I am using a 3.6V lithium ion coin cell battery (LIR2450) that I am regulating to 3.3V. I want a low battery disconnect feature so the circuit won't be operational if the regulated output voltage goes below 3.3V.
The MCP1825 regulator (http://ww1.microchip.com/downloads/en/devicedoc/22056b.pdf) has a "power good" signal (PWRGD) that is an open-drain output used to indicate when the LDO output voltage is within 92% (typically) of its nominal regulation value. I don't think it is intended to be used as a low battery indicator (it looks like it's meant to create a delay until the voltage is stable), but I was wondering if it could be used for the purpose of disconnecting the battery when it's low.
I'm not sure the best way to do this...there is a shutdown input (SHDN) on the regulator but it affects the power good signal, so that's confusing. Does it make sense to use a mosfet with the power good signal turning it on? That's also confusing because if the mosfet disconnects the battery from the regulator, then the power good signal would be floating...any suggestions on how I could accomplish low battery disconnect using the power good signal?
The MCP1825 regulator (http://ww1.microchip.com/downloads/en/devicedoc/22056b.pdf) has a "power good" signal (PWRGD) that is an open-drain output used to indicate when the LDO output voltage is within 92% (typically) of its nominal regulation value. I don't think it is intended to be used as a low battery indicator (it looks like it's meant to create a delay until the voltage is stable), but I was wondering if it could be used for the purpose of disconnecting the battery when it's low.
I'm not sure the best way to do this...there is a shutdown input (SHDN) on the regulator but it affects the power good signal, so that's confusing. Does it make sense to use a mosfet with the power good signal turning it on? That's also confusing because if the mosfet disconnects the battery from the regulator, then the power good signal would be floating...any suggestions on how I could accomplish low battery disconnect using the power good signal?