Ricoh Electronic Devices has launched a Voltage Tracker IC that can be used as a power supply for off-board sensors and modules and provide extra safety in automotive designs.
The R1540 has a wide input voltage range up from 3.5 to 42 V with a tracking precision of ± 15 mV.
ew automotive vehicles are equipped with an increasing number of electronic systems for various purposes; all these circuits need to be supplied from a primary voltage source to a lower secondary source. Power management is usually performed by an on-board power supply, but external sensors and modules must be wired throughout the vehicle and are exposed to harsh conditions.
To maintain power in the event of a failure in the off-board devices and that the ECU continues to operate, the Voltage Tracker replicates a reference voltage with high tracking accuracy. A regulator output voltage may vary due to electromagnetic noise interference (EMI), so advanced technology is built in to prevent such voltage variation. The R1540 has immunity to EMI noise over a broad frequency band (150 kHz to1 GHz) with a high ripple rejection ratio of 80 dB and a fast response to transients on input and load.
The combined CE / ADJ pin lead serves two purposes, it is used to provide the input voltage as a reference for the output and it can be pulled low to control the device in standby mode.
The R1540 has a series of safety features that protect the voltage tracker and other parts of the application from possible damage and defects. These include over-current protection, limiting the output current in the event of overload as well as short protection, an embedded fold-back short current limit circuit detects a short circuit and decreases the output current to a safe level of 40 mA, after removing the short circuit the regulator automatically resumes to normal operation.
Thermal protection is incorporated and will turn off the output voltage when an excess