Research And Design Of An Ultra-low Power 125KHZ Receiver

In recent years, the requirements of special wireless communication devices are becoming more specific, as people's living standards increasing very fast. For instance, in the Tire Pressure Monitor System, the wireless communication devices are required to have ultra-low power consumption and can remain stable work in harsh environments. The receiver, which serves at the front of the system, is used to check and demodulate the signal and filter the noise. And the receiver is usually an important part of the system. Based on the background, this paper presents an ultra-low power 125 KHz receiver.The presented receiver utilizes HHNEC 0.35μm CZ6H mix signal process. The main function blocks include a auto gain control amplifier, a pre-check circuit, a demodulate circuit and a reference generator circuit, etc. The receiver can check and demodulate 125KHz Sin carrier, Amplitude shift keying modulated signal, and then output the demodulated data. In order to decrease the power consumption, a sleeping-wake up function is introduced in the receiver on one hand. Some circuits are put into sleep mode when no input signal is detected. And if there is a correct input signal, all the circuits wake up. On the other hand, most MOSFETs in all the analog circuits, including amplifiers, comparators and demodulate circuits are designed to work in sub-threshold region. And all of the current sources, which can control the working current, are biased at sub-threshold region. Besides, this receiver is designed for battery power supply, thus it can work in a wide range of supply voltage, which would increase the battery efficiency.The simulation result shows that, the presented receiver can work in the environment of -40℃-125℃temperature range and 2.3V-5V supply voltage range. In typical working environment (supply voltage 3.3V, temperature 27℃), the average current in working mode is approximately 1.5μA, the average power consumption is approximately 5μW. And average current in sleeping mode is approximately 800nA, the average power consumption is approximately 2.5μW. In maximum current environment (supply voltage 5V, temperature 125℃), the average current in working mode is approximately 2.5μA, the average power consumption is approximately 12.5μW. And average current in sleeping mode is approximately 1.9μA, the average power consumption is approximately 9.5μW. In minimum current environment (supply voltage 2.3V, temperature -40℃), the average current in working mode is approximately 1.3μA, the average power consumption is approximately 3μW. And average current in sleeping mode is approximately 540nA, the average power consumption is approximately 1.3μW.