LED Matrix Control for Parasitic-Capacitor Light Suppression
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Solution Overview
Problem
Existing technologies are limited in effectively removing all types of abnormal light emission occurring during the driving of an LED matrix and key scanning of a key matrix, particularly due to charging and discharging of parasitic capacitors in digit and segment pins.
Innovation Solution
An LED control device with an LED driver, key scanner, first and second abnormal light emission removers, and a control unit that manages operation states to supply or discharge voltages during specific periods to remove abnormal light emissions by controlling the LED matrix and key scanner, utilizing ground and applied voltages to manage parasitic capacitors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing abnormal light emission removal technologies are used, then certain types of abnormal light emission can be removed, but not all types of abnormal light emission are effectively removed
Solution Approach 1:
The patent divides the abnormal light emission removal function into two separate circuits: a first abnormal light emission removal circuit for removing abnormal light emission during LED matrix driving, and a second abnormal light emission removal circuit for removing abnormal light emission during key scanning. Each circuit is activated at different time periods to address different types of parasitic capacitor discharge issues, thereby achieving comprehensive coverage of all abnormal light emission types.
2Duration of action of moving object
If voltage is continuously supplied to LED matrix, then LED matrix can operate continuously, but parasitic capacitors charge up causing abnormal light emission
Solution Approach 1:
The patent implements periodic voltage supply to the LED matrix by controlling the LED driver to operate in cycles: during a first time period, voltage is supplied to drive the LED matrix; during a second time period, voltage supply is stopped and the first abnormal light emission removal circuit is activated to discharge parasitic capacitors. This periodic on-off cycling prevents continuous charging of parasitic capacitors while maintaining overall LED matrix operation.
Solution Approach 2:
The patent applies preliminary action by activating the abnormal light emission removal circuits during the voltage supply stop period before the next voltage supply cycle begins. This ensures that parasitic capacitors are discharged in advance, preventing abnormal light emission from occurring when voltage is subsequently reapplied to the LED matrix.
3Productivity
If key scanning is performed continuously, then key input detection is maintained, but parasitic capacitors discharge causing abnormal light emission
Solution Approach 1:
The patent implements periodic key scanning by controlling the key scanner to operate in cycles: during a third time period, key scanning is performed to detect key inputs; during a fourth time period, key scanning is stopped and the second abnormal light emission removal circuit is activated to manage parasitic capacitor discharge. This periodic scanning maintains key input detection capability while preventing abnormal light emission.
Solution Approach 2:
The patent applies preliminary action by activating the second abnormal light emission removal circuit during the key scanning stop period before the next key scanning cycle begins. This ensures that parasitic capacitors are properly managed in advance, preventing abnormal light emission from occurring when key scanning is subsequently resumed.
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
Effectively removes abnormal light emissions generated by parasitic capacitors during LED matrix driving and key scanning, preventing damage and extending the life of the LED matrix.
Implementation Method 1
An LED is a semiconductor device composed of n-type and p-type junctions, which emits light by combining electrons and holes when a voltage is applied to the LED
Implementation Method 2
abnormal light emission generated by charging parasitic capacitors of digit pins or discharging parasitic capacitors of segment pins
Implementation Method 3
abnormal light emission generated by charging parasitic capacitors of digit pins or discharging parasitic capacitors of segment pins
Data Source
AI summary
An LED control device includes: an LED driver controlling a current flow for driving the LED matrix by supplying an applied voltage VLED to digit lines connecting a plurality of LED anode terminals to a plurality of digit pins and supplying a ground voltage VSS to segment lines connecting a plurality of LED cathode terminals to a plurality of segment pins within the LED matrix; a key scanner detecting a signal input to the key matrix by performing key scanning on the key matrix; a first abnormal light emission remover supplying the ground voltage VSS to the digit lines through the digit pins; a second abnormal light emission remover supplying the applied voltage VLED to the segment lines through the segment pins; and a control unit controlling operation states of the LED driver, the key scanner, the first abnormal light emission remover, and the second abnormal light emission remover.