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Hello!!! Everyone i am working on PIC32MX795F512L and i have to use it's RTCC for some time based application, and wants that if someone disconnect the supply from this controller, even then RTCC must run.
For which what i did, is just connect a battery as backup supply, in case of external supply failure, the controller gets supply from its internal battery and goes in sleep mode (In Sleep Mode RTCC continues to operate and other peripherals are disabled).
I am attaching my circuit below.
My External supply is a 12V DC Adapter, i decrease the voltage to 5V using 7805 Voltage Regulator, then LM1117 3.3V regulator is used to down it further, two schottky diode B2515LG are used to connect, the supply and Battery Supply, the output of diodes are going to controller's Supply Voltage.
When i disconnect the external supply(12V DC Adapter), the output of 7805 is 2V and through voltage divider i am getting around 1.15V at PIN INT2 of controller, and due to such high voltage no interrupt is generated.
This 2.0V at output of 7805 is creating problem, why is it so, please suggest me something to solve this problem.
For which what i did, is just connect a battery as backup supply, in case of external supply failure, the controller gets supply from its internal battery and goes in sleep mode (In Sleep Mode RTCC continues to operate and other peripherals are disabled).
I am attaching my circuit below.
My External supply is a 12V DC Adapter, i decrease the voltage to 5V using 7805 Voltage Regulator, then LM1117 3.3V regulator is used to down it further, two schottky diode B2515LG are used to connect, the supply and Battery Supply, the output of diodes are going to controller's Supply Voltage.
When i disconnect the external supply(12V DC Adapter), the output of 7805 is 2V and through voltage divider i am getting around 1.15V at PIN INT2 of controller, and due to such high voltage no interrupt is generated.
This 2.0V at output of 7805 is creating problem, why is it so, please suggest me something to solve this problem.