Using CMOS logic ICs to drive a P-channel FET

Question

I am attempting to implement a latching circuit without software. The results thus far seem promising, but now I want to drive a control line on a solid-state relay using its output as a high-side PNP switch. I opted to use some CMOS logic ICs to simplify the construction of the circuit, so I want to feed one of the IC's output to the gate of a PFET. These CMOS ICs have limited current output, so I thought to try a simple voltage divider to both A.) keep the current output low, and B.) keep Vg negative with respect tp Vs.

Does this design practice seem feasible? If not, what are some recommendations?

ICs: CD4043B cmos r/s latch CD4081B cmos and gate

EDIT: Schematic should read "Vg < Vs" or in this case basically 6V<12V

EDIT 2:

Truth tables for the CD4043/4044
Proposed pfet inverter

Answer 1

You have a PFET at the output instead of a PNP, so you should not worry about any current going into the PFET's gate. Sure, there is a current (i.e gate charge) that flows into it when turning it on or off and that mainly determines how fast you can operate the PFET.

Now, in the configuration you show, the PFET will always be ON. That is the case because at the output of the CD4081, you can either have a '1' (~12V) or a '0' (0V). The PFET turns on when \$V_S\$ is at a sufficiently high potential with respect to \$V_G\$. Say the output of your CD4081 is at 12V, then \$V_G=6V\$ and \$V_S=12V\$, so \$V_{GS}=-6V\$, that is good enough to turn on lots of PFETs. If on the other hand, the output of your CD4081 is at 0V, then \$V_G=0V\$ and \$V_S=12V\$, so \$V_{GS}=-12V\$, again, that is good enough to turn on most PFETs.

You really want to do something like this with your output PFET:

^{simulate this circuit – Schematic created using CircuitLab}

The control node is the output of the CD4081. When high (12V), \$V_{GS}=0V\$ and the PFET is OFF. If the control node is low (0V), \$V_{GS}=-12V\$, and the PFET is ON, and the load will see 12V across itself.

EDIT:

I looked at the circuit you linked and I see what you did wrong. This is what you really want to do:

^{simulate this circuit}