Switching Converter Reference Voltage Adjustment for Output Accuracy
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Solution Overview
Problem
Conventional switching converter controllers face challenges in accurately regulating output voltage due to errors introduced by control loops, which are difficult to trim for multiple output voltage options and require significant die area and test time for individual amplifier trimming.
Innovation Solution
A controller with a PWM circuit and a reference voltage controller that dynamically adjusts the control loop reference voltage based on error estimates, using a digital-to-analog converter to correct for errors introduced by the control loop, thereby reducing output voltage errors and supporting multiple output voltage options.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If individual amplifiers are trimmed separately at final test to achieve desired accuracy, then output voltage accuracy is improved, but die area increases and test time increases
Solution Approach 1:
The patent merges the trimming functions of multiple amplifiers into a single reference voltage adjustment mechanism. Instead of providing separate trim circuitry for each amplifier, a single reference voltage controller adjusts the reference voltage common to all amplifiers, thereby compensating for cumulative offset errors. This consolidation eliminates the need for individual trim circuits, reducing die area while maintaining output voltage accuracy.
Solution Approach 2:
The reference voltage controller serves multiple functions simultaneously: it provides the reference voltage for all amplifiers and dynamically compensates for their cumulative offset errors. This multi-functional approach replaces what would otherwise require separate dedicated trim circuits for each amplifier, reducing overall die area and test time.
2Measurement precision
If individual amplifiers are trimmed separately at final test to achieve desired accuracy, then output voltage accuracy is improved, but test time increases
Solution Approach 1:
The patent merges the trimming functions of multiple amplifiers into a single reference voltage adjustment mechanism. Instead of providing separate trim circuitry for each amplifier, a single reference voltage controller adjusts the reference voltage common to all amplifiers, thereby compensating for cumulative offset errors. This consolidation eliminates the need for individual trim circuits, reducing die area while maintaining output voltage accuracy.
Solution Approach 2:
The reference voltage is pre-adjusted to compensate for the cumulative offset errors of all amplifiers in the control loop. This preliminary calibration approach allows all amplifiers to be trimmed simultaneously through a single adjustment rather than requiring sequential individual trimming, significantly reducing test time.
3Measurement precision
If reference voltage is adjusted to achieve target output voltage, then output voltage accuracy is improved, but support for multiple output voltage options is lost
Solution Approach 1:
The reference voltage controller dynamically adjusts the reference voltage based on the desired output voltage target. Rather than being fixed for a single output voltage level, the reference voltage can be modified in real-time to accommodate multiple output voltage options. This dynamic adjustment capability allows the system to maintain accuracy across different output voltage configurations.
Solution Approach 2:
The system changes the reference voltage parameter to adapt to different output voltage requirements. By adjusting this key parameter, the controller can achieve accurate regulation for multiple output voltage targets without requiring separate trim circuits for each configuration, thereby maintaining both accuracy and versatility.
Data Source
AI summary
A controller includes: a pulse-width modulation (PWM) circuit; a control loop; and a reference voltage controller. The control loop has: a feedback input adapted to be coupled to an output voltage of a power stage; a control loop output coupled to a PWM control input; and an operational amplifier with a first feedback input, a first reference input, and an amplifier output, the first feedback input connected to the feedback input, and the amplifier output coupled to the PWM control input. The reference voltage controller has a reference voltage output coupled to the first reference input, the reference voltage controller configured to adjust a reference voltage provided to the reference voltage output responsive to a dynamic error estimate based on error in the operational amplifier.