Hi Team,
When Vout of LMR16030 change from heavy load to light load, the Vout drop.
When Vin inputs DC 12V/3A, Vout outputs 4.2V to supply power to the watchdog (U303), the watchdog 1 pin (VCELL_ON) will output a high level of 300mS (Q202 is not turned on, not to RL and the back end CPU power supply, light load is about 2mA), and then output low level (Q202 is turned on, power supply to RL and back-end CPU, about 100mA).
When the watchdog 1pin outputs a low level, the voltage of the DC/DC Vout drops briefly, which causes the watchdog to fail to work normally, so that the low-level output cannot be maintained. As a result, Q202 cannot be turned on and cannot supply normal power to our back-end circuit.
The SCH is as following:
VDC1 and VDC waveform(VDAC1 dropped from 4.2V to 2.3V)
D203 waveform
During customer SOP, the problem occurred. Could you kindly give some advice?
