Patent ID: 8671668

Claim:
A control circuit for a vehicle powertrain, comprising: a first power source that provides power to a vehicle load; a second power source that selectively provides power to a heater of a heated diesel particulate filter (DPF); and a switch having a first position and a second position, wherein when the switch is in the first position, the second power source is electrically connected to the first power source and the second power source is electrically connected to the heater of the DPF, and when the switch is in the second position, (i) the second power source is electrically connected to the heater, (ii) the second power source is electrically disconnected from the first power source to prevent the first power source from being loaded by the heater while the heater is energized, and (iii) the power provided by the first power source to the vehicle load is limited to maintain an output voltage of the first power source above a predetermined voltage.