LDO Input Source Switching for PWM Voltage Regulator Power Loss
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Solution Overview
Problem
Existing voltage regulator circuits face issues with excessive power loss and overheating due to significant voltage differences between the input and output of low-dropout (LDO) regulators in PWM voltage regulation ICs, which can lead to damage and instability in the PWM control chip.
Innovation Solution
A voltage regulator circuit with a switching PWM regulation control IC, first and second switches, and a voltage detector that monitors the output voltage and switches the input source of the LDO regulator from a higher input voltage to a lower output voltage once stability is reached, reducing voltage difference and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the input voltage source is directly adopted as the input source of the LDO regulator, then the LDO regulator can provide driving power, but the voltage difference between input and output causes excessive power loss and overheating
Solution Approach 1:
The patent introduces an intermediary voltage detection and control mechanism between the high-voltage input source and the LDO regulator. The voltage detector monitors the output voltage and controls the switching between direct connection and LDO regulation, preventing the LDO regulator from operating under excessive voltage difference conditions.
Solution Approach 2:
The patent implements dynamic switching between two operating modes: direct connection mode (when output voltage is below threshold) and LDO regulation mode (when output voltage exceeds threshold). This dynamic adaptation allows the system to optimize power loss based on real-time voltage conditions.
2Ease of operation
If the output voltage is directly fed back as the input source of the LDO regulator, then the LDO regulator can operate, but overvoltage causes continuous increase in voltage difference and damages the LDO regulator
Solution Approach 1:
The patent implements a feedback mechanism where the voltage detector continuously monitors the output voltage and feeds this information back to the control circuit. When overvoltage is detected, the feedback signal triggers the switching control to disconnect the LDO regulator from the output voltage source, preventing damage.
Solution Approach 2:
The patent applies preliminary protective action by detecting voltage abnormalities before they cause damage. The voltage detector and control circuit are designed to preemptively switch off the LDO regulator when overvoltage conditions are detected, preventing the continuous voltage difference from damaging the component.
3Loss of energy
If switches are added to switch between input voltage and output voltage sources, then power loss is reduced, but device complexity increases
Solution Approach 1:
The patent designs the voltage detector and control circuit to serve multiple functions: voltage monitoring, threshold detection, and switching control. This multi-functionality reduces the need for separate dedicated components for each function, thereby minimizing the increase in circuit complexity while achieving power loss reduction.
Data Source
AI summary
A voltage regulator circuit and a control method therefor are provided. A voltage regulator circuit includes a Switching Pulse Width Modulation (PWM) voltage regulation control integrated chip (IC), a first switch, a second switch, and a voltage detector. The Switching PWM voltage regulation control IC includes a low-dropout (LDO) regulator and a PWM voltage regulator. The voltage detector detects a predetermined voltage level range of the output voltage, and generates a power good signal of the output voltage. During the startup period, the first switch is turned on, and the input voltage supplies the power source for the LDO regulator to generate a driving source required by the Switching PWM voltage regulation IC. After the startup period, the power source of the LDO regulator are switched from the input voltage to the output voltage by the first switch and the second switch.