Enhanced P-Channel MOS tube (e.g. SI2333DS) switching conditions

enhanced P-Channel MOS tube (e.g. SI2333DS) switching conditions

when used as a switch, the PMOs tube is controlled by the VGS voltage value to control the continuity between S (source) and D (drain drain).

the minimum threshold voltage for the VGS is 0.4v, which means that the source and drain electrodes are on when the S (source) voltage-G (Gate gate) Pole > 0.4V.

and VS = Vd, the S-pole voltage is equal to the D-pole voltage.

For example:

s extremely 3.3v,g extremely 0.1V, then Vgs = Vg-vs = -3.2 PMOs tube conduction, D-Pole voltage is 3.3V

when the general PMOs tube is used as a switch, there is almost no pressure drop between the S-pole and the D-pole.

in practical use, the general G-pole is connected to the MCU control pin, s pole-connected power supply positive vcc,d connector input. Examples of actual use are as follows:

when the Rf_ctrl is low, the voltage on the Rf_rxd and Rf_txd is VDD.

The following circuits are used as circuit switches for the P-channel MOS pipe:

The circuit analysis is as follows:

PMOs open condition is the VGS voltage is negative pressure, and the absolute value of the voltage is greater than the minimum open voltage, the general small power of the pmos tube minimum open voltage of about 0.7V, assuming that the battery is fully charged, the voltage is 4.2v,vgs=-4.2v,pmos is conduction, the circuit is no problem. When 5V voltage, the voltage of the G-pole is 5v,s pole voltage is 5vv-diode voltage drop (0.5 or so) =4.5v,pmos tube Close segment, when there is no 5V voltage, G-pole voltage drop to 0V, The voltage of the S-pole is the battery voltage (assuming that the battery is fully charged 4.2V) The-mos tube does not have a diode voltage drop (0.5V) = 3.7, so that the PMOs on the conduction, the diode pressure drop is not so vgs=-4.2v. The PMOs Tong supplies power to the load. Using a Schottky diode (SS12) Here can also solve this problem, but there is a voltage drop of around 0.3V. Here use PMOs tube, PMOs tube fully conduction, internal resistance is relatively small, excellent and schottky, almost no pressure drop. However, the pull-down resistor is a bit large, the drive PMOs does not need current, as long as the voltage is reached, you can use large resistors, reduce the operating current, the recommended use of 10k-100k around the resistor.