Smartphone camera auto focus control IC

October 24, 2012 // By Julien Happich
The LC898212XA-MH from ON Semiconductor is an auto focus (AF) control IC for the camera modules found in smartphones.

This innovative solution is highly integrated, programmable and provides fast, accurate auto focus convergence while consuming less power and generating less noise interference than competing solutions, claims the manufacturer. 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-analogue converter (DAC) and gain adjustable operational amplifier to ensure accurate sensing.

The output of the positioning sensor is read by an integrated 10-bit ADC. Furthermore, the control circuit filter coefficients are adjustable via an I 2C 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. The LC898212XA-MH is housed in a lead-free, halogen-free WL-CSP 12-pin package.

Visit ON Semiconductor at www.onsemi