During the use of the TPS92518HV-Q1, the temperature of the IC is measured to be high. I think this is not normal. Please give pointers.
Details are as follows:
1. Design parameters
Vin: 48V
Vled: 0-37.6V
Iled: 0.7A
Fsw = 300Khz
△L-PP = 40%
2. 硬件原理图、PCB：
PCB - P18-027 Adaptive Driving Beam_POWER BOARD_Benjamin Zhang_181120.pdf
SCH - P18-027 Adaptive Driving Beam_POWER BOARD_Benjamin Zhang_181120.pdf
3. The software configuration is as follows:
(I, 2 channel output is 702mA, IL-PP: 276mA is about 39%)
LED1_PKTH_DAC = 0x91
LED1_TOFF_DAC = 0x35
LED1_MAXOFF_DAC = 0x80
LED1_PKTH_DAC =0x8F
LED1_TOFF_DAC = 0x35
LED1_MAXOFF_DAC = 0x80
phenomenon:
The circuit works stably with an efficiency of about 94%, but the temperature of the IC is somewhat high. I used SPI to read the value of the VTHERM register is B3, and the operating frequency measured by the oscilloscope is 335K.
After that, I modified the value of the register so that the IL-PP is increased while the output current is constant, and the temperature of the IC is measured, and the following law is found: the smaller the inductor ripple IL-PP, the higher the temperature of the IC; The higher the operating frequency, the higher the IC temperature;
I think the TPS92518HV-Q1 is just a controller in the circuit. It does not contain MOS. The temperature should not be so high during normal operation.
I want to ask if this phenomenon is normal?
If it is not normal, is it a hardware problem or a register configuration is not appropriate?
Can you suggest some suggestions for the configuration of my registers?
I hope to get your answer. I wish you a happy life!
