I have A circuit, DCDC buck to 4 g module power supply, DCDC maximum current of 2.5 A, more than current limiting, 4 g module instantaneous current can reach more than 2 A, because the DCDC and 4 g module in the distance on the PCB (about 10 cm), the design requirement is 4 g module power front need to add more than 470 uf electrolytic capacitor, I added two is currently 330 uf electrolytic capacitor, but found that electricity had been up to 4 g module, DCDC detailed FAE on electricity for electrolytic capacitor charging, current over 2.5 A, DCDC current limiting, but after A long time or have A 4 g module, then canceled A 4 g module can work normally after electrolytic capacitor, such A design will appear problem, is there any who have encountered similar problems to solve,

CodePudding user response:

DCDC moment to large capacitor charging must be current limiting protection, can a successively built with two MOS electric current circuit, the recommendations as to how the capacitance depends on the official manual, or act of god time interval value of capacitance calculation theory, and the oscilloscope fired at the measured pressure drop, you got enough before primary DCDC output ability, capacitance should be behind don't need too much,

CodePudding user response:

Dc - dc output current is enough, the problem is not big,

CodePudding user response:

Has a problem, 4 g module problems when the work of power supply voltage drop, the biggest 0.4 V, so need large capacitor to stable, can work after you remove the original factory irresponsible, but there is a problem is to choose the best current specifications DCDC device, more reliable,