Switching Power Supply Control Circuit with Shared Compensation

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Solution Overview

Problem

Existing switching power supply control circuits with multiple feedback loops require numerous independent compensation capacitors and resistors, leading to increased component area and potential current surges when switching between loops due to stored compensation voltages.

Innovation Solution

A control circuit with multiple feedback loops that uses a shared compensation capacitor and adjustable compensation resistors, where only one switching circuit is active at a time to transfer error signals to the compensation circuit, generating a PWM control signal for the power switch, thereby reducing component count and preventing current surges.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple independent compensation circuits are used for each feedback loop, then each loop can be independently compensated, but the circuit area increases and current surges occur when switching between loops

Engineering Contradiction:

Improvefeedback loop compensationVSAvoidcircuit area

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The patent merges multiple independent compensation circuits into a single shared compensation circuit. The compensation capacitor C1 is shared among all feedback loops (FB1, FB2, FB3), and only one loop is active at a time. This reduces the total circuit area while maintaining the compensation function for each loop when it is active.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The single compensation circuit is designed to serve multiple feedback loops universally. The compensation capacitor C1 and associated components can compensate for any of the multiple feedback loops depending on which loop is currently active, making the compensation circuit multi-functional rather than dedicated to a single loop.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If multiple independent compensation circuits are used for each feedback loop, then each loop can be independently compensated, but the device complexity increases

Engineering Contradiction:

Improvefeedback loop compensationVSAvoidcompensation circuit complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines multiple compensation circuits into one shared compensation circuit, reducing the total number of components. Instead of having separate capacitors and resistors for each feedback loop, a single capacitor C1 and shared resistive network serve all loops, significantly reducing device complexity.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The compensation circuit is designed as a universal unit that can handle multiple feedback loops. The same compensation components (capacitor C1, resistors R1-R4, transistors Q1-Q4) are used to compensate for any active feedback loop, reducing the overall device complexity while maintaining compensation capability for each loop.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If multiple feedback loops are implemented with independent compensation, then comprehensive control is achieved, but component quantity increases

Engineering Contradiction:

Improvefeedback loop controlVSAvoidcomponent quantity

Core Design Contradiction:

Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The patent merges the compensation components across multiple feedback loops. Instead of having independent capacitors and resistors for each loop, a single compensation capacitor C1 and shared resistive network (R1-R4) are used by all loops, significantly reducing the total component quantity while maintaining comprehensive control capability.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The compensation circuit components are designed to be universal and serve multiple feedback loops. The same capacitor C1 and resistive network can compensate for any active loop (FB1, FB2, or FB3), reducing component quantity while maintaining the adaptability to control multiple loops as needed.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS9525334B2Control circuit with multiple feedback loops and switching power supply thereof

Publication Date: 2016.12.20 SILERGY SEMICON TECH (HANGZHOU) CO LTD

AI summary

A control circuit with multiple feedback loops configured for a switching power supply, can include: (i) a plurality of feedback circuits configured to receive a plurality of feedback signals of a power stage circuit, and to correspondingly generate a plurality of error signals; (ii) a plurality of switching circuits configured to transfer the error signals to a compensation circuit, where each switching circuit is correspondingly coupled to one of the feedback circuits, and where only one of the switching circuits is turned on to correspondingly transfer one of the error signals to the compensation circuit when in a steady status; (iii) the compensation circuit being configured to receive the error signals, and to generate a compensation signal; and (iv) a PWM control circuit configured to receive the compensation signal, and to generate a PWM control signal to control operation of a power switch in the power stage circuit.