1. Introduction
In recent years, as smartphone imaging capabilities have continued to advance globally, imaging systems are shifting from "using algorithms to simulate optical effects" to "using physical optics to support effects." The VA variable aperture, representing the pinnacle of the imaging experience, is driving smartphone imaging from "computational photography" toward "optical photography." This article systematically introduces the physical nature of the aperture and the logic behind F-number definition, the technical implementation approaches and key performance indicators of VA variable aperture, and how it systematically addresses four major imaging pain points: low-light performance, bright-light handling, depth of field, and video. Emphasis is placed on how Awinic's SmartHolding closed-loop driver solution overcomes industry bottlenecks in power consumption, thermal drift, and service life.
2. Aperture (F1.4 / F2.0) in Plain Terms
The aperture can be understood as the pupil of the human eye: in bright light, the pupil contracts; in dim environments, the pupil dilates. The principle is exactly the same, as illustrated below:
Figure 1. Aperture Actuator Form Factor
Basic F-number Formula:
F-number = Lens Focal Length ÷ Entrance Pupil Diameter
Therefore, F1.4 > F2.0 (F1.4 represents a larger aperture).
3. VA Variable Aperture: A Key Hardware Enabler for Consumer Terminals Moving Toward Optical Creation
The VA variable aperture employs a high-precision multi-blade linkage mechanism combined with a miniature closed-loop drive unit to achieve seamless switching across multiple stops from F1.4 to F4.0, with a response time of ≤20 ms (precise, controllable, and free of stutter). For the first time, it brings the light control capability of DSLR cameras down to consumer-grade terminals. Its value lies not in "adding another feature," but in replacing algorithmic compromises with physical optics—all depth-of-field, light intake, and exposure control are physical imaging results, fundamentally avoiding issues such as AI algorithm bokeh distortion, excessive night scene processing, and dynamic range compression distortion in bright light.
4． Core of the awinic closed-loop solution: SmartHolding Solving VA the biggest bottleneck in aperture implementation
The industry commonly adopts ball-type VCM mechanisms to achieve aperture self-locking. Traditional constant-current holding schemes bring three fatal shortcomings: high power consumption (29mAstandby), heat-induced aperture drift, and VA accelerated mechanical structure fatigue. Relying on the AW86022/AW86026series with built-in Hall closed-loop VCM chips, awinic pioneers SmartHolding intelligent control algorithms for current management,mainly including LowPower and CuurentLimit. Its working principle is shown below:
Figure2. Low Power Consumption Schematic
Figure3. Current Limiting Schematic
1. Principle innovation,closed-loop real-time position locking→dynamically reduces holding current after reaching the target→millisecond-level response correction for displacement.
2. Graded dynamic current limiting + SmartHolding Closed-loop energy saving, achieving the optimal power solution for all scenarios: Current gears are preset to match the motor's basic thrust requirements; absolute value current limiting precisely constrains open-loop peak current, avoiding overdrive that causes mechanical stress and thermal drift. SamrtHolding Closed-loop holding technology can reduce the drive current in standby state from that of traditional constant-current schemes by29mA down to 8.3mA(↓71%).
3. Directly addressing mass production pain points:
Precision and stability: Hall sampling error <1.5%,F1.4/F2.0/F2.8/F4.0 improved consistency in multi-gear repeat positioning,enhanced drop resistance/and jitter tolerance.
Compromise-free response: Sleep modeI²C command wake-up latency <1ms, aperture switching speed remains unaffected by energy-saving modes.
Power Consumption and Thermal Control: 4K During video recording, the lens temperature rise is significantly reduced, CMOS noise is markedly decreased, and overall device battery life is extended.
Lifespan and Reliability: With the coil operating at low current+and zero magnetic pull on the blades, blade fatigue is minimized to the greatest extent, gaps are reduced,MTBF lifespan is improved, bidding farewell to the control method that relies on current to generate magnetic force, namely“magnetically hard-pulling the aperture blades”.
5． awinic Closed-Loop Driver ChipVAApplication Selection Recommendation
Figure4. AW86022Typical Application Schematic
AW86022CSRis a standard closed-loopCamaradriverVCMlaunched by awinic for smartphoneICmodules. It has been deeply optimized for6mmmotors with conventional blade sizes and aperture diameters aroundVA, integrating anSmart Holdingclosed-loop driver solution that supports±150mApeak drive capability and14bithigh-precisionADCsampling. This chip has been stably delivered in multiple mass-production projects, combining excellent optical control performance,good cost-effectiveness, and highly mature engineering implementability.
For application requirements involving larger apertures or higher loads, awinic simultaneously offers advanced models:VALong-Stroke Enhanced Type and AW86026CSR High-Voltage Enhanced Type, forming a matrix of closed-loop driver solutions covering full-scenario AW86026HCSR optical modules.VA．
6 Summary Variable aperture is not
VA just another motor upgrade“, but rather a return of mobile imaging from”computational photography“to the”essence of optics “”watershed. awinic closed-loop VCM + SmartHolding, with hardware-level low power consumption, high precision, and long lifespan, makes variable optical apertures truly viable for mass commercial adoption——This is not only an iteration of technical parameters, but also a paradigm shift in the imaging experience of consumer terminals.
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