The following operators can be used to better focus your queries.
( ) , AND, OR, NOT, W/#
? single char wildcard, not at start
* multi char wildcard, not at start
(Cat? OR feline) AND NOT dog?
Cat? W/5 behavior
(Cat? OR feline) AND traits
Cat AND charact*
This guide provides a more detailed description of the syntax that is supported along with examples.
This search box also supports the look-up of an IP.com Digital Signature (also referred to as Fingerprint); enter the 72-, 48-, or 32-character code to retrieve details of the associated file or submission.
Concept Search - What can I type?
For a concept search, you can enter phrases, sentences, or full paragraphs in English. For example, copy and paste the abstract of a patent application or paragraphs from an article.
Concept search eliminates the need for complex Boolean syntax to inform retrieval. Our Semantic Gist engine uses advanced cognitive semantic analysis to extract the meaning of data. This reduces the chances of missing valuable information, that may result from traditional keyword searching.
A transistor filter is described which reduces considerably the ripple voltage at the output of a switching regulator despite the use of low value capacitors.
English (United States)
This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately
85% of the total text.
Page 1 of 2
Transistor Filter for Switching Regulator
A transistor filter is described which reduces considerably the ripple voltage
at the output of a switching regulator despite the use of low value capacitors.
The figure is a circuit diagram of the transistor filter and its connection to the
switching regulator represented by block 1.
The DC voltage drop delta U = U(1)out - U(2)out of about 1 V occurring at
transistor T is sufficient for operating this transistor in the unsaturated mode. The
latter mode is required, since in the saturated mode parts of the ripple voltage
are directly transferred from the collector to the emitter. The collector/emitter
voltage of transistor T is made up of the base/emitter voltage drop and the
voltage drop generated at resistor R1, which is caused by the base current
forced by the emitter current. The ripple voltage amplitude, the transistor filter is
capable of handling, must not be set by resistor R1 but by the voltage drop at the
base/emitter diode of transistor T.
If the amplitude of the ripple voltage exceeds the voltage drop at the
base/emitter diode of transistor T, diodes D1 and D2 are series-connected to
resistor R1. If the switching regulator is to supply higher DC currents, transistor
T is designed as a Darlington circuit. A lower cut-off frequency of this transistor
prevents high-frequency oscillations occurring during switching from reaching the
output of the transistor filter. The control voltage necessary for the switching