Control of the body voltage of a HV LDMOS
US6031412A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 11, 1998 |
| Grant date | Feb 29, 2000 |
| Priority date | — |
| Expiry date | Jun 11, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K2217/0018
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A circuit for charging a capacitance using an LDMOS integrated transistor controlled in a manner to emulate a high voltage charging diode of the capacitance. The circuit avoids the switch-on of parasitic bipolar transistors of the LDMOS structure during transient states. The circuit includes a number of junctions directly biased between a source node and a body node of the LDMOS transistor, a current generator referred to a ground of the circuit, at least one switch between the source and a first junction of a chain of directly biased junctions, and a limiting resistor connected between the body and the current generator referred to ground. The switch is open during a charging phase of the capacitance and is closed when the charging voltage of the capacitance exceeds a preestablished threshold responsive to a control signal. The switch is controlled by a logic signal active during the phase in which the supply voltage of the integrated circuit is lower than the minimum switch-on voltage of the same integrated circuit, for charging the body with a current whose maximum value is limited to a preestablished value.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.