US 12,224,781 B2
Transmitter circuit
Johannes Petrus Antonius Frambach, Nijmegen (NL); Cornelis Klaas Waardenburg, Zeeland (NL); Stefan Paul van den Hoek, Winssen (NL); and Gerard Arie de Wit, Wijchen (NL)
Assigned to NXP B.V., Eindhoven (NL)
Filed by NXP B.V., Eindhoven (NL)
Filed on Sep. 7, 2023, as Appl. No. 18/463,174.
Claims priority of application No. 22198853 (EP), filed on Sep. 29, 2022.
Prior Publication US 2024/0120956 A1, Apr. 11, 2024
Int. Cl. H04B 1/04 (2006.01); H04L 12/40 (2006.01)
CPC H04B 1/04 (2013.01) [H04L 12/40 (2013.01); H04L 2012/40215 (2013.01)] 14 Claims
OG exemplary drawing
 
1. A transmitter circuit, comprising:
a first bus line terminal and a second bus line terminal for coupling to a bus;
a controller, wherein the controller is configured to provide a transmission data signal for the bus;
a voltage setting circuit configured to set a differential driver voltage on the bus;
an impedance setting circuit that has a first leg and a second leg, wherein each leg comprises an adjustable pull-up resistance and an adjustable pull-down resistance connected in series with each other between a supply terminal and a reference terminal, wherein:
a first-leg-node between the adjustable pull-up resistance and the adjustable pull-down resistance of the first leg is connected to one of the first bus line terminal or the second bus line terminal; and
a second-leg-node between the adjustable pull-up resistance and the adjustable pull-down resistance of the second leg is connected to another one of the first bus line terminal or the second bus line terminal, and
wherein the controller is configured to set the adjustable pull-up resistance and the adjustable pull-down resistance of the impedance setting circuit to adjust a driver impedance presented to the bus; and
wherein the controller is configured to detect a transition in the transmission data signal, and in response to a dominant to recessive transition the controller is configured to:
control the voltage setting circuit such that is sets the differential driver voltage on the bus to a recessive value;
adjust each of the adjustable pull-up resistances and the adjustable pull-down resistances of the impedance setting circuit with the same target impedance profile such that the transmitter circuit drives the bus with a target driver impedance for an active recessive period of a bit time.