Integrated Schottky Diode Bridge and LDO for Wireless Power DesignsOctober 31, 2017 by Paul Shepard
Torex Semiconductor Ltd. has launched the XCM414 multichip‐module power IC that integrate four Schottky diodes and an LDO regulator. The new XCM414 uses the ultra‐low and small USP‐8B10 package (2.6 x 2.9 x h0.33mm).
With the increase in recent years of smartcards and other products that are equipped with a thin lithium ion battery or super capacitor, a demand for simple wireless charging has emerged.
The XCM414 series connects four Schottky diodes in a bridge inside the package to perform full‐wave rectification of ac input, and this can be input into an LDO regulator following smoothing by an external capacitor.
The integrated LDO regulator supports high‐voltage input and outputs a stable voltage. By incorporating the Schottky diode bridge and LDO regulator that are required for simple wireless charging in the same package, a stable dc voltage can be output from an ac voltage input.
The VR consists of a voltage reference, an error amplifier, a current limiter, a thermal shutdown circuit and a phase compensation circuit plus a driver transistor. The output voltage is preset at 3.3V in the IC as a standard value, and it is selectable in 0.1V increments within the range of 2.0V to 12V using laser trimming technologies. The output stabilization capacitor (CL) is also compatible with low ESR ceramic capacitors.
The over current protection circuit and the thermal shutdown circuit are built-in. These two protection circuits will operate when the output current reaches current limit level or the junction temperature reaches temperature limit level.
The CE function enables the output to be turned off and the IC becomes a stand-by mode resulting in greatly reduced power consumption.
- SBD forward voltage of 0.33V (IF=10mA)
- SBD reverse current rating 2µA (VR=40V)
- Input voltage range of 2.0V to0V
- Output voltage range of 2.0V to0V (0.1V increments)
- Fixed output accuracy is ±2%
- Low power consumption of 5µA
- Stand-by current of 0.1µA
- High ripple rejection of 30dB @ 1kHz
- Built-in protections functions include current limit circuit and thermal shutdown circuit
- Operating temperature is - 40 to +85 degrees C
The package is an ultra‐low type with a height of only 0.33mm, and is also ideal for smartcards, IoT devices that require a small size and low power consumption, and hearable devices (wireless earphones, hearing aids, etc.), for which Torex has strengthened its lineup in recent years.