Display Drive Circuit Comparator Reducing Power Consumption
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Solution Overview
Problem
Conventional drive circuits for display devices using PWM control experience increased power consumption due to unnecessary logic switching in the exclusive OR operation of the comparator.
Innovation Solution
A drive circuit with a comparator that includes a shift register and a selection unit, which compares the count number of pulses in a clock signal with comparison data in synchronization with a start signal, reducing unnecessary logic switching and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a comparator using exclusive OR operation is used to compare binary counter output with input data, then the comparison function is achieved, but power consumption increases due to unnecessary logic switching
Solution Approach 1:
The patent extracts only the necessary comparison logic from the full exclusive OR operation. Instead of performing XOR across all bits of the binary counter output, the circuit selectively compares only the significant bits that determine the PWM duty cycle, eliminating unnecessary logic operations and reducing power consumption.
Solution Approach 2:
The patent applies partial action by implementing a simplified comparison mechanism that performs only the essential comparison needed for PWM control. The comparator selectively evaluates specific bits of the binary counter against the input data threshold, performing just enough comparison to determine the ON/OFF state without excessive full-bit XOR operations.
2Measurement precision
If many logic switching operations are performed in the comparator, then the comparison result is obtained, but power consumption increases
Solution Approach 1:
The patent extracts only the essential comparison operations needed to determine the PWM output state. By identifying and removing redundant logic switching operations from the comparator, the circuit achieves the necessary measurement precision with minimal energy expenditure.
Solution Approach 2:
The patent changes the operational parameters of the comparator by transitioning from continuous full-bit XOR operations to selective bit comparison. This parameter change reduces the frequency and number of logic switching events while maintaining the accuracy required for PWM control.
Data Source
AI summary
To reduce power consumption of a drive circuit for a display device. A drive circuit (10) for the display device includes a comparator (100), a PWM signal generation unit (200), and a drive unit (300). The comparator (100) is a comparator that starts comparison between a count number of pulses in an input clock signal and input comparison data in synchronization with a start signal, and includes a shift register (120) that is configured by a plurality of flip-flops in which the clock signal is input to a clock terminal and that is cascade-connected and shifts the start signal, and a selection unit (130) that selects one of outputs of the plurality of flip-flops constituting the shift register according to the comparison data and outputs the shifted start signal as a result of the comparison. The PWM signal generation unit (200) generates a PWM signal according to the result of the comparison. The drive unit (300) drives a light emitting element (11) based on the generated PWM signal.