The difference between LLC switching power supply and ordinary switching power supply
Circuit structure and working principle
LLC Switching Power Supply:
Circuit structure: LLC switching power supply adopts LLC resonant topology circuit, which consists of an inductor L, a capacitor C, and a transformer T. The inductor L, capacitor C, and transformer are connected in series, and the output voltage is adjusted by changing the half bridge switching frequency.
Working principle: LLC switching power supply operates based on the principle of resonance, by adjusting the switching frequency to change the working state of the resonant circuit, thereby achieving voltage regulation. This resonant converter can maintain good voltage regulation characteristics under a wide range of input voltage and load variations.
Ordinary switch power supply:
Circuit structure: Ordinary switching power supplies usually include rectifier circuits, filtering circuits, switch tubes, transformers, and other parts. Their circuit structures are relatively complex and diverse, and different circuit topologies are designed according to specific application requirements.
Working principle: Ordinary switching power supplies control the transmission and conversion of electrical energy through the rapid switching of switch tubes, in order to adjust the output voltage and current. Common modulation methods include pulse width modulation (PWM) and pulse frequency modulation (PFM).
Performance characteristics
1. Efficiency:
LLC Switching Power Supply: Due to the use of resonant conversion technology, LLC switching power supplies can reduce energy loss during input-output conversion, thus having high conversion efficiency. At the same time, the MOS transistor of the LLC resonant converter can achieve zero voltage turn-on (ZVS), and the diode can achieve zero current turn off (ZCS), further reducing switching losses.
Ordinary Switching Power Supply: Although ordinary switching power supplies also have high efficiency, their efficiency may be slightly lower compared to LLC switching power supplies. Especially in high-power applications, the switching losses of ordinary switching power supplies may be more pronounced.
2. Power density:
LLC Switching Power Supply: Due to the resonant topology circuit, the switching transistor operates at high frequencies, so the volume of LLC switching power supply can be made smaller and the power density higher. This makes LLC switching power supplies significantly advantageous in situations where high power density is required.
Ordinary switch mode power supply: The power density of ordinary switch mode power supply is relatively low, especially in high-power applications, which may require a larger volume to accommodate more components and heat dissipation devices.
3. Electromagnetic interference (EMI):
LLC Switching Power Supply: LLC switching power supplies have low EMI characteristics, which can reduce interference with other electronic devices. This is due to the design of its resonant conversion circuit, which effectively suppresses electromagnetic radiation during the switching process.
Ordinary Switching Power Supply: Ordinary switching power supplies may generate significant electromagnetic interference during the switching process, and additional measures need to be taken to reduce EMI levels.
application area
LLC Switching Power Supply: Due to its high efficiency, high power density, and low EMI, LLC switching power supplies are widely used in high-end fields such as industrial power supplies, communication equipment, servers, and electric vehicle chargers.
Ordinary Switching Power Supply: Ordinary switching power supplies are widely used in various electronic devices, such as household appliances, computer equipment, lighting equipment, etc. It has a wide range of applications, but may not meet performance requirements in specific high-end application areas.
