Voltage Tracking Circuit for Leakage Current Reduction
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Solution Overview
Problem
In high-voltage electronic circuits using N-type metal oxide semiconductor (NMOS) transistors, over-voltage events can lead to leakage currents due to the parasitic bipolar diode turning on, causing overheating and potential damage, which existing technologies have not adequately addressed.
Innovation Solution
A voltage tracking circuit comprising P-type transistors and a voltage reducing circuit is used to track and manage voltages, generating an output voltage that controls the parasitic bipolar transistor, thereby reducing leakage currents by applying the appropriate output voltage to the isolated deep well region surrounding the high-voltage-side component.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If an NMOS transistor is used on the high-voltage side, then the circuit can handle high voltage, but over-voltage events cause leakage current through the parasitic bipolar diode
Solution Approach 1:
The voltage tracking circuit acts as an intermediary between the high-voltage node and the isolated deep well region. It generates a control voltage that tracks the high-voltage level and applies it to the deep well, preventing the parasitic bipolar diode from turning on during over-voltage events, thereby eliminating leakage current without affecting the NMOS transistor's high-voltage handling capability
Solution Approach 2:
The voltage tracking circuit proactively applies a control voltage to the isolated deep well region before over-voltage events can cause leakage. By continuously tracking the voltage at the high-voltage node and preemptively adjusting the deep well voltage, the circuit prevents the parasitic bipolar diode from activating, thus preventing leakage current before it occurs
2Reliability
If a voltage tracking circuit is added to control the parasitic bipolar transistor, then leakage current is reduced, but the device complexity increases
Solution Approach 1:
The voltage tracking circuit performs multiple functions: it tracks the high-voltage level, generates the appropriate control voltage, and applies it to the isolated deep well region. By consolidating these functions into a single circuit module, the design achieves leakage current reduction without proportionally increasing overall device complexity
Solution Approach 2:
The voltage tracking circuit is self-regulating, automatically adjusting its output based on the voltage it detects at the high-voltage node. It requires no external control signals or additional complexity to determine when to activate the deep well voltage, as it autonomously tracks and responds to voltage changes, simplifying the overall control architecture
Data Source
AI summary
A voltage tracking circuit is provided and includes first and second P-type transistors and a voltage reducing circuit. The drain of the first P-type transistor is coupled to a first voltage terminal. The voltage reducing circuit is coupled between the first voltage terminal and the gate of the first P-type transistor. The voltage reducing circuit reduces a first voltage at the first voltage terminal by a modulation voltage to generate a control voltage and provides the control voltage to the gate of the first P-type transistor. The gate of the second P-type transistor is coupled to the first voltage terminal, and the drain thereof is coupled to a second voltage terminal. The source of the first P-type transistor and the source of the second P-type transistor are coupled to the output terminal of the voltage tracking circuit. The output voltage is generated at the output terminal.