Multi-Output Automotive Power Supply ICs with Enhanced Monitoring Functions
Toshiba Corporation has launched the TB9042FTG, a multi-output system power supply IC that enhances monitoring functions in general automotive applications. Sample shipments will start on November 1, 2013, with mass production scheduled to start in May 2014. The increasing importance of ISO 26262, the international standard for "Road Vehicles – Functional Safety", requires monitoring of the functions of power supply ICs. The new IC incorporates multiple monitoring functions that detect any malfunctions of the IC and external microcontrollers. It also integrates a transmitting function that transfers data on monitoring status to an external microcontroller, which further supports improved safety.
Increasingly higher current is required for automotive applications. The IC’s built-in highly electrically efficient dc-dc converters reduce power consumption, and its series regulators realize low noise power supply. Key features include: enhanced monitoring functions, two channels of switching regulated dc-dc converters and three channels of LDO regulators. The product incorporates abnormality detection for each output and transmits the detected data from either the SPI terminal or a special terminal dedicated to abnormality signals. An integrated diagnostic function monitors malfunction of the IC by comparing its data and signals from a microcontroller, helping to realize automotive functional safety. Detection circuits include under and over voltage (output) detection, inrush current limit, thermal shutdown, watchdog timer, and power-on reset.
The two channels of dc-dc converters (1 output) include, one dc-dc converter that steps down power supply from the vehicle battery to 6V while the other converter steps that down to 1.2V or 1.5V (selectable) for the microcontroller core. The three channels of LDO include: two series regulators that convert the 6V supply from the dc-dc converter and independently provide constant 5V supplies: 400mA current capacity is used for the microcontroller, and 100mA current capacity is used for a sensor or other interface. The other series regulator takes power from the battery and supplies 5V or 3.3V power (selectable), which is used as back-up power supply to protect the microcontroller’s RAM data.
