I've been trying to design a control circuit to switch supply.
What I want to achieve?
I need 24V voltage for supplying an ultrasound sensor. There are two ways of gaining 24V:
VIN is a physical 24V power supply and
24V_OUT is a boost converter placed in the other part of the circuit. I assume that when I plug any voltage to the
VIN connector I obtain this voltage in the output decreased by the voltage drop on the
D4 diode. For now, when I put 7.4V to the
VIN input, I receive 1.8V in the output. I've checked the datasheet and threshold voltage of the Q3 transistor is typically 1.8V. Could you explain where had I made a mistake?