LED Driver Circuit Synchronization Without Dedicated Pins
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Solution Overview
Problem
Existing LED driver circuits require dedicated pins for synchronization, which increases the number of pins needed, especially in low-cost and small devices, and complicates the simultaneous start-up and operation of multiple LED driver devices in star or chain topologies.
Innovation Solution
The solution involves reconfiguring non-dedicated LED driver input-output pins to assign local I2C addresses, allowing for simultaneous start-up and synchronization of multiple LED driver devices without dedicated synchronization pins, using a microcontroller to manage a single clock signal and I2C bus for communication, enabling each device to operate as a master or slave unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dedicated synchronization pins are used in LED driver circuits, then simultaneous start-up and synchronization of multiple LED driver devices is achieved, but the number of pins required increases
Solution Approach 1:
The I2C bus pins (SDA and SCL) are made multi-functional by enabling them to serve both their original communication purpose and the new synchronization function. The existing pins are reconfigured through software control to act as synchronization pins, allowing one pin to perform multiple functions and thereby reducing the total pin count while maintaining synchronization capability
Solution Approach 2:
The synchronization function is merged with the existing I2C communication function by using the same physical pins (SDA and SCL) for both purposes. This consolidation eliminates the need for separate dedicated synchronization pins, as the I2C bus is repurposed to carry synchronization signals between LED driver devices
2Reliability
If dedicated synchronization pins are used for each LED driver device, then reliable simultaneous operation is achieved, but the device becomes less suitable for low-cost and small applications
Solution Approach 1:
By making the I2C pins multi-functional, the design achieves reliable simultaneous start-up without adding extra pins, making the device suitable for cost-sensitive and space-constrained applications where pin count directly impacts manufacturing complexity and device size
Solution Approach 2:
The synchronization capability is implemented through software-based signal copying and transmission over the existing I2C bus infrastructure, rather than requiring physical duplication of dedicated synchronization pins for each device, thereby reducing hardware complexity and manufacturing cost
Data Source
AI summary
A circuit includes a set of LED driver devices and a controller including a set of nodes coupled to a first slave address pin and a second slave address pin in each LED driver devices in the set of LED driver devices. Each LED driver device includes: a finite state machine (FSM) configured to generate LED drive PWM-modulated signal patterns; an oscillator configured to generate a clock signal for the FSM; a first signal path activatable between the first slave address pin and the FSM; and a second signal path activatable between the FSM and the second slave address pin.