A Low-Power Low-Resistance Switched-Capacitors Bandgap Reference Generator with -40°C to 175°C Operative Range

The presented Bandgap Reference (BGR) generator for automotive applications provides both voltage and current references exploiting switched-capacitor techniques to reduce area and power consumption. The BGR is made up of two separate circuits to produce a Proportional-To-Absolute-Temperature (PTAT) current and a Complementary-To-Absolute-Temperature (CTAT) current to be properly summed up on two different branches to provide both voltage and current references. The CTAT current reference generator exploits switched-capacitor circuits, not relying on a high-precision clock generator, to achieve a VBE division and thus reduce both area, by minimizing resistors, and power consumption. A prototype to operate in automotive systems is realized in a 350 nm BCD process with a die area of 0.030 mm2. From a 3V supply it consumes 3 μW, of which the CTAT generator consumes only 1.125 μW. The current reference value provided is 1 μA with a TC of 110 ppm/°C, and the voltage reference value is 125 mV with a TC of 61 ppm/°C from -40°C to 175°C. The robustness of the technique is validated by PVT and Monte Carlo simulations and extended measurements.