Switching Power Supply Fast Response via Dual Feedback Control
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Solution Overview
Problem
Existing switching power supply devices face challenges in providing stable operation with fast response and high accuracy voltage supply, especially at high-frequency operations and low load conditions, due to increased current consumption and leakage currents caused by lowered voltages, making it difficult to design power supply circuits that meet requirements of stability and efficiency.
Innovation Solution
The solution involves a switching power supply device with a capacitor between the output inductor and ground, using a first and second power MOSFET to control the inductor's potential, and a control circuit forming PWM signals based on feedback signals from output voltage and current, along with a detection MOSFET sharing the same semiconductor substrate for high accuracy current detection, and a pulse generation circuit to set the PWM period, enabling parallel operation and noise reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the supply voltage is lowered to meet modern processor requirements, then power consumption is reduced, but leakage current increases and voltage regulation accuracy becomes difficult to maintain
Solution Approach 1:
The patent implements a feedback control system using an error amplifier that continuously monitors the output voltage and adjusts the PWM duty cycle to maintain precise voltage regulation. The feedback loop compares the actual output voltage with the reference voltage and corrects any deviations, enabling accurate voltage control even at low voltage levels where leakage current is significant.
Solution Approach 2:
The patent changes the operating parameters of the power supply circuit by adjusting the PWM frequency and duty cycle to optimize performance at low voltage conditions. The control circuit dynamically modifies these parameters to compensate for increased leakage current and maintain stable output voltage regulation.
2Speed
If the operating frequency is increased to improve processing capacity, then processing speed is improved, but current consumption and leakage current increase
Solution Approach 1:
The patent employs periodic switching action through PWM control, where the power MOSFET switches on and off at high frequency to transfer energy to the load. This periodic action allows the system to deliver the required average power at high frequency while minimizing instantaneous current draw and reducing overall power consumption through efficient duty cycle control.
Solution Approach 2:
The patent ensures continuous energy transfer to the load through the inductor, which maintains a continuous current flow despite the periodic switching of the MOSFET. This continuous useful action delivers steady power to the processor at high frequency operation while the control circuit optimizes the switching parameters to minimize current consumption.
3Device complexity
If a voltage control system with one feedback loop is used, then circuit design is simplified, but fast response to sudden load changes cannot be achieved
Solution Approach 1:
The patent implements a feedback control system using an error amplifier that continuously monitors the output voltage and adjusts the PWM duty cycle to maintain precise voltage regulation. The feedback loop compares the actual output voltage with the reference voltage and corrects any deviations, enabling accurate voltage control even at low voltage levels where leakage current is significant.
Solution Approach 2:
The patent introduces dynamic response characteristics by optimizing the compensation network and feedback loop parameters to achieve fast response to load changes. The error amplifier and compensation circuit are designed with appropriate bandwidth and phase margin to provide rapid correction of voltage deviations while maintaining system stability, thus achieving both simplicity and fast response.
4Speed
If a peak current control system with two feedback loops is used, then fast load response is achieved, but circuit construction becomes more complicated and high accuracy current detection is required
Solution Approach 1:
The patent implements a feedback control system using an error amplifier that continuously monitors the output voltage and adjusts the PWM duty cycle to maintain precise voltage regulation. The feedback loop compares the actual output voltage with the reference voltage and corrects any deviations, enabling accurate voltage control even at low voltage levels where leakage current is significant.
Solution Approach 2:
The patent uses an inductor as an intermediary energy storage element between the switching circuit and the load. The inductor smooths the pulsed current from the PWM switching and provides continuous current to the load, reducing the need for complex current detection circuits while maintaining fast response characteristics through its inherent current continuity.
Data Source
AI summary
A switching power supply device performs a stable operation with fast response for a semiconductor integrated circuit device. A capacitor is provided between the output side of an inductor and a ground potential. A first power MOSFET supplies an electric current from an input voltage to the input side of the inductor. A second power MOSFET turned on when the first power MOSFET is off allows the input side of the inductor to be of a predetermined potential. A first feedback signal corresponding to an output voltage obtained from the output side of the inductor and a second feedback signal corresponding to an electric current flowed to the first power MOSFET are used to form a PWM signal. The first power MOSFET has plural cells of a vertical type MOS-construction.