Adaptive Body Braking Control in Voltage Regulators
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Solution Overview
Problem
Existing voltage regulators face challenges in efficiently managing overshoot voltage, which can damage sensitive components, as current methods either increase capacitance, leading to cost and size issues, or use 'body braking' that generates heat and power loss.
Innovation Solution
A voltage regulator system with adaptive switching intervals and threshold body braking control schemes, utilizing high-side and low-side power transistors and control circuitry to optimize VR design, allowing for quicker dissipation of overshoot voltage based on the operating voltage of transient loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If output capacitance is increased to suppress overshoot voltage, then overshoot voltage is reduced, but cost and size of the voltage regulator increase
Solution Approach 1:
The patent extracts the overshoot voltage suppression function from the output capacitor and transfers it to the body diode of the low-side power MOSFET. By turning off the low-side MOSFET during overshoot conditions, the body diode conducts the inductor current, dissipating the excess energy without requiring additional or larger output capacitance.
Solution Approach 2:
The patent converts the previously harmful body diode conduction (which caused power loss and heat) into a beneficial overshoot suppression mechanism. By intentionally controlling the body diode conduction through MOSFET turn-off, the excess energy that would otherwise damage components is safely dissipated, transforming a harmful effect into a protective function.
2Object-affected harmful factors
If body braking is used to suppress overshoot voltage, then overshoot voltage is reduced, but power loss and heat generation increase
Solution Approach 1:
The patent implements dynamic control of the low-side MOSFET switching based on real-time operating conditions. The MOSFET is turned off to activate body braking only when overshoot is detected, and the duration is precisely controlled to match the overshoot event. This dynamic approach minimizes unnecessary body diode conduction and associated power losses while maintaining effective overshoot suppression.
Solution Approach 2:
The patent uses feedback from the output voltage monitoring to control the low-side MOSFET switching. When the output voltage exceeds the threshold indicating overshoot, the control circuit responds by turning off the low-side MOSFET to activate body braking. This closed-loop feedback ensures body braking is applied only when necessary, reducing unnecessary power loss.
3Object-affected harmful factors
If body braking is continuously applied, then overshoot voltage is suppressed, but thermal generation increases
Solution Approach 1:
The patent applies body braking as periodic, pulsed action rather than continuous operation. The low-side MOSFET is turned off in controlled pulses only during overshoot events, allowing the body diode to conduct briefly and dissipate the excess energy. Between overshoot events, the MOSFET remains on, avoiding continuous body diode conduction and associated heat generation.
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 optimizes VR design by achieving a balance between thermal generation, capacitor size, cost, and power density, effectively dissipating overshoot voltage while minimizing heat and power loss, especially at lower operating voltages.
Implementation Method 1
body braking by using the body diode of a power metal-oxide-semiconductor-field-effect transistor (MOSFET) in the VR to dissipate the excess current
Data Source
AI summary
A voltage regulator that includes a high-side and a low-side power transistor is implemented where the high-side and the low-side power transistors are operable to output power to a transient load. The voltage regulator further includes control circuitry coupled to the high-side low-side power transistors and the transient load, with the control circuitry operable to receive a control signal from the transient load or the system. The control signal may correspond to an operating voltage of the transient load. In response to a decrease in a power level, the control circuitry may turn off the high-side power transistor, turn on the low-side power transistor a first duration, and turn off the low-side power transistor for a second duration. The first duration and the second duration may be based, at least in part, on the operating voltage.