A Concurrent Multi-output Bandgap Circuit with Sub-1V and Plus-2V Reference, Minimum 5. 128 ppm/°C Temperature Coefficient in 0.18µm BCD Process

Aiming at the demanding for sub-1V and plus-2V reference voltages in an implanted medical chip, this paper presents a concurrent multi-output bandgap reference (BGR) scheme. In order to improve the high-order temperature coefficient, the bias circuit of the BGR generates a complementary-to-absolute-temperature (CTAT) current and a proportional-to-absolute-temperature (PTAT) current with no relation to the finite current-gain ß of triodes. Then the CTAT current and the PTAT current are combined to generate multiple reference voltages, which completely avoids the temperature dependency of finite current gain ß. Thus a low temperature coefficient (TC) over a wide temperature range is achieved. The proposed BGR circuit is implemented in 0.18µm BCD process. A minimum TC of 5.128ppm/°C from -40°C to 125°C is obtained with the output voltage of 0.65V and 2.29V concurrently. Also the BGR achieves a power supply rejection (PSRR) of -43 dB@100kHz.