A Fully Integrated Bluetooth Low-Energy Transceiver with Integrated Single Pole Double Throw and Power Management Unit for IoT Sensors

Sung Jin Kim; Dong Gyu Kim; Seong Jin Oh; Dong Soo Lee; Young Gun Pu; Keum Cheol Hwang; Youngoo Yang; Kang Yoon Lee

doi:10.3390/s19102420

A Fully Integrated Bluetooth Low-Energy Transceiver with Integrated Single Pole Double Throw and Power Management Unit for IoT Sensors

Sensors (Basel). 2019 May 27;19(10):2420. doi: 10.3390/s19102420.

Authors

Sung Jin Kim¹, Dong Gyu Kim², Seong Jin Oh³, Dong Soo Lee⁴, Young Gun Pu⁵, Keum Cheol Hwang⁶, Youngoo Yang⁷, Kang Yoon Lee⁸

Affiliations

¹ Department of Electrical and Computer Engineering, Sungkyunkwan University, Suwon 16419, Korea. sun107ksj@skku.edu.
² Department of Electrical and Computer Engineering, Sungkyunkwan University, Suwon 16419, Korea. rlarlarbrb@skku.edu.
³ Department of Electrical and Computer Engineering, Sungkyunkwan University, Suwon 16419, Korea. geniejazz@skku.edu.
⁴ Department of Electrical and Computer Engineering, Sungkyunkwan University, Suwon 16419, Korea. blacklds@skku.edu.
⁵ Department of Electrical and Computer Engineering, Sungkyunkwan University, Suwon 16419, Korea. hara1015@skku.edu.
⁶ Department of Electrical and Computer Engineering, Sungkyunkwan University, Suwon 16419, Korea. khwang@skku.edu.
⁷ Department of Electrical and Computer Engineering, Sungkyunkwan University, Suwon 16419, Korea. yang09@skku.edu.
⁸ Department of Electrical and Computer Engineering, Sungkyunkwan University, Suwon 16419, Korea. klee@skku.edu.

Abstract

This paper presents a low power Gaussian Frequency-Shift Keying (GFSK) transceiver (TRX) with high efficiency power management unit and integrated Single-Pole Double-Throw switch for Bluetooth low energy application. Receiver (RX) is implemented with the RF front-end with an inductor-less low-noise transconductance amplifier and 25% duty-cycle current-driven passive mixers, and low-IF baseband analog with a complex Band Pass Filter(BPF). A transmitter (TX) employs an analog phase-locked loop (PLL) with one-point GFSK modulation and class-D digital Power Amplifier (PA) to reduce current consumption. In the analog PLL, low power Voltage Controlled Oscillator (VCO) is designed and the automatic bandwidth calibration is proposed to optimize bandwidth, settling time, and phase noise by adjusting the charge pump current, VCO gain, and resistor and capacitor values of the loop filter. The Analog Digital Converter (ADC) adopts straightforward architecture to reduce current consumption. The DC-DC buck converter operates by automatically selecting an optimum mode among triple modes, Pulse Width Modulation (PWM), Pulse Frequency Modulation (PFM), and retention, depending on load current. The TRX is implemented using 1P6M 55-nm Complementary Metal-Oxide-Semiconductor (CMOS) technology and the die area is 1.79 mm². TRX consumes 5 mW on RX and 6 mW on the TX when PA is 0-dBm. Measured sensitivity of RX is -95 dBm at 2.44 GHz. Efficiency of the DC-DC buck converter is over 89% when the load current is higher than 2.5 mA in the PWM mode. Quiescent current consumption is 400 nA from a supply voltage of 3 V in the retention mode.

Keywords: Bluetooth low-energy (BLE); DC-DC buck converter; Gaussian frequency-shift keying (GFSK); automatic bandwidth calibration (ABC); one-point modulation; single pole double throw (SPDT); transceiver (TRX), low power.