Dear Sir Hero999,
Thank you for your response here.
Take a look my feedback on your comment.
I'm not sure exactly what you're asking.
As I said in my post, at first diagram when the V_USB_MGCN ( its a magnetic connector charger port) and CTRL_PHONE_CHG_ON_OFF micro-controller signal pin in action, the power path of both V_USB_MGCN and V_RING_5V (host mode power source) are forced to connect. That makes my device on charging mode, I want to stop it.
Yes two MOSFETs connected back-to-back is a fairly standard way to ensure it doesn't conduct in the reverse direction, when it's supposed to be off. Other than requiring more components, the main disadvantage is the on resistance is doubled.
Could you kindly explain its drawback? Between the Mosfet(
http://pdf.tixer.ru/1031640.pdf), the junction point both positive and negative current path meets together. If its OFF then, dont you think any imbalance in this circuit action? Both source to gate are biased by 100k resistor, when Q18 (second figure) is turned on, dont you see any abnormality on the circuit, where do you think to put components more?
What does R112 and C39 do? They will slow it down, which I think is a bad idea.
I think these are using a safe switching for Q18, if Q11 turned ON, the collector current need to flow steady.