Part Number: TMS320F280039C
Background and Hardware Architecture
The F280039C is used as the LLC controller. The chip-side power supply shares ground with the secondary-side power supply and is isolated from the primary-side power supply. The primary side is an 800 V constant-voltage source; the secondary side is 27.5 V, and synchronous rectification is independently controlled by an analog IC and is not directly driven by the DSP. The secondary-side load is a constant-current source.
Observed Behavior
The DSP runs normally when 800 V is not applied. After 800 V is applied, the DSP starts PWM switching, the secondary voltage rises in steps according to the programmed settings, and after about several hundred milliseconds the chip abnormally resets/stops running.
The behavior after reset falls into three conditions:
Condition 1: The RST pin is not pulled low, but the chip no longer runs.
Condition 2: The RST pin is pulled low and then returns high, and the chip no longer runs.
Condition 3: The RST pin is pulled low and then returns high, and the chip can run again.
The attachment contains the register parameters read via the emulator after Condition 3 occurred.
Already Checked
The NMIFLG and NMISHDFLG registers have been checked, and no abnormal flags were found.
Method used to determine that the chip is not running: the program toggles GPIO41 in the main loop and in all interrupts.
Request: What approaches can be used to further confirm the cause of the fault?