ng-change delete input in angularjs

I have a problem that I have an input

 <input    type="text"   id="tbusqueda" ng-model="Busqueda.texto"  placeholder="Estoy buscando"  ng-change="buscarPorDescripcion(Busqueda.texto)" >

that function is to receive the text, go to search the BD, and bring the list and then do a ng-repeat and show them, the problem arises that when I do the search is deleted what I wrote, I write b, search with the letter b, but delete the value of the input, how do I do it so that it is not deleted? The function does this

$scope.buscarPorDescripcion = function (val) {


        $scope.traerCampaniaPreciosBajos('t', 0, 0, 0,val);

}

that function ba to search of the bd and returns an array that I later go through with ng-repeat. Thanks