An apparatus includes first and second switches. The first switch is for coupling a first node to a second node responsive to a first control signal having a first value, and for decoupling these nodes responsive to the first control signal having a second value. The second switch is for coupling the first node to a third node responsive to a second control signal having the first value, and for decoupling these nodes responsive to the second control signal having the second value. A load is coupled between the second and third nodes. A detection circuit coupled to the first node is configured to generate a signal indicating whether voltage at the first node exceeds a threshold. First and second modules are configured to set the first and second control signals to the second value responsive to the signal indicating that the voltage at the first node exceeds the threshold.