Low Power Consumption, High PSRR and Accurate Bandgap Voltage Reference

Ângelo Filipe Rolo

Informações chave

Autores:

Ângelo Filipe Rolo (Ângelo Filipe Rolo Monteiro)

Orientadores:

Maria Beatriz Mendes Batalha Vieira Vieira Borges (Maria Beatriz Mendes Batalha Vieira Vieira Borges); Marcelino Bicho dos Santos (Marcelino Bicho dos Santos)

Publicado em

17/09/2008

Resumo

Bandgap reference circuits are widely used in analog, digital and mixed-signal systems since they can generate a stable, accurate and standard reference voltage from a battery supply. The steady-state (dc) and transient (ac) accuracy of reference circuits is critical to ensure that the further blocks of the IC present high levels of performance. This thesis investigates the possibility of implementing a bandgap reference which is able to present: high dc accuracy despite power supply, temperature and process variations; high dc and ac accuracy without using large on-chip capacitors; high dc and ac accuracy despite load variations, without introducing an additional output buffer; low power consumption, which allows it to be integrated in modern and battery-operated portable applications; an implementation that utilises a standard CMOS process which minimizes manufacturing cost. This bandgap voltage reference will be further integrated in a Charge Pump IP and in a Power Management Unit (PMU) constituted by DC-DC converters and low dropout regulators. Implemented in TSMC 65nm CMOS technology, the circuit includes a pre-regulator, a master bias cell and digital validation for the bandgap voltage. The current consumption is below 5uA at 50ºC, Power Supply Rejection Ratio (PSRR) of -110dB@1kHz and -61,3dB@10MHz using 27pF on-chip capacitance, reference output voltage is 1:208V and temperature coefficient is 3ppm/ºC considering a [-40; 125]ºC range and the typical process. The area occupied by the reference circuit is 0,04mm^2. The development of the proposed CMOS bandgap reference meets the low-cost, high-accuracy and low power demands of State-of-the-Art System-on-Chip environments.