Single-Inductor Boost Converter for Bipolar AMOLED Output
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Solution Overview
Problem
Conventional output converters for smart phone screens with AMOLEDs face issues of discontinuous current supply, poor output efficiency, inadequate control loop compensation, limited loop bandwidth, transient response, and inability to achieve cross-regulation, primarily due to the use of multiple inductors and discontinuous output voltage and current.
Innovation Solution
A boost converter power stage circuit incorporating a switched-capacitor converter and a flying capacitor to achieve bipolar output with a single inductor, utilizing a flying capacitor to double the inductor voltage and an interleaved switched-capacitor converter for negative voltage conversion, ensuring continuous output current and avoiding right-half-plane zeros.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If multiple inductors are used to achieve bipolar output, then the output voltage and current can be generated, but the current supply becomes discontinuous and the output efficiency deteriorates
Solution Approach 1:
The patent merges multiple inductor functions into a single inductor by introducing a switched-capacitor converter that synthesizes the second inductor's functionality. The switched-capacitor network, controlled by complementary switch signals, creates an equivalent inductance that works together with the physical inductor to generate bipolar output currents, thereby maintaining bipolar capability while ensuring continuous current supply and improving output efficiency.
2Device complexity
If conventional output converters are used, then the circuit structure is simple, but cross-regulation capability is lost and performance deteriorates
Solution Approach 1:
The switched-capacitor converter serves multiple functions simultaneously: it generates the second inductor's equivalent inductance for bipolar output, provides cross-regulation capability between output voltages, and enables continuous current supply. This multi-functional design allows the converter to handle various operating conditions and improve overall performance without proportionally increasing circuit complexity.
3Device complexity
If switched-capacitor converters are not employed, then the circuit is simpler, but transient response capability deteriorates
Solution Approach 1:
The switched-capacitor converter introduces dynamic switching capability that allows rapid adjustment of the equivalent inductance and current distribution. By dynamically controlling the switch states in response to load changes, the converter can quickly adjust the output current, significantly improving transient response capability compared to static conventional converters.
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
Enhances cross-regulation performance, improves efficiency, control loop compensation, and transient response by using a single-inductor bipolar output converter with a switched-capacitor converter, achieving better loop bandwidth and reduced inductor volume.
Implementation Method 1
By using the flying capacitor, the voltage of the inductor is doubled, thereby boosting the positive voltage of the output voltage
Implementation Method 2
This output voltage transmits energy to the organic light-emitting diode (OLED) power management integrated circuit unit via the inductor
Data Source
AI summary
The present invention discloses a boost converter power stage circuit, comprising: an organic light-emitting diode power management integrated circuit unit, a switched capacitor converter, and a boost converter, wherein, a flying capacitor is used to boost the voltage of the inductor to twice the voltage, and then the positive voltage of the output voltage source is boosted, and then use the switched capacitor converter to output the voltage in order to obtain the conversion of the negative voltage.