Renesas Provides Automotive Grade PMIC for MCU Power Solution

Recently, automotive technology, such as electrification, autonomous, connected, advance very rapidly. The number of microcontrollers (MCUs) and its performance are increasing along with the automotive technology progress.

On the other hand, the high-performance MCU requires multi power supplies such as 5[V], 3.3[V] and 1.25[V]. And power-rails' power up order and timing (i.e., power sequence) should be carefully investigated. The system designers, who use MCU, need to be careful at their development.

Also, the PMICs are usually required various monitoring /diagnosis functions and protective functions for automotive applications to realize safety systems. For examples, each power-rails' over-voltage and under-voltage detection, over-current detection, die-level over temperature detection, MCU operation monitoring.

For the problems mentioned above, RENESAS provides automotive grade PMICs dedicated for our top shared MCU as the MCU power solution. When you use PMIC and MCU as a kit, Renesas can provide following merits.

    ·Reduce development effort and time by using the PMIC which controls complicated power sequence(power-up power-down order and timing). 

    ·Reduce PCB area size by using the PMIC which is integrated several functions such as power supplies, power monitoring and diagnostic functions required by the target MCU.

    ·Reduce development costs and time by using qualified reference design, recommended BoM list and design guides.

As mentioned above, Renesas can provide an appropriate PMIC for the target MCU.

Now, I would like to introduce one of the PMIC's monitoring function.

A watchdog timer (WDT) function is implemented in the PMIC to monitor MCU operation. During MCU operating, PMIC requires a trigger to MCU. If the trigger is not replied in terms of timing/format correctly from MCU, PMIC generates a reset pulse to the MCU. Owing to the WDT function, the MCU can be backed to the safe state by the PMIC even if any problems occur to the MCU.

Also, RAA270005, which is dedicated designed PMIC for RH850/P1x MCU, can support automotive unique requirement "Cranking operation".

Automotive battery sends large current to starter motor when starting the engine. This large current temporary decrease battery voltage. (For example, in case of 200[A] flowing, 2[V] under-voltage occurs if the wiring resistance is 0.01[Ω] in simple estimation. The automotive battery is typically 12[V], so this under-voltage affects influence to the system. Now you understand, don't you?) 

In several automotive application, it is required to operate MCU during low battery voltage condition about 2V. Therefore, the RAA270005 implements a boost circuit and supports the requirement to provide stable power supply during under-voltage. Following figure shows an example of electric power steering system.