It is not recommended to use the LDO for 2A current. The LDO is in linear step-down mode and will dissipate excess voltage as heat. For high current applications, the LDO generates significant heat and has low efficiency (2.5V). * 2A)/(3.7V*2A)=67%? If the lithium battery is fully charged with 4.2V? The efficiency is lower (2.5V*2A)/(4.2V*2A)=59%. Use a synchronous Buck chip? You can choose YB2408D according to your application. Current can reach 2A, more than 90%. The peripherals are also very simple. time for lithium batteries!
When the 7805 is connected to the output terminal of the 7809, the input voltage of the 7805 is 9V and its operating voltage difference is 9 - 5 = 4V . It can work normally, but when the. The output current of 7805 is larger, the output current of 7809 will be too large. It is recommended to connect the input terminale of the 7805 to the 12V output terminal. Although the power consumption is greater, it can and will not ensure normal operation. increase the burden of 7809.