Hysteresis Input Circuit With Switched Resistors for Low Penetration Current
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Solution Overview
Problem
Prior CMOS type hysteresis characteristic input circuits in DC stabilized power supply apparatuses experience significant penetration currents, leading to increased power consumption, despite efforts to suppress them through reduced drive abilities of MOS transistors.
Innovation Solution
The proposed solution involves connecting resistors in parallel between power supply terminals and a connection point, with MOS transistors controlled by an input voltage, and switching elements in series with these resistors and transistors, which are complementarily controlled by the output voltage, resulting in a hysteresis curve characteristic with adjustable threshold voltages and reduced penetration currents due to high resistance values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the drive abilities of the p-channel MOS transistor and n-channel MOS transistor are decreased to suppress penetration current, then power consumption is reduced, but the penetration current remains large (several tens of mA)
Solution Approach 1:
Resistors are introduced as intermediary elements connected in parallel with the MOS transistors. These resistors act as mediators that limit and control the penetration current flow path, preventing excessive current from flowing through the MOS transistors during switching transitions, thereby reducing power consumption without completely disabling the transistor drive capabilities.
Solution Approach 2:
The circuit utilizes complementary control of switching elements based on output voltage states to dynamically change the resistance parameters in the penetration current path. When the output voltage indicates a specific state, the switching elements adjust the effective resistance values, thereby controlling the penetration current magnitude adaptively rather than using fixed resistance values.
2Object-generated harmful factors
If resistors with high resistance values are used to reduce penetration current, then penetration current is reduced to less than 2 μA, but the circuit complexity increases
Solution Approach 1:
The resistors are merged with the existing MOS transistor structures by connecting them in parallel between the power supply terminal and the connection point. This integration allows the resistors to share the same physical space and functional context as the transistors, reducing overall circuit complexity while still achieving effective penetration current suppression.
Solution Approach 2:
The resistors serve multiple functions simultaneously: they limit penetration current, provide alternative current paths, and work in conjunction with the switching elements to establish hysteresis characteristics. This multi-functionality reduces the need for additional dedicated components, thereby managing circuit complexity effectively.
Data Source
AI summary
In a hysteresis characteristic input circuit, first and second resistors are connected in parallel between a first power supply terminal and a connection point, and first and second MOS transistors are connected in parallel between the connection point and a second power supply terminal and are controlled by an input voltage. An inverter has an input connected to the connection point and an output adapted to generate an output voltage. A first switching element is connected in series to the second resistor, and a second switching element is connected in series to the second MOS transistor. The first and second switching elements are complementarily controlled by the output voltage.