SLAU915 May 2024 ULC1001
Texas Instruments created two diagnostic modes for limiting power and detecting faults in the lens cover system. These modes are System Fault and Power. The valid burst for diagnostic modes are listed in Table 4-5.
Burst # | Burst Name | Description |
---|---|---|
20 | CONTROL_Burst_Power_Region_1 | The power bursts are used to measure the peak real power in a particular region and adjust the amplitude for the respective cleaning region based on programmable thresholds. Initially, the burst amplitude must match the respective region settings and the frequency range includes the peak power frequency. |
21 | CONTROL_Burst_Power_Region_2 | |
22 | CONTROL_Burst_SystemFault | The system fault burst measures the maximum current magnitude and minimum impedance in the programmed frequency region to determine if there is an open load condition or the LCS is damaged. |
Power mode can be used to regulate the power to the system. This mode can contain two burst for the two calibration frequency regions, bursts 2 and 3, respectively. There is an upper and lower power threshold for each region. After running the Power mode, the device determines a new amplitude, Amp (PuV), for the clean bursts (8-17) and the power bursts (20 and 21) to get the power into the limits set by the upper and lower thresholds. The measured power values from calibration are stored in USER_Params_baselineParams_Pmax_W_Q24_1 (region 1) and USER_Params_baselineParams_Pmax_W_Q24_2 (region 2). The LCS power values after running Power mode are stored in USER_Flags_Pmax_W_region1_Q24 and USER_Flags_Pmax_W_region2_Q24.
For the System Fault mode, a current threshold, register USER_Params_sfaultParams_Imag_threshold_A_Q9, and an impedance threshold, register USER_Params_sfaultParams_Zthreshold_ohm_Q20, must be set appropriately for the algorithms to run correctly. TI recommends a value of 200mA. The impedance of the LCS can change significantly when damaged. Therefore, the impedance threshold must be set based on the delta impedance expected when the LCS is damaged. TI recommends a value of 225Ω.