Drive circuit for a power MOSFET with source-side load

US4691129A · kind A · utility

Assignee

• Siemens Aktiengesellschaft · DE

Inventors

• Josef Einzinger · Spalt, DE
• Christine Fellinger · Unterhaching, DE
• Ludwig Leipold · Munich, DE
• Jenoe Tihanyi · Tauberbischofsheim, DE
• Roland Weber · Munich, DE

Key dates

• Filing date: Jul 16, 1986
• Grant date: Sep 1, 1987
• Expiry date: Jul 16, 2006

Classification

• Technology area (CPC H): Electricity
• CPC primary: H03K17/165
• WIPO field: Basic communication processes
• WIPO sector: Electrical engineering

Abstract

When a power MOSFET operated as a source follower is driven by an electronic switch, an interruption of the connection between ground and the electronic switch may result in the output potential of the electronic switch to change so that the power MOSFET is partially switched on. This causes a considerable amount of power dissipation. Therefore, there is placed between the source and gate electrodes of the MOSFET a depletion MOSFET whose gate is connected to the terminal of the electronic switch intended for connection to ground. Thus, the power MOSFET remains non-conducting upon interruption of the connection between the electronic switch and ground.