LED Driving Circuit Substrate Segmentation for Power Reduction
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Solution Overview
Problem
The existing light-emitting element driving circuits in cellular phones consume excessive power when the CPU is activated for flickering operations, and the layout of electronic parts in two-substrate designs hinders downsizing due to inappropriate part arrangement.
Innovation Solution
A light-emitting element driving circuit is implemented on a second substrate with a pulse generation unit, an LED oscillator, and an LED driver unit, which reduces signal lines and allows for a more efficient layout, using a lower frequency oscillator and a boosting circuit to manage power effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the CPU is activated every time the LED performs flickering operation, then the LED can be controlled to notify unattended incoming calls, but a significant amount of current flows and electrical power is consumed excessively
Solution Approach 1:
The system is divided into two independent substrates: the first substrate contains the CPU and control circuit, while the second substrate contains the LED driving circuit with its own pulse generation unit. This segmentation allows the LED control function to operate independently without requiring CPU activation, thereby reducing power consumption while maintaining full LED control capability for notifying unattended incoming calls.
2Device complexity
If the pulse generation unit is provided on the first substrate with the CPU, then the control system is simplified, but the number of signal lines connecting the two substrates increases
Solution Approach 1:
The pulse generation unit is extracted from the first substrate and relocated to the second substrate. This extraction reduces the number of signal lines needed between substrates, as the second substrate no longer needs to receive pulse generation signals from the first substrate. The LED driving circuit on the second substrate generates its own pulses locally, minimizing inter-substrate connections while maintaining functional integration.
3Measurement precision
If a high frequency accuracy oscillator is used in the LED driving circuit, then the reference pulse signal is more precise, but the circuit size and complexity increase
Solution Approach 1:
The oscillator on the second substrate is designed with lower frequency accuracy requirements compared to the control oscillator on the first substrate. Since the LED flickering notification function does not require high-precision timing, a simpler, smaller oscillator can be used locally on the second substrate. This local quality adjustment reduces circuit complexity and size while maintaining sufficient performance for the notification function.
Data Source
AI summary
A light-emitting element driving circuit is installed on a second substrate, which is connected via a signal line to a first substrate, on which is mounted a CPU configured to generate an LED drive control signal. The light-emitting element driving circuit includes a pulse generation unit configured to start and stop an operation based on the LED drive control signal and output an LED drive signal when the pulse generation unit is in an active state, an LED oscillator configured to supply a reference pulse signal to the pulse generation unit, and an LED driver unit configured to cause a light-emitting element to perform a flickering operation based on the LED drive signal.