfer to output terminals.
Innovation Solution
The proposed high voltage control circuit incorporates a series configuration of inverters, acceleration units, and potential control units, including negative voltage transistors and high voltage PMOS transistors, to manage the high voltage supply and cutoff, ensuring complete blocking of high voltage to the output terminal by utilizing threshold voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single high voltage PMOS transistor is used to transmit high voltage, then the circuit structure is simple, but the transistor cannot be fully turned off with low power supply voltage (2.3V or 1.8V), causing current leakage and potential voltage transfer to output terminal
Solution Approach 1:
The patent divides the single high voltage PMOS transistor into multiple series-connected high voltage PMOS transistors (first, second, and third HPMOS transistors). This segmentation allows each transistor to be controlled independently, ensuring that all transistors in the series path are fully turned off even with low power supply voltage, thereby preventing current leakage and high voltage transfer to the output terminal.
Solution Approach 2:
The patent introduces intermediate control circuits and additional transistors (such as the fourth HPMOS transistor and various NMOS transistors) that act as mediators to properly control the gate voltages of the series-connected high voltage PMOS transistors. These intermediary elements ensure that sufficient voltage is applied to turn off all transistors in the series path, resolving the cutoff reliability issue.
2Reliability
If multiple high voltage PMOS transistors are connected in series to ensure complete cutoff, then the transistor cutoff reliability is improved, but the device complexity increases
Solution Approach 1:
The patent segments the high voltage transmission path into multiple series-connected high voltage PMOS transistors, each controlled by dedicated control circuits. This segmentation improves cutoff reliability by ensuring each transistor can be fully turned off, while the modular structure allows for systematic design and control.
Solution Approach 2:
The patent employs control circuits that prepare and apply appropriate gate voltages to the high voltage PMOS transistors in advance before the cutoff operation is needed. This preliminary action ensures that all transistors are properly biased and can be reliably turned off when required, improving cutoff reliability without requiring overly complex real-time control mechanisms.
Data Source
AI summary
A high voltage control circuit of a semiconductor device includes an output node control circuit configured to set an initial potential of an output terminal or to discharge the potential of the output terminal, in response to an input signal and a high voltage supply circuit comprising an acceleration unit and a potential control unit coupled in series between the output terminal and a supply terminal for supplying a high voltage. The acceleration unit is operated in response to the potential of the output terminal, and the potential control unit is operated in response to the input signal.