Booster Circuit Voltage Stabilization Using Feedback Control
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Solution Overview
Problem
Existing semiconductor devices using booster circuits with temperature-dependent elements, such as diodes, struggle to maintain a constant output voltage for N-channel MOS transistors, which can lead to damage due to voltage exceeding the gate withstand voltage, and are affected by temperature deviations.
Innovation Solution
A semiconductor device incorporating a Dickson charge pump circuit with a comparator and resistance elements, where the output voltage of the booster circuit is controlled using a Zener diode and resistance elements to maintain a constant voltage level, minimizing temperature effects by using resistance elements with lower temperature dependency and ensuring the output voltage does not exceed the gate withstand voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If temperature-dependent elements such as diodes are used in the booster circuit, then voltage boosting function is achieved, but output voltage deviation increases with temperature changes
Solution Approach 1:
The patent implements a feedback control mechanism using a comparator that compares the divided output voltage with a reference voltage. When the output voltage exceeds the reference, the comparator output changes state, controlling the booster circuit to stop boosting. This closed-loop feedback system automatically compensates for temperature-induced voltage variations, maintaining stable output voltage despite temperature changes affecting the diode characteristics.
Solution Approach 2:
The patent changes the control parameter from direct voltage regulation to comparative voltage detection. By using a comparator to detect when the divided output voltage equals the reference voltage, the system transitions from passive temperature-dependent voltage boosting to active temperature-compensated voltage control, resolving the contradiction between boosting capability and voltage stability.
2Power
If the output voltage of the booster circuit is increased to meet load requirements, then power delivery capability is improved, but the risk of exceeding gate withstand voltage increases
Solution Approach 1:
The feedback control mechanism continuously monitors the output voltage through the divider circuit and comparator. When the output voltage approaches the gate withstand voltage limit, the comparator detects this condition and stops the boosting operation, preventing overvoltage damage to the MOS transistor gate while maintaining adequate power delivery capability within safe limits.
Solution Approach 2:
The system takes preliminary protective action by establishing a reference voltage corresponding to the safe operating limit and using the comparator to prevent the output voltage from exceeding this limit. This preemptive control mechanism stops boosting before dangerous overvoltage conditions can develop, protecting the gate from damage.
3Reliability
If resistance elements with low temperature dependency are used, then output voltage stability is improved, but manufacturing precision requirements increase
Solution Approach 1:
The feedback control system compensates for resistance value variations and temperature effects, reducing the stringency of manufacturing precision requirements. Even if resistance elements have moderate precision, the feedback mechanism adjusts the boosting operation to maintain accurate output voltage, thereby achieving stable output voltage without requiring extremely precise resistance components.
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 stabilizes the output voltage of the booster circuit, reducing the risk of transistor damage and minimizing temperature-related deviations, ensuring reliable operation by maintaining the output voltage within safe limits and compensating for resistance value deviations.
Implementation Method 1
a Zener diode Dz... when a reverse breakdown voltage is exceeded, a constant voltage is maintained between both ends
Implementation Method 2
a first voltage obtained by dividing an output voltage by first resistance elements R1 and R2 is input to a gate of a fourth switching element Q4
Data Source
AI summary
According to embodiments, a semiconductor device includes a first switching element in which a first reference voltage is input to a gate; a second switching element in which a first voltage is input to a gate; a third switching element to which the first switching element is in Darlington connection; a fourth switching element to which the second switching element is in Darlington connection; a first current mirror circuit to regulate currents flowing in the third and fourth switching elements; a fifth switching element switched between ON and OFF states based on a difference between the first reference and the first voltages; a constant current circuit; a second current mirror circuit; and a voltage setting resistance element between a source of the first switching element and a gate of the third switching element or between a source of the second switching element and a gate of the fourth switching element.