Gate Driver Power Saving in Pulse-Skipping Mode

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Solution Overview

Problem

Existing gate driver architectures face challenges in sustaining floating supply voltage and minimizing quiescent current during pulse-skipping mode in switched-mode power supplies, particularly in reducing current consumption and avoiding boost-back issues during input removal detection.

Innovation Solution

A power supply circuit with a charge pump and SMPS circuit that operates in two phases, using a comparator to monitor the capacitor voltage and temporarily switch to a power-saving mode to recharge the capacitor, reducing switching frequency and optimizing gate-driver current consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the charge pump operates continuously in pulse-skipping mode to sustain floating supply voltage, then the supply voltage is maintained, but quiescent current consumption increases

Engineering Contradiction:

Improvefloating supply voltage sustenanceVSAvoidquiescent current consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The charge pump operates in periodic pulse-skipping mode rather than continuously, switching between active charging phases and idle periods. This periodic operation maintains the floating supply voltage at critical thresholds while minimizing quiescent current consumption during idle intervals, directly resolving the contradiction between voltage sustenance and energy consumption.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The system uses its own capacitor to store and reuse charging energy, eliminating the need for continuous external power supply. The capacitor self-maintains the floating supply voltage through stored energy, allowing the charge pump to enter low-power states while still fulfilling its voltage sustenance function.

Inventive Principle:

Principle #25Self-service

2Loss of energy

If the switching frequency is reduced to minimize switching losses, then power efficiency improves, but the ability to sustain driver supply voltage deteriorates

Engineering Contradiction:

Improveswitching lossesVSAvoiddriver supply voltage sustenance

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The charge pump performs preliminary charging action to build up sufficient voltage on the capacitor before entering idle periods. By pre-charging the capacitor to an elevated voltage level, the system can tolerate longer intervals between charging cycles, enabling lower switching frequencies that reduce losses while still maintaining adequate driver supply voltage throughout the idle period.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system dynamically adjusts the charging voltage parameter by operating the charge pump at elevated voltage levels during active phases. This parameter change allows the capacitor to store more energy per charging cycle, compensating for reduced switching frequency and maintaining voltage sustenance capability while minimizing overall switching losses.

Inventive Principle:

Principle #35Parameter changes

3Use of energy by moving object

If the charge pump is completely disabled in power-saving mode, then current consumption is minimized, but the capacitor cannot be recharged when needed

Engineering Contradiction:

Improvecurrent consumptionVSAvoidcapacitor recharging capability

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The system extracts only the essential recharging function from the charge pump, separating it from continuous operation. By taking out just the periodic recharging action needed to maintain minimum voltage thresholds, the system achieves minimal current consumption during idle periods while preserving the critical capability to recharge the capacitor when voltage drops接近 critical levels.

Inventive Principle:

Principle #2Taking out (Extraction)

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 sustains internal driver supply voltage, minimizes quiescent current, and simplifies input removal detection by reducing switching losses and avoiding boost-back issues, thereby enhancing power-saving capabilities in pulse-skipping mode.

Implementation Method 1

a first capacitive element having a first terminal and a second terminal

Methodology Applied

Scientific EffectCapacitance: Capacitance

Implementation Method 2

a first switch coupled between a first input node of the charge pump and the first terminal of the first capacitive element

Methodology Applied

Scientific EffectElectrical Conduction: Conduction (electrical)

Data Source

PatentUS11545897B2Gate driver power-saving method for switched-mode power supplies in pulse-skipping mode

Publication Date: 2023.01.03 QUALCOMM INC

AI summary

Techniques and apparatus for controlling gate drivers of a switched-mode power supply (SMPS) circuit—such as a three-level buck converter, a divide-by-two charge pump, or an adaptive combination power supply circuit capable of switching therebetween—in a power-saving mode (e.g., a pulse-skipping mode). During such a power-saving mode in which a capacitor of a charge pump is disconnected from at least one power supply rail (e.g., first and second input nodes of the charge pump) and is coupled to power terminals of one or more drivers of the SMPS circuit, the capacitor is temporarily disconnected from the power terminals and temporarily coupled to the at least one power supply rail (e.g., for a few microseconds).