Display Power Supply Circuit With External MOSFET Loss Reduction
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Solution Overview
Problem
Existing power supply circuits for liquid crystal modules, particularly those using LDMOS transistors, suffer from high on-resistance, leading to significant power loss, which becomes more pronounced in large-size designs, resulting in inefficient power supply for modern information devices.
Innovation Solution
A power supply circuit design that replaces LDMOS with a power transistor outside the power management integrated circuit (PMIC) and incorporates a detecting circuit with a current mirror and switch configuration to optimize voltage and current detection, allowing for adjustable drive signals and improved power management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If LDMOS transistors are used in the power management integrated circuit, then the circuit can be integrated on a single die, but the on-resistance becomes high (hundreds of milliohms) causing large power loss
Solution Approach 1:
The patent divides the power management system into two separate parts: the power management integrated circuit (PMIC) containing the control part, and a separate power transistor. This segmentation allows each component to be optimized independently - the PMIC can use low-resistance transistors while the power transistor can be designed for low on-resistance, solving the contradiction between integration and power loss.
Solution Approach 2:
The power transistor is extracted from the integrated circuit and placed externally. This extraction removes the constraint of single-die integration technology, allowing the use of advanced low-resistance transistor designs in the external power transistor while keeping the control logic integrated in the PMIC.
2Area of stationary object
If large-size liquid crystal modules are designed, then display area increases, but power supply loss becomes larger due to higher current requirements
Solution Approach 1:
The patent changes the key parameter of on-resistance by replacing the LDMOS transistor with an external power transistor that has significantly lower on-resistance. This parameter change directly reduces power loss (P=I²R) while supporting the higher current requirements of large-size display modules.
Data Source
AI summary
The present disclosure provides a power supply circuit and a display apparatus. The power supply circuit includes a power management integrated circuit. The power management integrated circuit includes a driving pin configured to transmit a drive signal. The power management integrated circuit includes a power transistor with a control terminal connected to the driving pin, a first terminal connected to a first power source, and a second terminal connected to a load. The power transistor is configured to supply a voltage to the load.