A serial bus signal conditioner circuit includes receiver circuitry, a mode identification circuit, and an edge-rate booster circuit. The receiver circuitry is configured to receive signals transmitted on a serial bus. The mode identification circuit is coupled to the receiver circuitry, and is configured to identify initiation of or return to high-speed signaling on the serial bus based on sequences of the signals transmitted on the serial bus. The edge-rate booster circuit is coupled to the mode identification circuit, and is configured to identify edges of a differential signal transmitted on the serial bus, and to supply a differential current to the serial bus based on identification of an edge of the differential signal.