The present invention relates to a microfluidic system including a temperature controller and a thermoplastic microfluidic chip that enables rapid PCR in a PCR chamber of the microfluidic chip. Thermal control of the PCR chamber is achieved by applying voltage to heater electrodes patterned directly onto one layer of the microfluidic chip. The temperature controller adjusts the voltage applied to the heater electrodes by changing temperature controller parameters selected to minimize duration of each PCR cycle. Furthermore, simple operation of the microfluidic chip is provided through using an integrated passive capillary valve, requiring minimum operator intervention and eliminating the need for fluidic interfacing, pumping, or metering during chip loading.