Adaptive Boost Loop Compensation for Stable Voltage Tracking

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Solution Overview

Problem

The existing boost circuits in infotainment systems face voltage tracking issues due to a right half plane zero, leading to phase lag and instability in the control loop, especially when the crossover frequency is set close to this zero, resulting in increased tracking errors and degraded transient response.

Innovation Solution

A compensation circuit that adjusts the crossover frequency dynamically by adjusting the voltage output proportionate to the voltage output of the boost circuit and inversely proportionate to the current input, using a differential amplifier and battery current compensation circuits to improve voltage tracking and transient response.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the crossover frequency is set close to the right half plane zero, then the phase margin of the control loop is reduced and the control loop can become unstable, but setting it too far away increases voltage tracking errors

Engineering Contradiction:
Improvecontrol loop stabilityVSAvoidvoltage tracking accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent applies dynamics by making the crossover frequency adjustable rather than fixed. The compensation circuit dynamically changes the crossover frequency based on operating conditions (particularly the frequency of the right half plane zero), allowing the system to maintain stability when the zero is at low frequencies while achieving good tracking accuracy when the zero is at high frequencies.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of crossover frequency adaptively. By modifying the compensation circuit's characteristics in response to varying operating conditions, the system adjusts the crossover frequency parameter to optimize both stability and tracking performance under different load and signal conditions.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If the crossover frequency is decreased to reduce tracking errors, then the response time of the boost circuit increases and transient response degrades

Engineering Contradiction:
Improvevoltage tracking accuracyVSAvoidresponse time
Core Design Contradiction:
Measurement precisionVSSpeed

Solution Approach 1:

The system dynamically adjusts the crossover frequency based on real-time operating conditions. When transient response is critical, the crossover frequency can be increased to improve response speed, while during steady-state operation, it can be decreased to improve tracking accuracy, thus resolving the contradiction between speed and precision.

Inventive Principle:
Principle #15Dynamics

3Ease of operation

If the tracking signal is at low amplitude, then the boost circuit's right half plane zero moves to a much higher frequency, but maintaining a fixed crossover frequency increases voltage tracking error

Engineering Contradiction:
Improvewide operating rangeVSAvoidvoltage tracking accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The compensation circuit uses feedback mechanisms to detect the frequency of the right half plane zero and adjusts the crossover frequency accordingly. This feedback loop ensures that the system maintains optimal tracking accuracy across different operating conditions, including wide variations in tracking signal amplitude.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP4336727A1System and method for adaptive voltage control loop compensation for tracking power supply applications
Publication Date: 2024.03.13 HARMAN INT IND INC
  • EP4336727A1 patent drawingFigure 1
  • EP4336727A1 patent drawingFigure 2
  • EP4336727A1 patent drawingFigure 3

AI summary

Embodiments are disclosed for a compensating circuit for a boost circuit that outputs a voltage that is a function of a voltage signal. In one or more examples, the compensation circuit may include a gain that is adjustable in proportion to voltage output of the boost circuit and inversely proportionate to input current to the boost circuit.