When I run the LM3150 controller at a load current of 2A, there are high-frequency oscillations on the transistors gates and on the "SW" pin.
These oscillation are startted when I raise the input voltage to a certain value. This value depends on mosfet transistors. After this value if I rise input voltage for 1-2 V a amlitude and duration of this ocillations are increasing, then operation become unstable and the higt-side mosfet is destroed.
When I ran controller with IRLML0030 at both sides this value was about 22 V.
Then I changed destroyed high-side mosfet and use IRLML0030 at low-side and IRFR1205 at hight side and reached normal property operation without ocillation up to target voltage 25V.
When I tryed use IRLML0030 at high-side and IRFR1205 at low side the "critical" value of input voltage was been decreased to 7V. There is waveform of this test below (pink chart is gate of high-side mosfet, blue chart is SW pin):
Waveforms of low side gate (blue) and higt side gate (pink) relative to GND at"critical" input voltage:
Waveforms of low side gate (blue) and higt side gate (pink) relative to GND above "critical" input voltage:
Based on datasheet both types of these transistors are suitable for use for this mode of operation (Vin=6...25V; Iout = 2A; Vout=5V; Switching frequency = 200 kHz). I don't understand what wrong with them.
When I tryed to install shottky diode in parallel with low-side mosfet the controller started work property with any configuration of transistors in based configuration with IRLML0030 on both sides in all range of input voltage. But I could not find any information that it has so much effect on stability of the operation.
Installing addition 1uF bosst ceramic capasitor and 470uF electrolytic output capacitor don't change anything.
This effect also depends on Load current - with lower load currend such as 200mA there is not this effect.
PCB top: https://yadi.sk/i/7yLDyYhx3aGUWV
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Schematic: https://yadi.sk/i/n_vMb7YI3aGSTu
In addition to it I was added ceramic capacitor 10uF at the 5V output. R6 changed to 300 kOhm fo switching frequency 200 kHz.
