Auto focus control IC offers low power benefits for smartphone camera modules

October 22, 2012 // By Paul Buckley
ON Semiconductor has introduced an Auto Focus (AF) Control IC for camera modules in smartphones. The solution is highly integrated, programmable and provides fast, accurate auto focus convergence while consuming less power and generating less noise interference than competing solutions.

The space-saving design has been optimized to enable thinner and lighter smartphones.

The LC898212XA-MH features digital logic with a closed loop control system and a function for a positioning sensor. Its closed loop architecture provides for more accurate auto focus control while also lowering power consumption relative to open loop solutions.

The function for a positioning sensor is a constant current digital-to-analog converter (DAC) and gain adjustable operational amplifier to ensure accurate sensing. The output of the positioning sensor is read by an integrated 10 bit analog-to-digital converter (ADC). Furthermore, the control circuit filter coefficients are adjustable via an I2C interface, allowing the LC898212XA-MH to be programmed for optimal convergence time when paired with various different actuators. This innovative new device also incorporates an improved pulse width modulation (PWM) drive system to further lower power consumption while also minimizing noise which can affect image quality.

LC898212XA-MH is housed in a lead-free, halogen-free WL-CSP 12pin package and is now in production.

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