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CROSS-CONDUCTION CURRENT ELIMINATION IN MOS TOTEM-POLE DRIVER CIRCUITS AND METHOD

IP.com Disclosure Number: IPCOM000010960D
Publication Date: 2003-Feb-05
Document File: 5 page(s) / 2M

Publishing Venue

The IP.com Prior Art Database

Abstract

Key Words: totem pole, cross-conduction current, On-resistance (RDSON)

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CROSS-CONDUCTION CURRENT ELIMINATION

IN MOS TOTEM-POLE DRIVER CIRCUITS AND METHOD

Key Words: totem pole, cross-conduction current, On-resistance (RDSON)

 

It is often necessary to switch a field-effect transistor (FET) at high speeds with a driver circuit.  It is common for such driver circuits to have a totem-pole output, which includes a "source" transistor for sourcing current to the gate of the FET and a "sink" transistor for removing charge from the gate of the FET. The source and sink transistors may respectively be considered to be part of active pull-up and pull-down circuits.

PROBLEM DESCRIPTION

An example of the circuit with cross-conduction current is illustrated in Fig.3.

                    The pull-up circuit is represented by M01, the pull-down circuit is represented by M02.  There are two “useful” currents Ich (I charge) and Id (I discharge) and a cross-conduction current Icross that flows when both pull-up (M01) and pull-down (M02) circuits are both on the ON state.  Cross-conduction current results in a relatively large current flow from the power supply wasting energy and causing unwanted heating and supply line pollution.  If the FET is ON with the pull-up/pull-down circuits ON/OFF respectively, then it is desirable when switching OFF the FET that the by pull-up/pull-down circuits be switched OFF/ON respectively.  Also, if the FET is OFF with the pull-up/pull-down circuits OFF/ON respectively, then it is desirable when switching ON the FET that the pull-up/pull-down circuits be switched ON/OFF respectively. 

 

Using the totem pole output, the present disclosure will show switching the FET v...