‘Power supply in package’ boost from capacitor power conversion
While Helix Semiconductors has started production of its capacitor-based DC-DC converter chip, pSemi, formerly Peregrine Semiconductor and now part of Murata, has introduced a ‘power supply in package (PSiP)’ based on a charge-pump, switched-capacitor architecture that offloads most of the power conversion from the inductor to capacitors in the charge pump. This enables a smaller embedded package.
pSemi solves the tradeoff between size and efficiency with two-stage architecture that offloads most of the power-conversion work from the inductor to a virtually lossless charge pump and relies on small, multilayer ceramic capacitors (MLCCs) to do most of the work. As a result, the inductor — usually the largest and tallest component — can be significantly reduced in size and traditional wire-wound inductors can be replaced with chip inductors. This patented architecture was first developed by Arctic Sand Technologies, an MIT spin-out acquired by pSemi in March 2017, and commercialized this year.
Beyond the smaller inductor and higher efficiency, this architecture delivers several other key benefits for LED boosts, including full short-circuit protection and a very flat efficiency over the entire load range. Also, efficiency is virtually independent of the output voltage, and this allows more LEDs per string. With fewer strings, efficiency is optimized, and the display-bezel size can be reduced in width. The resulting PE23300 features low power dissipation — up to half that of competing products — that improves reliability and supports portable applications’ extensive battery run times.
“The PE23300 truly demonstrates pSemi’s power-semiconductor capabilities. The PSiP delivers a unique, two-stage architecture that brings ground-breaking conversion efficiency and small solution size and is packaged with Murata’s advanced, 3D-packaging technology and passive components,” said Stephen Allen, director of strategic marketing at pSemi.
“All components required for operation are integrated into a 7.7 x 11.7 mm laminate-based LGA package, which is just 1.6 millimeters in height. To achieve this small size, we used a ‘die-in-substrate’ 3D-packaging technology. The low profile is also a result of our two-stage architecture that allows us to use a tiny chip inductor. All of this can be achieved with an efficiency that is on average about 5 to 7 percent higher than the competition, halving the losses in the LED boost.”
Powering up to eight LED strings at a total power level of up to 10W, the PE23300 is designed specifically to power LED backlight arrays in ultra-high-definition (UHD) and high definition (HD) LCD panels for 2-cell and 3-cell narrow-voltage DC notebooks, industrial and automotive displays. It has an input voltage range of 4.5V to 15V DC and powers up to eight strings of LEDs at up to 45V and 40 mA per string.
The PSiP provides full programmability via an I2C interface with settings stored in non-volatile memory or by using GPR pins. Dimming resolution is up to 12-bits resolution with an additional 3-bit dithering and can be either linear/logarithmic analog and PWM dimming or direct PWM dimming for maximum flexibility and resolution. The part features an LED brightness ramp up/down control with programmable ramp rate, linear/logarithmic ramp profiles and phase-shifted PWM dimming among active strings to minimize audible noise.
Related stories:
- HELIX SAMPLES ITS FIRST POWER CHIP
- SEMITREX REBRANDS TO HELIX SEMICONDUCTORS
- PEREGRINE CHANGES NAME AS PART OF MURATA INTEGRATION
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