Charging of a bootstrap capacitance through an LDMOS
US5883547A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 13, 1996 |
| Grant date | Mar 16, 1999 |
| Priority date | — |
| Expiry date | May 13, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K17/063
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A charging circuit for a bootstrap capacitance employing an integrated LDMOS transistor and including a circuital device for preventing the turning on a parasitic transistors of the integrated LDMOS structure during transients that comprises a plurality of directly biased junctions (D1, D2, . . . , Dn) connected in series between a source and a body of the LDMOS transistor structure and at least a current generator, tied to ground potential, coupled between said body and ground, has at least one switch (INT1) between said source and a first junction (D1) of said plurality of junctions and a limiting resistance (R) connected between the body and the current generator (GEN). The switch (INT1) is kept open during a charging phase of the bootstrap capacitance (Cboot) and is closed when the charge voltage (Vboot) of the bootstrap capacitance reaches a preset threshold. Moreover, the body voltage (VB) is prevented from exceeding the source voltage (VS) plus a Vbe, by controlling a discharge path (T2) with a control stage (T1, R1) in response to a drop of the voltage on the limiting resistance (R). This body voltage control circuit is enabled by a second switch (INT2) driven in phase with…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.