Protection circuit

Amplifiers – With semiconductor amplifying device – Including protection means

Patent

Rate now

  [ 0.00 ] – not rated yet Voters 0   Comments 0

Details

330288, 361 79, H03F 304, H02H 720

Patent

active

045995788

ABSTRACT:
To protect a transistor its emitter current is converted by a resistor into a voltage which by means of a voltage-current converter is converted into a current which is proportional to the emitter current. The collector-emitter voltage is converted by means of a voltage-current converter into a current which is proportional to the difference between a knee voltage which is applied to the converter, and the collector-emitter voltage, the converter not producing an output current for collector-emitter voltages exceeding the knee voltage. The difference between the output currents of the converters is compared with the current carried by a current source. The protection circuit becomes operative when this difference current exceeds the current carried by the current source. A control amplifier then drives the transistor in such manner that the difference current becomes equal to the current. Above the knee voltage a residual current which has a value proportional to the current carried by the current source continues to flow through the transistor T.sub.1. As a result thereof the value of the residual current depends to a lesser extent on variations, which reduces the risk of damage to the transistor due to overloading at high collector-emitter voltages.

REFERENCES:
patent: 4355341 (1982-10-01), Kaplan
Phillips Data-Handbook: Integrated Circuits, "20 W Hi-Fi Audio Power Amplifier", Jan. 1983.

LandOfFree

Say what you really think

Search LandOfFree.com for the USA inventors and patents. Rate them and share your experience with other people.

Rating

Protection circuit does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Protection circuit, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Protection circuit will most certainly appreciate the feedback.

Rate now

     

Profile ID: LFUS-PAI-O-1453897

  Search
All data on this website is collected from public sources. Our data reflects the most accurate information available at the time of publication.