“There is a strong and growing demand for improved smartphone camera features – specifically for fast, accurate, power-friendly auto-focus,” said Tomofumi Watanabe, general manager of ON Semiconductor’s SANYO product division. “We developed this highly integrated, compact and highly power efficient auto focus solution for the specific needs of smartphone applications. It provides an effective, single-chip solution to the technical limitations that have challenged many of our industry-leading wireless communications customers.”
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.