In recent years, as application technologies continue to evolve, the power demands of terminal applications have been increasing, such as fast-charging chargers and LCD TV power supplies. When power consumption exceeds a certain level, power supplies need to incorporate Power Factor Correction (PFC) functionality. According to the EU EN61000-3-2 standard, all electronic products with input power greater than 75W must have power factor correction capabilities. Additionally, the specifications are becoming increasingly stringent. Previously, requirements might have only focused on efficiency and power factor (PF) values at full load, but now efficiency within certain load ranges must meet specific levels, and PF values must also reach certain thresholds. For example, for the 80 Plus Gold certification, under 115Vac input voltage, the efficiency requirements are greater than 87%, 90%, and 87% at 20%, 50%, and 100% load, respectively, and under specific conditions, the PF value must reach 0.9 or 0.95 or higher.
This solution is based on replacing the onsemi NCP1622 with the NCP1623A without making any modifications to the NCP1622 160W demo board. Onsemi 's NCP1622 is an earlier CrM PFC controller that features Valley Synchronized Frequency Fold-back (VSFF) CrM PFC. Figure 1 illustrates the switching frequency changes of traditional CrM and VSFF under different loads with respect to input voltage. The VSFF operating mode enables the power supply to achieve optimal overall efficiency under varying load conditions. Additionally, onsemi 's NCP1622 offers several practical features: First, the NCP1622 uses a TSOP-6 package to minimize the size of the PFC controller; second, the NCP1622 integrates Zero Current Detection (ZCD) and current sensing functionality.Current sensorThe circuit is designed to provide a simplified PFC circuit. Thirdly, the NCP1622 offers two Zero Current Detection (ZCD) circuits, catering to various application scenarios. Fourthly, the NCP1622 includes a Skip function, enabling excellent power consumption performance under light load conditions. On the other hand, onsemi NCP1623 is a recently launched CrM PFC controller. In addition to retaining the features and advantages of the NCP1622, the NCP1623 introduces the following new functionalities: First, it provides a Follower Boost function (available only in NCP1623A) to enhance efficiency under low input voltage conditions. Second, it includes a Disable function for low Sleep Mode current to improve efficiency under light or ultra-light load conditions. Third, it offers secondary-side OVP protection, giving designers more options for protection features. Fourth, it uses the MOSFET drain for ZCD detection, enhancing stability in non-auxiliary winding designs. Fifth, it provides multiple packaging options, including TSOP-6 and SOIC-8, for designers to choose from. Table 2 illustrates the key differences between the NCP1623 and NCP1622.
Figure 1, CrM and VSFF in relation to the switching frequency and changes in input voltage.
Table 1, Key differences between NCP1623 and NCP1622
This solution uses the onsemi NCP1623A CrM PFC controller as a direct replacement for the NCP1622, serving as a 160W front-end voltage regulation solution. As shown in Figure 2, under a low voltage input of 110Vac and a load of 0.4 amps, the output voltage of this solution is 290Vdc. As shown in Figure 3, under a high voltage input of 230Vac and a load of 0.4 amps, the output voltage is 400Vdc. Figure 4 illustrates the efficiency performance of this solution under different input voltage and load conditions. From Figure 4, it can be observed that this solution maintains an efficiency of over 89% across different input voltages, ranging from 10% load to 100% load.
Figure 2 shows the output voltage condition of this case at 110Vac, 0.4A.
Figure 3 shows the output voltage condition of this case at 230Vac and 0.4A.
Figure 4, the efficiency performance of this case under various input voltages and load conditions.
►场景应用图
►展示板照片
►方案方块图
►核心技术优势
1. The NCP1623 features a Follower Boost function. 2. The NCP1623 combines CS and ZCD on the same pin. 3. The ON-time modulator of the NCP1623 maintains an appropriate current waveform during frequency foldback. 4. The NCP1623 provides valley switching functionality in CRM operation mode. 5. The NCP1623 supports zero current detection through either the MOSFET drain voltage or an auxiliary winding. 6. The NCP1623 offers thermal shutdown, non-latching overvoltage protection (Non-latching OVP), brown-out detection, and skip functionality.
►方案规格
1. Full voltage input: 90Vac ~ 264Vac 2. Output voltage: 290/400Vdc 3. Minimum/Maximum output current: 40mA/400mA 4. Maximum output power: 400Vdc/400mA 5. Efficiency ＞89% @(10%~100% load) 6. Features secondary OVP protection, overcurrent limit, Pass Diodes short-circuit protection, FB/GND pin open-circuit protection, etc. 7. Demo board PCB dimensions LxWxH = 190 mm x 110 mm x 10 mm