The known for their lambda control in IC, the Lambdatronic LT4 from Bosch Motorsport, is a very compact unit that provides a controlled pumping current for up to four Bosch lambda sensors (LSU 4.2, LSU 4.9 or the Mini-LSU 4.9). All diagnostic data, sensor temperature and lambda value are available via CAN and analog signal which can be configured freely.
The LSU contains a Nernst and a pump cell. The lambda in the Nernst cell is controlled to lambda = 1.013 independent of the oxygen contents on the emission side, through a current through the pump cell. The current proportional output voltage of the IC is a measure of the lambda value.