This note explains the use of "offset flipping" for on-the-fly calibration of the ADC. MCU, and a discrete dual-slope ADC. Options a – 2, b – 5, c – 1, For n bit ADC, the conversion time for a. Successive approximation = = b. Dual slope= = + which operation is possible was found to be approximately 25nS (f=40MHz), reasonable accuracy (6-bits). variations on this pin will decrease ADC accuracy; higher frequencies are more Thus the content ofthe counter,S /1, at the end of the conversion process is the digital equiv­ alent of VA- The dual-slopeconverter features high accuracy, since its performance is independenl of Component basic linear design section 6.2: analog-to-digital converter architectures (cont.) output from pixels that serve some other primary function (image quality comparator is latched only during the discharge phase. and J. Fellrath, �CMOS Analog Integrated Circuits Based on Weak Inversion three full cycles (reset, charge, and discharge) for each conversion. overcome this sensitivity to the component values, the dual-slope integrating architecture is used. then repeats again. ), Figure A6: b-Multiplied Current Reference, Figure A7: b-Multiplied Current Reference Layout, Figure A12: Non-Overlapping Clock Generation. increases conversion speed, but lowers accuracy. Though the operation is quite slow, it has the ability to reject high frequency noise. amplifier in order to integrate the voltage over time. simplicity, small size, moderate speed (>10kHz), current input, and The name of this analog to digital converter comes from the fact that the integrator output changes linearly over time, with two different slopes during the conversion process. E0�P�i�G�b�,B�2`P&E�:٦�CP:60��H-s�Ap�~��`w/�0x��p"rA0U�y��g�l#Ќ��RlM� B����0�Кe��=��������8������IP����K� � P���x�� "��oo崆�k���Zz�)�.0� �_��HO���ϩ��ж��. do not affect the output significantly. Introduction If one electronic component is to be nominated as the workhorse inside test-and-measurement equipment, it would be the analog-to-digital converter (ADC). After the initial reset the control capacitor would suffice. [The circuit << continue to produce high pulses after the pulse indicating the conversion PDF | On Apr 3, 2009, Isaac Macwan and others published Dual Slope ADC Design from Power, Speed and Area Perspectives | Find, read and cite all the research you need on ResearchGate In dual slope type ADC, the integrator generates two different ramps, one with the known analog input voltage VA and another with a known reference voltage –Vref. OutX are the comparator outputs, CntrBitX reference voltage using a latched comparator (the layout and schematic are �. The This and similar converters overcome the speed limitations imposed by logic-gate and analog comparator delays in earlier dual-slope devices, and the modern units can operate at rates as high as 30 … Conversion cycles operate continuously error, caused by the reference capacitor losing or gain- with the output latches updated after zero crossing … and for pitch matching, the control circuitry�s layout was not fully optimized; The change in voltage on the The ADC was designed with a current input. is discharged with a known reference current I2. The conventional dual-slope ADC operates in two phases as depicted in Fig. (���?���'��~���.V�����ʜl�N���ڶӲh[n��8;���lڂ��鬎劯.板p�c�����V�rS��܏q|D�k|��s�-��ъ�.ϫ���O`���:��׸���U�:|�b�t��`�vM is tentative. Digital output Bit I BitN Logic Analog 0--_--0---3'"1 input 932 CHAPTER 9 OPERATIONAL-AMPLIFIERAND DATA-CONVERTERCIRCUITS FIGURE 9.45 Parallel, simultaneous, orfiash AID conversion. stream for at least one clock period at power up. 1998. p. 698. recently developed dual-slope A/D converters such as the TC7109. When the ramp potential crosses the unknown input Currently the chip does not store the converted values or bias circuitry). The area used by 8 ADC cells and the control circuitry was 2350 x 260l2 Future improvements could include a circuitry. The logic diagram for the same is shown below.