Charge Pump Switch Control for LCD Voltage Stability
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Solution Overview
Problem
Conventional charge pumps in liquid crystal displays (LCDs) have limited application flexibility and generate undesired peak currents, leading to increased power consumption and inefficiencies, particularly in portable consumer electronic products.
Innovation Solution
A charge pump design featuring a capacitor and multiple switches controlled by a voltage detector and controller, which dynamically adjusts the number of active switches based on detected voltage values to minimize peak current and optimize voltage generation, allowing for flexible targeting of voltage values without redesigning the circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional charge pump structure is used, then voltage generation function is provided, but application flexibility is poor and circuit redesign is required when target voltage values change
Solution Approach 1:
The charge pump controller dynamically adjusts the number of active switches in the charge path and pump path based on the detected output voltage. This dynamic configuration allows the charge pump to adapt to different target voltage values without requiring circuit redesign, thereby improving application flexibility while maintaining a fixed circuit structure.
Solution Approach 2:
The invention changes the operational parameters (number of active switches) rather than the physical circuit structure when target voltage values need to be adjusted. By varying the number of parallel switches activated, the charge pump can generate different voltage levels using the same hardware configuration, eliminating the need for circuit redesign.
2Power
If conventional charge pump operates, then voltage is generated, but peak current is considerable and power consumption increases
Solution Approach 1:
The charge pump controller continuously detects the output terminal voltage and uses this feedback information to adjust the number of active switches. This feedback mechanism ensures that the charge pump operates efficiently by activating only the necessary number of switches to achieve the target voltage, thereby avoiding excessive peak current and reducing power consumption.
Solution Approach 2:
Instead of activating all switches simultaneously which would cause peak current, the charge pump controller activates only the necessary number of switches (partial action) based on the voltage detection. This approach provides just enough charging current to reach the target voltage without excessive current spikes, thus reducing power consumption.
3Power
If conventional charge pump is used, then voltage generation is provided, but generated voltages deviate from target value due to load current
Solution Approach 1:
The voltage detector continuously monitors the output terminal voltage and provides feedback to the charge pump controller. Based on this feedback, the controller adjusts the number of active switches to compensate for voltage deviations caused by load current, ensuring that the generated voltage remains accurate and close to the target value.
Data Source
AI summary
A charge pump with limited peak current and improved application flexibility and an LCD having the same. The charge pump has more than three switches in a charge path and more than three switches in a pump path. Furthermore, the charge pump has a voltage detector detecting voltage of the output terminal of the charge pump and a charge pump controller controlling the switches based on the detected voltage. According to the detected voltage, the charge pump controller determines the number of turning-on switches in the charge path and determines the number of turning-on switches in the pump path.