Soft Start Circuit for Display Power Supply Inrush Current
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Solution Overview
Problem
Existing display device power providers face inefficiencies in generating power voltage during power-on and under voltage lock out (UVLO) operations, requiring improved methods to optimize power supply and reduce inrush currents.
Innovation Solution
A power provider system that includes multiple power sources and detection circuits, such as low voltage detection and short-circuit detection, along with soft start and boost converter circuits, to manage power voltage levels and prevent short-circuit conditions, ensuring efficient power delivery and reduced inrush currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the power provider generates power voltage during power-on and UVLO operations, then the display device can be powered up, but inrush currents occur causing inefficient operation
Solution Approach 1:
The soft start circuit is activated before the main power conversion circuit during power-on and UVLO recovery operations. This preliminary action gradually ramps up the output voltage, preventing inrush currents from occurring when the power provider transitions from off to on state, thereby resolving the contradiction between ensuring reliable power-up and minimizing energy loss.
2Power
If the first boost converter continuously converts input voltage to power voltage, then sufficient power is provided to pixels, but inrush currents occur during voltage transitions
Solution Approach 1:
The soft start circuit performs preliminary voltage ramping before the boost converter operates at full capacity. By gradually increasing the output voltage during transitions, the system ensures sufficient power delivery to pixels while preventing the harmful inrush currents that would otherwise occur during sudden voltage changes.
Solution Approach 2:
The system dynamically switches between the soft start circuit and the main boost converter based on operational conditions. During power-on and UVLO recovery, the soft start circuit handles gradual voltage establishment, while during normal operation, the boost converter provides efficient power conversion. This dynamic allocation optimizes both power delivery and energy efficiency.
3Device complexity
If the power provider operates without voltage detection circuits, then the device complexity is reduced, but inefficient operation occurs during UVLO conditions
Solution Approach 1:
The low voltage detection circuit continuously monitors the input voltage level and provides feedback to the control logic. When the input voltage falls below the UVLO threshold, the circuit detects this condition and triggers appropriate responses (such as activating the soft start circuit or preventing boost converter operation), thereby maintaining efficient power conversion without requiring complex additional circuitry.
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 system efficiently operates during power-on and UVLO releases, optimizing power voltage levels and preventing short-circuit faults, thereby enhancing display device performance and reducing power consumption.
Implementation Method 1
a first soft start circuit connecting the first input terminal to the first output terminal during a first period when a first control signal for the first power source is changed from a disable level to an enable level
Implementation Method 2
a first boost converter converting the input voltage to provide the first power voltage greater than the input voltage to the first output terminal after the first period
Implementation Method 3
a low voltage detection circuit providing a low voltage detection signal of an enable level when the input voltage is less than a reference low voltage, and providing the low voltage detection signal of a disable level when the input voltage is greater than the reference low voltage
Data Source
AI summary
A power provider includes: a first power source configured to receive an input voltage and to provide a first power voltage to a first output terminal; a low voltage detection circuit configured to provide a low voltage detection signal of an enable level in response to the input voltage being less than a reference low voltage, and to provide the low voltage detection signal of a disable level in response to the input voltage being greater than the reference low voltage; a first soft start circuit configured to connect the first input terminal to the first output terminal in response to a first control signal for the first power source being changed from a disable level to an enable level; and a first boost converter configured to convert the input voltage to provide the first power voltage greater than the input voltage to the first output terminal.