Design of a High Performance Bandgap Reference with a stable DC variation in Power Management IC’s Applications. Qurat ul Ain, Danial Khan, Young-Jun Park, and Kang-Yoon Lee School of Information and Communication Engineering Sungkyunkwan University, Suwon, Korea E-mail: [quratulain, klee]@skku.edu Abstract— In this paper, we described a high-performance Bandgap reference (BGR) circuit to provide a constant voltage of 1.2 V. In the proposed circuit NPN BJT is used along with MOSFETs to improve the performance and stable DC variation. The proposed BGR results have been checked for three temperature range i.e. -40 O C, 27 O C and 125 O C. Bearing in mind the mismatches between transistors and process variations Monte Carlo simulation has been done for 200 samples. ｨV of 1.8 mV has been achieved with the DC simulation results. Power supply rejection ratio of -66 dB has been attained. The output voltage of BGR from a 5 V supply is 1.2 V. The proposed circuit is implemented on the CMOS 0.18um process. Keywords; Power Management integrated ciruits(PMICs); Bandgap Reference(BGR); proportional to absolute temperature (PTAT); complementary to absolute temperature (CTAT); I. INTRODUCTION In the recent years Power management ICs are a major trend in the portable electronics. Supply voltage to PMICs are generated by different switching regulators. DC-DC Buck converter is a major switching regulator used to convert the battery voltage to the regulated step-down voltage. All the analog circuits need a reference voltage or a bias current that must be unresponsive to process, temperature, and supply variations. Therefore Bandgap reference (BGR) forms a key building block in the power management ICs (PMICs) to produce a reference voltage. By the Bandgap reference a fixed dc reference voltage is provided to the other blocks of PMICs that does not vary with power supply voltage, temperature or process variations. Previously BGR provided the reference current and the reference voltage to the PMICs and analog blocks using resistors which occupies large area and consumes power. The proposed BGR introduces fewer resistors to obtain a high performance Bandgap reference for the effective operation of the PMICs. II. PROPOSED STRUCTURE Figure 1. Presents the block diagram of the proposed Bandgap circuit. The output voltage Vref of the Bandgap reference is aimed to be 1.2V. The proposed BGR is composed of a start- up circuit, low voltage high gain operational amplifier, Proportional to Absolute Temperature (PTAT), Complementary To Absolute Temperature (CTAT), and a low pass filter. The start-up circuit produces the voltage to start the BGR circuit. In order to obtain a stability characteristics of the BGR, low voltage high gain operation amplifier regulates the start-up voltage. Control to the NPN BJTs collector current is provided by BGR trimming blocks. TRIM<3:0> trimming bits are delivered to BGR_TRIM_1 and TRIM<5:4> trimming bits are delivered to BGR_TRIM_2. Compensation circuit compensates the slope of the PTAT and CTAT voltages. Low pass filter is used to remove the excess noise. The performance of BGR is specified by Line and Load Regulation. Power Supply Rejection ratio (PSRR) satisfy the performance requirements of the BGR. AVSS AVDD VRef R1 R2 R3 M1 M2 M3 M4 M5 M6 OP_AMP FB_A FB_B FB_B OP_AMP R4 M7 M8 M9 R5 R6 R7 Q1 Q2 Q3 BGR_ TRIM <3:0> TRIM <3:0> BGR_ TRIM <5:4> TRIM <5:4> Figure 1. Proposed Bandgap reference (BGR) circuit III. EXPERIMENTAL RESULTS The BGR is implemented in a 180 nm CMOS process. Figure below shows the simulation results. All the simulation results have been plotted for temperature of -40 o C, 27 o C and 125 o C. Figure 2. Presents the Transient Simulation Results of Bandgap reference for temperature range of -40 o C, 27 o C and 125 o C. The results clearly shows the BGR output voltage to be 1.198V, 1.206V and 1.193V respectively. Figure 3. Presents the DC Simulation Results of BGR for the before mentioned Startup Circuit CTAT Generator PTAT Generator 978-1-5386-7960-9/18/$31.00 ©2018 IEEE 198 ISOCC 2018