Laser Driver Energy Recycling for Efficient TOF Pulsing
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Solution Overview
Problem
Time-of-flight sensors face power efficiency challenges due to high energy requirements for laser emission, leading to increased power consumption and heat dissipation issues, particularly in mobile applications where space is limited.
Innovation Solution
A laser pulse emitter circuit with an inductive and capacitive circuit element in series, utilizing duty cycling to store and recycle energy, reducing power loss by reusing stored energy in subsequent activations of the laser diode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high energy is emitted by the laser emitter to get sufficient reflection from the object, then the time of flight measurement capability is improved, but the power consumption increases
Solution Approach 1:
The laser emitter is activated using duty cycling with periodic on-periods and off-periods, converting continuous high-power emission into periodic pulses. This allows the laser to emit high energy only when needed for measurement while consuming less power on average during off-periods.
Solution Approach 2:
Energy storage circuit elements (inductors and capacitors) store energy during the off-period when the laser is not active, and then recycle this stored energy during the on-period to activate the laser. This recovers energy that would otherwise be wasted, reducing overall power consumption while maintaining measurement capability.
2Power
If high power is used to drive the laser emitter, then the laser energy emission is improved, but heat dissipation increases
Solution Approach 1:
By using duty cycling with periodic on/off operation, the laser emits high power only during brief on-periods and remains off during off-periods. This reduces the average power and consequently reduces heat generation and dissipation requirements while maintaining sufficient laser energy emission during active periods.
3Use of energy by moving object
If duty cycling is used to activate the laser diode, then the power efficiency is improved, but the energy storage and recycling mechanism increases device complexity
Solution Approach 1:
The patent implements energy recovery by capturing energy from the laser diode's inductive load during turn-off and storing it in energy storage circuit elements (inductors and capacitors). This recovered energy is then reused during subsequent on-periods, improving power efficiency by reducing the energy that would otherwise be wasted.
4Loss of energy
If energy storage circuit elements are added to recycle energy, then the power loss is reduced, but the device complexity increases
Solution Approach 1:
The patent adds energy storage circuit elements (inductors and capacitors) to capture and store energy during the laser diode's off-period, then recycle this energy during on-periods. This reduces power loss by recovering energy that would otherwise be dissipated, accepting the trade-off of increased device complexity.
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
Improves power efficiency by minimizing energy dissipation and extending battery life in mobile applications while reducing heat dissipation concerns.
Implementation Method 1
storing activation energy from an on-period of the duty cycling in an inductive circuit element of the laser emitting circuit
Implementation Method 2
storing activation energy from an on-period of the duty cycling in an inductive circuit element of the laser emitting circuit
Implementation Method 3
A laser pulse emitter circuit according to various aspects includes a laser diode and a laser diode driver circuit
Data Source
AI summary
A laser pulse emitter circuit comprises a laser diode and a laser diode driver circuit. The laser diode driver circuit includes an inductive circuit element in series with the laser diode, at least one capacitive circuit element connected in series with the inductive circuit element, and a switch circuit configured to activate the laser diode using duty cycling that includes an on-period and an off-period, wherein energy used in an activation of the laser diode is stored in the inductive circuit element and the at least one capacitive circuit element, and the stored energy is recycled by use in a subsequent activation of the laser diode.