In some examples, a device comprises a first driver coupled to a first node, the first node to couple to a first load external to the device. The device comprises a second driver coupled to a second node, the second node coupled to a second load internal to the device. The device comprises a comparison circuit having an inverting input coupled to the first node and a non-inverting input coupled to the second node. Sizes of the second driver and the second load are configured proportionately to sizes of the first driver and the first load, respectively.