Integrated high voltage differential sensor using the inverse gain of high voltage transistors
US5424663A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 22, 1993 |
| Grant date | Jun 13, 1995 |
| Priority date | — |
| Expiry date | Apr 22, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R19/16519
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An integrated high voltage differential sensor which uses the inverse gain of a pair of parasitic JFETs to provide a low power circuit for translating a differential high voltage signal down to a lower voltage level that can be easily sensed by the low voltage control circuitry in a power IC and without the use of a resistive voltage divider. The IC includes, between a first high voltage input and ground, a first series circuit of a first JFET, a first voltage level shifting resistor and a bias current source (I.sub.B). A second series circuit of a reference resistor (R.sub.L), a second JFET, a second voltage level shifting resistor and a bias current source (I.sub.B) is coupled between a second high voltage input and ground. A feedback circuit including an operational amplifier is coupled between a low voltage point of the first series circuit and the gates of both JFETs so as to adjust the bias voltages of the JFETs. A comparator is coupled to a low voltage point of the second series circuit and switches about an input differential threshold value of I.sub.B R.sub.L.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.