Title :
A 14-bit 12 μV/LSB resolution A/D converter for sensors using only digital circuit with low-pass filter effect
Author :
Watanabe, Takamoto ; Mizuno, Tamotsu ; Makino, Yasuaki
Author_Institution :
Res. & Dev. Dept, DENSO CORP, Aichi, Japan
fDate :
6/23/1905 12:00:00 AM
Abstract :
A compact, high-resolution A/D converter (ADC) for sensors is presented. The basic structure is a completely digital circuit including a ring-delay line with delay units (DUs), along with a frequency counter, latch and encoder. The operating principles are, firstly, the delay time of the DU is modulated by the A/D conversion voltage; secondly, the delay pulse passes through a number of DUs within a sampling time, and the number of DUs through which the delay pulse passes is output as conversion data. Compact size and high resolution were realized with an ADC having a circuit area of 0.45 mm2 (0.8 μm CMOS) and a resolution of 12 μV (10 kHz). Sample holds are unnecessary, and a low-pass filter function eliminates high-frequency noise simultaneously with A/D conversion. This ADC can be shrunk and operated at low voltage, so it is an ideal means to lower the cost and power consumption
Keywords :
CMOS integrated circuits; analogue-digital conversion; delay lines; digital filters; low-pass filters; low-power electronics; sensors; 0.8 micron; 10 kHz; 12 muV; 14 bit; CMOS IC; delay unit; digital circuit; encoder; frequency counter; high-frequency noise; high-resolution A/D converter; latch; low-pass filter; low-voltage operation; power consumption; ring-delay line; sensor; Counting circuits; Delay effects; Delay lines; Digital circuits; Frequency; Latches; Low pass filters; Pulse modulation; Sampling methods; Voltage;
Conference_Titel :
Electronics, Circuits and Systems, 2001. ICECS 2001. The 8th IEEE International Conference on
Print_ISBN :
0-7803-7057-0
DOI :
10.1109/ICECS.2001.957566
