DC/DC Converter Shunt Circuitry for Ripple Reduction
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Solution Overview
Problem
DC/DC converters experience increased output ripple voltage due to decreased switching frequency caused by increased duty cycle, which conventional approaches like low-drop-out (LDO) circuits fail to adequately address, leading to inefficient power supply to loads.
Innovation Solution
Incorporation of shunt circuitry that measures duty cycle and generates a shunt current to bypass the DC/DC converter, reducing ripple effects by controlling the PWM controller to operate at maximum duty cycle when necessary, thereby providing additional power to the load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the DC/DC converter operates at increased duty cycle to maintain power output under decreased supply voltage or increased load current, then the power delivery is maintained, but the switching frequency decreases resulting in increased output ripple voltage
Solution Approach 1:
The patent introduces shunt circuitry as an intermediary component that provides an alternative current path parallel to the DC/DC converter. This shunt circuitry includes a shunt switch and shunt resistor that can divert excess current away from the converter output, thereby reducing the ripple voltage while maintaining stable power delivery to the load.
Solution Approach 2:
The patent dynamically changes the operating parameters by monitoring the duty cycle and switching frequency, and accordingly adjusting the shunt switch state. When the duty cycle exceeds a threshold or switching frequency drops below a threshold, the shunt circuitry is activated to alter the current distribution, effectively changing the system's electrical parameters to reduce ripple voltage.
2Object-affected harmful factors
If conventional LDO circuits are used to reduce output ripple, then the ripple voltage is reduced, but considerable power is dissipated reducing efficiency
Solution Approach 1:
The patent employs dynamic control of the shunt switch based on real-time monitoring of duty cycle and switching frequency. The shunt circuitry is activated only when necessary (when duty cycle exceeds threshold or switching frequency drops below threshold), allowing the system to adapt its power dissipation characteristics to actual operating conditions, thereby minimizing energy loss while maintaining ripple suppression.
Solution Approach 2:
The system dynamically changes its operational state by switching the shunt circuitry on or off based on monitored parameters. This parameter-based control allows the system to maintain low power dissipation during normal operation while providing ripple suppression only when needed, unlike LDO circuits that continuously dissipate power.
3Stability of the object's composition
If the switching frequency is decreased to maintain duty cycle within limits, then the duty cycle is controlled, but the output ripple voltage increases due to lower switching frequency
Solution Approach 1:
The patent implements a feedback mechanism that continuously monitors the duty cycle and switching frequency of the DC/DC converter. Based on this feedback, the control circuitry adjusts the shunt switch state to compensate for ripple voltage increases that would otherwise result from frequency limitations, thereby maintaining both duty cycle control and low ripple voltage.
Data Source
AI summary
The present disclosure provides, in one embodiment, a method of shunting a power supply to reduce output ripple. The method includes determining at least one performance parameter of a DC/DC converter circuit; generating a first reference signal, wherein the first reference signal is based on the performance parameter; comparing the first reference signal to the performance parameter; and generating a shunt current from an input power source to an output node of the DC/DC converter circuit based on, at least in part, the comparison of the performance parameter and the first reference signal.