I made a switching power supply, using boost dc-dc transform, input 18V, output 30-36V variable. Found that the output voltage has 300mv ripple and 1V burr.
Has been added 10mh inductance and 6600uf capacitor filter.
Switch tube plus RCD buffer
Output with choke and EMI filter,
You said the burr is the overshoot
Your inductance is not wrong? 10mH too big? Will it be 10uH wrong?
In the out there, the overshoot is sure to exist, but this should be gone in the capacitor
This has a lot to do with your measurement
1. Must be in the capacitance of the positive or the amount of load above, do not in the amount of inductance, there is no capacitance
2. With the oscilloscope, the ground connection will have a great impact on the measurement results you can move their own line of the line to see the extent of the test will certainly move
The probe on the ground to try to short, the measurement results are correct
The above two points to do, the measurement results should not be so big
And to be honest, for the 30V output, there are 1V "glitches" that should be acceptable
You can check the specifications of other switching power supply, this one usually 5%, 30V * 5% = 1.5V, 1V should be acceptable
Output in series with an inductor and then a capacitor in parallel LC filter circuit try to see if feasible?
If you are measuring the ground wire, 1V thorn is not large, but you must take it out of the case, you can consider two ways
1, electrolytic capacitors and more can not solve the high-frequency noise, but with ceramic capacitors such as 10uF / 50V several and in the output port, the effect will be very good.
2, in the output plus a common mode, high frequency. You can reduce noise.
The above two methods are feasible, you try it yourself
Low frequency ripple burr suppression of several commonly used methods:
A, increase the output low-frequency filter inductance, capacitance parameters, so that low-frequency ripple reduced to the required indicators.
B, using feedforward control method to reduce the low frequency ripple components.
High-frequency ripple to suppress the purpose of the glitch is to provide high-frequency ripple path, commonly used methods are the following:
A, to improve the switching power supply operating frequency, in order to improve the high frequency ripple frequency, is conducive to suppress the output high frequency ripple.
B, increase the output high-frequency filter, can inhibit the output high-frequency ripple.
C, using multi-level filtering.
