Direct Current To Direct Current Converter (G2300020): Operation: Notes

The Direct Current to Direct Current (DC/DC) converter converts the MHEV battery Direct Current (DC) voltage of approximately 48V DC to 12V DC.

The DC/DC converter supplies all the vehicle 12V systems and charges the startup battery. The DC/DC converter receives communications from the Body Control Module/Gateway Module (BCM/GWM). The communication is through the High Speed (HS) Controller Area Network (CAN) power mode zero systems bus. The BCM/GWM sends charging load requests to the DC/DC converter. The DC/DC converter produces the correct output voltage and current to match the vehicle electrical load requests.

The electrical systems are powered from the DC/DC converter. The DC/DC converter supplies power only when the vehicle is in Power Mode 7 (engine running). The DC/DC converter also charges the startup battery through the Battery Junction Box (BJB).

For additional information, Refer to: STARTUP BATTERY AND CABLES

For additional information, Refer to: MHEV BATTERY AND CABLES

The HS CAN power mode zero systems bus is also connected to the following:

• The Battery Energy Control Module (BECM) in the MHEV battery.
• The Powertrain Control Module (PCM).

Direct Current to Direct Current Converter Temperature Control 

The DC/DC converter is cooled by the DC/DC converter electric cooling fan. The DC/DC converter electric cooling fan is controlled by the DC/DC converter. The DC/DC converter has temperature sensors within the housing to monitor the internal temperatures. The DC/DC converter sends a Pulse Width Modulation (PWM) signal to control the DC/DC converter electric cooling fan speed. The lower DC/DC converter housing is finned to increase the surface area for the air to cool the DC/DC converter.

the DC/DC converter determines the operation and speed of the DC/DC converter electric cooling fan. The DC/DC converter uses internal temperature data and a computer model to determine the operation and speed.