Browse Prior Art Database

Car Adapter with Thermal Sensors

IP.com Disclosure Number: IPCOM000115390D
Original Publication Date: 1995-Apr-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 2 page(s) / 58K

Publishing Venue

IBM

Related People

Narita, I: AUTHOR

Abstract

Disclosed is a car adapter with thermal sensors. In general, the car adapter is powered by the cigarette lighter of a car. The cigarette lighter tends to become dirty with the nicotine. Therefore, in some cases, the cigarette lighter may get too hot if it supplies the power to the car adapter for a long time. Such dirtiness makes high resistance for the connection between the car adapter and the cigarette lighter. The dirtiness depends on each car and can't be known at the design of the car adapter. The car adapter with thermal sensors makes it possible to stop the power supply from the cigarette lighter to the car adapter when they get too hot with the monitoring of the temperature at the car adapter's power inlet.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 60% of the total text.

Car Adapter with Thermal Sensors

      Disclosed is a car adapter with thermal sensors.  In general,
the car adapter is powered by the cigarette lighter of a car.  The
cigarette lighter tends to become dirty with the nicotine.
Therefore, in some cases, the cigarette lighter may get too hot if it
supplies the power to the car adapter for a long time.  Such
dirtiness makes high resistance for the connection between the car
adapter and the cigarette lighter.  The dirtiness depends on each car
and can't be known at the design of the car adapter.  The car adapter
with thermal sensors makes it possible to stop the power supply from
the cigarette lighter to the car adapter when they get too hot with
the monitoring of the temperature at the car adapter's power inlet.

      The Figure shows the circuit of the invention.  In the Figure,
TH1 shows the thermistor at the plus terminal of the car adapter, and
TH2 shows the thermistor at the minus terminal.  Thermistor is the
device whose resistance value decreases with the temperature
increase.  The principle of the operation is as follows:  In the
normal operation case when the temperature is not too high, the plus
input of the Cmp1 is higher than the minus input(Vref1) of the Cmp1
and the CMP1 outputs the high.  It is the same for the CMP2.  So, D1
and D2 are OFF and Tr1 becomes ON and this makes SW1 ON.  In this
case, the output of the car adapter is supplied to the system.  The
following shows the operation when...