Level Translation b/w PWM control output and FET switch input?

Just use a high side load switch.

Thanks for your suggestion. How is a high side switch different from a regular power switch?

Also, if you could take a look at the following circuit:

page 5 @

This is more detailed circuit of a demonstration board for this IC. I can see that the level translator block has been replaced with several components (including four bipolar transistors). Do these form a level translator? Why would they use so many components when a high-side load switch will do the work?

l> > Page 10, Figure 12:

Because transistors are much cheaper.

Take a look at the data sheet:

It states that the mod pin pulls high (towards the positive supply pin of the chip) to enable current and low to turn it off. If you use a PNP or P-channel mosfet as the high side switch, you need a pull down polarity to turn either of these on, and essentially the full positive supply voltage to turn them off.

Tell us whether you want to use a PNP bipolar transistor or a mosfet for the switch, and we can help you design the inverting level shifter to convert the mod output to the required drive signal for the switch.

Either an NPN transistor or an N-channel mosfet would require drive that is more positive than the voltage source feeding the switch to turn it fully on. Using either a P-channel mosfet or a PNP transistor allows turn on by pulling negative (below the supply voltage) to turn it on. There are high side switches made that use an N-channel;l mosfet, and contain an internal charge pump that produces a gate drive supply that is more positive than the positive supply to be switched. But that is a more complicated solution than just using a PNP or P-channel. The app note you listed earlier includes the inverting level shifter that converts the MOD high output to a negative drive related to the positive supply, clamped in its swing by zener diode and driven fast in both directions, to change and discharge the gate capacitance. The mod output is just a logic level signal that tells the driver (level shifter) when the power switch is to be turned on or off. It does not provide the drive current and voltage swing necessary to actually turn it on and off.