OmniVision has been working on products related to car cameras. In addition to the image sensor, the ORX1210 is the latest highly integrated PMIC for car cameras. The PMIC comes in a QFN4x4mm2 package with a 4.0V to 18V wide input voltage range and consists of a medium-voltage DCDC Buck regulator, two low-voltage DCDC Buck regulators, and a high-PSRR low-noise LDO. Among them, LDO is optimized for the sensitive frequency range of the camera (100K~1MHz), which can better suppress the influence of power noise on image quality.
In recent years, the loading rate of ADAS(Advanced Driving assistance System) is increasing rapidly, and the technology is mainly concentrated in L2~L3 level driving assistance system. To realize these functions, the number of cameras in the bike sensing system should be at least 5, mainly including the forward/circumnavigation camera, the side camera for blind spot monitoring, the rear camera for astern assistance, and the internal camera for cabin monitoring. Together, the cameras perform lane departure maintenance, adaptive cruise control, 360 panoramic images and assist driving.
ORX1210 has flexible power-on timing control to ensure stable operation of the system. Support frequency spreading function, improve the EMI performance of the system. High power efficiency and good heat dissipation enable the system to work normally at higher ambient temperatures. As the first camera power management chip that supports functional security ASIL B in China, it integrates richer functional security mechanisms and meets the requirements of ASIL B level.
With the evolution of ADAS from L2+ to a higher level of auxiliary driving system, the types and number of cameras are gradually increasing, and the functions are gradually becoming stronger. Therefore, higher requirements are put forward for the power management chip for the on-board camera, such as small package, low power consumption, high efficiency, and having the functional safety standards that meet ISO26262.
ORX1210 application principle advantage
（1）Automatic power-on detection ensures system reliability
ORX1210 has the power-on self-detection function. When the system power supply voltage VSYS exceeds UVDET(3.7V), the chip starts to import the MTP configuration. Then the self-detection starts immediately. The PMIC performs three self-checks in total. If the checks fail, the PMIC enters the safe mode to ensure that the system enters the safe state.
（2）Timing control ensures system stability
ORX1210 can be powered on by PWRON pin or internal register control, and supports independent control of three step-downs and LDO power-on sequence.
● When PWRON control is selected, when PWRON pin input voltage is high level, PMIC recognizes as power on event, that is to turn on the output of power sequence;
● When the internal register control is selected, after importing the register configuration, the corresponding power output channel starts the soft start according to the set time sequence and the voltage output reaches the set value;
● When the power supply voltage VSYS is less than UVDET, all output power channels are powered off at the same time. The PMIC enters the POR mode until the power supply voltage recovers.
（3）Frequency spreading function, improve EMI performance
In order to improve EMI performance, ORX1210 uses the frequency spreading function to extend the original fixed 2.3MHz switching frequency by ±10%, which greatly reduces EMI noise at 2.3M frequency points and improves EMI performance. Meanwhile, the Buck2/3 converter supports switch phase offset setting, which reduces the influence of switching noise from Buck1, reduces switching ripple, and improves the overall EMI performance of the chip.
（4)High conversion efficiency, high PSRR
ORX1210 integrates efficient primary and secondary Buck synchronous step-down converters, with a maximum conversion efficiency of over 90%. In addition, in order to reduce the impact of noise on the camera sensor, LDO optimizes the noise suppression rate of the input power supply. The PSRR of the frequency band below 100KHz is up to 65db, and the PSRR of the frequency band from 100k to 1MHz is up to 45db.
(5)Intelligent communication interface
Integrated with I2C intelligent communication interface, ORX1210 supports the host to query the working state of the chip in real time and read the fault information under the fault state.
(6)Highly integrated security mechanism, functional security ASIL B
In order to meet the functional safety requirements of ADAS(Assisted driving system), ORX1210 integrates the safety diagnosis mechanism for functional failure to the maximum extent, to improve the system diagnosis coverage for single points of failure and potential failures, and improve the level of functional safety of the system.
