I have an electronic device that I need to power with a DC/DC converter. The problem is the electronic device is an embedded system so I can only power it by applying power (no EN pin or anything like that is available.)
So basically the DC/DC converter will charge a capacitor and when that capacitor reaches a certain voltage I would like the embedded device to operate for about 30 seconds.
So the only solution I can come up with is to use a n type MOSFET and a comparator. The comparator will read the voltage on the capacitor and apply the bias voltage to the gate of the MOSFET when the voltage reaches a certain level. That will allow charge to flow to the embedded device.
So I have a few questions. What MOSFET do you recommend for this job? The current flowing through it will not exceed about 20-30mA. How can I get the comparator to continue applying the bias voltage for 30 seconds after it has started? Since the voltage on the capacitor will be dropping, the output of the comparator will naturally go low. I need it to remain on no matter what to ensure the device has time to operate (30 secodns).
Or maybe there is a better way of doing this? I usually try to avoid these kind of designs since the MOSFET burns quite a bit of power.
So basically the DC/DC converter will charge a capacitor and when that capacitor reaches a certain voltage I would like the embedded device to operate for about 30 seconds.
So the only solution I can come up with is to use a n type MOSFET and a comparator. The comparator will read the voltage on the capacitor and apply the bias voltage to the gate of the MOSFET when the voltage reaches a certain level. That will allow charge to flow to the embedded device.
So I have a few questions. What MOSFET do you recommend for this job? The current flowing through it will not exceed about 20-30mA. How can I get the comparator to continue applying the bias voltage for 30 seconds after it has started? Since the voltage on the capacitor will be dropping, the output of the comparator will naturally go low. I need it to remain on no matter what to ensure the device has time to operate (30 secodns).
Or maybe there is a better way of doing this? I usually try to avoid these kind of designs since the MOSFET burns quite a bit of power.