Switching Power Converter Hysteretic Mode Control

Solution Overview

Problem

Existing switching power converters face inefficiencies and increased hardware complexity due to the need for counters in hysteretic switching mechanisms, which affect response rates and stability during load changes.

Innovation Solution

A switching power converter employing a logic circuit and dual control circuits that use different threshold values to switch between modes, eliminating the need for counters and providing a hysteretic mechanism for improved stability and efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a counter is used to provide hysteretic switching mechanism for mode switching, then the switching power converter can switch between PWM mode and PFM mode according to load changes, but the determination time of the counter affects the overall response rate of the system and increases the complexity of the hardware structure

Engineering Contradiction:

Improvemode switching capabilityVSAvoidhardware structure complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent extracts and removes the counter component from the hysteretic switching mechanism. Instead of using a counter to determine mode switching timing, the invention uses a direct comparison circuit that compares the inductor current with a reference current to determine when to switch between PWM and PFM modes. This elimination of the counter simplifies the hardware structure while maintaining the adaptability of mode switching.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical counting mechanism with an electrical comparison mechanism. The comparison circuit directly compares current signals to generate mode switching control signals, substituting the sequential mechanical counting process with a parallel electrical comparison process, thereby improving response rate and reducing hardware complexity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Adaptability or versatility

If a counter is used to provide hysteretic switching mechanism for mode switching, then the switching power converter can switch between PWM mode and PFM mode according to load changes, but the determination time of the counter affects the overall response rate of the system

Engineering Contradiction:

Improvemode switching capabilityVSAvoidresponse rate

Core Design Contradiction:

Adaptability or versatilityVSSpeed

Solution Approach 1:

The patent extracts and removes the counter component from the hysteretic switching mechanism. Instead of using a counter to determine mode switching timing, the invention uses a direct comparison circuit that compares the inductor current with a reference current to determine when to switch between PWM and PFM modes. This elimination of the counter simplifies the hardware structure while maintaining the adaptability of mode switching.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical counting mechanism with an electrical comparison mechanism. The comparison circuit directly compares current signals to generate mode switching control signals, substituting the sequential mechanical counting process with a parallel electrical comparison process, thereby improving response rate and reducing hardware complexity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If different threshold values are used for mode switching, then the hysteretic mechanism improves system stability and output efficiency, but requires dual control circuits with different threshold values

Engineering Contradiction:

Improvesystem stabilityVSAvoidcontrol circuit complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the dual control circuits into a single integrated control circuit that contains both comparison functions. The control circuit includes a first comparison circuit for PWM mode (comparing inductor current with reference current) and a second comparison circuit for PFM mode (comparing inductor current with a different reference current). By integrating these comparison functions into one control unit, the patent achieves the stability benefits of different threshold values while minimizing the increase in hardware complexity.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The control circuit is designed with multi-functionality, serving both PWM mode control and PFM mode control within a single unit. The same control circuit structure performs different comparison operations depending on the operating mode, eliminating the need for completely separate control circuits for each mode and reducing overall system complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS8674673B2Switching power converter

Publication Date: 2014.03.18 UPI SEMICON CORP

AI summary

A switching power converter including an upper-bridge switch, a lower-bridge switch, an impedance circuit, a first control circuit, a second control circuit and a logic circuit is provided. The impedance circuit generates an output voltage and a sensing current according to a conductive state of the upper-bridge switch and the lower-bridge switch. The first control circuit generates a first pulse signal according to the output voltage. The second control circuit has a first mode and a second mode for generating a second pulse signal and a third pulse signal individually. Furthermore, the second control circuit uses different threshold values in different modes to determine whether to switch the mode thereof, so as to form a hysteretic effect in mode switching. The logic circuit controls the upper-bridge switch by the first pulse signal, and controls the lower-bridge switch by the second pulse signal or the third pulse signal.