SMPS Single PWM output translation into separate MOSFET gate outs

[Jovan1]

Well hello, ive come about an interesting problem and a solution to it (i hope), im utilizing an SMPS buck controller which does not have separate top and bottom gate outs, rather it has a single PWM out. The idea is to hook the PWM up to a power stage with integrated mosfets, where +5V HIGH on PWM represents TG=on BG=off, 0V LOW on PWM represents TG=off BG=on. Now, the power stages i could use with a single PWM input are either too expensive or unavailable, so i decided on a power stage with TG and BG inputs, basically two MOSFETS in one package. Now, of course i cannot hook up PWM to both TG and BG, this would result in both TG and BG turnign on when only TG should. What I have devised to get around this problem is a circuit which firstly inverts PWM so that where 0V LOW on original pwm represents BG on, on inverted PWM BG on is represented as +5V HIGH, this line goes straight to BG. The inverted PWM line hooks up to another inverter referenced to SW instead of GND, this inverter inverts the inverted PWM so that it is the same as on the output of the controller, difference being that LOW is not GND, but SW, this line ges straight into TG. I have attached the schematic of the described circuit to this post, i hope that some knowledgeable people will point out flaws and errors in this circuit and/or suggest how to improve and/or simplify it. Thanks very much for reading 

[T3sl4co1l]

Heh no, not quite like that.  There are a couple things missing:
- Dual transistor inverters have enormous shoot-through
- High side +V needs to be bootstrapped to source, not fixed(!)
- No delay (output shoot-through prevention), UVLO, etc. protection shown

Just get a gate driver chip with complementary outputs, e.g. https://www.ti.com/lit/ds/symlink/tps28225.pdf

Tim

[Jovan1]

Oh, well thats convenient, didnt know those existed  . Yeah, i thought the delay might be a problem and possibly short out everything by turning on both MOSFETS on for a split second, forgot about the bootstrap cap, oops. Thanks for your help