Design And Verification Of System Status Monitoring Module For Power Management IC

With the rapid development of IC,the number of function components could be integrated into a So C chip is becoming greater and greater.Based on security considerations,it's necessary to take system temperature into account when power management IC,which is PMIC for short,supply power to these components.The voltage and temperature of battery should be monitored when PMIC is handling battery charging.On the other hand,in order to calculate real-time battery capacity monitoring battery voltage is indispensable,too.For the reasons listed above,it's essential for PMIC to have the function feature of monitoring the system's ambient temperature,chip temperature,battery voltage,battery temperature and other information.In this paper,based on an analog circuit that has a SAR ADC in it,a digital circuit module for system status monitoring is designed with VHDL which controls ADC to measure multiple input channels.In order to eliminate the ADC output code noise,improve the measurement accuracy and implement timing control of SAR ADC,an average sub-module is implemented in the design,of which the average number is programmable.In order to compensate the offset error and gain error of the ADC output,the calibration sub-module is added to the design to digitally correct the ADC output.In order to maximize the adaptability of measurements on different channels,the idea of the microprocessor executes instructions is referenced in the design.Executing a task instruction sequence in address order enables sequential controllability of the channel measurement configuration.Completely free programming of the instruction memory ensures that the freedom of the channel configuration is maximized.In order to achieve free programming of the instruction memory,the mailbox mechanism is added to the design to program the instruction memory.The measurement of a channel can be achieved by writing appropriate instruction sequence into the instruction memory and then initiating an execution request for the corresponding measurement task.Measurement task execution requests can be initiated by software and hardware.When measuring the resistance or temperature,if you do not know the size range of the resistance value,you can set the current source configuration strategy to the automatic current source mode.In automatic current source mode,the optimum current source could be selected automatically.If there is an exact requirement for resistance measurement accuracy in advance,you can set the current source configuration strategy to the automatic current source mode with normalization.This design will output the measurement results to the register bus,by reading the specified result register to obtain the measurement results.The measurement results are output to an external registers,and the measurement result can be obtained by reading the specified register via register bus.Finally,this design compares measurement results with threshold values which are from outside threshold registers to figure out which zone the battery temperature is in and initiate the corresponding temperature alarm interrupt.On the other hand,this paper lists all the verification function points in the verification plan.Based on the verification plan,an UVM test bench is set up for the verification of the system state monitoring module.The functional division of each verification component and the working principle of the whole verification platform is discussed in this paper.In order to create all the verification scenes to verify all these function points in verification plan,different test cases are created.Several simulation waveforms are analyzed to show system status monitoring module' s function features.With a high code coverage more than 95%,requirements of project are met and all these verification function points are covered.