“The power budgets of advanced SoC (system on chip) solutions for industrial and automotive systems continue to increase. Each subsequent generation of SoC will add high-power demand devices and increase data processing speed. These devices require reliable power, including 0.8 V (for the core), 1.2 V and 1.1 V (for DDR3 and LPDDR4) and 5V, 3.3V and 1.8V (for peripherals and auxiliary components).
The power budgets of advanced SoC (system on chip) solutions for industrial and automotive systems continue to increase. Each subsequent generation of SoC will add high-power demand devices and increase data processing speed. These devices require reliable power, including 0.8 V (for the core), 1.2 V and 1.1 V (for DDR3 and LPDDR4) and 5V, 3.3V and 1.8V (for peripherals and auxiliary components).
Compared with the performance that traditional PWM controllers and MOSFETs can provide, advanced SoC solutions require higher performance. Therefore, the solution required by the SoC must be more compact, with higher current capability, higher efficiency, and more importantly, excellent EMI performance. ADI’s Power by Linear? Single-chip Silent Switcher? 2 step-down regulator can meet the advanced SoC power budget, while also complying with SoC size and thermal constraints.
20 V input, 20 A solution for SoC
The LTC7150S raises the high-performance standard of industrial and automotive power supplies. It has high efficiency, small size and low EMI characteristics. The integrated MOSFET and thermal management function of LTC7150S can reliably and continuously output up to 20 A current through an input voltage of up to 20 V without a radiator or air flow, so it is very suitable for SoC, industrial, transportation and automotive applications. FPGA, DSP, GPU and microprocessor solutions. ?
Figure 1 shows a 20 A, 1.2 V output solution for SoC and CPU power supply when using LTC7150S with a switching frequency of 1MHz. The circuit is very easy to modify to adapt to other output combinations, including 3.3 V, 1.8 V, 1.1 V and 0.6 V, so as to take full advantage of the wide input range of the LTC7150S. LTC7150S has the output current capability that can be used as the first-level 5 V power supply, and supports multiple back-end second-level switching regulators or LDO regulators with different outputs.
Figure 1. The schematic and efficiency of a buck converter: 12 VIN to 20 A, 1.2 VOUT.
Figure 2. VIN = 14 V, VOUT = 1 V, 20 A. fSW = 400 kHz.
Silent Switcher 2 provides excellent EMI performance
Passing EMI regulations at high currents usually involves complex design and test challenges, including many trade-offs in solution size, efficiency, reliability, and complexity. Traditional methods control EMI by reducing the MOSFET switching edge rate and/or reducing the switching frequency. Both strategies require some performance trade-offs, such as reduced efficiency, increased minimum on and off time, and larger solution size. Alternative mitigation technologies, such as bulky and complex EMI filters or metal shielding, add a lot of cost to board space, components, and assembly, and complicate thermal management and testing.
ADI’s proprietary Silent Switcher 2 architecture automatically eliminates EMI by integrating thermal loop capacitors, thereby minimizing the size of the noise antenna. And in combination with the integrated MOSFET, it can significantly reduce the ringing of the switching node and the related energy stored in the thermal loop, even if there is a very fast switching edge. Therefore, excellent EMI performance can be obtained while minimizing AC switching losses. LTC7150S uses Silent Switcher 2 technology to minimize EMI and achieve high efficiency, greatly simplifying the design and layout of EMI filters, making it an ideal choice for noise-sensitive environments. The LTC7150S only needs to use a simple EMI filter in the front end to pass the CISPR 22/CISPR 32 conducted and radiated EMI peak limits. Figure 3 shows the test results of the radiated EMI CISPR 22.
Figure 3. Radiated EMI performance of Figure 2
High frequency and high efficiency suitable for compact space
Integrated MOSFET, integrated thermal loop decoupling capacitor, built-in compensation circuit-all of these eliminate the complexity of the system design, and minimize the size of the overall solution through the simplicity of the circuit and the Silient Switcher architecture.
Thanks to high-performance power conversion, LTC7150S can provide large current without the need for additional heat sinks or airflow. LTC7150S is different from most solutions in that it can achieve low EMI and high efficiency at high operating frequencies and ensure that the size of passive components is very small. Figure 4 shows a 2 MHz solution for FPGA and microprocessor applications, using small 72 nH inductors and ceramic capacitors to make the solution very flat.
Figure 4. LTC7150S schematic and thermal performance image at 5 V input to 0.85 V/20 A output, fSW = 2 MHz.
Industrial and automotive applications require higher levels of intelligence and automation, as well as more detection functions, which has led to a surge in the number of Electronic systems and higher requirements for power supply performance. In addition to the size, high efficiency, thermal efficiency, robustness, and ease of use of the solution, how to reduce EMI has been elevated from a consideration in the later stage of the design to a key power requirement. LTC7150S uses Silent Switcher 2 technology to meet stringent EMI requirements in a compact size. The integrated MOSFET and thermal management function can reliably and continuously output a stable current of up to 20 A through the input voltage range of up to 20 V, and the switching frequency range of up to 3 MHz.