Switched Mode Regulator Phase Pin Voltage Sensing
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Solution Overview
Problem
Conventional switched mode regulator controller integrated circuits require a dedicated output voltage sense pin for regulation and frequency control, which limits package pin availability and functionality, increasing costs and affecting market viability.
Innovation Solution
A system and method that determines output voltage information from phase voltage, allowing the phase sense pin to be used for output voltage sensing instead of a dedicated pin, eliminating the need for an additional input pin and enabling additional functionality by using the phase voltage sense pin to extract output voltage information for the modulator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a dedicated output voltage sense pin is used, then output voltage sensing accuracy is improved, but package pin availability deteriorates
Solution Approach 1:
The phase sense pin is designed to perform multiple functions: it senses the phase voltage for switching control and simultaneously provides output voltage sensing information. The phase voltage waveform contains both the phase information needed for switching and the output voltage level information needed for regulation, allowing one pin to replace what would traditionally require two separate pins.
Solution Approach 2:
The patent uses the phase voltage waveform as an intermediary carrier that contains embedded output voltage information. By filtering and processing the phase voltage signal, the output voltage level can be extracted without requiring a direct connection to the output voltage node, thus using the phase sense pin as a mediator for dual-purpose sensing.
2Reliability
If a dedicated output voltage sense pin is used, then regulation control is improved, but device complexity increases
Solution Approach 1:
The phase sense pin serves dual purposes: providing phase information for switching control and providing output voltage information for regulation. This multi-functionality reduces the total pin count and simplifies the device package while maintaining both switching and regulation control capabilities.
Solution Approach 2:
The patent merges the phase sensing function and output voltage sensing function into a single pin. The phase voltage signal, which naturally occurs at the phase node, is processed to extract both the phase timing information and the output voltage level information, combining what would traditionally be separate sensing functions into one integrated approach.
3Measurement precision
If phase voltage filtering is applied, then output voltage information extraction is improved, but response time deteriorates
Solution Approach 1:
The patent applies moderate filtering to the phase voltage signal - enough to extract accurate output voltage information but not so much as to significantly delay transient response. The filtering is tuned to the switching frequency and its harmonics, allowing AC coupling to block the DC component while preserving the dynamic phase information needed for fast transient response.
Solution Approach 2:
The phase voltage signal is inherently periodic at the switching frequency, and the filtering is designed to exploit this periodicity. By using AC coupling and filtering at the switching frequency, the system can extract output voltage information from the periodic phase waveform while maintaining the ability to respond to transient changes in the periodic signal.
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
This approach reduces package pin requirements, allowing for additional features and cost savings by eliminating the need for a dedicated output voltage sense pin while maintaining accurate regulation and transient response, as the phase node's voltage information is used to generate on-chip output voltage information.
Implementation Method 1
A filter has an input coupled to the phase pin and an output providing output voltage level information
Data Source
AI summary
A controller integrated circuit for a switched mode regulator which converts an input voltage to an output voltage. The controller includes a phase pin, a modulation circuit and a filter. The modulation circuit is configured to regulate the output voltage using the input voltage and output voltage level information. The filter has an input coupled to the phase pin and an output providing the output voltage level information which approximates the output voltage based on phase pin voltage. Various filters are contemplated, including passive and active low pass filters and the like. A regulator using such a controller is disclosed. A method of determining a voltage level of an output voltage includes receiving a phase voltage from a phase pin coupled to the phase node, and filtering the phase voltage to provide an output sense voltage having a voltage level approximating the voltage level of the output voltage.