LP87745-Q1: LP87745-PMIC Shutdown Request without any failure

Hi,

okay great .... and what about the wake up request to start over again?

Thanks,

Best Regards,

Hi,

how can i Rise the Enable pin while the MCU is OFF !!

in my knowledge the Enable pin is raised automatically when a proper voltage applied to PMIC so how can i control the Enable Pin.

Thanks,

Best Regards,

Hi,

okay I got that but if i need to shutdown as i want and wake it up as i want.

not to restart it "separating the restart". What should I do ?

Thanks,

Best Regards,

Hi Amir,

Then the ENABLE pin is the only option if the shutdown sequencing must be followed. You can shutdown individual regulators by writing to the BLOCK_EN_CTRL register but the shutdown delay settings will not be followed and the disabled regulator will start to shutdown immediately. Those regulators could then be enabled through SPI again.

Unfortunately the only way to move from STANDBY to ENABLE state is the rising edge of the ENABLE signal. The state of ENABLE is also sensed when the device is entering INIT mode and the PMIC proceeds to ACTIVE state.

BR,

Samuli

HI,

to make sure i got you Right, i can not shutdown the ECU totally by software but i can shutdown some regulators through SPI and enable them back through SPI too, As i know Enable Pin Can not be controlled by SW because it is handled automatically by the voltage applied to the ECU.

another question regarding PMIC can i make the ECU sleep in a certain time or only shutting it down?

Thanks,

Best Regards, 

Hello,

Also i want to know what is the default threshold voltage value which the ECU will shutdown.

because i am using power supply by default it operates on 12V.

and when i am reducing the voltage until i reach the 3.5V it will shutdown so is this value right ?

also the same include the over voltage.

so please i need to know exact value for over/under voltage to make sure the PMIC works fine with me.

Thanks,

Best Regards,

Hello Samuli,

i have a problem with the INT-SPI-STATUS and all the status in the PMIC like under voltage status that when i am plugin off the ECU power and connect it again the status is cleared automatically does it make any sense ?

Thanks,

Best Regards,

Hi Amir,

Interrupts don't clear automatically unless cleared through SPI or device has reset. Maybe connecting the ECU causes such a large swing in the 3V3 power plane that the input voltage for LP87745-Q1 drops below UVLO.

BR,

Samuli