In described examples, an integrated circuit (IC) includes multiple subcircuits. The subcircuits include a first subcircuit that receives a current and sinks a portion of the current that is responsive to a threshold. In response to the current being greater than the threshold, the first subcircuit provides a difference between the current and the portion to a second subcircuit and asserts a signal corresponding to an ordinality of the first subcircuit. The second subcircuit is configured to repeat the actions with respect to the first subcircuit, with the second subcircuit in place of the first subcircuit and a third subcircuit in place of the second subcircuit, and with the difference in place of the current, in response to the IC comprising the third subcircuit.