Apply PI to your text layer (or any layer that contains alpha transparency information), then in PI search for “logo” and add the “Logo Burst 01” emitter – its particles take both their color and alpha from the source layer.
In general, add any emitter (probably Area or Box) and select the particle node. In the Color / Alpha section there is an “Alpha Type” parameter: set it to “Alpha from layer”. This will make any particles that are created over transparent areas of the layer invisible.