Electricity: power supply or regulation systems – Output level responsive – Using a three or more terminal semiconductive device as the...
Reexamination Certificate
2000-02-10
2001-10-23
Han, Jessica (Department: 2838)
Electricity: power supply or regulation systems
Output level responsive
Using a three or more terminal semiconductive device as the...
C330S297000
Reexamination Certificate
active
06307357
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to battery powered devices, and, more particularly to a direct current step-up circuit for a battery powered device.
BACKGROUND OF THE INVENTION
One of the factors which affects the commercial success of mass produced battery powered equipment, such as car radios and portable tape recorders, is the output. The output depends, apart from the electrical characteristics of the equipment, on the input. For example, in the case of a multichannel audio amplifier for a car radio, given the number of channels, the conformation of the final stages and the impedance of the speakers, the only way to increase the output is to increase the input. The input is, on the other hand, determined, in the case of the car radio, by the power of the battery of the vehicle and, in the case of portable equipment, by the number and the capacity of the batteries, which in turn is determined on the basis of the acceptable weight and bulk.
DC/DC converters capable of converting incoming direct current into a higher level of outgoing direct current (step-up DC-DC converter) are commonly used in order to increase output. One application of a converter of this type on an amplifier is shown in
FIG. 1. A
direct current power supply
10
, for example a car battery having a current of 14 V between the positive and negative terminals when the vehicle generator is working, is fitted to a voltage step-up circuit
8
, including a DC/DC converter
11
capable of supplying 18 V direct current. Note that, in the case of a car radio system, the change from 14 V to 18 V is advantageous since it is possible to obtain a significant increase in output (around 60%) using audio amplifiers built in an integrated circuit using standard technology. If power above 20 V is required it would be necessary to use special integrated technologies for the amplifiers with considerably higher production costs.
The output of the converter
11
, which is also the output of the step-up circuit, is applied to an audio frequency amplifier system
12
, for example of the 4 channel type in which each channel includes two coupled 30 W amplifiers. A circuit, which senses the output with a voltage divider Rf
1
and Rf
2
and stabilizes it, is included in the step-up circuit
8
.
The distribution of the power in a system of the type described above, with a 14 V battery and a converter
11
sized in order to allow output of 18 V, is shown in FIG.
2
. As can be seen, in order to have an output of 60 W per channel it is necessary to have a DC/DC converter
11
of 300 W, i.e. a large circuit with components capable of operating at high power levels and therefore relatively expensive. As has been shown, the power dissipated—Pdiss—by a converter of this kind is typically around 30 W. The power dissipated by the amplifier
12
has the same value.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a direct current step-up circuit suitable for use in systems of the type described above that is smaller in size, more economical to run and which offers improved performance while requiring the same input.
This object is attained by providing a defined step-up circuit step-up circuit having first and second input terminals for connection to a battery, first and second output terminals for connection to an electronic device to be fed by a DC/DC converter having a first and second input terminals connected respectively to the first and second input terminals of the step-up circuit. The second output terminal of the step-up circuit is connected to the second input terminal of the step-up circuit, one output terminal of the converter is connected to the first input terminal of the step-up circuit and the other output terminal of the converter is linked to the first output terminal of the step-up circuit, therefore, when operating, the output of the step-up circuit is the sum of the power of the battery and of the output of the converter. The step-up circuit is smaller, supplies the same output, is cheaper to produce and offers improved performance over the prior art.
REFERENCES:
patent: 5350994 (1994-09-01), Kinoshita et al.
patent: 5825248 (1998-10-01), Ozawa
patent: 5847550 (1998-12-01), Schie et al.
Botti Edoardo
Cassani Fabrizio
Han Jessica
STMicroelectronics S.r.l.
LandOfFree
Direct current step-up circuit for use with battery powered... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Direct current step-up circuit for use with battery powered..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Direct current step-up circuit for use with battery powered... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2614517