Recently to do school projects, draw PCB for the first time, was to get the board very happy, USB power supply found the power light is not on, 1117-3.3 - V is also very hot, heart cold half ah oneself also analyzes the reasons, feel the PCB design has a problem, when I was not sure, attached great god teach schematic and PCB,
If there is something wrong with the PCB really, the great god has blocked the board of the original 1117-3. 3 v circuit method, poor students have no money to do the board, I think the outer voltage regulator circuit,

CodePudding user response:

Schematic and PCB can't see the problem,
Generally 5 V to 3.3 V is very simple, no skills to speak of,
Screening, whether the load current is too large, AMS1117_3. 3, as if 800 ma, I tried 600 ma is very hot, later by DCDC solution,

CodePudding user response:

refer to 1st floor to the scarecrow to reply:

schematic and PCB can't see the problem,
Generally 5 V to 3.3 V is very simple, no skills to speak of,
Screening, whether the load current is too large, AMS1117_3. 3, as if 800 ma, I tried 600 ma is very hot, later by DCDC solution

Excuse me for external DCDC module, the original 1117 voltage regulator circuit board need how to deal with?

CodePudding user response:

You first need to determine the current?
If 500 ma, they will become,
If less than 2 a, can consider to TPS5430, pay attention to the filter,
Don't worry in power supply, make sure heat root causes, and excessive current, short circuit, etc., will be fever,
You on the suggestion:
1. The capacitance, pressure value if more than two times, the line voltage of you "front-end with 5 v to change
2. Via, directly on the bonding pad pass hole more reasonable, lines to clear, easy wrong, of course, this is a bad habit, automatic placement machine welding components, problems, but practice, is all hand welding, afraid of MAO,

CodePudding user response:

Chip packaging is wrong, check the technical manual carefully

CodePudding user response:

Well well thank you, I design the flight control board, power adjustable power supply, BEC output 5 v/2 a, power supply, negligence should also want to change
But now I'm still not BEC power supply, the board is just a piece of STM32 minimum system, it should be no problem with USB power supply is normal, is likely to be some short circuit, on the screen,

CodePudding user response:

Check, no problem

CodePudding user response:

Flight control do you have? The school play?
I also play flight control

CodePudding user response:

Bosses, school of engineering design topic, has just started many don't understand, the board has got headache

CodePudding user response:

Disconnect the AMS1117 multimeter is 3.3 V to GND impedance, in general should be very high, if directly through it's 3.3 V power supply circuit short circuit, also pay attention to the circuit boards of tantalum capacitor is welded inside out, it is easy to flow,

CodePudding user response:

Suggest 3.3 working current under 200, otherwise, will be hot,
If the current is less than 100, the output capacitance too far.

CodePudding user response:

This is via ground? A hole has a resistance welding?

If the hole is GND, I doubt that 1117 of the big welding plate with this via short circuit,

If the short circuit, the solution: remove the 1117, and then use paper tape to live hole, welding 1117 again.

CodePudding user response:

Generally saw, you should do is small four shaft such as flight control board, if there is no power to move, just around the stm32 circuit current is very small, 1117 chip is meet the requirements, doubt somewhere short circuit, suggest you don't open 1117 first, can put 1117 broken at the back of the load, the multimeter measure before and after the end if there is any short circuit, did try to electric hot phenomenon, and then analysis

CodePudding user response:

You this is below 1117 via short circuit, is back with the output of 1117, so you this is output with short circuit, and don't want to redo the plate, at any rate, after high temperature tape on hole 1117 chip welding

CodePudding user response:

Is not you buy fake goods,,,,