Browse Prior Art Database

Field Effect Transistor with a Switch at the Gate to Reduce the Power Consumption for the Gate Control

IP.com Disclosure Number: IPCOM000114841D
Original Publication Date: 1995-Feb-01
Included in the Prior Art Database: 2005-Mar-29
Document File: 2 page(s) / 47K

Publishing Venue

IBM

Related People

Narita, I: AUTHOR [+2]

Abstract

Disclosed is a Field Effect Transistor (FET) gate control circuit which has the function for reducing the current flow during the suspend mode. In suspend mode, the system power consumption is very small (for example, 0.2W). This invention enables to reduce the extra current flow during suspend mode.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 81% of the total text.

Field Effect Transistor with a Switch at the Gate to Reduce the Power
Consumption for the Gate Control

      Disclosed is a Field Effect Transistor (FET) gate control
circuit which has the function for reducing the current flow during
the suspend mode.  In suspend mode, the system power consumption is
very small (for example, 0.2W).  This invention enables to reduce the
extra current flow during suspend mode.

      Fig. 1 shows a conventional FET control circuit in the power
system of the notebook PC.  We assume that Nch FET is used to connect
and disconnect the Vcc line to the system.  During suspend mode, Vcc
(5V or 3.3V) line is disconnected from the system while the Vcc line
is connected and supply the power to the system during normal
operation mode.  Fig.1 shows the control circuit for the gate of the
Nch FET.  The gate is pulled-up to 20V and the current (I) flows via
the pull-up resister R1 to the emitter (=GND) of the TR1.  During
suspend mode, the SUSPEND# signal becomes low, the TR2 becomes off,
and the TR1 becomes on.  For example, if the R1 is 100K&Omega., the
extra power consumption is 4mW, and it reaches the 5% of the whole
power consumption during suspend mode (0.2W).

      Fig. 2 shows the circuit of the subject invention.  During
suspend mode, TR3 becomes off and the current flow via R1 becomes 0A.
Therefore both the TR3 and TR4 becomes off and the gate becomes GND
voltage via TR1.  In normal operation mode, the SUSPEND# signal
beco...