Optical Navigation Sensor Integrated Charge Pump Power Management
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Solution Overview
Problem
Conventional optical navigation systems require external DC-DC boost converters that consume significant power and increase hardware costs due to the need for control pins and switches to manage the supply voltage to the light source, posing safety risks if the light source is improperly shorted.
Innovation Solution
An optical navigation sensor with an integrated charge pump that intermittently provides a supply voltage to the light source, eliminating the need for external converters and control pins by using a capacitor to maintain voltage during operation and stopping the charge pump when a fault event is detected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If external DC-DC boost converters are used to provide supply voltage to the light source, then the supply voltage can be provided continuously, but the power consumption increases considerably
Solution Approach 1:
The charge pump operates intermittently in periodic cycles: during the first time period it provides supply voltage to the light source, and during the second time period it stops providing voltage while the driving circuit drives the light source. This periodic operation reduces power consumption compared to continuous operation of external DC-DC boost converters.
2Reliability
If external DC-DC boost converters and control pins are used to manage supply voltage, then fault detection capability is improved, but the hardware cost increases
Solution Approach 1:
The charge pump is integrated within the optical navigation sensor package, merging the voltage provision function with the sensor. The driving circuit also serves dual purposes: it drives the light source during the second time period and simultaneously detects fault events by monitoring whether the light source is properly shorted to ground, eliminating the need for separate control pins and external converters.
Solution Approach 2:
The driving circuit performs self-diagnosis by detecting fault events itself without requiring external control pins. When a fault is detected, the driving circuit automatically stops providing driving current to the light source, enabling the system to monitor its own health status using existing internal resources.
3Object-affected harmful factors
If switches and control signals are used to turn off the light source during fault events, then eye safety is ensured, but the pin count and hardware cost increase
Solution Approach 1:
The driving circuit automatically detects fault events and stops providing driving current to the light source without requiring external control signals. This self-protective mechanism ensures eye safety by preventing harmful light emission while avoiding the need for additional control pins and switches.
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
This solution reduces power consumption and hardware costs while ensuring user safety by eliminating the need for external converters and control pins, and preventing harmful light emission in case of a fault event.
Implementation Method 1
The charge pump is employed for intermittently performing an operation of providing a first supply voltage to the light source
Data Source
AI summary
An optical navigation sensor includes: a driving circuit and a charge pump. The driving circuit is employed for driving a light source externally connected to the optical navigation sensor. The charge pump is employed for intermittently performing an operation of providing a first supply voltage to the light source. When the driving circuit drives the light source, the charge pump does not perform the operation of providing the first supply voltage to the light source.