When designing circuits, engineers may encounter systems that require negative voltage power supply, such as using negative voltages to provide negative turn-off voltages for IGBTs, and op amp systems using positive and negative symmetrical bias voltages to supply power. So how to generate a stable and reliable negative voltage? This article will introduce you to different solutions.
There are many different schemes for negative voltage design according to different load currents. The following are several common negative voltage schemes currently on the market, and suitable schemes can be used according to different occasions.
1. Power frequency transformer output positive and negative voltage
Figure 1 Power frequency transformer positive and negative output power
Do engineers have a strong sense of intimacy when they see the circuit in Figure 1, and can they remember the scene when they were exposed to electronic design in college? This classic circuit has obvious advantages, simple circuit structure, extremely low interference noise, and good stability. At the same time, this circuit also has shortcomings. The input AC power range is narrow (usually 220VAC±5%) and the volume and weight are large; although the shortcomings of this circuit are obvious. Some applications adopt this scheme design. This scheme is mainly to use the transformer to generate negative voltage in the linear regulator 7905 for voltage stabilization.
2. The power module outputs negative voltage
As the manufacturing technology of electronic components is getting better and better, the energy loss is getting lower and lower, which is more and more conducive to the modular development of power supplies. And the design can also be miniaturized and light-weighted.
1. Non-isolated negative voltage output negative voltage
Figure 2 Non-isolated regulated output module
Figure 3 Connection of positive output and negative output of non-isolated module
As shown in Figure 3, the application of this power module is similar to the commonly used LM7805, and no heat sink is required. As shown in the figure above, when we need positive and negative voltages to supply power to the op amp, we only need two E78xxOS-500 power supplies.
2. Isolated power supply module outputs positive and negative voltages
Figure 4 Isolated power supply module positive and negative dual output
Figure 5 Typical application of E_URADD-6W power supply
In power, industry, communications and other occasions with high requirements for anti-interference performance, it is generally necessary to isolate the power supply to isolate the interference from the main power supply side. If a negative voltage is needed in this application, the isolated power module can be directly used to directly output the positive and negative voltages to supply power to the system.
Three, Buck-Boost topology design output negative voltage
In addition to using the isolation module solution, we can also choose the chip to design the negative voltage circuit by ourselves. Here we introduce the non-isolated negative voltage output Buck-Boost circuit that is easier to design. As shown in Figure 6, this circuit only needs chips such as main control chip, inductor, capacitor, etc. At present, the DC-DC power chip of MPS supports the design structure of Buck-Boost, and the appropriate model can be selected according to different output currents.
Figure 6 Buck-Boost topology principle
It can be seen from the topology of Figure 6 that the input voltage and the output voltage have opposite polarities, so the Buck-Boost topology is also referred to as an inverting topology. Figure 7 is a -15V power supply circuit designed with MP2359DT. MP2359DT is packaged with SOT23-6, and the entire circuit occupies a small PCB area.
Figure 7 MP2359 negative voltage output circuit
Three, summary
There are many kinds of negative voltage design schemes. Which scheme is suitable for your design still needs to be determined by comprehensive consideration of different applications and different technical requirements.
ZLG Zhiyuan Electronics has nearly 20 years of research and development experience and can provide a variety of options for negative pressure generation. It is isolated from multiple series such as 1000VDC, 1500VDC, 3000VDC and 6000VDC, with various packaging forms, compatible with international standard SIP, DIP and other packaging. At the same time, ZLG Zhiyuan Electronics has built a first-class testing laboratory in the industry to ensure the performance of power products, equipped with the most advanced and complete testing equipment. The full series of isolated DC-DC power supplies have passed complete EMC tests, and the electrostatic immunity is as high as 4KV, surge The immunity is as high as 2KV, which can be applied to most complex and harsh industrial sites, providing users with stable and reliable power isolation solutions.
Wireless Vacuum Cleaner,Best Wireless Vacuum Cleaner,Wireless Car Vacuum Cleaner,Best Vacuum Cleaner Wireless
Ningbo ATAP Electric Appliance Co.,Ltd , https://www.atap-airfryer.com