Bandgap Reference Voltage Circuit With HVNW Noise Isolation
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Solution Overview
Problem
In semiconductor devices with NDMOS transistors, noise and parasitic currents affect reference voltage generation circuits due to unconnected HVNWs to supply voltage, leading to voltage variations and parasitic collector currents.
Innovation Solution
A reference voltage generation circuit incorporating a band gap reference circuit and a conversion circuit that converts the first reference voltage into a second reference voltage relative to a ground voltage, ensuring all HVNWs are connected to the supply voltage, thereby avoiding noise and parasitic current effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the reference voltage generation circuit is configured without connecting all HVNWs to supply voltage (as in prior art), then the circuit structure is simpler, but noise and parasitic current adversely affect the reference voltage
Solution Approach 1:
The patent inverts the conventional approach by connecting all HVNWs to supply voltage instead of leaving some unconnected. This inversion eliminates the parasitic current path that flows when HVNWs are left floating, thereby preventing noise and parasitic current from affecting the reference voltage while maintaining circuit functionality
2Reliability
If all HVNWs are connected to supply voltage to prevent noise and parasitic current, then reference voltage stability improves, but the circuit configuration becomes more complex
Solution Approach 1:
The patent extracts the problematic unconnected HVNW configuration from the circuit design. By removing the option to leave HVNWs unconnected and mandating that all be connected to supply voltage, the patent eliminates the source of parasitic current and noise while simplifying the overall design rules and configuration requirements
3Ease of manufacture
If NDMOS transistor is used with unconnected HVNW, then device fabrication is easier, but voltage variation propagates as noise through capacitance coupling
Solution Approach 1:
The patent applies preliminary anti-action by proactively connecting all HVNWs to supply voltage before noise or parasitic current can develop. This preventive measure blocks the capacitance coupling path that would otherwise allow voltage variations to propagate as noise, addressing the harmful effect before it can manifest
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 effectively generates a stable reference voltage relative to ground, reducing noise and parasitic current impacts, allowing for widespread use without restrictions in other circuits.
Implementation Method 1
a band gap reference circuit configured to generate a first reference voltage that depends on a band gap reference voltage and a supply voltage
Data Source
AI summary
A reference voltage generation circuit includes a band gap reference circuit configured to generate a first reference voltage that depends on a band gap reference voltage and a supply voltage, and a conversion circuit configured to convert the first reference voltage into a second reference voltage. The second reference voltage depends on the band gap reference voltage and a ground voltage. The ground voltage is lower than the supply voltage.