Fast-acting current comparator
US5136184A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 24, 1991 |
| Grant date | Aug 4, 1992 |
| Priority date | — |
| Expiry date | May 24, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K5/2472
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A comparator for use in an A/D converter such as an algorithmic type. The circuit includes a push-pull inverter gain stage having two series-connected MOSFETs. The input of this inverter is driven by a signal from a preceding current-comparison stage where an input current is compared to a reference current to set the signal level on an input node of the inverter. The trigger point of the inverter is altered by an additional MOSFET, connected in parallel with one of the inverter MOSFETs, and having its gate controlled by the output of a bias voltage control circuit. This circuit includes a control inverter stage matched to the comparator inverter and driven by a control current-comparison circuit matched to the corresponding comparator current-comparison circuit. The input and output nodes of the control inverter are connected to the inputs of an op-amp the output of which controls the gate voltage of an additional MOSFET in parallel with one of the control inverter MOSFETs so as to force the input and output nodes to be of equal voltage. The resulting op-amp output signal serves as the bias signal for the additional MOSFET in parallel with one of the comparator inverter MOSFETs, a…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.