Using a 89C4051 MCU with a DS1833-10 reset chip. The chip puts out a 350 ms positive going reset pulse at power up.
After power up a N-Channel, 5V gate MOSFET is turned off by the MCU.
Before the reset pulse has finished the MOSFET turns on briefly.
How do I keep the MOSFET turned off during power up long enough for the MCU to take over?
The MOSFET gate circuit is described as a 10 Ohm resistor tied to the gate, on the other side of the 10 Ohm there is a 10K resistor tied to ground and a 1K Ohm resistor tied to Vcc. This 3 resistor junction connects to a port pin on the MCU.
The MCU port pin can sink more current then it can source so I am using this feature to turn the MOSFET off and the 1K pullup resistor as the means of turning the MOSFET on.
After power up a N-Channel, 5V gate MOSFET is turned off by the MCU.
Before the reset pulse has finished the MOSFET turns on briefly.
How do I keep the MOSFET turned off during power up long enough for the MCU to take over?
The MOSFET gate circuit is described as a 10 Ohm resistor tied to the gate, on the other side of the 10 Ohm there is a 10K resistor tied to ground and a 1K Ohm resistor tied to Vcc. This 3 resistor junction connects to a port pin on the MCU.
The MCU port pin can sink more current then it can source so I am using this feature to turn the MOSFET off and the 1K pullup resistor as the means of turning the MOSFET on.