iC-DC: Fully integrated DC/DC converter for intelligent sensor systems
4–36 V buck/boost DC/DC converter with two programmable voltages ranging from 1.5 V to 5.5 V with very low residual ripple
From just one chip and a variable input voltage of 4 V to 36 V iC-DC generates two stabilized output voltages that can be adjusted between 1.5 V and 5.5 V for the compact voltage supply of industrial sensors and small subsystems. The combination of switching converter plus two back-end linear regulators minimizes the amount of space required for the power pack and achieves a good residual ripple of typically 10 mVpp – ideal for the supply of precision analog circuits.
The buck/boost switching converter technology used here makes any distinction between devices supplied with 5 V or 10–30V unnecessary, as a steady +5 V supply is provided for sensor electronics, for example. The two independently adjustable output voltages Vcc1 and Vcc2 can provide a total of 300 mA and supply digital and analog circuit components separately.
The switching converter typically operates at 3 MHz, thus reducing the size of the external coil to approx. 2 mm x 2 mm and that of the external back-up capacitors to a few microfarads while adhering to the EMC requirement for industrial sensors.
iC-DC has been optimized for intelligent sensor systems and subsystems, such as:
• Incremental and absolute encoders
• Linear measuring systems
• Bus-compatible sensors and hubs (e.g. I/O links)
• Decentralized industrial subsystems
• Split voltage supplies in controllers and drives.
The circuit monitors both the chip temperature and the input and output voltages. iC-DC signals faults using separate diagnostic outputs configured as open collectors. Both output voltages can be switched on and off separately. Once the set voltage has been reached, a Power OK signal is generated at V1OK/V2OK. The integrated autarky function enables an additional capacitor to provide a buffered energy supply should the input voltage fail, allowing a microcontroller to perform a data backup.
iC-DC comes in a tiny 4 mm x 4 mm DFN10 package with a thermal pad on the reverse for improved thermal dissipation. The device operates within an operating temperature range of -40°C to 125°C and protects itself against overload with an overtemperature shutdown feature. An iC-DC EVAL DC1D evaluation board is also available as a reference design, saving time during test configuration.