MOSFET Ideal Diode Circuit With Periodic Gate Control
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Solution Overview
Problem
Conventional ideal diode circuits face challenges in high temperature and low current conditions, where the forward body diode voltage of MOSFET is small, and the charge pump's pumping ability is weak, leading to failure in reaching the upper limit voltage and resulting in the circuit being unable to turn on the MOSFET and operate normally.
Innovation Solution
The proposed ideal diode circuit includes a capacitor unit, a transistor unit, a voltage conversion unit, and a control unit. The control unit outputs driving signals based on the capacitor voltage to periodically control the conduction and closure of the transistor unit, even under extreme conditions, allowing the capacitor to be pumped after the transistor is turned off.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the conventional hysteresis comparator control mode is used, then the circuit structure is simple, but under high temperature and low current conditions the charge pump pumping ability is weak and cannot reach the upper limit voltage
Solution Approach 1:
The patent implements dynamic control of the MOSFET switching process by dividing it into multiple stages: constant current charging phase, constant voltage charging phase, and discharge phase. The control circuit dynamically adjusts the switching timing and charging current based on real-time capacitor voltage feedback, ensuring reliable operation under high temperature and low current conditions while maintaining controlled complexity through systematic phase management.
Solution Approach 2:
The patent employs a feedback mechanism where the control circuit continuously monitors the capacitor voltage and uses this information to regulate the MOSFET switching timing and charging current. This feedback loop ensures that the system adapts to varying operating conditions (temperature, current levels) and maintains stable operation, resolving the reliability issue without requiring overly complex external control circuits.
2Reliability
If the MOSFET is controlled to turn on only when capacitor voltage reaches the upper limit, then the voltage drop across MOSFET is minimized, but under high temperature and low current the capacitor voltage cannot reach the upper limit and the circuit fails to operate
Solution Approach 1:
The control circuit performs preliminary action by predicting when the capacitor voltage will reach the optimal switching point based on the charging rate and remaining voltage headroom. Instead of waiting for the voltage to actually reach the upper limit (which may never happen under adverse conditions), the controller proactively triggers the MOSFET turn-on at the optimal moment, ensuring both reliability and minimal energy loss.
Solution Approach 2:
The patent implements dynamic control of the MOSFET switching process by dividing it into multiple stages: constant current charging phase, constant voltage charging phase, and discharge phase. The control circuit dynamically adjusts the switching timing and charging current based on real-time capacitor voltage feedback, ensuring reliable operation under high temperature and low current conditions while maintaining controlled complexity through systematic phase management.
3Reliability
If the charge pump operates continuously to maintain upper limit voltage, then the voltage regulation is improved, but the pumping ability becomes insufficient under high temperature and the circuit cannot function periodically
Solution Approach 1:
The patent implements periodic action by controlling the MOSFET to switch between on and off states in a regulated periodic manner. The control circuit monitors capacitor voltage and triggers MOSFET turn-on at optimal intervals, creating a periodic charging-discharging cycle. This approach ensures reliable periodic operation under high temperature conditions by adapting the switching frequency and timing to the actual charge pump capability, rather than requiring continuous operation at a fixed rate.
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
This solution enables the ideal diode circuit to operate reliably under high temperature and low current conditions by periodically controlling the transistor's conduction and closure, thus ensuring the capacitor is pumped without waiting for an accurate set voltage upper limit.
Implementation Method 1
configured to charge the capacitor unit via a parasitic diode in the transistor unit
Data Source
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AI summary
An ideal diode circuit comprises a capacitor unit and a transistor unit electrically connected thereto, a voltage conversion unit electrically connected to the capacitor unit and the transistor unit respectively and configured to charge the capacitor unit via a parasitic diode in the transistor unit, the input end of the control unit electrically connected to the capacitor unit, the output end of the control unit electrically connected to the control end of the transistor unit, the control unit configured to output a first driving signal or a second driving signal based on the voltage signal of the capacitor unit, drive the transistor unit to turn off under the first driving signal, or drive the transistor unit to turn on under the second driving signal.