Compact units connected to 8V secondarly rail
- Compact units directly connected to 12V battery
- Compact units connected to 8V secondarly rail
- Automotive camera modules
Examples of various types of sensors and modules operated by a power supply of roughly 8V, generated from 12V battery through a primary power supply.
Simple, ultra-compact power supplies with low noise are introduced.
|Block Diagram||Power Supply Requirements||Recommended Products||Features|
DC 8V to unit internal
|XDL603 / XDL604
(XD9263 / XD9264)
Inductor built-in step-downDC/DC, PWM (XDL603), PWM/PFM (XDL604)
|Step-down / LDO
Low consumption ,low noise voltage regulator
There are many cases where various sensors and modules connected to main units for infotainment are supplied by a power supply of roughly 8V created by a primary DC/DC within those main units.
Primary step-down DC/DC
The voltage is already stabilized to a constant value of 8V and then input, so it can be directly decreased to the ECU voltage of 3.3V. Since there are some cases where the harness will be longer, in such cases use a DC/DC with a switching frequency of 2MHz or greater in consideration for EMI.
If a light load condition will be experienced for a long time, and a decrease in frequency during that time is allowed, select the PWM/PFM automatic switching type. If it is desired to keep the operating frequency constant regardless of the load condition, select the PWM fixed type.
Also, during cold cranks, due to a decrease of this 8V and fluctuations caused by long harnesses, the Pch SW type, which supports a duty ratio of 100% and can easily maintain the output voltage even when there is a drop in input voltage, is suitable in such cases.
- Step-down DC/DCs, 18V operation (Absolute maximum rating of 20V)
- XDL603: Inductor built-in PWM
- XDL604: Inductor built-in PWM/PFM
- XD9263: PWM
- XD9264: PWM/PFM
The PG (Power Good) pin of the primary DC/DC can be used as the RESET output for monitoring the power supply voltage of the ECU.
By signaling that the voltage has risen up sufficiently before starting operation of the ECU, and also signaling when there is a drop in voltage, ECU malfunctions can be prevented.
LDO for sensor
Obtaining power supplies for sensors in this way from the power rail for the ECU using LDOs is a simple and efficient method of controlling heat generation characteristics.
Since low noise and ripple are important, LDOs which have low power and low noise are ideal.
- Voltage regulator
- XD6506: Low consumption
The sensor is only turned ON when necessary, so the CE signal is controlled by the ECU.
In simple units like this, simple configurations using only voltage regulators have been used for some time up until now, but heat generation caused by an increase in the number of ECUs installed in automobiles, as well as their associated miniaturization and advancements in performance, is becoming an important issue, so their replacement with DC/DCs is proceeding.