How to close a popover through another controller?

I was trying the popover as the example in here http://ionicframework.com/docs/api/service/$ionicPopover/

<ion-side-menu side="left" ng-controller="SideBarController">
<ion-content>
    <a href="#" class="item" ng-if="true" ng-click="openLogPop($event)">Login/Register</a>
</ion-content>
</ion-side-menu>

now in > SideBarController I have the pop over functions: open and close.
How could I close the pop over through anther controller, say the popoverController?
and how could I manage two pops from the same controller?