Emulator Circuit for Switched Mode Power Supply Ripple Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Inductor-based DC to DC converters face challenges in controlling ripple current and maintaining stable output voltage, especially when the input voltage is close to the output voltage, leading to instability and delayed control responses due to noise and integration delays in current measurement.
Innovation Solution
An emulator circuit that generates a signal representing the integral of voltage across the inductor, allowing for real-time estimation of inductor current and modifying the control loop to compensate for 0 Hz poles, thereby stabilizing the control system and reducing noise-related uncertainties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If instantaneous current measurement is used in the inductor, then real-time current information is obtained, but noise and voltage bounce are introduced when the transistor is switched
Solution Approach 1:
The patent introduces an emulator circuit as an intermediary that generates a simulated inductor current signal based on voltage measurements across the inductor. This emulator output serves as a clean proxy for the actual inductor current, avoiding direct measurement of the noisy switching nodes while still providing real-time current information for control purposes.
Solution Approach 2:
The emulator creates a copy or simulation of the inductor current signal by integrating the voltage across the inductor. This copied signal replicates the essential characteristics of the inductor current without containing the high-frequency noise and voltage bounce present in direct transistor switching measurements.
2Reliability
If a delay is introduced before measuring current to increase reliability, then noise is reduced, but control frequency is limited due to minimum ON duration
Solution Approach 1:
The emulator circuit performs preliminary computation of the inductor current signal by integrating voltage measurements in advance. This allows the control system to have immediate access to accurate current information without waiting for delay periods, thereby maintaining high control frequencies while ensuring measurement reliability.
3Object-affected harmful factors
If filtered version of measured current is formed, then noise is reduced, but integration effect and delay are introduced causing instability
Solution Approach 1:
The emulator acts as an intermediary that computes the inductor current signal through voltage integration without introducing additional filtering delays. The emulator output directly represents the inductor current waveform, providing a clean signal that maintains temporal accuracy and does not contribute to control loop instability.
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 emulator circuit enables stable output voltage regulation by providing a real-time estimate of inductor current, reducing noise-induced instability and allowing for faster control cycles, thus improving the frequency response and stability of the switched mode power supply.
Implementation Method 1
the emulator circuit forms a emulator output signal representing the integral of voltage with respect to time of the voltage difference across the inductor
Implementation Method 2
the current in the inductor can be built up such that energy is stored in it by virtue of its magnetic field
Implementation Method 3
that energy can be discharged from the inductor in order to charge a storage capacitor at the output of the DC to DC converter
Data Source
AI summary
An emulator circuit for forming a signal representative of current flow in an inductor of a switched mode power supply, where the inductor is associated with a switching arrangement operational to connect a first node of the inductor to a first voltage (Vin) or to one of a reference voltage (gnd) or a current flow path, a second node of the inductor to a second voltage (Vout) or to one of a second reference voltage (gnd) or the current flow path, and wherein the emulator circuit forms a emulator output signal representing the integral with respect to time for which the first and second node of the inductor are connected to the first voltage and the second voltage respectively.