IPhone : Ble peripheral are disconnected

i am using ble peripheral tag after scanning i found identifier and name . when i click on any cell the desire peripheral are connected .. and button in peripheral tag will detect and didUpdateValueForCharacteristic method are called on button click. but when we are moving to another screen the button will not detect and peripheral will disconnect .. I want when the peripheral are connect one time they always to be connected until app are not suspended ..

application is working in same screen thanks in advance ...