Charge Pump Parasitic Transistor Protection
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Solution Overview
Problem
Charge pumps in electronic devices face performance deterioration and power efficiency reduction due to parasitic bipolar junction transistors turning on, especially in high-temperature environments, leading to prolonged rise times and potential starting failures.
Innovation Solution
Incorporating a chopper or clamp circuit, such as a Schottky diode, between the pump capacitor and output capacitor to prevent parasitic transistors from turning on, ensuring charges are directed correctly and maintaining power efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a charge pump uses MOS devices as switches for capacitors, then the charge pump can achieve voltage conversion functionality, but parasitic bipolar junction transistors are formed that can turn on unexpectedly and cause performance deterioration
Solution Approach 1:
The patent introduces a clamp circuit as an intermediary component between the pump capacitor and output capacitor. This clamp circuit includes a control transistor and clamp transistor that work together to prevent the parasitic bipolar junction transistor from turning on, thereby resolving the contradiction between maintaining voltage conversion functionality and ensuring performance stability.
2Temperature
If parasitic bipolar junction transistors turn on in high-temperature environments, then charge leakage occurs, but this leads to prolonged rise times and potential starting failures
Solution Approach 1:
The patent applies preliminary anti-action by using the clamp circuit to prevent charge leakage before it can occur. The control transistor detects potential charge leakage conditions and activates the clamp transistor to block the leakage path in advance, preventing the parasitic bipolar junction transistor from turning on even in high-temperature environments, thus maintaining fast rise times and reliable starting.
3Loss of energy
If parasitic bipolar junction transistors conduct, then power efficiency is reduced, but adding protection circuits increases device complexity
Solution Approach 1:
The patent merges the protection function into the existing charge pump circuit structure. The clamp circuit is integrated with the switching mechanism, where the control transistor and clamp transistor are combined with the existing pump capacitors and switches. This merging approach provides effective protection against parasitic transistor conduction and maintains power efficiency without significantly increasing device complexity.
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 reduces the rise and fall times of the output voltage, enhances power efficiency, and improves reliability in high-temperature conditions by preventing parasitic transistor activation and charge leakage.
Implementation Method 1
Incorporating a chopper or clamp circuit, such as a Schottky diode, between the pump capacitor and output capacitor to prevent parasitic transistors from turning on
Data Source
AI summary
The present invention relates to a charge pump, which uses a chopper circuit or a clamp circuit coupled between a pump capacitor and an output capacitor for preventing a parasitic transistor produced by a switching mechanism from turning on. Thereby, the performance of the charge pump is improved effectively.