针对常见电压调整器芯片由于热保护电路高温端性能的限制,导致调整器在较高工作温度下输出电压稳定性变坏的缺点,提出一种可用于低压差电压调整器的高性能热保护电路的设计。通过改进热保护电路的电路结构及版图设计,在保证热保护电路的关断精度达到±0.5℃的同时,改善了电压调整器高温段的输出电压稳定性。用Spectre对电路进行仿真的结果表明,采用该热保护电路的电压调整器在0℃~150℃范围内的输出电压精度保持在0.5%之内,输出电压的温漂达17.5ppm/℃。此外。设计的热保护电路结构简单,占用芯片面积小,可在双极型或BCD(Bipolar CMOS DMOS)工艺下实现,应用于多种电源管理芯片设计中。
To improve the output voltage accuracy of the low-dropout voltage regulator within the high temperature range, which was affected by the performance of the thermal protection circuit, a new thermal protection circuit applicable to regulators was proposed in this paper. The simulation results showed that by improving the circuit configuration and layout design, the new thermal protection circuit made the accuracy of the regulator as high as 0.5% over the temperature range of 0℃ to 150℃ while the precision of shutdown temperature was kept within ±0.5℃. And its temperature drift was 17.5ppm/℃. In addition, the structure of the new circuit was quite simple and it cost less area on the chip. The thermal protection circuit could be realized in the bipolar or BCD (Bipolar CMOS DMOS) technology and applied to various power management chips.